AAF Technical Report 5230 ATSC COLD WEATHER TESTS WINTER 1944-1945 ARMY AIR FORCES AIR TECHNICAL SERVICE COMMAND Wright Field Dayton, Ohio NOTE When drawings, specifications, and other data prepared by the War De- partment are furnished to manufacturers and others for use in the manufacture or purchase of supplies, or for any other purpose, the Government assumes no responsibility nor obligation whatever; and the furnishing of said data by the War Department is not to be regarded by implication or otherwise, or in any manner licensing the holder, or conveying any rights or permission to manu- facture, use, or sell any patented inventions that may in any way be related thereto. Espionage Act Notice: This document contains information affecting the national defense of the United States within the meaning of the Espionage Act (U. S. C. 50:31, 32). The transmission of this document or the revelation of its contents in any manner to an unauthorized person is prohibited by law. (AR 380-6, para- graph 17 b.) Report No. 5230 Date: 31 May 1945 ARMY AIR FORCES HEADQUARTERS AIR TECHNICAL SERVICE COMMAND ARMY AIR FORCES TECHNICAL REPORT No. 5230 ATSC COLD WEATHER TESTS WINTER 1944-1945 By Climatic Requirements Office Service Engineering Branch Engineering Standards Section Service Engineering Subdivision Engineering Division Approved: HARLAN Y. 'SMITH, Colonel, Air Corps Chief, Engineering Standards Section For the Director: Content and classification authenticated by: L. C. CRAIGIE, Brig. General, USA Deputy Chief, Engineering Divisior Section No. TSESE-4 E. O. No. 446-24 No. of Pages: 214 No. of Photos: 60 No. of Drawings: 4 ACKNOWLEDGEMENT This opportunity is taken to express the appreciation of Air Technical Service Com- mand for the cooperation and assistance in the cold weather test program contributed by the Cold Weather Testing Detachment of the Proving Ground Command, and the Technical Representatives of the various manufacturers represented. The cold weather performance of Army Air Force aircraft and equipment showed a marked improvement over previous years and data and information was gathered which will make possible yet more improvement by next winter. The evident success of the past winter’s test program would not have been possible without the facilities and personnel furnished by Cold Weather Test Detachment and the technical aid con- tributed by manufacturers’ Technical Representatives. TABLE OF CONTENTS Page INTRODUCTION 1 SECTION I: Organization and Conduct of Cold Weather Test Program Winter of 1944-1945 2 SECTION II: Summary of Conclusions 3 SECTION III: Final Reports of Project Engineers of the Climatic Requirements Office 5 Cold Weather Tests: 1944-1945 5 Carburetor Heat for Turbo-supercharged Engines 11 B-25 Carburetor Heat System 25 Cold Weather Test of A-26B Airplane 27 Cold Weather Test of B-17G Airplane 29 Cold Weather Test of B-24J Airplane 31 Cold Weather Test of B-25J Airplane 34 Cold Weather Test of B-29 Airplane 36 Cold Weather Test of B-29 Airplane 38 Cold Weather Test of C-47A Airplane 41 Cold Weather Test of C-54B Airplane . 43 Cold Weather Test of P-38L Airplane 46 Cold Weather Test of P-51D-10 Airplane 48 Cold Weather Test of P-59A Airplane 51 Cold Weather Test of P-6 IB Airplane 54 Cold Weather Test of P-63A Airplane 57 SECTION IV: Final Reports of Project Engineers and Observers from the Engineering Division Laboratories, Maintenance Division and Supply Division 60 Final Report of Cold Weather Tests on Airplane Structures and Controls 60 Cold Weather Testing of Landing Gears and Hydraulic Systems 62 Alaskan Field Test of Emergency and Survival Equipment . 66 Power Plant Cold Weather Test Program 78 Oil Tank Hopper Design 83 Oil Spewing Tests on P-5 ID Airplanes with V-1650-7 Engines, Part 1 84 Oil Spewing Tests on P-5 ID Airplanes with V-1650-7 Engines, Part 2 85 Engine Breathing Tests with Diluted Oil on C-54B Airplane with R-2000-7 Engines 86 Oil Spewing Tests on V-1710 Engines Conducted at Ladd Field During 1944-45 87 Oil Dilution and Spewing Tests Conducted on the C-69 Airplane 88 Test Stand Cold Starts on a V-1650-7 Engine Equipped with a Speed Density Pump 89 Ladd Field Cold Weather Engine Test Stands 91 Fuel Volatility Flight Test Program 94 Hamilton Standard Propeller Feathering Tests 95 Final Report on the Aeroproducts A532FX6 Propeller .... 99 Report on the Curtiss Electric Propeller Equipment 100 Cold Weather Tests on Teleflex Controls 102 Cold Weather Tests on Eclipse Electric Governor Control Heads 103 Report on the Electric Anti-Icing Generators Installed on the C-54B 104 Service Tests of Experimental Oil and Coolant Hose Installed with Aeroseal Type Clamps ,. 105 TABLE OF CONTENTS (Cont’d) Page SECTION IV: Lubrication of Aircraft Control Systems 107 Lubrication of the P-63 Airplane 109 Turbosupercharger Lubrication 110 Starter Lubrication Ill Lubrication of B-29 Retracting Motor . Ill Performance of Non-Inflammable Hydraulic Fluid in Struts 112 Investigation of Reported Engine Roughness during Service Test of PPO-265 by Alaskan Division, ATC 113 Cold Weather Observation with Respect to Bombing Equipment 115 Low Temperature Tests of the Eight (8) Gun Nose Installed on B-25J Airplane 118 Low Temperature Tests of the Armament of A-26B Airplane 119 Low Temperature Tests of B-29 Fire Control System .... 120 Cold Weather Operation of Stewart Warner Corporation Model 904A Ground Heaters 120 Experimental Installation of Stewart Warner Corporation Model 911A Combustion Heaters in B-17G 122 Cold Weather Tests of Heating Oil and Batteries on Types C-13 and C-13A Auxiliary Power Units 123 Generator and Starter Failures During Cold Weather Tests : 126 Type D-2 Auxiliary Power Plants, Cold Weather Tests 127 Electrical Loads, Feathering Propellers at Cold Temperatures and Hydraulic Pump Motors 128 Main Generators—Type B-29 Airplane, Cold Weather Tests 129 Power to Operate Landing Gear Retraction Motors at Low Temperatures, Type B-29 Airplane 130 Type C-12 Engine Driven Power Plant, Cold Weather Tests 130 Oil and Fuel Pressure Gage Installations 131 Tests of Cabin Heating and Defrosting Systems of P-59 A 133 Type E-l, Artificial Horizon Indicators Type C-l, Directional Gyro Indicators 135 Type F-4 Airspeed Indicator „ 135 Navigation Instruments 136 Air Driven Gyro Instruments 137 P-59 Instruments 139 Cold Weather Testing of Type C-11A Electric Power Plant 140 Cold Weather Testing of Lamp Assembly, Rigid Drum Type Rotating Beacon, 24" AN-L-4 .... 140 Lamp Assembly, Rigid Drum Type Rotating Beacon, 24" AN-L-4 141 Cold Weather Testing of Lamp Assembly, Type C-3 Acetylene Operated Flashing Beacon 141 Cold Weather Test of Direct Cranking Starters, Power Input to Crank Cold Engines, Type B-29 Airplanes * 142 Instrument Hose and Fittings 144 Instrument Vacuum Selector Valves and B-29 Vacuum System, Part I 144 Instrument Vacuum Selector Valves and B-29 Vacuum System, Part II 145 Page SECTION IV: Final Report from TSEPL-3G Representatives on Temporary Duty at Ladd Field. Alaska 146 Cold Weather Tests of the Type A-5, 35 mm Motion Picture Camera 148 Cold Weather Tests of Stereo-Mounted K-35 (35 mm) Cameras 148 Cold Weather Tests on the Types B-l and B-1A, 16 mm Motion Picture Cameras 149 Cold Weather Tests on the Type A-7, 35 mm Motion Picture Camera 150 Water Repellent Jacket for K-17 or K-22 Camera 150 Cold Weather Test of Color Film 151 Cold Weather Test of the Type N-5 Kit. 16 mm Motion Picture Film Field Processing 152 Cold Weather Tests with F-5E Airplane 153 Low Temperature Tests on Aerial Photographic Cameras 153 Ground Cameras 155 Report to Chief, Maintenance Division 156 Report of Visit to Ladd Field, Alaska 159 Report of Temporary Duty at Ladd Field 160 Report of Visit to Ladd Field, Alaska 162 Cold Weather Tests of Radio and Radar Equipment 164 SECTION V: Reports of Manufacturer’s Technical Representatives 172 Allison Division of G. M. C 172 Bell Aircraft Corporation 175 Bell Aircraft Corporation 176 Bendix Products Division 179 Chandler Evans Corporation 182 Consolidated Vultee Aircraft Corporation 183 Curtiss-Wright Corporation 187 Douglas Aircraft Co., Inc 188 Fairchild Camera and Instrument Corporation 189 General Electric Company 190 Lockheed Aircraft Corporation 192 Northrop Aircraft, Inc 195 Packard Motor Company 195 Perfection Stove Co 197 Pratt & Whitney Aircraft Division 199 Socony-Vacuum Oil Company 201 Sperry' Gyroscope Company 202 Lausen Engine Company 202 The Texas Company 203 Western Electric Company 206 APPENDIX: Table I, Hourly Surface Temperatures 209 Table I, Hourly Surface Temperatures 210 Table I, Hourly Surface Temperatures 211 Table I, Hourly Surface Temperatures 212 Table II, ATSC Developmental Test Airplanes 213 Table HI, CWTD Service Test Airplanes 213 Table IV, ATSC Personnel Attending 1944.45 Cold Weather Tests 213 Table V, Manufacturer’s Technical Representatives Attending 1944-45 Cold Weather Tests 214 TABLE OF CONTENTS (Cont’d) AIR TECHNICAL SERVICE COMMAND COLD WEATHER TESTS Winter of 1944-1945 INTRODUCTION In order to save space and reduce the bulk of this report to a reasonable size, many charts, tables, photographs, and ap- pendixes have been omitted from the reports of Sections III, IV, and V. However, reference to these data has not been omitted from the portion of the reports printed. Anyone desiring reports in their entirety may obtain them by zvriting to the Director, Air Technical Service Command, Wright Field, Dayton, Ohio, Attention : TSESE-4F3. 1. The purpose of this report is to describe the pro- gram conducted at Ladd Field, Alaska, by Engineering Division of Air Technical Service Command to test AAF aircraft and equipment under conditions of ex- treme cold during the winter 1944-1945, and report the conclusions and recommendations resulting therefrom. 2. The Air Technical Service Command is wholly responsible for the development and procurement of aircraft and equipment for the Army Air Forces that will operate satisfactorily at all temperatures down to —65°F outside air temperature. To insure meeting this requirement tests and investigations must be conducted upon which to base corrective engineering of reported and anticipated deficiencies. As part of this program the Engineering Division installed instrumentation and test equipment on several current model airplanes and con- ducted experimental and developmental tests at Ladd Field, Alaska. 3. The AT SC test program was planned, organized supervised by the Climatic Requirements Office of En- gineering Division. Project engineers of the various En- gineering Division Laboratories were present to conduct tests on and observe malfunctions of their respective in- stallations and equipment. Various aircraft and equip- ment manufacturers’ technical representative attended in order to gain first-hand knowledge of the difficulties of cold weather operation, aid in operation of their equipment, and obtain data and information which would be used to improve the performance and utility of their equipment. 4. Section I describes the organization and conduct of the test program, 5. Section II summarizes the more important con- clusions arrived at as a result of the tests. 6. Section III is the final reports written by the pro- ject officers of the Climatic Requirements Office. 7. Section IV is the final reports written by project officers and engineers of the various Engineering Div- ision Laboratories. 8. Section V is reproduction in part or whole of re- ports written by Technical Representatives to their res- pective organizations. 9. The Appendix contains miscellaneous informa- tion such as airplane models, flying time, hourly tempera- ture data, and personnel attending the tests. 5230 1 SECTION t Organization and Conduct of Cold Weather Test Program Winter of 1944-1945 1. Air Corps interest in cold weather operation dates back several years. In 1938 the Cold Weather Test De- tachment was established as an independent Air Corps activity at Fairbanks, Alaska, to conduct tests, determine the aircraft requirements for cold weather operation, and recommend corrective action. The first tests by that Detachment were conducted during the winter of 1940- 1941. These tests and the ferrying of airplanes over the Alsib and North Atlantic routes revealed critical defici- encies in AAF aircraft and equipment when operated in extremely low temperatures, and the advent of war in the North Pacific emphasized the importance of develop- ing aircraft that would operate in all arctic theaters. 2. Starting in the winter 1942-1943 Engineering Div- ision, ATSC has conducted extensive test programs each year at Ladd Field in conjunction with the Cold Weather Testing Detachment, In 1943 the Cold Weather Testing Detachment was placed under the administration of Proving Ground Command. Since that time the Detach- ment has been responsible for service test of all standard production aircraft and equipment, while Engineering Division has been responsible for all experimental and developmental testing. 3. The coordinating office for all cold weather devel- opment and testing in ATSC is the Climatic Require- ments Office of the Engineering Division. Climatic Requirements office is responsible for planning, organ- izing, and supervising test programs for Engineering Division at cold weather test bases, evaluating and con- solidating test results, aiding and following up the En- gineering Division Laboratories to insure solutions to reported and anticipated deficiencies, after proper co- ordination establishing the aircraft and equipment requirements for cold weather operation, and informing Procurement Division and industry the requirements and action to be accomplished. 4. The procuring of test airplanes, instrumentation, and installation of test equipment therein, organization and supervision of actual testing, and the flying and maintenance of airplanes, was performed by the Ex- treme Temperature Operations Unit of Climatic Re- quirements Office. The airplanes tested by Engineering Division during the past winter are listed in Table II of the Appendix, The bulk of the instrumentation and test equipment was installed in the airplanes at Dayton Army Air Field, Vandalia, Ohio, during the summer and fall of 1944. Certain installations were also made at contractor’s plants. The installations were made at the direction and with the help of Engineering Division Lab- oratory project engineers and contractor’s engineers. 5. Each test airplane was assigned a project officer who acted as project engineer and pilot for his own air- plane. At the conclusion of instrumentation in the United States the airplanes were flown to Ladd Field where the test program was gotten underway approximately 1 De- cember 1944. It was the responsibility of the project office to insure that all tests requested by Laboratory engineers and contractor’s representatives were com- pleted as nearly as was feasible, and that the maximum benefit was derived from the test program on their re- spective airplanes. 6. The Cold Weather Testing Detachment furnished to Engineering Division hangar space and shop facili- ties, enlisted maintenance and flight crews, office facili- ties, extra pilots when required, airplane servicing, sup- plies, spare parts, and other facilities. 7. Cold Weather Testing Detachment procured two or more of each current production airplane upon which to conduct tests to determine their operational suitability. These airplanes contained no instrumentation or experi- mental installations. CWTD also performed service tests on all available types of standard ground and accessory equipment. In addition it performed some service tests on experimental equipment for ATSC. The airplanes service tested by CWTD are listed in Table III of the Appendix, CWTD submitted reports on their tests to Headquarters, Proving Ground Command. 8. The Air Technical Service Command personnel and manufacturer’s representatives attending the tests are listed in Tables IV and V of the Appendix. 2 5230 SECTION II Summary of Conclusions 1. Temperatures at Ladd Field during the past winter were above average. Table I of the appendix gives hourly temperatures during the months of November, Decem- ber, January, and February. During the winter —40°F or colder was reached on three days. The lowest ground temperature was —45 °F. A few airplanes experienced lower ground temperatures at Northway, Alaska, and Snag, Canada. However, in spite of the lack of extreme- ly low temperatures certain deficiencies were noted, and recommendations can be made that, if complied with, will improve the operability of aircraft down to —65°F. In general, it can be stated that current production air- craft are operable down to —45°F and are greatly im- proved over previous years, but certain items are not as satisfactory as is desirable or possible. It is anticipated that at temperatures below —45°F AAF aircraft may not be entirely satisfactory for all tactical operations that may be required of them. Following is a brief summary of some of the more important conclusions reached as a result of the 1944-45 test program. These and other conclusions and recommendations are discussed in more detail in the reports in Sections HI, IV, and V. a. SURFACE CONTROL SYSTEMS. Practic- ally every airplane had at least on control or trim tab that was stiff at —40° F. Investigation revealed that very lit- tle stiffness was caused by congealing of the lubricants. The primary cause of stiff or frozen controlls was dif- ferential expansion and contraction of component parts or mountings. Cable tension could not be maintained, especially on larger airplanes. Cable tension regulators were of value. b. RUBBER HOSE. Standard winterized hy- draulic and instrument hose was satisfactory. Standard oil and coolant hose was not entirely satisfactory, but new types tested experimentally were good. c. WEATHERSTRIPPING AND FUSELAGE SEALS. There were numerous instances of rubber and synthetic seals breaking, cracking, or becoming so hard that canopies, doors, etc. could not be opened or closed with ease or sealing properties were lost. d. PLASTIC PARTS. There were several in- stances of plastic canopies, domes, and windshields cracking due to differential contraction of the part and the mounting. volume diluted oil. 4. The test data are shown in Appendix I of this report. 5. Due to the short time the airplane was available for test purposes, additional runs could not be secured to elaborate on the abve data. C. CONCLUSIONS 1. On the basis of these tests, the R-2000-7 engines and installation in the C-54B airplane does not comply with AN-9500-C, paragraph 31q. Even though the O. A. T. was approximately 12°F. above the maximum specified in paragraph D-31q, it is not considered that a small lowering of the O. A. T. would have materially altered the breathing characteristics of the engine. D. RECOMMENDATIONS 1. It is recommended that action be taken by Pratt and Whitney Aircraft Division to improve the breathing characteristics of the R-2000-9 engines so as to comply with Specification AN-9500-C paragraph D-31q. Ice found in fuel inlet line Draining fuel tank sump 86 5230 Oil Spewing Tests on V-1710 Engines Conducted at Ladd Field During 1944-45 Prepared by: Win. Weitzen, Power Plant Laboratory A. PURPOSE 1. To report on engine breathing oil spewing tests con- ducted on V-1710-93, -111, -113 and -117 engines in- stalled in P-63A and P-38L aircraft to compare with the present requirements as described in Specification 9500C, paragraph D319. B. FACTUAL DATA 1. On the basis of tests conducted during the winter of 1943-44 the “E” type Allison engine was known to have poor breathing characteristics with the result that oil spewing occurred with moderate dilutions. The Al- lison Company worked continuously on this problem and evolved in conjunction with Air Technical Service Com- mand a baffled engine front cover, in accordance with drawing No. 54808, which modification materially im- proved the breathing characteristics of the type “E” en- gines. Previous tests conducted at Ladd Field during 1943- on the V-1710-89 and -91 “F” engines installed in P-38 aircraft indicated these installations were rela- tively satisfactory. 2. The Bell Aircraft Company worked simultaneously on this problem and evolved a system utilizing an air-oil separator, Type B-ll, which was installed in the engine breather line, and a venturi in the scavenge oil line to which the separator drain was connected. Insofar as the Bell Company was concerned, this air-oil separator in conjunction with venturi, Part No. 33-674-036-1, ac- complished the desired result and prevented oil loss with 30% diluted oil. 3. At Ladd Field, for the winter test program of 1944- there were available for tests one P-63 A with an Allison V-1710-93 engine which had the modified engine front cover, and several P-38L airplanes with -111 and -113 engines. These latter two engines were new models having twelve counterweighted crankshafts, (sometimes referred to as 100% counterweighted crank- shafts). The V-1710-93 engine still retained the old crankshaft and plans were made to incorporate in the airplane at a later date a V-1710-117 engine also having the twelve counterweighted crankshaft. 4. Oil spewing tests were conducted on the P-63A and P-38L aircraft in accordance with procedures previously established. In conducting these tests, the oil system is diluted in the normal fashion to a desired amount to pro- vide dilution in the engine oil, oil lines, and oil cooler; then the oil tank is drained and filled with a.premixed quantity of diluted oil. In testing, takeoff is usually ac- complished within 5 minutes after starting the engine. Takeoff power is maintained for 5 minutes unless exces- sive spewing occurs in which case a power reduction is made. On the P-63 airplane, a mirror is installed on the wing to enable the pilot to watch for engine spewing. On the P-38 airplane, only one engine is tested at a time and there is no convenient way for the pilot to detect spewing. 5. The initial tests conducted were on the P-63 A having the standard installation of B-ll air-oil separator and production venturi, No. 33-674-036-1. Results of this test are shown in Appendix I. This airplane satis- factorily handles 30% diluted oil. 6. Tests were then conducted on the P-38L aircraft. The “F” engines and installation do not have any special anti-spewing provisions. The results of these tests are tabulated in Appendix II. Also see Exhibits A and B. 7. The test results on the P-38 airplane showed that the V-1710-111 engine (right hand engine) is not as unsatisfactory as the V-1710-113 (left hand engine). Some of these tests were duplicated on the cold weather test P-38 airplane to confirm the results obtained on the E. T. O. U. P-38 airplane. AAF No. 44-24050. Result of oil spewing 5230 87 8. One check run was made on the P-63 airplane with the air-oil separator removed and the two engine breath- ers teed together in an arrangement similar to that pre- viously used on the P-39 type aircraft. This brief check indicated oil spewing with as little as 15% total dilution. 9. The V-1710-117 engine was then installed in the P-63A airplane for further testing. This engine had, in addition to the standard production separator used pre- viously, the latest Allison modifications including: a. a front breather screen of enlarged exit area, b. a rear breather restriction, and c. a front oil pump elbow tube. In addition, the breather outlet was scarfed 3° forward for pressure as per Bell Technical Memorandum 63 :670: 84 dated 18 November 1944. This installation satisfac- torily handled 30% premixed dilution as shown in Ap- pendix III. Also see Exhibit C. C. CONCLUSIONS 1. All the Allison engines tested, the V-1710-93, -111, -113, and -117 engines, are unsatisfactory by themselves insofar as oil spewing is concerned. These engines would not comply with the requirements now established in Specification AN-9500-C, paragraph D-31q. 2. The P-63A type aircraft with the Bell air-oil sepa- rator, Type B-ll, and venturi No. 33-674-036-1, satis- factorily handles 30% diluted oil when using the V-1710- 93 engine or when using the V-1710-117 engine with the latest Allison modifications. 3. The P-38L type aircraft cannot satisfactorily handle 30% diluted oil under takeoff power conditions. The left engine. V-1710-113, is worse than the right engine, V-1710-111, and is sufficiently critical to impose a severe handicap to combat operation. The V-1710-113 engine can handle only up to 15 % dilution while the V-1710-111 engine can handle up to 25% dilution. D. RECOMMENDATIONS 1. It is recommended that the Allison Division con- tinue their test program in an effort to improve the breath- ing and spewing characteristics of these later engines which, with the twelve counterweighted crankshafts, are more unsatisfactory than previous model engines. 2. It is suggested that the Lockheed Company consider the incorporation of some type of air-oil separator, or similar arrangement, in their P-38 type aircraft to eli- minate this unsatisfactory oil spewing condition. Oil Dilution and Spewing Tests Conducted on the C-G9 Airplane Prepared by: N. Barron, 1st Lt., A. C. Power Plant Laboratory A. PURPOSE 1. To report the results of tests conducted on the C-69 airplane, Army Air Forces No. 43-10314, with respect to the oil dilution system breathing characteristics of the R-3350-35A engine, and the dilution, warm-up, and op- erational characteristics of the C-69 oil tank. B. FACTUAL DATA 1. Dilution tests were conducted to determine the time periods necessary to obtain specified percentages of di- lution. Appendix I contains the description of the oil tank and the discussion of the test. Dilution and boil-off curves are included as Appendix III. 2. Tests using 20% and 30% prediluted grade 1100 oil in engine No. 1 were accomplished, maintaining take- off power for five minutes in order to determine the scav- enging and breathing ability of the present installation. Test data is contained in Appendix II. Discussion of test is contained in paragraph c, Appendix I. 3. See Appendix I, paragraph d, for discussion of the flight operational data on the oil tank of engine No. 1, which was the only oil tank with thermocouples. See Ap- pendix IV for warm-up curves. 4. Due to the late arrival of the subject aircraft, this report on dilution and spewing tests is submitted in ad- dition to the general CWTD report written at Ladd Field (S.T. No. 10-45-1). C. CONCLUSIONS 1. The oil dilution system is unsatisfactory. Six min- utes of dilution is the maximum amount that can be ap- plied to the present system. This provides only 10% di- lution which is sufficient for an anticipated starting tem- perature of -f-10°F. 2. The R-3350-35A engine, as installed in the C-69 airplane, satisfactorily handles 30% prediluted grade 1100 oil. 8 3. There are indications that under extreme cold tem- perature conditions portions of the oil tank can congeal and remain congealed during operation. This may result in hopper depletion after some oil consumption. 4. Inacessibility of the oil tank precludes obtaining samples for a thorough analysis of the dilution character- istics of the tank with respect to segregation and diluent flow rate. D. RECOMMENDATIONS 1. It is recommended that the oil dilution system be 88 5230 modified to correct the present unsatisactory condition. 2. It is recommended that no more than 6 minutes (10% dilution) be attempted for cold starting and that heat be used in addition to 6 minutes dilution at tempera- tures below 10°F. 3. It is recommended that further oil dilution tests be conducted on this type aircraft to obtain samples from the oil tank or an accurate evaluation of its dilution char- acteristics. 4. It is recommended that further tests be conducted to determine dilution and warm-up characteristics of the oil tank after cold soaking at extreme low temperatures, both on the ground and in flight. Appendix I A. DESCRIPTION 1. This aircraft does not contain the type of oil tank usually found in Army Air Forces aircraft. Each engine oil tank is located immediately outboard of its engine na- celle and is integral with the wing. The top and bottom are formed by the wing leading edge-skin, the inboard end by the nacelle skin, the other end and sides by bulk- heads. Each tank is vented to its engine crankcase and provided with fittings for immersion heaters at the in- board and outboard ends as well as at the oil filler-well screen. The conventional aircraft oil tank is generally constructed with the hopper located centrally. The sub- ject oil tank hopper is located at the inboard wall of the oil tank. This prevents making use of a sufficient amount of the hopper wall area considered necessary to warm up the surrounding oil in the tank during extreme low tem- perature conditions. a. Tests were performed on the C-69 airplane in the same manner as on the various other Army Air Forces aircraft at Ladd Field during the winter of 1944-45. The dilution and boil-off results are included in Appendix IV. As shown in Appendix IV, diluting for 11 minutes produces only 17% dilution. From an evaluation of this set of curves, it is concluded that 6 minutes (10% dilu- tion) is the maximum practical operational limit of di- lution for anticipated cold starts (-(-10oF.) and that in addition, the application of heat is necessary for start- ing at temperatures below 10°F. b. In general, the ability of an oil tank hopper to segregate the oil in the circulating system from that in the tank surrounding the hopper is shown by analysis of samples taken from various sections of the oil tank. This would indicate whether a tank design change or changing the diluent flow rate would be necessary for the improvement of the dilution system. Since oil tank- samples could not be obtained, this portion of the prob- lem remains unsolved. c. To determine if the R-3350-35A engine could satisfactorily handle 30% prediluted grade 1100 oil, the oil system of engine No. 1 was completely drained and refilled with 20% prediluted grade 1100 oil. Take-ofif was accomplished as soon as practicable with no reduc- tion in power on engine No. 1 for five minutes after take- off. Engines Nos. 2, 3 and 4 were operated in the normal manner. No spewing or excessive oil loss occurred through the engine breathers. The test was repeated with 30% prediluted grade 1100 oil with similar successful results. From this, it can be concluded that 30% pre- diluted grade 1100 oil can be successfully handled at high powers by the R-3350-35A engine installation. The data for these runs are shown in Appendix II. d. Flight tests were conducted at temperatures down to —45°F. to secure data on the warm-up and operation- al characteristics of the oil tank. Readings were taken during 6 flights and plotted in graphs, Appendix IV. It can be seen from valves of point No. 18, which is located at the outboard end of the oil tank, that there are indica- tions of the possibility of oil congealing occurring at ex- treme low temperatures. As previously stated, this tank is not of the conventional design and it is therefore rec- ommended that further tests be accomplished at tempera- tures down to —65°F. to obtain additional information on the characteristics of this type of oil tank. Test Stand Cold Starts on a V-1650-7 Engine Equipped with a Speed Density Pump Prepared by: J. W. Whittle, Pozver Plant Laboratory A PURPOSE 1. To determine the cold starting characteristics of a V-1650-7 engine equipped with a speed density pump. B. FACTUAL DATA 1. Appendix I—Discussion. 2. Appendix II—Test Data. 3. Appendix III—Airplane cold starting and crank- ability record. C. CONCLUSIONS 1. The cold starting characteristics of the peed-dens- ity pump are satisfactory. 2. Cold starts with the present fuels are dependent upon the effectiveness of the engines’ priming system. 3. Engine roughness encountered in a cold start and during the following warm-up period could damage the engine or installation. D. RECOMMENDATIONS 1. It is recommended that the starting characteristics of the speed-density pump be considered equivalent to the standard carburetors. 5230 89 Appendix I data, it was necessary to develop and standardize on a test procedure that would be suitable for any tempera- ture which may have been encountered. A series of start- ing tests showed that where heat was not used, better results were obtained, with the longer priming periods. The cold starting procedure developed for the subject engine consisted of: c. Pulling the propeller through two revolutions. b. Priming for a minute. c. Priming and cranking for a minute. d. Repeating the minute of priming followed by a minute of priming and cranking until a start was effected. 2, The engine was equipped with the standard V-1650- 7 starter, ignition system, and priming system. A speed- density pump was installed in place of the Bendix Strom- berg carburetor and a 4 blade 7 foot diam. test club was used for absorbing the power. Electrical power was sup- plied by the conventional 24 volt airplane ground ener- gizing unit wired in parallel with the stands 24 volt system which consisted of two heavy duty 12 volt bat- teries hooked in series. A G-9 fuel pump with a relief valve setting of fifteen pounds was used for maintaining priming pressure. The entire engine coolant system was located in the test cell and subjected to the existing free air temperature, while the after-cooler coolant heat ex- changer and oil system was located in the operator’s room which was held at 50 or 60° F. TEST RESULTS: 1. Appendix II is a record of four starts made under the coldest temperatures which were encountered dur- ing the test season. The engine temperature for tests 1, 2 and 4 were approximately —22°F. The engine tem- peratures for test No. 3 were near —18°F. 2. Minus 22 degrees Fahrenheit is believed to be the minimum temperature at which the Packard engine can be started on Grade 130 fuel. These starts and warm-up periods in tests 1 and 2 can only be accomplished through use of the primer system. The excessive primer warm- up periods are also characteristic of cold starts on the carburetor equipped V-1650- engines. It is believed that excessive primer warm-up periods are due to the neces- sity of warming the coolant in the after-cooler before satisfactory fuel vaporization and carburetor operation is possible. Starts under these conditions result in ex- treme engine roughness and are not desirable for safe airplane operation. On the basis of this information, it is estimated that cold starts using grade 130 fuel could be satisfactorily accomplished at an engine temperature of —15°F without endangering the engine. 3. Tests three and four were made with fuel RAF- V-44 No. 24. These starts using a more volatile fuel and not requiring a primer warm-up period, indicate that the cold starting characteristics of the speed-density pump are satisfactory. INTRODUCTION: 1. The following is considered to be a few of the de- termining factors which pertain to effecting a cold start on other than fuel injection engines. a. On engines equipped with an ignition boost system, cranking speed is not a critical item. (1) One of the purposes and the result of satis- factory oil dilution is to effect a cold weather cranking torque which is equivalent to the cranking torques en- countered under summer conditions. See Appendix III “Airplane Cold Starting and Crankability Record” pre- pared by Mr. Wm. Weitzen, Pvt. R. G. Dunn and Lt. S. Barron. (2) It is understood that the Navy uses 30 RPM as a minimum design value. Engine starts can and are being made under summer conditions at approximately 8 RPM; this is being done on the test stands in making starts for torsional vibration runs and on the flight line in the ships of two and three hundred horsepower which are not equipped with starters. b. The order of the importance of the priming system, fuel metering system, and manifold system de- pends on the volatility characteristics of the fuel. (1) In the case of a fuel which volatilizes readily at the temperature under condition, the fuel me- tering (carburetor) system is of major importance; thus, the need for a priming and manifold system which aids fuel volatilization decreases, (2) In the case of a fuel which has poor volatil- ity characteristic for the temperature being investigat- ed, the priming system is of major importance followed by a manifold design which affords a maximum amount of liquid or wetted area. TEST PROCEDURE: A. AIRPLANES. 1 Flight line cold weather starting technique on any given airplane will vary in procedure between the dif- ferent crews. However, it is general practice that if the engine is too stiff to pull the propeller through (indicat- ing insufficient oil dilution) or if some of the cylinders do not fire during the first few attempted starts (indi- cating insufficient volatilization of the fuel), the ground heating equipment is utilized. Any radical deviations from this general procedure may result in damaged ac- cessores, scoured cylinder walls, or cylinder hydraulic lock. This damage or possible failure cannot be risked on an engine which is installed in an airplane. B. TEST STANDS. 1. On the test stand, in order to obtain comparative 90 5230 Ladd Field Cold Weather Engine Test Stands Prepared by: Joseph W. Whittle, Power Plant Laboratory Jet engine test stand A. PURPOSE 1. To discuss the development and the testing facilities of the Ladd Field Engine Test Stands. B. FACTUAL DATA 1. Appendix I is a discussion covering the history, de- velopment, testing facilities, and a cold room comparison of the subject stands. 2. Appendix II contains the following correspondence which covers in detail the progress made on the stands during the test season of 1944-45. a. Exhibit A—Letter to Major W. Woodard, dated 9 November 1944. b. Exhibit B—Excerpt from Power Plant Progress Report No. 2, dated 21 December 1944. c. Exhibit C—Excerpt from Power Plant Progress Report No. 3, dated 13 January 1945. d. Exhibit D—Excerpt from Power Plant Progress Report No. 6, dated 7 March 1945. e. Exhibit E—Letter to Major W. Woodard, dated 16 March 1945. f. Exhibit F—Excerpt from Power Plant Progress Report No. 7, dated 30 March 1945. 3. Appendix III contains drawings showing the pre- sent and proposed modifications of the stands and instru- mentation. 5230 91 C. CONCLUSIONS 1. The summer of 1945’s proposed instrumentation, modification, and completion of test cells one through four will provide facilities for the cold weather sea level or altitude calibration or endurance testing of 3000 HP air-cooled aircraft engines. 2. The stands are the only cold weather engine test stands in the United States or Territory of Alaska. 3. The stands are the only test house where sufficient refrigeration is available to be able to conduct cold weath- er calibration or endurance tests of any duration on con- ventional aircraft engines. 4. Engine tests that are being run in cold rooms can be conducted at a much lower cost without too much in- convenience due to weather variations. 5. The stands are the only test house where sufficient refrigeration is available to conduct cold weather cali- brations on jet-propulsion units. 6. After this year, the stands and engines with a limit- ed number of personnel will be available during the sum- mer months for conducting the standard types of calibra- tion or endurance tests. D. RECOMMENDATIONS 1. It is recommended that cells numbers one through four be finished and instrumented as tenatively approved and proposed. 2. That the completion and modification of the four cells be completed by August 1945. 3. That the test programs and engines for the season of 1945-46 be available by 15 September 1945. Appendix I Discussion of History, Development, Testing Facilities and Cold Room Comparison of Engine Test Stands INTRODUCTION 1. The subject building is known as the Cold Weather Testing Test House, building number 338, and is located at Ladd Field, Alaska. 2. This six-cell test stand is jointly operated during the winter months by the Cold Weather Testing Detach- ment of the Army Air Forces and the Power Plant Lab- oratory of the Engineering Division of Wright Field. 3. The responsible officer in charge of this project is 1st Lieutenant S. Barron of the Cold Weather Testing Detachment of the Army Air Forces. 4. The building is supplied and maintained by the Cold Weather Testing Detachment of the Army Air Forces. The instrumentation of the stands and the test engines are furnished by the Power Plant Laboratory of the Engineering Division of Wright Field. During the test season, October 15 to March 15, the personnel re- quired to operate the stands are jointly supplied by the two organizations, while during the summer months, the stands are maintained by personnel of the Cold Wea- ther Testing detachment. HISTORY 1. The building was originally designed for the block testing of overhauled engines. Construction, the erec- tion of the concrete walls, was started the summer of 1942, after which the demand for an engine overhaul stand was eliminated; this resulted in the project’s being discontinued. 2. During the winter test season of 1943-44, the need for a cold weather engine test stand was recognized; plans were made to utilize two Jacobson Engine Block Test units in conjunction with the partially finished test house. 3. In February of 1944 the project was assigned to 1st Lieutenant S. Barron. At the end of that year’s test season, drawings for the completion of the test house were started; these drawings were completed in July of 1944. DEVELOPMENT 1. Construction, completion of the partially finished engine block test building, was started the latter part of August 1944. 2. Drawings numbers one and two, Appendix III, show the plan and elevation views of the stands at the start of the winter season, November 1944. 3. The major portion of the work done during the test season of 1944-45 consisted of the development and the proving of the test stands. 4. The details covering the development of the test house and the adapting of a Jacobson Engine Block Test unit, to the building are described in the correspondence and photographs which are included as Appendix II. 5. The stands are the first of their kind; that is, they are the only cold weather engine test stands in the Unit- ed States or Territory of Alaska. For this reason and because the original building was designed for engine overhaul block testing, it was necessary to make and test numerous modifications of the building and methods of installation of the test equipment. This work or development of a satisfactory cold weather engine test stand is not considered complete by any means, but the experience gained during this last test season is being applied to the completion of cells 3 and 4 and the necessary modification of cells 1 and 2. 6. The modifications of the test house and the meth- ods of installing the test equipment, all of which will be incorporated into cells 1 through 4 during the summer of 1945, are shown in drawings one through seven. These modifications provide for the following items: a. Provisions for obtaining proper air flow into the propeller. This is necessary in order to be able to main- tain a constant engine rpm and even cooling of air cooled engines. b. Provisions for utilizing the maximum amount 92 5230 of propeller clearance that can be made available with- out making major changes to the building. This will fa- cilitate the use of airplane flight propellers that are re- quired for engine calibrations on a torque stand. c. Provisions for a test cell exhaust system which provides for a minimum amount of back pressure, be- hind the propeller. This will increase the horsepower capacity of the cells by eliminating the re-circulation of air and exhaust gases through the propeller. Erratic re- circulation would cause rpm fluctuations and possibly uneven cooling in the case of air cooled engines. d. Provisions for streamlining and obtaining a min- imum number of obstructions to the airflow directly be- hind the propeller. A nearby unstreamlined obstruction can cause excessive propeller stresses and/or engine rpm fluctuations. e. Provisions for the use of a maximum amount of overhead plumbing in the operator’s rooms. This will go a long ways towards the elimination of the freezing and the failure of steam and water pipes and valves. /. Provisions for obtaining efficient lighting of the stands. This is an important item, inasmuch as half of the test running has and will be done at night. g. Provisions for the most efficient utilization of the building’s heating facilities. Small modifications will make additional heated working space available. 7. These drawings one through seven have not been checked or officially approved. Upon their completion they will be submitted to the Commanding Officer of the Cold Weather Testing Detachment, who has tenta- tively approved them, and to the Commanding Officer of the Resident Engineers of Ladd Field. It is believed that only minor changes will be made in these drawings and plans for the work to be accomplished during the summer of 1945. 8. In making plans for the completion of cells 3 and 4 it was necessary to give some thought to the possible completion of cells 5 and 6 and to their utilization for the test season of 1945-46. In order to facilitate the making of these plans and in order to eliminate the possibility of making an installa- tion in or a modification to cells 5 and 6 whch would have to be removed if the test cells were to be completely utilized for engine tests at a later date, drawings num- bers seven and eight were made. The only purpose of these two drawings is to provide tentative plans for the entire completion of the test house in the event that the project warrants final completion at a later date. At the present, neither the equipment nor the personnel for the operation of six cells are available. Plans for the test season of 1945-46 will utilize cell number 5 and operator’s room number 3 for a jet engine installation, which is very portable, while cell number 6 and the adjoining space will be used as a temporary of- fice and storage room. 9. In addition to the previously mentioned drawings, the following plans are being made for more complete instrumentation of the stands and engines: a. Ducting and equipment for measuring engine air consumption and simulating altitude induction pres- sures. b. Incorporating mercury switches and an electric stop watch on the fuel scales to provide for a more accu- rate means of determining fuel consumptions. c. The use of more mercury monometers or provid- ing sensitive manifold pressure gages to be used for measuring carburetor drops and deck pressures. d. The use of torque-meters on all radial engines. e. The complete thermocoupling of all test engines. f. The development of an accurate means of meas- uring cranking torques. g. The development of a reliable rpm counter for use on cold starts. h. Provisions for controlling engine fuel flow by the use of needle valve throttling on the carburetors where this is possible and by the use of special reworked mixture control plates on the other types of carburetors. i. Providing special re-worked flight propellers for the larger engines. ;. Providing thermocouple wire and potentiomet- ers. k. Providing radial engines with cowl shutters to control cylinder temperatures. TESTING FACILITIES: 1. Upon completing the planned instrumentation and modification of the stands, facilities will be available for conducting the following types of tests on engines of 3000 horsepower and less: a. Cold starts. b. Distribution and fuel volatility tests. c. Fuel metering tests. d. Oil dilution and crankability investigations. e. Spark plug fouling tests. /. Fuel consumption. g. Oil consumption. h. Air consumption. 2. These tests and the various engine variables which are involved may, with the exception of altitude exhaust- ing, be controlled and investigated under either sea level or simulated altitude conditions. 3. The significance of these facilities is not realized until it is pointed out that during the months of Decem- ber, January and February of 1944-45 there was a total of 166 hours of temperatures below a —20° F. and that this season was supposedly the mildest winter Fairbanks had had in twenty years. This temperature is equivalent to a standard altitude temperature of 22,000 feet; that is, sufficient refrigeration and time were available to conduct a complete altitude calibration or endurance test on any engine. 4. In addition to the cold weather winter test pro- grams, the stands and engines, after this year’s modifi- cations, will be available for any summer months with a limited number of personnel for the conducting of any type of calibration or endurance test. COLD ROOM COMPARISON: 1. Cold rooms are ideal for investigating cold starts* crankability, and oil dilution characteristics of aircraft and engines but are not practicable in the case of calibra- tion or endurance testing of aircraft engines. 2. The liquid cooled engines are best adapted to cold room calibration and endurance testing. Endurance testing does not require accurate power measurements; during this type of test, satisfactory power compliances are maintained through the use of the speed, manifold pressure, and carburetor air temperature relationship. In the case of calibration work where accurate power 5230 93 measurements are required, it is necessary to use a dynamometer for absorbing and measuring the power developed; to date, a satisfactory torque meter has not been developed for the in-line engines. 3. The refrigeration required to obtain —20° F. op- erating conditions for a liquid cooled engine is an appre- ciable amount. Using average operating conditions, the following rough heat balance can be made : Using an F/A ratio of .075, Using a BSFC of .55 #/BHP-HR, Using a 2000 BHP engine, Using a thermal efficiency of 35%, Using a heating valve of 21,400 BTU/# Amount of air consumed = 14.600 #/hr. Amount of fuel consumed = 1100 #/hr. a. Refrigeration required to remove the heat from the air consumed by the engine assuming a specific heat of .2 and a temperature drop from a + 50°F. to a —20° F. is Approximately 22,500 BTU /Hr. or 2 tons of refrigeration. b. Refrigeration required to handle the radiation losses of the engine assuming the coolant and oil heat exchangers are located outside of the cold room and that the exhaust gases are also discharged outside of the cold room would be Brake thermal efficiency = 26% Heat rejected to coolant = 30% Heat rejected to oil = 4% Heat rejected to exhaust = 38% Radiation Losses = 2% With this extreme temperature differential the radiation losses would be high, probably 2%. Required refrigeration to handle radiation losses would be Approximately (.35) (1100) (21,400) (0.02) = 165,000 BTU/Hr. or 13 tons of refrigeration. 4. The foregoing assumptions result in an estimated refrigeration capacity of 15 tons required to operate a 2000 BHP liquid cooled engine in a cold room at —22°F. In the case of an air-cooled engine using a propeller to absorb the power and which did not exhaust outside of the cold room, the refrigeration required would be ap- proximately equal to the thermal efficiency of the engine for a 2000 HP engine; this would be approximately 515 tons. TEST WORK COMPLETED ON THE STANDS DURING THE SEASON OF 1944-45: 1. Two engines were run, a V-1650-7 and an R-1830- 65. Thirty hours of testing were conducted on the V-1650-7 engine, while 50 hours of operation were ob- tained on the R-1830-65. 2. Details of the type of tests conducted are dis- cussed in Exhibit F of Appendix II. 3. Analysis and discussion of the test results will be available at a later date in a final report entitled, “Ladd Field Test Stand Results.” Fuel Volatility Flight Test Program Prepared by : W. J. Rusnack, Capt. A. C. Pozver Plant Laboratory A. PURPOSE: 1. To report on a conference held at Wright Field with representatives of aircraft engine manufacturers, aviation fuel industries, and the military services in re- gard to fuel volatility flight test work accomplished at Ladd Field, Alaska. B. FACTUAL DATA: I. A conference on fuel volatility flight test work was held in the Power Plant Laboratory, Wright Field, 28 March 1945 and was attended by the following: R. T. Agster Phillips Petroleum Company E. V. Albert Transcontinental and Western Air, Inc. Carl Blakely Pratt and Whitney Aircraft Division G. A. Bleyle Wright Aeronautical Corporation E. A. Droegemueller Pratt and Whitney Aircraft Division J. O. Eisinger Standard Oil Company of Indiana R. E. Ellis Standard Oil Development Company Sam Gibbons Wright Aeronautical Corporation C. O. Henneman Phillips Petroleum Company R. D. Kelly United Airlines L. A. McReynolds Phillips Petroleum Company R. A. Walker Transcontinental and Western Air, Inc. Eric Bloomfield, Lt., U.S.N.R. Bureau of Aeronautics M. K. McLeod,.Captain, A.C. Air Technical Service Command W. J. Rusnack, Captain, A.C. Air Technical Service Command R. E. Klein, 2nd Lt., A.C. Air Technical Service Command A. Hundere Air Technical Service Command 2. The fuel volatility flight test program is being con- ducted at Ladd Field, Alaska, by Phillips Petroleum Company on C-49K airplane and Transcontinental and Western Air, Inc., on C-46 airplane under Contracts W-33-038-ac-6628 and W-535-ac-35716, Special Service Order No. 3, Fiscal Year 1945, respectively. 94 5230 3. A summary of the data presented at the conference appears in Appendix A. 4. The test engineers from Transcontinental and West- ern Air, Inc., and Phillips Petroleum Company were re- called from Ladd Field to review the work accomplished on the airplanes so that definite plans could be made to most efficiently utilize the remainder of the test time at Ladd Field. 5. General discussion of the problem of volatility and the specific troubles encountered by the C-49K and C-46 airplanes took place, which led to the general opinion that one of the main factors affecting cold temperature oper- ation is the ability of the engine to distribute fuel evenly. 6. The problem of evaluating the effect of fuel volatility was discussed, but it was agreed that final conclusions and interpretation of results could not be justified until a complete analysis of all the test data was made, For further discussion of results see Appendix B. 7. After considerable discussion it was decided to con- tinue the program as originally set forth and pay parti- cular attention to special groups of fuels. An outline of this program is given in Appendix “C”. C. CONCLUSIONS: 1. Operation of the C-49K airplane is satisfactory on the heaviest of the test fuels down to —21 °F. at maximum power cruise conditions, and down to —6°F. at maxi- mum economy cruise power. 2. Operation of the C-46 airplane is satisfactory on the heaviest fuel down to 0°F. at approximately maximum economy cruise power. 3. Operation of the C-49K on V-7 fuel, which has a volatility approximately equal to AN-F-28 fuel, was sat- isfactory down to —2°F., which was the lowest tempera- ture at which it was run. Based on operation of the heaviest fuels, it would appear to he satisfactory down to approximately —40°F. 4. Operation of C-46 airplane on V-7 fuel with a volatility approximately equal to AN-F-28 fuel is satis- factory down to -\-2°F at which point engine misfire was obtained at approximately maximum economy cruise power. 5. Fuel volatility can cause improper engine opera- tion at low carburetor air temperatures. The minimum carburetor air temperature at which normal operation can be obtained on any given fuel at any given engine speed is primarily determined by the induction system design. 6. In order to obtain a valid analysis of the test data accurate determinations of the ASTM distillations of the test fuels should be made. D. RECOMMENDATIONS 1. It is recommended that fuel volatility flight test program be completed under conditions outlined in Appendix “C”, and that resulting data be analyzed with the object of establishing a correlation between fuel char- acteristics and actual engine performance. 2. It is recommended further that the Coordinating Research Council be requested to have its Aviation Fuels Division Exchange Group determine the ASTM distil- lation curves of the test fuels. Hamilton Standard Propeller Feathering Tests Prepared by: J. F. Schmidt, Capt., A. C. Propeller Laboratory A. PURPOSE 1. The purpose of the subject test is threefold and consists of the following: a. To test the special hydraulic fluid feathering system and determine its operating limits; b. To compare the feathering operation of the hy- draulic fluid feathering system to the present standard bleed back feathering system ; c. To investigate and determine any other means or installations that will possibly facilitate the feathering operation at low temperatures. B. FACTUAL DATA 1. A description of feathering systems that were in- stalled and tested on the various airplanes ‘is available in Appendix I. A complete record of all flights conducted and the test data obtained, along with paragraphs, are in- cluded in Appendix II; these data are arranged in sepa- rate tables for each airplane. The flight data are arranged in chronological order. 2. The following is a brief summary of the test results obtained on each airplane during the test period: a. B-29, Serial No. 42-65214. (1) At minus 22° F. all the feathering systems operated satisfactorily on the subject aircraft. (2) At minus 45°F. premature button operation was encountered on the hydraulic fluid systems used in conjunction with 1100 engine oil; this condition was also encountered on the standard systems using synthetic en- gine oil but not as frequently. It was noted at this tem- perature all propellers still fully feathered even though the feathering buttons had to be bumped to accomplish the operation. (3) At temperatures between minus 45°F. to minus 58°F. the hydraulic fluid systems used in con- junction with 1100 engine oil encountered difficulty. The distributor valve would shift during the feathering op- eration. This was undoubtedly caused by heavy and/or congealed 1100 engine oil on the outboard side of the 5230 95 dome piston. The standard system using synthetic engine oil still allowed the propeller to be fully feathered even though the feathering button had to be bumped several times during the operation. The standard system incor- porated with the Pesco 777 pump and utilizing synthetic engine oil still operated normally at the lowest tempera- tures enountered (See Appendix II, Table I—graph). It was noted that this system required more time to op- erate ; however, the operation was slow but steady at all temperatures encountered. (4) The synthetic oil has made it possible to feather at extreme temperatures, and where other sys- tems failed, beacuse it did not congeal and remain suffi- ciently fluid to be forced out of the dome gradually during the feathering operation. b. B-24J, Serial No. 44-41378. (1) The hydraulic fluid feathering system used in conjunction with the synthetic engine oil operated satisfactorily at all temperatures encountered and was a little faster than the standard systems used with synthetic engine oil. It may be said, however, that all four feathering systems were satisfactory down to minus 45°F. (2) The standard 1100 engine oil was then used in all four engines. It was noted that at minus 45 °F. none of the systems were satisfactory. The hydraulic feather- ing system would not feather the propeller due to con- gealed 1100 oil in the propeller dome. Likewise, the standard systems were sluggish and only in one case did the propeller feather and that required considerable man- ipulation of the feathering button and required 23 seconds to accomplish the feathering operation. The distributor valve shifted with all other propellers and the results were unsatisfactory (see Appendix II, Table 2, baragraph). (3) It is noted that synthetic oil is a merit and makes it possible to feather propellers at low tempera- tures since it does not tend to congeal. c. B-17G, Serial No. 43-38221. (1) The hydraulic fluid feathering system used in conjunction with regular 1100 engine oil operated satisfactorily down to minus 45 °F. At temperatures be- tween minus 45 to minus 55°F., the operation is question- able and requires much manipulation of the feathering button and occasionally the distributor valve shifts to the unfeathering position. At temperatures below minus 55°F, and down to minus 65°F., the subject system used with 1100 engine oil is definitely unsatisfactory. (2) The standard feathering systems used with synthetic oil were found to be operable at extreme low temperatures although the operating times are longer than normal. The feathering operation may be described as steady but somewhat slow from minus 45 to minus 65°F. (3) A new type pump (IE-521 EC) was instal- led on Engine No. 1 and operated with synthetic engine oil. It operated satisfactorily; however, it could not be relied upon. On several occasions this system using the new pump would reduce the rpm but then the rpm would gradually increase and in this way establish a wandering condition. Actually, more testing is necessary before this particular type pump is stated as satisfactory or unsat- isfactory. At present, however, it is not considered an improvement in the feathering operation on this aircraft. (See Appendix II, Table 3, baragraph). (4) It is to be noted that the greatest improve- ment in propeller feathering is contributed to the syn- thetic oil which did not congeal at extreme low tempera- tures and made it possible to feather the propeller. d. C-47A, Serial No. 43-48088. (1) The hydraulic fluid system used in conjunc- intion with 1100 engine oil was considered to give satis- Sludge deposited in propeller dome from synthetic engine oil factory operation at the temperatures encountered. The lowest temperature was minus 49°F. On one occasion, (minus 33°F.) the propeller could not be fully feathered; this was apparently due to stiff or thick 1100 engine oil in the propeller dome. (2) The standard system used with synthetic engine oil showed that it was possible to feather fully the propeller at temperatures down to minus 52°F. On sev- eral occasions the propeller could not be feathered and it appeared as though the pump was starved or possibly airlocked. It was later noted that the feathering pump had a 34 inch air bleed line connected to the high pressure side of the pump relief valve. It is believed that this bleed line was a source of leakage when the feathering pump operated and thus caused the several unsuccessful feather- ing operations encountered. (3) A new type Pesco, IE-521-EC pump was installed on the standard system. This pump was tested in several different ways to determine its operating abilities. (a) It was first tried in conjunction with standard 1100 engine oil. This test showed that excessive trials were required to feather the propeller at compara- tively moderate temperatures (minus 31°F.). (b) In the second test the previously men- tioned air bleed line was connected between the intake side of the subject pump and the main engine oil “in” line. This line served to bleed air from the system and to furnish some oil to the pump when the feathering reserve oil becomes thick. The test showed that the system was improved but still rather sluggish at minus 40 degrees. (c) The third test was made by changing from the 1100 engine oil to the synthetic engine oil. This proved satisfactory at the temperatures encountered; however, in one instance the new type pump showed very slow and indifferent operation even though the tempera- ture was reasonably high (plus 12°F.). (4) It is noted that the synthetic engine oil tends to assist the feathering operation. The new type pump IE-521-EC is not considered satisfactory until the slow or indifferent operation can be eliminated. (5) At the beginning of the test period, elec- trical difficulty was encountered. The generator fuses were blown out during the feathering operations. This 96 5230 difficulty is presented in a separate report, listed in Ap- pendix III, References. c. C-54B, Serial No. 43-17157. (1) The hydraulic fluid system used in conjunc- tion with 1100 engine oil is considered satisfactory down to minus 45°F. Feathering operation below this tem- perature is definitely handicapped because of thick and/or congealed oil in the propeller dome. Operations below minus 45°F. are definitely unsatisfactory. (2) The standard feathering system on this aircraft may be considered satisfactory down to minus 40°F. Temperatures below this cause questionable op- eration and may be considered wholly unsatisfactory below minus 45°F. (3) It is obvious from the test data on this air- craft that hydraulic fluid is not the “cure” for low tem- perature feathering operation when used in conjunction with 1100 engine oil. f. A-26B. This aircraft; was not tested at extreme low tem- peratures since it was not equipped with oxygen facil- ities. The systems, both hydraulic and standard, were satisfactory at the temperatures encountered, which were considered moderate. The electrical loads were checked during the feathering operations and were not found to be excessive on the two engined aircraft. (See Appendix IV, References). g. C-47, ATC Aircraft. Considerable sludge was found in the dome and piston assemblies of several aircraft propellers. This condition was more noticeable on engines operating with synthetic oil. A report was submited on the 5th of De- cember 1944 entitled, “Hamilton Standard Propeller Sludge Conditions”. 5. The new type Pesco feathering pump, model E-777 operated satisfactorily although it appeared to require more time to complete the feathering operation than the standard Pesco 301 pump. The E-777 pump shows pos- Hydraulic propeller feathering tank mounted in bomb bay of B-24 airplane 5230 97 sibilities when used with synthetic engine oil or possibly with some lighter oil. 6. The Pesco pump, model IE-521-EC gave ques- tionable operation and was not considered a merit to the feathering operations. Further investigation is necessary to determine its possibilities. 7. It is concluded that more careful inspections and cleaning operations should be conducted on the Hamilton Standard Propeller dome and piston assemblies during each 100-hour aircraft inspection. This is definitely a necessity in arctic regions of operation to avoid exces- sive amounts of hard sludge in the propeller dome assem- blies in that this condition causes feathering malfunction. D. RECOMMENDATIONS The recommendations stated below have been derived from the flight tests and observations concerning the arctic propeller feathering program during the cold weather test period of 1944-45 in Alaska. 1. It is recommended that synthetic engine oil be used in all multi-engined aircraft for arctic operation whether in conjunction with the separate hydraulic fluid feathering system or the standard bleed back feathering system, as this synthetic oil facilitates and assists the propeller feathering operation due to its lack of congeal- ing in the propeller dome and hub assemblies. 2. If the above recommendations should be approved by the Propeller Laboratory, Power Plant Laboratory and the Materials Laboratory, it is furthur recommend- ed that the propeller dome and piston assembly be cleaned during each 100-hour aircraft inspection, in accordance with existing T.O. No. AN-03-20CC-1 to prevent the formation of sludge in the dome, or oftener if excessive sludge deposits are encountered. 3. It is recommended that the new type Pesco pump model E-777 be further service tested to determine its possible merits. 4. It is recommended that on the C-47A aircraft, the feathering pump intake line be relocated at the main oil tank end. The new location should be made at the bottom of the main oil tank beneath the hopper and utilizing the modified sump with increased stand pipe. This was rec- ommended after the cold weather test period of 1943-44 and if this change has been incorporated, the above need not be heeded. C. CONCLUSIONS The following conclusions were made after the com- pletion of the arctic feathering test program conducted during the cold weather test period of 1944-45 in Alaska. The conclusions are based on low temperature operation only: 1. The standard bleed back feathering system used with 1100 engine oil is not satisfactory at temperatures below minus 40 degrees F. 2. The separate hydraulic fluid feathering system, whether centralized or independent, when used in con- junction with 1100 engine oil, is only satisfactory down to minus 45°F. The feathering operation tends to be limited by the viscosity of the 1100 engine oil in the propeller dome and hub assembly which congeals when soaked at minus 45 °F. or at lower temperature. This conclusion is based on low temperature operation only and emphasizes the problem of heavy or congealed 1100 engine oil in the propeller hub and dome assemblies at extreme low temperatures. 3. The standard bleed back feathering system, when used in conjunction with synthetic engine oil (Spec. PPO-265) is considered satisfactory down to minus 65°F. The feathering operation below minus 45°F. is generally slower than normal; however, the feathering operation is complete since the synthetic oil still flows under the subject operating conditions. The viscosity of the synthetic oil at low “operating” temperatures is not excessive and this oil can be forced out of the dome during the feathering operation. 4. The separate hydraulic fluid feathering system, when used in conjunction with synthetic engine oil, is considered satisfactory down to minus 65°F. At tem- peratures below minus 45°F. the time required to feather was greater than normal; however, the feathering cycle could be completed. The nature of the synthetic oil at extreme low “operating” temperatures is such that it cannot be “rushed” but insists on a gradual flow regard- less of the fluid medium used in the feathering pump. On this basis the separate hydraulic fluid feathering system, although satisfactory, is not deemed necessary for arctic operation since the feathering operation can be accom- plished with the standard bleed back system when used in conjunction with the synthetic engine oil. In the event, due to factors not considered in this report, that the sepa- rate hydraulic fluid feathering system is used as a stan- dard installation on production aircraft the synthetic en- gine oil should be used in the engines for arctic operation. 5. When the engine oil system (bleed back feather- ing system) is used it is recommended that dilution lines be installed in the intake line to the feathering pump as close as possible to the main oil tank sump. This should be accomplished when the bleed back feathering system is used with 1100 engine oil or synthetic engine oil. By thorough dilution of the feathering line, the oil will not tend to congeal in the line when the aircraft remains out- side under extreme low temperature conditions. This will facilitate rapid bleed back operation when the engine is started before flight. This installation is recommended on all multi-engine aircraft operating in the arctic regions. 6. The following recommendations are listed for pos- sible consideration regarding the propeller feather prob- lem : a. The hot air propeller deicing installation now being tested may be utilized to keep the propeller hub and dome reasonably warm and prevent the congealing of regular engine oil at low temperatures. If this were pos- sible the propeller icing problem and the feathering prob- lem may be eliminated with one system. b. Another possible way of eliminating the feath- ering problem may be to use reverse cams in the dome piston, thus moving the piston away from the congealed mass of oil when feathering, instead of the present con- dition where this mass must be forced out to fully feather. 98 5230 Final Report on the Aeroproducts A532FX6 Propeller Prepared by: Hoyt B. Graham, Jr., 1st Lt., A. C. Propeller Laboratory A. PURPOSE 1. To service test the A532FX6 propeller and study maintenance difficulties. 2. To test various oils and greases and determine the minimum temperature at which each would operate satisfactorily. B. FACTUAL DATA 1. Number of hours to date on installation—200. Mechanical troubles encountered: a. Weak spring in ball check valve. In three feathering valves there were one heavy spring and two light springs. To date only one of the latter is known to have failed. First, when the pro- peller accumulator failed to charge, it was found that the ball had slipped through the inside of the spring. This spring was repaired and re-installed. During a later disassembly it was found that four turns of the spring on the end next to the ball had compressed it beyond its elastic limit. b. Nitrogen leakage. At first the accumulator always lost some nitrogen when the accumulator was on the ship and sometimes leaked when the accumulator was in the shop. After the last installation (5 March) no nitrogren leakage was observed. Leakage was attributed to three things: (1) Nitrogren filler valve—the original valve assembly was not winterized. To be specific, a brass seat in the valve cap is not satisfactory. It should be synthetic rubber. (2) Etching of accumulator. Etching occurred wherever an “o-ring” seal (AN-6227-46) made contact with bare steel. For more details see paragraphs 6(c), 6 (d), and 23(b) of refer- ence 2 and also pictures in reference 3. The Materials Laboratory of Wright Field will conduct further investi- gation of the seals used and determine if the seals were at fault. (3) Normal operation of accumulator. During the feathering cycle some nitrogen seerped to leak past the piston seal. c. Oil and grease leakage. The two seals (AN6230-23) on the outside of the accumulator practically always leaked. It was very difficult to install the accumulator and it was by chance if these two seals were not damaged. It was noted that even if the -seals were not damaged, propeller oil was usually found in the hub. See reference 4, paragraph 5(g)- d. Difficulty in tripping feathering valve. This was encountered only when the propeller was stationary, as was the case on the ground or when un feathering in flight. This condition was made worse by the control installation but the root of the trouble was in the propeller itself. To try to correct the trouble, leaves were removed from the trigger spring on the feathering valve but no appreciable difference was noted between three leaves and one leaf installations. e. Loosening of Regulator Nut. In two instances the regulator nut worked loose while in service. A two-foot bar and heavy hammer were used to tighten the nut but neither the bar nor hammer was necessary to remove the nut during dis- assembly. f. Propeller overspeeding when unfeathering. On several occasions the propeller was completely out of control at 2700 to 3000 rpm, sometimes momen- tarily and once for 20 to 30 seconds at 2900 rpm. The take-off setting for this installation was 2500 rpm, The governor was thought to be the trouble but careful inspection failed to support that theory. To date the cause is still not known. For details on overspeeding, see reference 2, paragraph 5(a), and reference 4, paragraphs, 3(b), 6(c), and 6(d). g. Windmilling. At the beginning of the test season it was noticed that in feathering, the propeller would sometimes start to feather normally, windmill at 100 to 200 rpm, stop sud- denly, and then back up part of a revolution. At the end of the test season when the spare propeller was installed, this same condition was again encountered. No satis- factory explanation is known. h. Feathering twice on one accumulator charge. Several attempts were made on a flight (14 March) to feather, unfeather, and feather again immedi- ately. The idea was to conserve oil in the accumulator by using the governor down to about 400 rmp. The ex- periment was partly successful but was hardly practi- cable even for practice feathering. See reference 4, paragraph 11. i. When the feathering valve failed, it was found that the propeller could be feathered by means of the pump and governor. If the engine power was kept on and the mixture not cut off until the rpm was around 400 or 500 rpm, the propeller could be feathered in about 50 seconds. Without power—that is, cutting off the throttle and mixture and then reducing the rpm—the time re- quired was doubled and sometimes the propeller would not feather at all but windmilled at 100 rpm. 2. DATA ON OPERATION: a. Ordinarily the propeller feathered in 2.5 to 5 seconds. As the low temperature limit for any oil was approached, the time went to about 8 or 9 seconds. When an oil got too stiff, the time jumped up to 75 to 120 seconds, if it feathered at all. Mechanical malfunctions would, of course, affect the feathering time but only a few readings were obtained between 15 and 75 seconds. Since there were practically no “in-between” readings, it was not difficult to determine if an oil was satisfactory or not. 5230 99 b. Data on oils and greases : (1) ANG-4 and AN03L—satisfactory down to minus 25°C. (—13°F.) (2) ANG4 and AN06a—satisfactory down to minus 45°C. (—49°F.) (3) ANG4and AN-VVO-366a—ground checks indicated that this combination would operate at a lower' temperature than oils previously used. Due to mechanical trouble with the propeller, flight checks proved nothing. See ANG3 and AN-VVO-366a. Also see reference 2, paragraph 22 and reference 4, paragraph 3. (4) ANG3 and AN-VVO-366a—the minimum temperature for this combination is not known but it operated satisfactorily down to minus 57°C. (—70°F.) See reference 4, paragraphs 6 and 9 for detailed data. C. CONCLUSIONS 1. During the 1944-45 Cold Weather Test season, the following conclusions were reached regarding the operation of the A532FX6 propeller when the proper oil was used: a. Governing action was faster and more sensitive than other standard installations. b. Feathering operation was faster than other standard installations. c. The propeller was a self-contained unit and did not depend on the rest of the airplane for oil supply or electrical power. d. Installation, removal, and repairs on the pro- pellers were simplified. Only two special wrenches were required. e. Operation of the feathering system did not prove dependable because of : (1) Windmilling at 100 to 200 rpm when feathering; (2) Overspeeding when unfeathering; (3) Accumulator leakage. This was chiefly oil leakage and occurred during operation of propeller in flight. /. The FX6 had the disadvantage that two minutes time was necessary for charging the accumulator. See reference 4 paragraph 11. In case of emergency, the propeller could not be feathered if one feathering cycle had just been completed. 2. Conclusions reached concerning oils and greases: a. No conclusion was reached as to the relative merits of ANG3 and ANG4. b. AN-VVO-366a operated satisfactorily between plus 32°F. and minus 70°F. c. AN-03L operated satisfactorily between plus 32°F. and minus 13°F. d. AN-06a operated satisfactorily between plus 32°F. and minus 49°F. D. RECOMMENDATIONS 1. The Propeller Laborattory should make further service tests on later model Aeroproducts feathering propellers with emphasis on solving problems of: a. Seal leagage; b. Overspeeding when unfeathering; c. Windmilling when feathering; d. Difficulty in tripping feathering valve. 2. In future tests, more positive propeller control linkage should be used. 3. The accumulator should be charged so that at the coldest temperature anticipated in flight there would be a minimum nitrogen pressure of 400 psi (400 psi at minus 65 °F. would be about 450 psi at 0° and 480 psi at plus 60°F.) 4. Oils to be used : a. Above 0°F. use AN03L; b. Below 0°F. use AN-VVO-366a or AN-VVO- 366b. Report on the Curtiss Electric Propeller Equipment Prepared by. J. F. Schmidt, Capt., A. C. Propeller Laboratory A. PURPOSE 1. To conduct a service test with special Curtiss propeller installations on the subject airplanes, recording any malfunctions or equipment failures. B. FACTUAL DATA 1. Summary of tests on P-38L aircraft, serial No. 44-24050. a. The special propeller installations on the sub- ject airplane were completed on or about 23 September 1944. The hours of operation, at this time, were 16 hours and, 40 minutes. The airplane arrived at Ladd Field, Alaska, on 2 December 1944 and had accumulated 46 hours and 15 minutes of operation. On 1 March 1945 the tests on the ship were considered completed antf the operating time was 157 hours and 17 minutes. The special installations concerning the propellers will remain on the airplane until it is delivered to Wright Field, at which time the service test iaems will be removed and forwarded to the Curtiss Propeller Plant for inspection. b. A complete description of all propeller installa- tions on the aircraft is furnished in Appendix I, Table I. c. The maintenance required on this airplane throughout the test season is discussed and listed chrono- logically m Appendix 2, Table I. „ jf- The propeller controls, utilizing the Teleflex push pull control installation did not require any special maintenance on this aircraft during the test period. Several loads are shown at various temperatures in Ap- pendix III, Table I. V 100 5230 2. Summary of tests on P-61B aircraft, Serial No. 42-39402. a. The special propeller installations were accom- plished at Vandalia, Ohio, and at this time the airplane had 29 hours of operation. The aircraft was then re- turned to the plant for further installation at which time the Simmonds Aerocessories propeller control was installed on Engine No. 1. The airplane arrived at Ladd Field, Alaska, on 7 December 1944 and had acquired 60 hours of operation. On 23 February 1945 the tests were closed-out on this aircraft due to a crash. The total time of operation on this ship was 120 hours and 45 minutes. The service test equipment on the aircraft will not be available for inspection. b. A complete description of all propeller installa- tions on this ship are shown in Appendix I, Table 2. c. The maintenance required on the subject air- craft during the test period is included chronologically in Appendix II, Table 2. It is worth noting that the major portion of maintenance was due to grease leakage from the propeller blade nut seals. d. A comparison of the Simmonds propeller con- trol and the standard pulley-cable installation is shown in Appendix III, Table 2. This type of Simmonds con- trol with the 180 degree radian head required no main- tenance whatsoever during this test season. C. CONCLUSIONS 1. It is concluded that the following equipment and lubricants gave satisfactory operation on the P-38L and the P-61B aircraft during the test period of 1944-45: a. Governor Installations. The two types of governors, namely, the standard governor with the stainless steel rack and pinion and the lubricated cap type governor gave satisfactory operation. b. Lubricants (1) The ANG-3 and ANG-4 greases were sat- isfactory and did not interfere with the operation of the propellers. (2) The AN04 oil and the AN-VVO-366 hydraulic fluid contributed to the satisfactory operation of the speed reducer units. c. Relief Fittings The grease relief fittings were satisfactory and did not show any signs of “grease throwing” from operation. d. Seals The shaft nut seal and shaft seal gave efficient sealing throughout all operations. e. Electrical Modifications The moulded connector plugs and the straight through brush block terminal connections did not fail or cause any difficulties. f. Propeller Controls (1) The Teleflex push pull controls installed between the firewall and governor operated satisfactorily on the P-38L, and are considered comparable to the standard pulley and cable type controls. (2) The Simmonds Aerocessories push-pull controls are considered superior to the standard pulley cable type of control on the P-61B aircraft. 2. It is concluded that the following seal installations are not considered satisfactory: a. The blade nut seals used on the P-61B propeller assemblies showed definite indication of grease leakage during operation at temperatures below minus 40° F. b. The blade nut seals and the blade shank seals used on the P-38L propeller assemblies are questionable since some grease leakage was experienced. The blade shank seal is considered to be the most probable source of leakage. c. The speed reducer spline and housing seals on the P-38L showed signs of wear after approximately 100 hours of operation. This is not necessarily a cold weather problem; however, these seals should be improved before used as standard part installations. 3. The above conclusions are based on the operation of the subject installations and equipment during the cold weather test period. D. RECOMMENDATIONS 1. The following are the recommendations concern- ing the special propeller installations on the P-38L and the P-61B aircraft; a. The stainless steel rack and pinion should be further tested and possibly incorporated as a standard governor part. The lubricated cap type governor, although satisfactory, does not merit change since this involves a change in the governor body and in the long run accomplishes the same result as the stainless steel parts mentioned above. b. The ANG-3 grease should be continued as the hub lubricant, since it is a standardized low temperature grease in frequent use on aircraft. c. The speed reducer lubricant, namely AN04 oil, is satisfactory and should be used. It is worthwhile noting at this point, however, that the Materials Labora- tory is considering AN06a oil as a superior low tempera- ture oil with improved lubricating qualities. d. The speed reducer grease relief fitting is recom- mended as a standard part. e. The shaft nut seal and shaft seal are recom- mended as satisfactory for cold weather operation. /. Continued service tests should be conducted on the moulded connector plugs and straight through type brush block terminal connections. g. The Teleflex control should be further service tested at extreme temperatures and an improved method of anchoring the conduit to the swivel connection is rec- ommended. (For more details on this control see Report on Teleflex Operation and Maintenance during Cold Weather Test Period of 1944-45.) h. The Simmonds Aerocessories control is recom- mended for use on the P-61B and later models of this aircraft. i. The blade nut seals and blade shank seals should be improved and more extreme temperatures tests con- ducted. The grease leakage problem still exists at low temperatures. 5230 101 Cold Weather Tests on Teleflex Controls Prepared by: H. B. Graham, Jr., 1st Lt:, A. C. Propeller Laboratory A. PURPOSE 1. To test Teleflex propeller control installations on the P-38L and B-17G under cold weather operations. 2. To test the effect of temperature and compare two different lubricants in two identical Teleflex controls mounted in a panel. Pictures in Appendix III. B. FACTUAL DATA 1. P-38L, AAF Serial No. 44-24050. a. Hours on installation at time of report—136. b. Maximum loads to operate controls—12-lb, average at —43°C (—45°F) after soaking all night. For complete data see Appendix I. c. Maintenance troubles—At 100-hour inspection (86 hours on Teleflex) found conduit had slipped part way out of split nut in swivel coupling, at forward end of left engine installation. Also found chaffing between conduit and support clamps. See pictures Appendix III. 2. B-17G, AAF Serial No. 43-38221. a. Hours on installation at time of report—175. b. Loads encountered—Varied irregardless of temperature. Minimum: 6 lb., maximum; about 30 lb. See Appendix II. c. Maintenance troubles—Mainly ends of conduit slipping out of split nut. See Appendix II. 3. Teleflex test set-up on panel: a. Length of test: 12-5-44 to 2-21-45. b. Specimen No. 1 lubricated with Aero Mobil- grease LO-H1 PD 535A, (Spec. ANG3). Complete data and charts in Appendix HI, With a five pound weight on one end it took about 12%-lh. shot on the other end to operate the control. The load for the first try each morning was very little different from the daily average for three other tries. The load curve was practically flat down to —35°C (—31°F). Below that temperature it showed signs of increasing. Lowest temperature ob- served was —-40°F. c. Specimen No. 2 was lubricated with Standard Oil Company of Indiana SG-4455, also manufactured in accordance with Spec. ANG3. No, 2 had the same gen- eral characteristics as No. 1. It took slightly more load to operate (about 14*4 lbs. on the flat part of the curve). Temperature variations had more effect on this control than on No, 1. C. CONCLUSIONS 1. P-38L: a. Operation—satisfactory, but no improvement over standard system. h. Installation—probably lighter in weight. Should be considerably easier to install under factory set-up, c. Maintenance and safety—method of fastening ends of conduit is definitely unsatisfactory. 2. B-17G: a. Operation—unsatisfactory. h. Installation—Should be easier in production. c. Maintenance and safety—method of fastening ends of conduit unsatisfactory and not safe. See Appendix II for chronological record of troubles encountered. 3. Test Panel No. 2 was harder to operate, especially at low temperatures. D. RECOMMENDATIONS 1. Use AN-742 “cushion” type clamp for conduit support. 2. Flare ends of conduit so that clamp nut can get positive grip on conduit. 3. On future tests install Teleflex 100% and not in connection with other experimental equipment, as with the propeller on the B-17. 4. Obtain spare parts and keep them with the ship. 5. Regarding test panel—switch lubricants to see if differences noted were due to lubricants or to the controls. 6. Future tests with other than actual aircraft in- stallations should be made under controlled atmospheric conditions. 102 5230 Cold Weather Tests on Eclipse Electric Governor Control Heads Prepared by: J. F. Schmidt, Capt., A. C. Propeller Laboratory A. PURPOSE 1. During the winter of 1944-45 it was desired to : a. Check the operation of the electric governor control heads on standard aircraft installations. b. Check the operation of subject heads on ground “mock-up” installations at various temperatures. c. Record any service difficulties encountered on B-29’s and B-24’s using this equipment. B. FACTUAL DATA 1. Electric head-test information obtained from four different aircraft; namely B-24J, Serial No. 44-41378 (See Appendix I, Table I) B-24J, Serial No. 42-51660 (See Appendix I, Table H) B-29, Serial No. 42-24612 (See Appendix I, Table III) B-29, Serial No. 42-65214 (See Appendix I, Table IV) a. The test data as shown in the Appendix shows that in most cases the operating time tends to increase as the temperature decreases. There are exceptions, but these are usually due to part failures in the unit. b. In one instance, on the B-29 (214), when the heads soaked at temperatures below -40° F., two of the electric heads became inoperative; however, after heat was applied, they were normal. This is the most critical example encountered throughout the winter. c. The following information was obtained on the No. 3 electric head of the B-29. (1) At -14°F. it required 12.9 seconds to oper- ate from Inc. to Dec. RPM position. (2) At -45°F. it stuck and would not operate until heat was applied. (3) This is by no means general hut is a specific case showing the effect of temperature on operation in this particular incident. d. It may also be noted from the test data in the Appendix that operating times on four electric heads installed on one aircraft tend to vary. This necessitates setting the RPM on each control separately. 2. Electric head test data obtained from the ground “mock-up” installations can be observed under the Ap- pendix ; namely: Head Serial No. B.A. 5338, Appendix II, Table V Head Serial No. B.A. 17992, Appendix HI, Table VI Head Serial No. A.F. 43-34351, Appendix IV, Table VII Head Serial No. A.F. 43-34353, Appendix V, Table VIII a. The electric head and governor assemblies were mounted on a test board and set outside for the winter test. A switch and indicator light were used in the elec- trical circuit. The operating time was obtained by a stop watch. The power was furnished by a Waukesha power unit and the operating voltage was maintained at 28 volts. The procedure was to turn on the switch, start- ing from the Inc. RPM position, and start the stop watch. When the indicator light went on, showing that the electric head had reached full low RPM position, the watch was stopped and the time recorded. A series of these readings were recorded throughout the test season. b. It is interesting to note that the subject heads were operated daily and no malfunction, mechanically speaking, was encountered. On the other hand, electric heads installed on aircraft encountered numerous fail- ures. This tends to show that electric head failures are in practically all cases due to the engine vibration and not due to the unit itself. c. The operating times tend to increase as the temperatures decrease, and in one case, the time required was above the maximum limit of 20 seconds. The soaking periods were generally 24 hours. d. The following tabulation is set up to show the operating times against decrease in ground temperatures after soaking for at least 24 hours at temperatures from -j-30°F. to that indicated. The times recorded on this sheet are the first readings after the soaking period. Time Required From Inc. to Dec. RPM Position On Temp. °F. Head Nn. 1 Head No. 2 Head No. 4 Head No. 3 + 36 11.4 13.4 + 32 12.5 13.1 13.9 + 30 12.5 13.9 13.8 + 28 14.2 14.3 13.7 + 23 14.6 13.3 + 22 15 + 15.3 15.5 + 21 12.2 15.7 + 17 13.7 13.8 + 16 15.8 14.3 13.8 + 14 11.6 14.2 13.7 + 10 12.4 16.0 14.9 14.0 + 9 14.8 14.0 + 8 19.3 + 7 14.5 13.9 + 3 12.5 18.6 + 2 14.5 14.0 + 1 17.9 0 — 1 — 4 — 5 12.1 12.8 19.0 ' 21.1 13.9 — 6 19.1 16.5 14.5 — 8 —10 —11 —12 —13 —22 12.8 13.8 20.0 22.4 23.7 23.1 —23 17.2 15.8 14.7 —31 14.4 14.1 14.0 —33 12.6 13.7 13.8 The above values are averages obtained at the various indicated tem- peratures. 3. Service difficulties encountered on electric control heads during the test season : a. The failures experienced were numerous and in most instances were either due to resitors, resistor clips, and/or open armatures. 5230 103 b. In Appendix III of this report, reference is made to service reports which were forwarded to the laboratory during the test season. C. CONCLUSIONS 1. The electrical control head operation is considered satisfactory at temperatures as low as -40°F. 2. No conclusions have been reached on the operation of subject control heads at temperatures below -40°F. and as low as -65°F. since sufficient data is not available, 3. From the maintenance standpoint, the electric head controls are unsatisfactory since the part failures are entirely too numerous. 4. These conclusions are based on tests, observations, and maintenance problems experienced during the cold- weather test period of 1944-45. D. RECOMMENDATIONS 1. In order to reduce the maintenance problems on electric head controls, it is recommended that: a. The resistor and resistor clip be eliminated from the assembly. b. The armatures be more thoroughly inspected for “opens” before assembly at the plant. 2. More tests be conducted at temperatures below -40°F. and down to -65°F. to determine effects on oper- ating characteristics. Report on the Electric Anti-Icing Generators Installed on the C-54B Prepared by.J.FSchmidt,Capt.,A.CPropeller Laboratory 1. The purpose of this report is to present the Labor- atory with the problems encountered on the subject anti- icing equipment. 2. The problems and difficulties encountered up to 15 February 1945 were included in the previous progress report dated 23 February 1945. It is now desired to present the problems which were experienced since then. 3. On 23 February 1945, the cracked shield was re- moved from the No. 3 Generator, Serial No. D-35 and a new one installed. The spare generators were received on the previous day. The reinforcement ring was also installed with the new armature shield in order to prevent the new shield from being cracked at the bolt holes. (The accumulated operating time on the generator was 239 hours and 55 minutes.) 4. On 27 February 1945 the generators on No. 1 and No. 2 engines were again checked: a. Prop No. 1. Generator Serial No. D-46, the following was noted; (1) The lead between the fire wall and the field cannon plug showed a short circuit condition. It was found that the wire had worn and was grounding out through the metal conduct. This lead was removed and repaired. (2) One armature cannon plug had failed. The prongs in the male portion of the plugs were broken off. This was replaced with a new cannon plug. b. Prop No. 2, Generator Serial No. D-45, the following was noted: (1) During runup the indicator warning light blinked and the prop generator was thoroughly in- spected. It was found that the field ground connection had failed. This was a soldered connection and apparent- ly vibration caused the failure. The break was repaired and the propeller generator then worked satisfactorily. 5. On the 4th of March, 1945, the operating time on the generators was 244 hours and 35 minutes. It was reported that the warning indicator lights on No. 1, 2, and 4 were blinking during operation. An inspection was conducted and the following was noted: a. Prop No. 1, Generator Serial No. D-46. (1) The armature showed on “open” in one plug. The solder connection at the receptacle was broken. (2) The lead connecting the blade element to the armature showed a break or open. h. Prop No. 2, Generator Serial No. D-45. The generator checked out satisfactorily accord- ing to the continuity meter. The indicator warning light, however, still blinked when the engine was operating and the deicer switch was turned on. There was probably an open which only shows up when the engine is oper- ating. c. Prop No. 3, Generator Serial No. D-35. The generator checked out satisfactorily. d. Prop No. 4, Serial No. D-30. One armature plug showed an open. The soldered connection at the receptacle was broken. 6. At this time, the aircraft was scheduled to leave this field and the deicers could not be repaired. The elements on these propellers were coated with some anti- icing compound No. 314 as a temporary means of ice protection. When the ship returns to this post again, it is planned to remove the electrical deicers and install the standard alcohol system. 7. The service test conducted on the subject instal- lation during the OUT period of 1944-45 indicates that the electric generator deicers are not satisfactory from the maintenance standpoint. It is the opinion of this detachment that the generators should be more carefully manufactured and rigid inspections should be stressed on the final assembly stage. 8. It was noted that the resistance of the blade ele- ments have remained approximately the same through the entire test period. The resistance of the elements ranges from 4.5 ohms to 5.0 ohms on all elements in- stalled. 9. No actual icing tests have been conducted on the subject equipment during this test period, however, the problem of maintaining these units is evident. 104 5230 Service Tests of Experimental Oil and Coolant Hose Installed with Aeroseal Type Clamps Prepared by: T. F. Brick, 1st Lt., A. C. Materials Laboratory A. PURPOSE 1. To determine the performance characteristics of experimental fuel, oil and coolant hose at extreme low temperatures. B. FACTUAL DATA 1. Due to difficulties encountered on premature fail- ures of fuel, oil and coolant hose line connections in cold weather, winterization service tests were conducted on numerous aircraft at Ladd Field, Fairbanks, Alaska, during January and February, 1945. Data were collected on various manufacturer’s experimental hose to deter- mine bulging and hardening properties, leakage periods and loss of clamp torque with relationship to “cold flow”. Numerous cold starts were attempted in an effort to re- cord the ability of the hose to withstand high surge pres- sure incident without bursting or blowing from the con- nection. Additional tests were conducted on methods of hose installation to facilitate ease of application at low temperatures. 2. Previous data accumulated in laboratory tests and Unsatisfactory Reports received by Air Technical Serv- ice Command show the above deficiencies are encounter- ed at temperature limits below 20°F. 3. The discussion under Appendix I outlines the completed service tests. 4. Torque data of all hose tested on fuel, oil and cool- ant lines, together with the type aircraft used are graphic- ally presented in Appendix II, Figures 1 to 8. 5. Photographic presentation of various installa- tions maybe found in Appendix III, Figures 1 to 11. 6. Photographic evidence of abnormal “cold flow” in specification coolant hose is shown in Appendix IV, Figure 1. 7. Temperature data for the period January and February, 1945, are found in Appendix V, Figures 1 and 2. C. CONCLUSIONS 1. All test hose used on the oil lines, with the excep- tion of S-l, S-2 and H-3, which leaked, adequately sur- vived the service test. 2. All test hose used on the oil lines will perform satisfactorily at extreme low temperatures. 3. All test hose used on coolant lines with the excep- tion of R-80, 3-braid, which leaked prior to twenty-five (25) hours of engine time and which leaked excessively at —43°F., is satisfactory for use in extreme low tem- peratures. 4. All test hose performs more satisfactorily than specification hose inasmuch as less clamp torquing is re- quired and little or no leakage is observed. 5. Adhesion of braided construction to the tube should be improved on coverless hose, 6. “Cold flow” is still a factor with which to contend, although it is less severe on test hose than on specifica- tion hose. 7. All hose hardens considerably at temperatures be- low 20° F. 8. Improper methods of installation and excessive clamp torque can be a contributing factor toward pre- mature failure of hose. D. RECOMMENDATIONS 1. The Materials Laboratory (TSEAL-4) will take the following action; a. Continue service testing experimental hose with the objective toward obtaining a satisfactory all pur- pose hose to serve in the fuel, oil and coolant lines of Army Air Forces aircraft, b. Acquaint all interested rubber companiees with the problems covered by this and previous reports so that additional laboratory work may be continued on the methods of best eliminating the “cold flow” and fraying characteristics of coverless type hose. Appendix I Service test installations were made on fuel, oil and coolant lines of Cold Weather Testing Detachment and Extreme Temperature Operations Unit aircraft based at Ladd Field, Fairbanks, Alaska. The types of hose used are as follows: a. Goodyear R-8 Cotton braid, neoprene tube and cover b. Goodyear R-5 Rayon braid, neoprene tube and cover c. Goodyear R-50 Rayon braid, neoprene tube, no cover d. Goodyear R-80 2 and 3 cotton braids, neo- prene tube, no cover 5230 105 e. Goodrich H-40 Rayon braid, buna tube, no cover /. Goodrich H-30 Cotton braid, buna tube, no cover g. Goodrich H-30N Cotton braid, buna tube and cover h. Goodrich H-4 Rayon braid, buna tube and cover i. Goodrich H-3 Cotton braid, buna tube and cover Hewitt T-4 Rayon braid, neoprene tube and cover k. Goodyear R-l Specification AN-ZZ-H-456- A, Cotton braid, buna N tube and cover /. U. S. Rubber Co. S-l and S-2, Specification AN-H-26, cotton braid and neoprene tub and cover. All aeroseal type hose clamps were torqued to values in- dicated in graphs with a “Skyway Torque Control Wrench”, which is designed to tighten to a specific amount and then cut out. Wrenches of twenty-five (25) and twenty (20) inch pounds were used during the test- ing period. The correct procedure for clamp torque was considered important, as many hose failures can be traced to improper determination of clamp torque values due to the fact that wrenches of the above mentioned type have not been provided—a condition since rectified by the issuance of Technical Order 04-1-17, dated 25 January 1945. In previous service tests it had been the policy to re- torque clamps after each flight, but during the winteriza- tion tests it was decided to apply no additional torque on clamps until leakage occurred or the aircraft were grounded due to engine change, experimental installa- tions affecting the coolant and oil systems or inspection periods. Clamp torque losses on experimental hose were check- ed weekly by means of a special recording wrench. Daily inspections were made each morning before preflighting for leakage, excessive hardening or any malfunctioning of hose which would interfere with effective operation of the aircraft. Graphic explanation in Appendix II reveals torque loss values of clamps and their relationship to “cold flow” in the hose. Extreme caution was exercised during the installation of test hose in order that no kinking, stretching or exces- sive bending was allowed to take place. Maintenance personnel were cautioned that all hose was to be cut to the required length and under no circumstances were clamps to be installed over the beaded nipples. A con- dition such as this was noted on one (1) P-51 aircraft where double hose clamps had been used on a 2 coolant line. Hose clamps were positioned to insure proper relationship between the band and the hose, the band and the head and the wings of the tightening screw so that a maximum of space was provided for use of the special recording torque wrench to evaluate “cold flow” loss in the hose. Numerous methods to facilitate hose application over the nipples were used. It was found that all hose could be applied readily by using a lubricant of oil. However, it is believed that this method creates a problem inas- much as maintenance personnel may be prone to use oil as an aid to installation on self sealing hose. Again, it is felt that an oil lubricant may at some time cause a slipping action to take place between the tube and the nipple and during a cold start or semi-cold start act as the impetus in allowing a connection to blow loose. Outer covering cracked on aromatic resistant oil hose The method of pre-insertion before actual installation was found to be the most satisfactory. Various sizes of nipples were inserted in a vise, and cut lengths of hose were forced over the nipples a number of times. This expanded the hose and actual installation was accom- plished with a minimum of effort and without the use of lubricants. By the use of this method it was observed that a mechanic’s hands were free from oil and the brand- ing identification of the hose was not obliterated or rubbed off by constant reworking. All hose became extremely hard at temperatures of 20°F. All test hose had been stored in Stout houses exposed to climatic conditions, so that it was necessary to warm each piece over a blower for twenty (20) minutes before it was flexible enough for installation purposes. Hose stored in coils in localities such as this becomes brittle at temperatures below zero. In attempting to straighten the coils it was found that the braided and rubber covers cracked, thereby rendering the hose use- less. Throughout the testing season much experimentation was done in the cold starting of engines. Actual normal starts without the use of pre-heating were accomplished on Extreme Temperature Operations Unit B-25 and P-51 aircraft at outside air temperature down to —10°F. with adequate oil dilution. In no case were experimental oil hose lines burst or blown from their connections dur- ing these operations. A semi-cold start was made on Extreme Temperature Operations Unit B-25 at —55°F. after one (1) hour of heat from a small heater. No deficiencies or malfunc- tioning of test hose lines was noted on engine start or after eight (8) hours of flying time. A successful cold start at —12°F. was made on Ex- Temperature Operations Unit P-63 using grade 130 fuel. However, when the aircraft was started two (2) hours later, oil was observed leaking from the Young-Houde cooler. It could not be determined wheth- er the malfunction was due to a faulty cooler or failure of the surge valve to relieve pressure within the cooler. Previous failures of surge valves in P-39 and P-63 air- craft have been a cause of premature oil hose failures and, 106 5230 assuming that the above condition may have been in the surge valve, it is well to note that no failures occurred on H-40 and R-80 hose as a connection on the “oil in” and “oil out” lines to the surge valve. Experimental oil hose installed on B-29 and B-24 air- craft has performed successfully during the testing period. Experimental fuel hose installed on B-25 aircraft per- formed satisfactorily in that little “cold flow” was noted. However, the majority of hose was tested in fuel vent lines where little or no pressure is experienced. A considerable amount of trouble has been encounter- ed at Ladd Field on leaking coolant lines in P-51 air- craft. This condition is not only critical during cold weather but may be found on extremely mild days. Leakage in coolant hose is usually noted the morning following the previous day’s flight after the aircraft is allowed to stand overnight on the flight line. Only experimental test hose of the types H-30, H-30N, R-80, 2 braid and R-80, 3 braid, were used in the coolant systems of the aircraft. Installations were made at those places where coolant temperatures were thought to be severe. With the ex- ception of leakage being observed on R-80, 3 braid hose at different times, all hose performed adequately. Clamp torque losses were extreme at all times. R-80 3 braid hose leaked excessively at a temperature of —43°F. The leak was stopped by retorquing both clamps to twenty-five (25) inch pounds. During the three (3) days of sub zero temperatures, specification hose was closely watched. Leakage was observed in these lines every morning. Clamp torque was found to read less than two (2) inch pounds. In a number of cases, raising the clamp torque to twenty-five (25) inch pounds failed to retard the flow of coolant. It was necessary to use a wrench to tighten the clamps, causing excessive strain on the hose and in a number of cases compressing the outer rubber cover through to the fabric. Many man hours as well as flying time were lost in removing the cowling to find these leaks. Leakage in inaccessible localities caused the aircraft to be grounded and their removal from the flight line to the hangars. At inspection periods, clamps were loosened from the experimental hose and examination made for “cold flow”. Little was noted on the cover but further examination of the tube revealed “cold flow” to be prevalent thus ac- counting for clamp torque loss. No bulging of the hose was observed at any time, although all hose with the exception of H-30N had frayed on the ends. All test hose on the coolant lines had hardened considerably, al- though H-30N hose was found to appear softer than the others. The latter statement is one of conjecture as the “finger feel” method was used. Until such time as a durometer reading can be taken on hardness, it is be- lieved advisable to make no decisions on the qualities of hose in this respect. No trouble was encountered on any oil lines in P-51 aircraft. It is believed all test hose will give adequate service. Lubrication of Aircraft Control Systems Prepared by: S. C. Britton, Major, A. C. Materials Laboratory A. PURPOSE 1. To determine low temperature limit of practical operation of control systems pf current production air- craft available for test and determine the effect, if any, the lubricant used in the systems has on this limit. B. FACTUAL DATA 1. Cold weather tests made during the two preceding winters have indicated that airplane surface control systems generally would become critically stiff when temperatures dropped below —40° F. to —50° F. Last winter’s tests indicated that further improvement in the low temperature torque value of the AN-G-3 grease used would not materially lower this low temperature op- erating limit. In this winter’s test program on control systems it was planned to determine whether any im- provement had been made in any of the systems, obtain more extensive data on control systems of airplane models previously tested, and obtained data on airplanes not previously tested. 2. An experimental lithium base grease (Texas TG-455) having approximately one-fourth the average low temperature (—67°F.) torque of Standard AN-G-3 greases was used to relubricate completely several con- trol systems in order to check again the effect of this vari- able on control stiffness at low temperatures (Note h, Table I.) 3. Table I summaries the data obtained at various temperatures on forces necessary to move surface con- trols on the ground after standing overnight. Figure I gives a graphical summary of these data on the larger air- planes tested. The extremely low tempratures desired for test (below —50°F.) were encountered on but a few of the airplanes. However, the following observations can be made: a. In several instances remarkable check results (considering the roughness of the methods used) were obtained between different airplanes of the same model. However, in a few cases there was a wide variation noted, particularly in B-24 trim tabs and B-29 main rudders. b. Trim tabs were generally more critical at low temperatures than main controls. c. Considerable difference exists in the control forces required by different models of airplanes, even in the same class. Fighter aircraft are generally much 107 5230 better as to control stiffness at low temperatures than heavier models. d. In a number of systems the force necessary to work the control sharply increased around —40°F., for example, B-17G aileron trim tabs, B-24J main elevators, B-29 main elevators and rudders, and all C-46A trim tabs. It is believed that such a sharp break is the result of factors other than the lubricant. In other cases, such as the B-17G rudders, the increase was more gradual. It is believed that this indicated the effect of gradual stiff- ening of the grease with decrease in temperature. e. Where the experimental grease was used to lub- ricate controls, no significant improvement in control forces was noted at the lowest temperatures encountered. /. The most critical control systems below —40° F, appeared to be the following: (1) B-17 aileron trim tab; (2) B-24J main elevators and rudders; (3) All B-24J trim tabs; (4) B-24J control locks; (5) B-29 main elevator and rudder; (6) B-29 aileron and rudder trim tabs; (7) C-46A, all trim tabs. g. The P-61 aileron, which was quite critical at low temperatures on last year’s tests, was found to be quite satisfactory at low temperatures on the model (P-61B) tested this year. This improvement appeared to be due to the change in spoiler hinge bearing design which was changed form grease lubricated bronze bush- ings to oilite bearings. Ball bearing supports might be even better. 4. Data on P-63 controls are given in Table II. In this case readings were taken on a number of lend-lease airplanes as well as the one assigned to Extreme Tem- perature Operations Unit. It will be noted that all sur- face controls of this model airplane were entirely satis- factory down to the lowest temperature encountered. This was a marked improvement over the P-39Q air- planes tested last year. 5. Measurement of control stiffness on the ground presents only a part of the information required to evalu- ate control performance at low temperatures. Data must also be obtained during actual flight at low air temperatures, after taking off at comparatively low tem- peratures. Accordingly, the project officer-pilots of Ex- treme Temperature Operations Unit airplanes were ask- ed to give their opinions of control performance of their airplanes in flight. This information is summarized in Table HI. It will be noted that most systems were satis- factory in flight at lower temperatures than were avail- able for test on the ground. On the other hand, a num- ber of the controls found to be stiff on the ground were critical in the air. Those included B-17 aileron trim tabs and B-29 aileron and rudder trim tabs. 6. The P-59A elevator trim tab system was found to be completely inoperative in flight at temperatures below —40°F. In order to localize the stiffness, if possible, ele- ments of the control system were gradually taken out of operation until free operation was obtained. Removal of the final actuator did not help, but after removal of the vertical chain drive in the tail, free operation was ob- tained at —55°F. After replacement of the chain and re- moval of the flexible drive shaft, a flight was made and again the control was stiff, indicating that the final chain drive is critical. Further work is being accomplished as of the date of this report. 7. C-46A trim tabs were again found to be critical be- low —45 °F. and would become completely inoperative between —50°F. and —55°F. The final actuator of the rudder trim tab of one airplane (No. 42-96803) was re- lubricated with TG-455, but very little, if any, improve- ment was noted. However, at a ground temperature of —49°F. when all trim tabs of both airplanes were in- operative, heat was applied to the final actuator only, and the tabs quickly became free. 8. No complaints have been reported with respect to wing flap operation except in the case of B-29 No. 42-65214. Trouble was first noted on 12 February. Ground temperature was—20°F. (with previous 12 hour low of —35°F.) After flying about 20 minutes at 1500 ft. at —24°F. the flaps were lowered for a landing but could not be actuated more than 25 degrees. Trouble was again experienced on a later landing the same day and the flap motor failed. The following morning at —45°F. actuation was tried with the emergency motor and the flaps were found to be completely inoperative. After replacing the main flap motor and applying heat to the rear bombay, satisfactory operation could still not be obtained (ground temperature approximately —25°F.). After applying heat to the flap actuating screws for 30 minutes, the flaps were actuated, down in 17 seconds. However, during the 12, 13 and 14 February, when temperatures ranged between —20°F. to —45°F., B-29 No. 42-24768 operated with no difficulties being reported due to flap operation. It was reported that No. 42-65214 was manufactured by Glenn L. Martin Co., Omaha plant and No. 42-24768 by Boeing Aircraft at Seattle. No information was available as to lubricants applied at the two plants. C. CONCLUSIONS 1. The surface control systems of Army Air Forces airplanes as now designed and lubricated will be operable down to approximately —40°F. Some systems, such as noted in paragraph 3(f) of Factual Data will become critical between —40°F. and —50°F., but a great many airplanes appear to be satisfactory at —50°F. and below. 2. It is indicated that the controlling factors limiting satisfactory operation of aircraft surface controls at low temperatures are those relating to mechanical design, air- plane manufacturing procedures and inspection rather than the low temperature properties of the lubricant used (AN-G-3). In view of high temperature difficul- ties recently reported, further lowering of the torque requirements of Specification AN-G-3 does not appear to be advisable at this time. 3. Improvement can be made in the performance of controls, using present lubricants as indicated by the improvement made in P-63 and P-61 controls. 4 Improvement can be made in C-46 trim tab opera- tion by improving the performance of the final actuator. 5 Improvement can be made in C-46 trim tab opera- tion by improving the performance of the final elements in the system. 6. Low ground temperatures will affect control operation considerably more than low air temperatures in flight. Hence, any improvement made in ground low temperature operation will result in less difficulty in flight. 108 5230 D. RECOMMENDATIONS It is recommended that: 1. No change be made at present in the low temper- ature torque requirements of specification AN-G-3. 2. Cold room tests be made on aircraft control system to determine torque in the range between —65°F. and +160°F. a. Characteristics of control system mechanisms and assemblies; b. Characteristics of complete control systems as installed in production aircraft. In view of the possible influence ot lubrication on these characteristics, such tests should be made a joint Air- craft Laboratory-Materials Laboratory project. 3. Attention be given to the immediate improvement of low temperature operation of the critical systems noted in Paragraph 3 (f)*of Factual Data. Lubrication of the P-63 Airplane Prepared by. S. C. Britton, Maj., A. C. Materials Laboratory A. PURPOSE 1. To determine low temperature performance charac- teristics of several P-63 components, as affected by their lubrication. In particular, the following were to be studied: a. Lubrication of the extension engine reduction gear. This test is to include determination of oil tempera- tures in flight and torque required to turn the gear at low temperatures. b. Lubrication of surface controls systems. c. Lubrication of Aeroproducts Propeller. B. FACTUAL DATA 1. The program covering lubrication of the engine reduction gear is a continuation of a similar study made during last winter’s tests on the P-39 gear box. The most important use for gear oil covered by Spec. AN-O-3 is in reduction gear of E-series Allison engines and the data obtained on these tests will be used to establish the viscosity limits of the winter or light grade of the oil. At low temperatures, the viscosity of the gear box oil will be controlled by its influence on the torque required to turn the gears or by its effect upon pumpability of the oil. The oil temperatures measured in flight will be a major factor in determining how viscous the oil must be at higher temperatures. 2. AN-O-3, light grade oil was used for lubrication of the gear box in all tests conducted. Gear oil tempera- tures were determined under various conditions of speed, load altitude, and air temperature; a total of 12 flights were made. The temperatures obtained in flight at rated power (2600 RPM and 42.5 inches Hq manifold) at 5000 ft., 14,000 ft. and 21,000 ft. are shown in Figures 1, 2, and 3 respectively. From the data given, it will be noted that (a) an appreciable time of operation at high power is required to warm the oil to equilibrium (b) the oil temperature reached depended upon the outside air temperature (c) considering the air temperatures at altitude to be representative of winter conditions, the maximum gear oil temperature to be expected will be approximately 180°F. Oil temperatures obtained when higher powers are used, such as in a climb, are given in Table I. Temperature equilibrium is probably never reached under such conditions since comparatively short time limits are placed upon operation at such powers, and a maximum oil temperature of 185°F. is obtained. Thus, temperature compares with a maximum of 155°F. obtained last year on the P-39 oirplane. 3. The gear box torque was obtained, independent of the torque imposed by the rest of the engine by disengag- ing the engine at the extension shaft coupling. Torque Measurements were made with a simple spring balance. The results of the torque measurements at various low temperatures are given in Table II. It will be noted that (a) the torque required to turn the gears at low tempera- tures is very low and (b) this torque is practically inde- pendent of the temperature within the temperature range studied. 4. Surface controls of the P-39 airplane, particularly trim tabs, were found to be critically stiff at temperatures of —40°F. and below in last year’s tests. Thus, similar information was sought on the P-63 airplane during this winter’s tests. Rudder and elevator trim tab systems of the E. T. O. U. P-63A airplane were relubricated with TG-455 and control stiffness measured at low tempera- tures on both this airplane and lend-Iease P-63’s. De- tails are given in report TSEAL-4-M4966-II. In gen- eral, considerable improvement was noted at low tem- peratures over P-39 airplanes. 5. Aeroproducts propeller tests have indicated that AN-O-3, light grade would be suitable as a regulator oil for winter operation. This winter’s performance was in the nature of a check service test on this recommendation. Although operation of this airplane was not accomplished at extremely low temperatures (below —25°F.) no diffi- culty was experienced at the temperatures encountered. 6. Other lubrication of the P-63 airplanes appears to be satisfactory for low temperatures since no low tem- perature malfunction affected by lubrications have been reported on either test or lend-lease airplanes of that model. C .CONCLUSIONS 1. The limiting performance factor governing low temperature viscosity of the lubricating oil for the Allison 5230 109 E-series engine reduction gear is the pumpability of the oil. The oil in the gear box contributes little or nothing to engine stiffness and resultant loss of crankability at low temperatures. 2. Engine stand tests evaluating load carrying capa- city of light grade gear oil and governing selection of viscosity grade of this oil should be run at oil tempera- tures not exceeding 185°F. • D. RECOMMENDATION 1. It is recommended that pumpability tests be carried out in the cold room to more accurately define the low temperature viscosity requirements of AN-O-3, light grade oil. Until such tests can be completed, the pumpa- bility data from last winter’s tests can be used. 2. Present winterization lubrication instructions cov- ering the P-63 airplane be continued in force. Turbosupercharger Lubrication Prepared by: S.C. Britton, Maj., A. C. Materials Laboratory A. PURPOSE 1. To determine performance characteristics of turbo- supercharger lubricating oils at low temperatures, with particular reference to: a. Pumpability of the lubricant; b. Oil temperatures in flight; c. General evaluation of the performance of low temperature oil recommended by Extreme Temperature Requirements Sheet No. 56-2. B. FACTUAL DATA 1. Current instructions for lubrication of turbosuper- charger bearings not lubricated by the engine oil system call for use of grade 1065 engine oil (Spec. AN-VV-O- 446) at ground temperatures down to 0°F., and hydrau- lic oil (Spec. AN-VV-O-366) for sub-zero temperatures. 2. The above recommendations have not been entirely concurred in by the supercharger manufacturer because: a. It was felt that low oil temperatures might be en- countered in high altitude flights when summer grade oil is used, with resultant sluggish flow of oil and im- perfect lubrication; b. If excessively high oil temperatures are reached in flight when ground conditions require use of AN-VV- O-366 oil, the base stock might evaporate from the oil, leaving a sticky residue of viscosity index improver on the supercharger bearings; c. An all temperature oil is desired. Accordingly, Spec. 3580 hydraulic oil has been recommended for super- charger lubrication. However, this oil has the following disadvantages: (1) Cold room tests have shown the oil to be too heavy at low temperatures (below —30°F.) for satis- factory pumpability. (2) This oil also contains a viscosity index im- proper which could cause the same trouble noted above, although the base stock of 3580 is somewhat less volatile than that used in AN-VV-O-366 oil. (3) The oil is obsolete and stocks are no longer being procured. 3. In order to meet the need for a suitable all-tempera- ture turbo-supercharger lubricant as indicated above, it has been tentatively recommended that newly developed AN-0-6a oil be used. The tests described herein were prepared in order to obtain information to substantiate this recommendation. 4. Pumpability tests were conducted on P-38L No. 44-24050, using Spec. AN-0-6a oil (Texas TL-534). A by-pass petcock was installed in the oil scavenge line and observations on the flow characteristics immediately after starting the engine at low temperature were made. These observations and an evaluation of the pumpability of the oil are given in Table I. Satisfactory pumpability was obtained down to the lowest temperature encounter- ed (—46°F.) 5. In order to obtain information on supercharger oil temperature in flight, thermocouples were, installed on the oil in and oil out lines of Nos. 1 and 2 engines of B-17G No. 44-24050. Flights were made under normal cruise conditions at various altitudes. The data obtained is summarized in Table II. It will be noted that in this installation rather low oil in temperatures are obtained at high altitudes, low enough in fact, that it is doubted that grade 1065 engine oil would be pumpable. However, this should be a function of the installation since the am- bient air in installations such as the P-38 is higher than outside air because the supercharger oil tank and lines are mounted in the wheel well. 6. AN-VV-O-366 oil has been used to lubricate all externally lubricated turbosuperchargers on ships as- signed to low temperature testing at Ladd Field for the past two years. No reports of bearing failures of the nature indicated in par. 2 above have been received. C . CONCLUSIONS 1. Spec. AN-0-6a oil will satisfactorily lubricate tur- bosuperchargers down to ground temperatures of —45 °F. or lower. 2. Low oil temperatures are obtained in some instal- lations in flight at low temperatures indicating the de- sirability for having an all temperature turbosupercharg- er lubricant. 3. AN-VV-O-366 hydraulic oil will satisfactorily lubricate turbosupercharger under arctic operating con- ditions. 110 5230 D. RECOMMENDATION It is recommended that: 1. As soon as an adequate supply is available, oil meeting Spec. AN-0-6a be used as an all-temperature lubricant for turbosuperchargers (other than for those lubricated by the engine oiling system). 2. AN-VV-O-366 oil be considered as a satisfactory turbosupercharger oil for sub-zero temperatures until AN-0-6a is available. Starter Lubrication Prepared by.: 5. C. Britton, Major, A. C. Materials Laboratory A. PURPOSE: 1. To determine whether or not Eclipse starters lub- ricated with specification greases heavier than recom- mended by Extreme Temperature Requirements Sheet No. 56-2 will function satisfactorily at low tempera- tures. B. FACTUAL DATA: 1. On the basis of previous test work, including last winter’s tests on 4 Jack and Heintz starters installed on a B-17 airplane, the Materials Laboratory has recom- mended that starter hearing be lubricated with specifica- tion AN-G-3 grease and gears with specification AN-G-10 grease. However, Eclipse Division, Bendix Aviation Corporation has indicated that from their tests and experience it appears necessary to use a somewhat heavier grease to insure desired starter life under all conditions. 2. In order to determine the low temperature per- formance of starters lubricated with heavier greases, four Eclipse G6a starters were lubricated at the factory and installed on B-24J No. 44-41378 as shown in Table I, 3560E med. and GN-G-6 was used on two starters, rep- resenting standard greases now available in stock. TG-404 was used in the remaining two starters, repre- senting the intermediate grease of Army-Navy specifica- tion greases to be available in the near future. 3. The performance of the starters at various tem- peratures down to —43°F is summarized in Table I. Entirely satisfactory performance was observed at all temperatures encountered. C. CONCLUSIONS 1. Satisfactory low temperature performance of starters lubricated with intermediate type greases can be expected down to at least —45 °F. It is probable that such lubrication will be satisfactory at much lower tem- peratures. D. RECOMMENDATIONS 1. Technical orders covering lubrication of Eclipse starters require use of intermediate type greases for bearings and gears. 2. Further tests be carried on in the cold room to determine whether the specially lubricated starters used for this test will operate satisfactorily at —65°F. It is further recommended that yellow dot approval not be granted for Eclipse starters until and unless such tests are successfully completed. Lubrication of B-29 Retracting Motor Prepared by :S.C. Britton, Major A. C. Materials Laboratory A. PURPOSE 1. To determine the lowest temperature of practical operation for retraction of B-29 landing gear with motors lubricated with intermediate-type grease. B. FACTUAL DATA 1. Extreme Temperature Requirements Sheet No. 56-2 specifies use of AN-G-3 grease for lubrication of landing gear retracting and other similar intermittent duty motors. 5230 111 2. However, in the case of larger units, such as used for B-29 airplanes, some doubt has existed as to whether a light, low temperature grease such as AN-G-3 would provide adequate lubrication at high temperatures. The motor manufacturer proposes using a lithium-base grease with an oil approximately twice as heavy as that used in AN-G-3 grease. The equivalent specification material is the intermediate type grease soon to be covered by an AN specification and represented by Texas TG-404. The low temperature torque of intermediate-type grease is, of course, not as low as for AN-G-3 grease and the ques- tion has arisen as to the performance of the heavier grease at low temperatures. 3. The test was run on B-29 No. 42-65214. The left landing gear motors were removed and returned to the factory (Eclipse-Pioneer Division, Bendix Aviation Corporation) where they were relubricated with Texas TG-404. The right landing gear retained the original factory lubricants, Royco 6A and Royco 50. 4. The performance of the gear was evaluated by measuring two factors; the electrical load required to raise the gear and the time required for retraction. Elec- trical load was measured using an ammeter with external shunts mounted in the power circuits to the motops, using calibrated leads back to the navigator’s station where the readings were taken. Readings were taken on first retraction on take-off on the first flight of the day. The ammeters were read every 5 seconds after the circuit was closed, since a con- siderable variation of load was noted over the retraction cycle. Data was also taken on the ground with the airplane on jacks in the hangar and on the ramp outside in order to get as large a temperature spread as possible. (These readings were taken when the airplane was jacked up for turret tests.). 3. The test results are tabulated in Table I. The lowest temperature at which readings could be taken was —20°F. No data was obtained at lower temperatures be- cause the wing flaps were inoperative (See Part I, Lubri- cation of Aircraft Controls). However, over the temper- ature range in which tests were conducted, there was no noticeable trend of electrical load of retracting speed in- dicating difficulty at low temperatures. Some difference between the left and right gear readings exists, but since neither showed significant change with temperature, this is thought to be due to mechanical idiosyncrasies of the system rather than differences between the greases used to lubricate the two motors. It should be noted that the peak sustained load is quite high (260-275 amps) and undue increase in frictional horsepower could cause ex- cessive loading of the airplane electrical systems. C. CONCLUSIONS 1. Intermediate type greases will permit satisfactory operation of B-29 retracting motors down to at least —20°F. Malfunctions of other systems will limit opera- tion of the B-29 airplane at temperatures higher than the limiting value for landing gear retraction. D. RECOMMENDATIONS 1. Further work be accomplished in the cold room and cold hangar to evaluate the use of intermediate grease in B-29 landing gear, with final proof being ob- tained by cold weather flight tests. Tentatively, inter- mediate grease should be considered satisfactory for B-29 landing gear motor lubrication. Performance of Non-Inflammable Hydraulic Fluid in Struts Prepared by: S. C. Britton, Major, A. C. Materials Laboratory A. PURPOSE 1. To determine the serviceability of a newly de- veloped non-inflammable hydraulic fluid in struts under low temperature operating conditions. B. FACTUUAL DATA 1. At the direction of higher authority, the Materials Laboratory has developed a hydraulic fluid considerably less flammable than the present petroleum base fluid. The viscosity of this fluid at low temperatures is higher than for the present AN-VV-O-366 oil, but lower than the old 3580 oil. Other properties, such as shear break- down, lubricating value, rubber swelling, corrosion, etc., have been evaluated by laboratory tests which indicate generally that the oil should be suitable for service. The test described herein was set up to obtain some informa- tion on its performance in actual service, particularly at low temperatures. 2. The fluid was installed in struts of several E. T. O. U. airplanes at Vandalia in preparation for cold weather tests. Information on the installation of fluid and its performance during the test season is summarized in Table I. Operation was entirely satisfactory under all conditions encountered. 3. Arrangements have been made to have the struts returned to Wright Field for internal examination. More complete evaluation of the test will depend upon the findings of this examination. C. CONCLUSIONS 1. The results obtained to date indicate that the non-inflammable hydraulic fluid developed by the Ma- terials Laboratory is suitable for airplane shock struts under low temperature operating conditions. D. RECOMMENDATIONS 1. It is recommended that more complete service tests be conducted to further evaluate the suitability of non-inflammable hydraulic fluid for military aircraft use. In particular, the fluid should be tested in main hydraulic systems. 112 5230 Investigation of Reported Engine Roughness during Service Test of PRO-265 by Alaskan Division, ATC Prepared by: S. C. Britton,-Major, A. C. and Wm. Weitzen Materials Laboratory and Power Plant Laboratory A. PURPOSE 1. To determine cause of excessive engine roughness, “cut-outs”, and similar troubles reported by operating personnel of Alaskan Division, ATC, since inaugura- tion of service test of PPO-265 synthetic engine oil. B. FACTUAL DATA 1. Service test on PPO-265 in Alaskan Division air- planes was begun 1 October when this oil was placed in service on all transport airplanes under Division super- vision, including those operated by contract carriers. This test was initiated primarily to obtain a large amount of information on the value of PPO-265 as a winter grade engine oil. General information as to its service- ability in transport operation was also desired, although previous tests stand and service tests on various types of engine have indicated that this oil is a generally satis- factory aircraft engine lubricant. 2. Performance of the oil has apparently been satis- factory on the service test, and its value as a winter grade oil has been indicated by the fact that practically no di- lution had been necessary up to 17 December 1944. However, a number of apparently unexplained cases of engine roughness, “cut-out”, “burping”, etc., had been reported by Army pilots since using the oil. A summary of typical complaints on one airplane is given in Ap- pendix I. It will be noted that a few reports were re- ceived in October and that they ceased until the end of November. This is typical of all the airplane reports. By the first part of December, the number of complaints had reached a level where it was decided to discontinue the use of the oil entirely on the three Army-operated C-46 airplanes and continue on the right engine only on the ten Army-operated C-47 airplanes. 3. A summary of the amount of service on both grade 1100 and PPO-265 oil (up to 17 December) as well as an analysis of the complaints of engine roughness is given in Appendix II. It will be noted that while PPO-265 has been in service approximately the same number of hours on both right and left engines, more complaints had been received on the right engine, A large number of these were unexplained although an equal number were reported to be due to ignition trouble, followed by carburetor trouble, propeller surging, and a few miscellaneous other causes. The majority of the reports of engine roughness or “cut-out” have been re- ceived on three airplanes. 4. Information on performance of PPO-265 was also obtained from the contract carriers, Northwest Airlines and Western Airlines. Both of these organizations re- port no increased difficulty with engine roughness since using PPO-265, although a somewhat greater tendency to leak had been noted. Oil consumption was indicated to be somewhat less with PPO-265 than with grade 1100. There had also been an increased number of off-schedule engine changes since 1 October, although it is too early to state that there is a definite permanent trend in this direction. Refer to Appendices III and IV. 5. Considerable emphasis had been placed upon the amount and appearance of sludge in propeller domes, blade bearings and distributor valves since using PPO- 265 in attempting to explain the engine roughness ob- served. The sludge in this oil is composed almost en- tirely of blow-by lead compounds and is not mixed with tarry material formed by oil decomposition and oxida- tion as is the case with ordinary mineral engine oil. This has resulted in a deposition of sludge in the pro- peller system of a harder than usual consistency, which might cause uneven propeller functioning with resultant surging. A number of instances of excessive quantities of propeller sludge deposits have been noted. It is not believed that this condition is general, because inspection of three propellers in the Army propeller shop at Edmon- ton showed only a moderate quantity of deposit. In the case of one propeller examined, very little sludge was found after 1163 total hours, comprising 675 hours on grade 1120 oil and 488 hours on PPO-265 and 145 hours after last dome inspection and clean-out. Further, more diligent cleaning of domes has not eliminated roughness difficulties, in some cases complete propeller changes have not helped, and test runs involving “exercising” the propeller in flight have not resulted in any improvement in operation, 6. In order to obtain a more definite idea of the na- ture of the roughness or “cut-out” reported, observations were made on one of the airplanes (No. 8160) on which numerous complaints had been received, during a regu- lar flight from Edmonton to Fairbanks. Log of this flight is given in Appendix V. It was noted that after about six hours in flight, a short period (2-3 seconds) of roughness was observed with an accompanying momen- tary drop in tachometer reading of 50 to 75 RPM. This was repeated at intervals and was not eliminated by several procedures tried in flight. Increased power setting appeared to aggravate the trouble. Questioning of the pilots indicated that the roughness observed was typical of that being reported. 7. Later, airplane No. 8160 was obtained for more extensive flight check. A record of the test flights made is given in Appendix VI. Three test flights and one 5230 113 short ferry flight were made, totalling 16.3 hours under various conditions of operation, during which no indi- cation of engine roughness of any kind was noted. Since, a number of minor mechanical adjustments were made at Whitehorse just prior to receiving the airplane at Fairbanks, it appears that the cause of the roughness previously observed is mechanical and may be only re- motely related to the oil. 8. Noticeable greater leakage of PPO-265 past seals, gaskets, and other passageway has been noted. Con- siderable leakage past the main shaft seal into the blower section and into the lower intake pipes has been reported. 9. Previous to installation of the oil, most instances of engine roughness, which were occasionally quite troublesome, were found to be due to malfunction of various parts of the ignition system, particularly the magneto. 10. Operating personnel were generally of the opin- ion that changing back to grade 1100 engine oil elimi- nated difficulties due to roughness and in one instance it was reported that a complete fix was obtained on a return flight after making such a change. However, it cannot be stated with any certainty that other things were not also adjusted at the same time; and such reports, where uncontrolled changes have been made, are valueless. C. CONCLUSIONS 1. Abnormal momentary engine roughness is being encountered in some engines in flight. 2. Data available do not indicate conclusively that PPO-265 used as engine oil is a direct cause of the en- gine roughness observed. In numerous instances, mech- anical difficulties which ordinarily cause rough engine operation have been indicated to be the source of trouble. The most prevalent cause appears to be ignition trouble. However, some reports of roughness cannot be so ex- plained and might be attributable to properties of the oil. 3. PPO-265 differs in a number of properties from regular engine oil, particulary. a. Greater “creeping” or power to wet metal sur- faces ; b. Different effect on rubber compounds used for seals and gaskets; c. Lower inflammability; d. Lower viscosity at temperatures below approxi- mately 250° F. The possible effect of these properties is indicated in the following paragraph. 4. There exist several possibilities in which the oil may directly or indirectly cause engine roughness. These are evaluated below; a. Spark plug fouling due to oil leakage into in- duction system, with subsequent difficulty of cleaning plugs because of the low inflammability of the oil. This explanation has been considered one of the most likely but has not been supported so far by actual examination of the plugs. b. Fouling of distributor points by oil leaking past magneto shaft seal. Some instances of oil on points have been reported and this would tend to cause roughness. However, in most instances where typical roughness is reported, satisfactory ground magneto check for RPM drop has been obtained. c. Oil in ignition harness. Some instances of ex- cessive amounts of oil in the harness have been reported. However, since the oil is an insulator, the possibility of this causing actual engine malfunction is remote. d. Sludge in prop dome, blade bearings and seals and governor valve. This condition is discussed in Para- graph 5 of factual data, and from the data it is concluded that this explanation of engine roughness is not valid. e. Valve sticking. This source of engine rough- ness could be caused by low oil flow due to plugging of oil passageways or valve stem deposits. The type of rough- ness or engine “cut-out” observed particularly after long running could easily be explained by valve sticking. However, consideration of properties of the oil as well as disassembly inspection of some engines which have used PPO-265 seem to preclude this explanation. f. Plugging of Torsional Vibration Damper. This has been suggested by a Pratt and Whitney representa- tive. Too much credence is not given to this suggestion in view of the type of roughness encountered, plus the fact that this vibration damper was designed to elimi- nate high order torsional vibration in the accessory end and smooth operation, insofar as can be detected without instruments, can be obtained with the pucks rigidly fixed to the crankshaft, 5. Increased rate of occurrence of off-schedule en- gine changes since using of PPO-265 gives some indi- cation that entirely satisfactory lubrication is not always obtained. However, this does not seem to be directly associated with the cause of engine roughness and data taken over a longer period of time could easily reverse the trend noted. D. RECOMMMENDATIONS 1. It is recommended that action be taken as given below, by the organizations indicated. a. Alaskan Division, ATC. (1) Continue oil service test on C-47 airplanes as now set up. On Army-operated C-47’s use grade 1100 on left engine and PPO-265 on right engine. (2) Take steps to prevent mixing or changing from one oil to the other on any engine. Stringent orders should be issued that either oil should not be changed at the discretion of operating personnel for “engine roughness” or similar reasons. Oil change for any reas- on should be considered an emergency procedure and should be done only on authorization by Maintenance at Division Headquarters. Adequate precautions should be taken to preclude accidental mixing ot oils at service bases. (3) More careful maintenance should be ac- complished in order to better isolate the various causes of engine roughness and correct those causes. In addi- tion to normal accessory corrections, attention should be given the following, which are possibly affected by the oil: (a) Magneto inspection. Check for oil leak- age past drive shaft seal and evidence of malfunction of distributor and breaker points. Excessive seal leakage should be corrected by installing new seals. Also check magneto shaft for excessive looseness. (b) Spark plug inspection. Check plugs for fouling. On engines where other procedures are not effective, change plug to IS 87 or equivalent. (c) Remove, clean and inspect propeller dome every 100 hours in accordance with TO-03-20-5. If ex- ceedingly large quantity of hard sludge is found in dome, propeller should be changed at the discretion of person- nel in charge of propeller shop. (d) An effort be made to include more corn- 114 5230 plete details of maintenance and operation with PPO- 265 in order that such difficulties as engine roughness may be better analyzed by engineering personnel. In order to accomplish this, the check sheet given in Table I should be added to the form now carried in the airplane, form 1 covering performance of PPO-265. b. Engineering Division, Air Technical Service Command. (1) Send representative to Headquarters, Alas- kan Wing, to follow service test of PPO-265 full time for a minimum of 2 weeks. (2) Take into consideration the various ways the oil might contribute to engine roughness as pointed out in this report, when making disassembly inspection of engines which have used PPO-265. (3) Investigate effect of PPO-265 on various rubber compounds, particularly the type of compounds used for engine and propeller seals, such as accessory drive seals, cylinder flange oil ring seals, sump pipe seals, rocker box seals, and propeller blade and hub seals. It is recommended that such work be done in cooperation with the oil manufacturer. (4) Investigate spark plug fouling tendency of PPO-265 as compared with mineral oil by means of single cylinder engine tests, (5) Determine effect of various amounts and kinds of sludge in propeller domes and blades on pro- peller operation. (6) Determine effectiveness of full-flow filters in removing blow-by lead compounds from PPO-265. (7) Take steps to obtain better oil seals on R-1830 engines. Cold Weather Observation with Respect to Bombing Equipment Prepared by N. S. Lestz, Armament Laboratory A. PURPOSE 1. To report observations in connection with behavior of bombing equipment during the winter of 1944-1945 at Ladd Field, Alaska. B. FACTUAL DATA 1. The present winterization program of tests for bombing equipment has been carried out in the mildest winter period yet experienced, except for two cold snaps, since the inauguration of the winter tests at Ladd Field in 1942. 2. The daily maximum and minimum temperatures in degrees Fahrenheit for this winter period are contained in Appendix I to this report. Daily means and monthly means are also listed. The coldest snap for the period was recorded on February 12 to 14 when the low, —45 °F so far experienced, was reached. 3. The ground checks and flight checks performed on bombing equipment have followed the pattern estab- lished in the previous winter periods, and the equipment checked (see Appendices II, III, and IV) have not, with the exceptions listed below, given trouble during the temperatures experienced: a. Bomb racks P51-D airplane. These items were affected at —40°F. The locking latch was binding. Racks were thus hard to cock. Net effect was to increase bomb loading difficulties which are multiplied by the extreme temperatures acting on the personnel. The racks are generally difficult to load even though hooks are designed to be snapped into position by the bomb lugs. Personnel feel that the method of locking can be improved and that means for unlocking the hooks at the racks should be pro- vided. The present shield on racks prevent unlocking hooks at the rack. b. Bomb Release Interval Control, Type B-2a. A unit installed on the B-29 airplane was reported frozen when ground checked at —40°F. A study of facts avail able seem to indicate that the bombardier’s master switch was frozen rather than the control. During this check no electrical current was available at the interval control or at the indicator lights. Both of these circuits are fed from the master switch circuit which, with the other toggle switches on the bombardier’s panel that control the bomb- ing circuits, was stiff and did not operate readily at —40°F. c. B-24 Aircraft—The installation of the Type A-15 Emerson nose turret in these airplanes is not air- tight. The airplane nose is exceedingly drafty in the im- mediate vicinity of the bombsight. A flight test was con- ducted in B-24J, 44-41378 to measure this leakage. At 12,000 feet, indicated airspeed 180 MPH, the airflow is 1880 feet per minute (a small gale), or approximately 20 CFM. Most of the air enters the compartment from beneath the bottom of the turret doors which fit im- properly in the bottom of their bulkhead. Consequently the compartment is at the same temperature as the Out- side air which in this test was -—1.4°F. The cold affects the bombardier’s efficiency of operation, and it also affects the bombsight, if it lacks the protection of its heating cover and is exposed overly long (20 minutes or longer), during a bombing run when the free air temperature is sufficiently low (—20°F. or lower). See succeeding para- graphs for details of bombsight operation. d. Bomb Hoisting—The C-3 hoist and the webb straps were used for all bomb loading details. Equipment functioned well, but the time consumed to raise each bomb to its station in the airplane by this manual method worked difficulties on the personnel engaged in this work in cold weather. The webb strap was favored for cold weather use over the chain sling by personnel experi- enced with both types. The webb strap can be manipulated more quickly and can be handled with gloves. The C-6 hoist was not used. Airplanes with hoisting systems adapted for use with the C-6 hoist were not available. The C-3 motor drive set was used on four loading details, but difficulties in obtaining a source of 110 volts D.C. to drive 5230 115 it arose. (Both these items had been successfully used in previous winter tests). e. M-Series Bombsights find Stabilizers—Low temperature effects varied for each of the sight and stabil- izer assemblies tested when they were not protected by the operation of their heating covers. Bombsight and stabilizers were exposed to cold weather at all times except for routine maintenance on units in the shop. The caging knobs, levelling knobs, drift and turn knobs, rate and displacement knobs, telescope rheostats, rate racks, telescope motors, and displacement quadrants could be freely operated on some units while binding on others in temperatures of —20°F or lower. Stabilizers were un- affected in operation. All the cold weather malfunctions occured with bombsights installed on the B-24 airplanes. On these airplanes the sights although protected by their covers before missions, (except when installation of GBA prevented closing covers) were exposed to the cold during bombing runs and their various parts, enumerated above, became stiff and sometimes inoperative due to cold air blowing directly over the installation. Appendix IV gives a running account of the various malfunctions. On the other airplanes, B-25’s, B-17’s and B-29’s, the bomb- sight installation is not subject to cold drafts, the com- partments do not leak, and with the additional protection of the heated covers no cold weather malfunctions dur- ing operation occured. Inspection of the malfunctioning sights revealed in some cases an excessive amount of grease on parts. However, in the case of binding quad- rants the parts were clean. f. C-l Automatic Pilot—No cold weather difficul- ties occured with these items where they were protected by their heating covers. Appendices III, and IV list the history of these units for this winter period. B-24J’s, 44-41378 and 44-41377, had no C-l automatic pilot heat- covers installed, resulting in sluggish operation of these units. Covers later installed on B-24J, 44-41377, pre- vented any further cold weather difficulties. The B-24M, 44-42190, had all covers installed by the factory except for the aileron servo, because of interference that would result with the elevator control chain drive which is close by this servo. g. Lubrication— Two types of oil were used with the M-series bombsights, stabilizers and C-l automatic pilots on test. Eight groups of equipment were oiled with the regular light bombsight oil while seven groups of equipment were lubricated with AN-0-6A oil. Append- ices III and IV carry the record of the lubrication of the units. AN-0-6A oil, newly developed for bombsights, has a pour point of —70°F. It was not known definitely whether the L-oil used is of type covered by specification 3582-A or of the old type. The old L oil has a pour point of -f-4°F. The 3582-A oil has a pour point of —50°F. The oil used flowed freely at temperatures experienced. How- ever, samples of L-oil used and also of the H-oil on hand were turned over to the Materials Laboratory repre- entative for analysis at Wright Field. Of the seven sets of equipment oiled with the AN-0-6A oil, four were winterized before being sent to Alaska. The other three sets were units on test using L-oil (part of the eight groups mentioned above) and later flushed with the AN-0-6A lubricant for test. During the test gyro rotor bearing failures developed on five stabilizers and one bombsight. One of the stabilizers of the five and the one bombsight were lubricated with L-oil only. Three stabil- izers, one of which failed twice, were lubricated with AN-0-6A oil only. The fifth stabilizer failed, first using L-oil, and then failed when AN-0-6A oil was used in it after its repair. Five groups oiled with L-oil and three groups oiled with AN-0-6A developed no bearing troubles. Of the units damaged, three were on B-17’s and three we re used on B-24’s. Some of the damaged bearings have been turned over to the Materials Laboratory rep- resentative for examination at Wright Field. The others are being returned to the Armament Laboratory for ex- aminatiton. All the damaged bearings failed similary on stabilizer gyro rotors regardless of lubricant. In several of the failed bearings a reddish foreign substance similar in appearance to rust was found. The outer races of the bearings were also deeply scored. The gyro rotor locked end bearing was more severely damaged than the free end bearing. Failure of bombsight gyro rotor bearings, flight gyro rotor bearings, and servo bearings did not occur except for the one bombsight already mentioned. Lubri- cation of the foregoing units was similar and as frequent as with stabilizers. Because of the failure of bearings, shop tests for comparison of the L, the H, and the AN-0-6A oils were made with a check on the amount of oil being thrown from bearings. The maintenance shop at Anchor- age Air Depot was also consulted regarding bearing fail- ures. Other than the fact that bearings drawn from stock have been found defective, no information was available on bearing failures in this area. It was also learned that confusion exists concerning the L- and H-oils in use. Some of the old oil in stock is being used along with the 3582-A oil and the VV-O-581 oil recommended in place of the old H- and L-oils. 4. The following service difficulties with bombing equipment occured during tests: a. Flight Gyros. Intermediate gear on roller cut- out stripped. Metal particles from gear entered bearing causing it to fail. Lower roller of cut-out stuck on another flight gyro. The pinion drive gear teeth were stripped. The metal chips from the gear scored the shaft of the roller cut-out. b. Type C-13A Thermometers. These units are erratic. No two of the same airplane register the same temperatures. c. B-2A Interval Control. Relays stick at room temperature as well as at outside temperatures below freezing. d. Hydraulic fluid may drip into the flight gyro in B-24J airplanes in its present location besides the navigator’s table. In airplane B-24J, 44-41378 the drip is excessive necessitating constant attention to flight gyro. This gyro was flooded. e. B-7 Bombsight Mount. One failure occured. Bottom plate of the mount cracked at pivot block jaw and locking device was broken. Personnel lacking familiarity with the locking arrangement had forced it by brute strength. This mount was one of three carrying glide bomb units. No other failures found. Mounts have been found poorly adjusted especially at the pressure tips. The failed mount was one of these. /. A-4 Releases. During installation weight of the release falls on the electrical connector. Pins in the con- nectors of three of the releases were twisted off as a result. A photograph of a release so damaged is being sent to the laboratory. The spring contacts of the receptacles, Type A-l, receiving the A-4 release connector pins have been found open after removal of releases. This failure of the inserts to close occured on B-29, 42-24768. g. Aileron Servo—B-17G Airplanes. Installation of other equipment prevents access to this unit and dyna- motor for servicing. h. Servo units of Minneapolis-Honey well manu- facture. Reduction in the size of the inspection hole in the end-bell at the commutator makes it difficult to clean the commutator segments. 116 5230 i. The Q-1A heated suit rheostat is not accessible for plugging in the Type A-l bombsight heating cover on B-17G aircraft. 5. In tests with the glide bomb attachment (GBA), the rate of climb and descent failed to correspond to airplane rates of climb and descent. Wide discrepancies have been noted. No shop facilities were available to re- calibrate these items and check their correctness. The units had registered correctly in calibration checks in the Armament Laboratory before installation in the air- planes. 6. Action has been taken to have returned to the Armament Laboratory bombsights, stabilizers, automatic pilots and GBA’s which were installed on Wright Field test airplanes. The equipment is to remain with airplanes until their return to Wright Field. Proving Ground bomb- sight maintenance personnel have been requested to recal- ibrate bombsights and stabilizers and check automatic pilots before departure of aircraft and reoil units with AN-0-6A oil, noting any malfunction in data books of units. C. CONCLUSIONS 1. The following conclusions are submitted with re- spect to the behavior of bombing equipment for the winter period 1944-1945: a. Insofar as the severity of the weather is con- sidered, the season has been very disappointing except for an occasional cold snap. b. Bombing equipment is independent of the air- plane for its efficiency of operation, more so than in pre- vious winter tests, since the introduction of the all- electric bomb release system. Conquently, best results for determining cold weather behaviour of the equipment from a design standpoint can best be worked out in the cold room where temperatures can be controlled at will. However, the winterization field tests are considered necessary for new equipment still in the experental stage to check its feasibility for cold weather use form the point of view of field personnel. Flight conditions which can hardly be expected to be duplicated in every phase in the laboratory is another factor which must be considered in cold weather field tests. c. The behavior of bombing equipment in the win- ter tests has been satisfactory and very dependable. d. P-5 ID bomb racks would not have failed to operate with a bomb load. The difficulty from the cold arose only in the increased resistance to cocking. e. Bombsights, stabilizers, and the C-l Automatic Pilot for best operation in cold weather and where the units have been chilled on the ground, must be protected by operation of their heating covers. Only with condi- tions as on airplanes of the B-24 type may trouble be expected if the units are exposed any great length of time in flight in the cold. f. Bomb hoisting difficulties would be reduced by use of the motor drive for C-3 hoist or by use of the motorized C-6 hoist. g. The following conclusions are advanced for bearing failures, although for the complete picture design tolerances, the type of lubricant and conditions of bear- ings must be considered. It is felt from analysis of data in Appendices HI and IV that the bearing troubles de- veloped from the maintenance procedure followed. In every case of bearing failures in these tests, maintenance procedures followed a standard practice of a 30-day inspection or 25-hour operational inspection, whichever was first. Bearing failures occured because units were operated when bearings were dry. The occurrence of a reddish material of the appearance of rust in damaged bearings, whether they had been treated with L-oil or AN-0-6A oil, seems to bear out the fact that failures were from similar causes, namely, overstress resulting in corrosion fatigue (a break down of the metal structure due to stresses imposed). Bombsight (one exception noted on which rotor bearings had become extremely dry) and flight gyro bearings did not fail because stresses imposed on them are slight compared to those on the directional gyro which is imposed upon by the servo motor. More failures occurred with AN-0-6A oil used, because as tests showed, this light oil is lost from the bear- ings during gyro operation more easily than is the L-oil or H-oil. Consequently bearings become dry more quickly when AN-0-6A oil is used and require more frequent maintenance periods than with the L or H oils in use. h. The method of lubrication on bombsights, stabilizers, flight gyros, and other C-l equipment should be improved. The units are not readily oiled and the oil can be lost form the bearings during operation. i. Breakage of the pins in the A-4 releases is be- lieved to be due to careless handling at installation of the releases by personnel. The weight of the releases when suspended on the receptacles may have also caused the spring contacts to separate in the type A-l receptacle boxes. j. The design feature of unlocking the plates of the B-7 bombsight from its base has proved very desirable for personnel responsible for bombsight maintenance. Re- moval of stabilizers from aircraft is facilitated especially in cold weather. However it has been noticed that little attention is paid to properly adjusting mounts during service use. D. RECOMMENDATIONS 1. The following recommendations are submitted with respect to the observations of behavior of bombing equipment for winter tests of 1944-45. a. Action should be taken to correct the unsatisfac- tory condition of air leakage in B-24 type aircraft with the Type A-15 Emerson nose turret for the following reasons: (1) To prevent bombsight operation from be- ing adversely affected. (2) To make the compartment more comfor- able for operating personnel thus increasing their effi- ciency of action. h. Further steps should be taken to increase the efficiency of the method of bomb hoisting in order to shorten loading time over methods now in use to over- come the discomforts of cold weather on personnel. c. Investigation of bearing failure that ocured on stabilizers should be undertaken, not only considering infrequent lubrication as a source of the trouble, but also considering the effects of cold on tolerances and whether the series of damaged bearings could be poor stock items. d. Determine the frequency with which the bomb- sights, stabilizers and C-l pilot should be lubricated and the types of oil to be used. e. Investigate the possibilities of improving meth- ods of lubrication on bombsights, stabilizers and the C-l automatic pilot. f. Investigate whether the weight of the A-4 release resting on its electrical connector at installation can result in broken pin connectors, and, whether it would be prac- tical to improve the method of mounting by the addition of a locating pin to support weight. 5230 117 g. Investigate whether the spring contacts of the receptacle Type A-l for A-4 releases need strengthen- ing. h. Action be taken to have heating covers installed on C-l automatic pilot units on B-24 aircraft and protect the flight gyro from possible drippage of hydraulic fluid. On B-24 aircraft in which the aileron servo is located near the elevator control chain, action should be taken to relocate it and furnish it with its heated cover. i. If P-51D bomb racks of the present type are con- tinued in use, the desirability for unlocking the bomb hooks at the rack should be investigated. This can be achieved by cutting away the shield at access points already provided on the rack for unlocking it. Remov- able dust shields should be provided if the present shield is cut away. j. Reaction to extreme cold of toggle switches of the type used on bombardier’s panels should be further investigated. k. Action should be taken to make the aileron servo and dynamotor accessible on B-17 aircraft for ser- vicing. l. The discrepancies in the type C-13A thermom- eter installations should be investigated. m. The inspection hole in the end-bell of MH C-l automatic pilot servos should be increased in size. n. B-17G aircraft in production should be fur- nished with an electric outlet in the nose for the type A-l heating cover or the Q-1A rheostat in the nose should be relocated so that it is accessible for plugging in the cover. Low Temperature Tests of the Eight (8) Gun Nose Installed on B-25J Airplane Prepared by: 0. E. Hopkins, Capt., A. C. Armament Laboratory A. PURPOSE 1. The purpose of these tests was to prove the opera- tional reliability of the pneumatic gun charger system at low temperatures. 2. The B-25J-22 was used for test because it had the only standard production installation of the charger system. This charger system is being proposed for numerous other installations and a low temperature test was desired before these production installations were made. B. FACTUAL DATA 1. The eight (8) gun nose for the B-25 airplane is a standard production item designed to the requirements of the Southwest Pacific and the China-Burma-India theatres. It is produced in the form of a kit that will replace the nose on any B-25 airplane produced since the B-25B. The guns are arranged in two (2) banks of four (4) guns each. All guns are mounted on a cant to a common center wall of the nose. The links and cases are ejected through the center wall and are collected in the lower part of the nose. Each of the guns (including the package guns) is fitted with a Kidde Pneumatic Charger, The chargers are operated by three (3) sole- noid valves, one for each bank in the nose and one for the package guns. The pressure is supplied by a Corne- lius Compressor and three reservoir tanks mounted in the nose just aft of the guns. The solenoid valves have two (2) coils. The larger is the actuating coil and the smaller is used to hold the valve open after the actuating coil has opened it. This permits the guns to be operated on the hold back principle, i.e. the guns can be charged to the rear and held there to eliminate “cook-oflf” rounds and to speed cooling of the barrels. 2. The temperatures at Ladd Field during the test season of 1944-1945 have been unusually mild and, as a result, the tests were not conclusive. Only two failures due to low temperatures were found; however, it was not possible to duplicate these failures because of the mild weather and the continuous engine trouble on the airplane. One of these failures occurred on 18 January when one charger did not operate and one occurred on 14 February when the compressor would not start. At- tached as Appendix I of this report is a record of all tests performed. 3. Several failures did occur during tests prior to 22 January; however, these failures could not be at- tributed to low temperatures. These failures were caused by the peening of the stem of the exhaust piston. The result of the peening was that the ball was held off center when the high pressure valve was open and when it was closed, the ball struck the nylon valve seat off center and made a dent in the seat. The ball would no longer seat properly and seal, and all of the pressure reserve was lost. As will be noted in Appendix I of this report, on 22 January new designed parts were in- stalled and no further trouble was experienced. (See 19 February entry of Appendix I). 4. In the early part of December 1944, a visit was made to the Anchorage Air Base by the test officer, and it was learned that there was a B-25J-22 at that base with a defective charger. The airplane was being ferried to the 11th Air Force and had arrived at Anchorage with one gun held out of battery by the charger. The person- nel atthe depot at Anchorage had removed and disas- sembled the charger. The valving rod had been found bent and peened and the washers that form a seat for the spring were bent and battered. A new valving rod had already been made up and the old one scrapped. The 118 5230 charger was brought to Ladd Field and repaired by straightening the washers and replacing the valve seat. The charger then worked satisfactorily and was returned to Anchorage. 5. To facilitate maintenance of this equipment, the following items are noted : a. Certain threads on the chargers and solenoid valves were found to be non-standard, for example 3/8-27. Threads should be made standard so that they can be retapped in case of damage. b. The mounting holes on the solenoid valves need to be at least 1/16 in. further apart so that the valve can be removed with a socket wrench. Present dimensions require that the valves be removed with an open end wrench at the rate of 1/6 turn at a time. c. The elevation boresight adjustment on guns Nos. 4 and 8 cannot be made with the gun installed. This results in “cut and try” methods of boresighting and the gun must be replaced and removed for every try, C. CONCLUSIONS 1. The test season was too mild for the tests to be considered conclusive. 2. The modifications made of the chargers and sole- noid valves on 22 January corrected the failures due to denting the valve seat as a result of peening of the piston stem. D. RECOMMENDATIONS None. Low Temperature Tests of the Armament of A-26B Airplane Prepared by. 0. E. Hopkins, Capt., A. C. Armament Laboratory A. PURPOSE 1. The purpose of these tests was to prove the opera- tional reliability of the A-26B armament at low tem- peratures. B. FACTUAL DATA 1. The armament of this airplane consists of two turrets remotely controlled form a periscope and a “All Purpose Nose.” The nose is so designed that six (6) caliber ,50 machine guns, two (2) 37 m.m. guns or one (1) 75 m.m. gun can be installed. The nose guns are all fixed forward and are fired by the pilot. 2. A record of all tests is included as Appendix No. 1 of this report. The turrets were operated at tempera- tures as low as —38°F. without malfunction. Several malfunctions of the guns occurred due to low tempera- ture. The only low temperature trouble found was that the automatic stowing of the turrets is very slow at low temperatures. The eyepiece of the periscope frosted up severely when cold; however, cabin heat would elimi- nate this. The lower turret is extremely hard to service at low temperatures because of the necessity of having to wear gloves and bunglesome clothing. Three (3) hours were required to remove the guns at minus 40°F. 3. No cold weather problems occurred on the nose armament; however, numerous malfunctions did occur, as will be noted in Appendix No. 1 of this report. 4. The temperatures at Ladd Field were unusually mild during the test season of 1944-1945 and therefore the tests cannot be considered conclusive. C. CONCLUSION 1. The temperatures during the test season were much too mild for the tests to be conclusive. D. RECOMMENDATIONS 1. It is recommended that the inclosures for the “all purpose nose” be built to much closer tolerances or sup- plied purposely oversize and without the fasteners in- stalled so that they can be fitted to each airplane. 5230 119 Low Temperature Tests of B-29 Fire Control System Prepared by: 0. E. Hopkins, Capt., A. C. Armament Laboratory A. PURPOSE 1. The purpose of these tests was to determine the operational reliability of the B-29 fire control system and to determine the effects of low temperatures on the system. B. FACTUAL DATA 1. Attached as Appendix I of this report is the test procedure written for these tests. The procedure was followed through Paragraph 3 on B-29 airplane No. 42-65214. The tests in Paragraph 4 were covered by tests made by Cold Weather Testing Detachment on B-29 airplane No. 42-24768, assigned to that detachment. The tests in Paragraph 5 were not made because the gunners had not had enough practice to be rated and the low temperature weather for the season had passed when the time came to make the tests. 2. The data taken in accordance with the test pro- cedure will be found in Appendix II of this report. a. The data concerning the effect of temperature change on the turret level are fairly reliable; however, they should not be used as specific quantitative data. They should only be considered as qualitative data which indicate that further investigation along these lines should be made. b. The data concerning the accuracy of the com- puter are as reliable as it was possible to make them with- out the use of a computer checker, c. The turret slewing speeds were taken with a stop watch by a man watching the turret. The data are very unreliable because the man who took the speed at plus 76°F was in the hospital when the speeds at minus 25 °F. were taken and the readings had to be taken by another man. d. The data on the static pull necessary to move the turrets are accurate from a comparative standpoint. The pull varies with the angle of elevation of the guns; however, all readings were taken under the same condi- tions. Only three turrets are recorded because heat had been applied to the upper forward and the tail when the readings were made. C. CONCLUSIONS 1. The level of the turrets does vary with a change in temperature. Since the specification calls for the turrets to be levelled to within 0.5 mills with respect to the lower forward turret, the variation due to tempera- ture change warping the fuselage is of sufficient magni- tude to warrant further investigation. 2. The fire control system will operate satisfactorily when the free air temperature is as low as minus 58°F. when cabin heat is on. No tests were made with the cabin heat off. D. RECOMMENDATIONS 1. It is recommended that the change in turret level due to temperature change warping the fuselage be in- vestigated further. Cold Weather Operation of Stewart Warner Corporation Model 904A Ground Heaters Prepared by: W. H. Giedt, 1st Lt., A. C. Equipment Laboratory. A. PURPOSE 1. To report on the cold weather operation of two Stewart Warner Corporation Model 904A Gound Heat- ers during the 1944-45 test period at Ladd Field, Alaska. B. FACTUAL DATA 1. The two test units were operated from 14 Decem- ber, 1944 to 8 March, 1945. A record of the surface tem- peratures encountered during this period is included as 120 5230 Engine overhaul—B-24 Appendix I of this report. The lowest temperatures were experienced during the period from 11 to 14 Feb- ruary, 1945, at which time the lowest temperature re- corded was —45 °F. 2. Attention is called to Appendix II for the operat- ing and maintenance record of Stewart Warner Ground Heater, Model 904A, Serial No. X598. 3. Attention is called to Appendix III for the oper- ating and maintenance record of Stewart Warner Ground Heater, Model 904A, Serial No. X599. 4. The engines required maintenance approximately 112 hours of operation. Maintenance on the heat ex- changers was required approximately every 85 hours of operation. 5. The use of 73 octane fuel caused the formation of carbon deposits in the exchangers (see photographs Nos. 1 and 2). No similar deposits, were noted with the use of 100/130 octane fuel. 6. It was noted at the close of the test period that the flexible ducts of the heater, Serial No. X598, were be- ginning to deteriorate. 7. Considerable difficulty was experienced in disas- sembling the heat exchangers due to the inadquacy of the bosses on the heat exchanger flanges. This unnecessar- ily increased the time required for heat exchanger main- tenance. 8. Curves showing representative engine temperature rises during engine preheating are included as Appendix IV of this report. Engine preheating tests were run with a Stewart Warner Model 904A heater, an F-l Util- ity heater, and a D-l heater to obtain comparative data. C. CONCLUSION 1. More maintenance was required on both the en- gines and the heat exchangers than is desired. 2. The return spring on the kick starter is not satis- factory, D. RECOMMENDATIONS 1. Modifications should be made to the engine so that less maintenance is required. 2. The heat exchanger should be modified tosecure more satisfactory operation with 73 octane fuel. 3. The bosses on the heat exchanger flange should be made larger. 4. A stronger return spring for the kick starter should be provided. 5230 121 Experimental Installation of Stewart Warner Corporation Model 911A Combustion Heaters in B-17G Prepared by: W. H. Giedt, 1st Lt., A.C. Equipment Laboratory A. PURPOSE 1. To report on cabin heating tests conducted in B-17G No. 43-38221 with two Stewart Warner Corporation Model 911A heaters installed in place of the secondary heat exchangers of the production heating system. B. FACTUAL DATA 1. Under the supervision of company engineers two Stewart Warner Model 911A heaters were installed in place of the secondary heat exchanger now installed in production B-17G airplanes. The primary heated air system was disconnected. Attention is called to the photograph section of this report for further details of the installation. 2. Heater operation was very satisfactory up to ap- proximately 20,000 ft., somewhat irregular from 20,000 to 25,000 ft., and definitely unsatisfactory above 25,000 ft. Although some malfunctions were noted in the oper- ation of the thermal switch controls and the fuel metering controls, the primary difficulty above 20,000 ft. was igni- tion. For further information concerning the operation of the subject heaters during the flight testing attention is called to Appendix I. 3. Flight test data is included as Appendix II to this report. The following items are noted: a. The highest temperature rises were obtained in the pilot’s compartment. Heat supplied to this compart- ment was sufficient to meet winterization requirements. b. Insufficient heat was supplied to the bombardier’s and radio compartments to meet winterization require- ments. Although the temperature distribution through- out these compartments was rather uneven, temperature rises observed indicate that approximately 75 to 80 per- cent of winterization requirements were met. Insulation of these compartments is a possible solution to this de- ficiency. c. Although temperatures in the tail gunner’s com- partment showed that insufficient heat was supplied, it is not possible to make a definite statement to this effect, insofar as some of the ductwork in this compartment had been removed when the tail guns were removed and the compartment modified. However, it is felt that, if the airplane were to be heated by combustion heaters, use of a separate heater mounted in the ,waist compartment and supplying heated air to the tail compartment and for de- frosting the waist windows should be considered. C. CONCLUSIONS 1. The installation as tested was not satisfactory. 2. The subject heaters could be used for heating this type airplane if they were modified so as to give satisfac- tory operation up to the service ceiling of the airplane. D. RECOMMENDATIONS 1. Flight tests should be conducted on improved com- bustion heater ignition systems and combustion heater operation at altitudes above 25,000 ft. 2. The thermal switch controls and fuel metering con- trols used in the subject installation should be removed from the airplane and sent to the Stewart Warner Cor- poration for inspection. Appendix I A. The Model 911A heaters as installed were supplied with ventilating and combustion air from scoops in the leading edges of the wings, and with fuel under pressure from the No. 2 and No. 3 engine pumps. The fuel-air mixture to each heater was controlled by a Stewart Warner fuel metering control (See Photograph No. 5). Top view of surface combustion heater installed in place of the secondary heat exchanger. Note aluminum tubing above heater. Small holes in bottom side of this tubing discharge CO., in case of fire 122 5230 Restricting solenoid valves used with the fuel shut-off solenoid valves permitted “Hi” and “Lo” control over heater output. Glow coil type ignition was used. B. In general heater operation up to 20,000 ft, was satisfactory. Above 15,000 ft. on “Hi” output both heaters cycled on overheat. Above 20,000 ft. reignition of the heaters was very difficult. Results obtained on several different flights indicated that reignition above 24,000 ft. and at temperatures below —40°F. was im- possible. C. To obtain information on the cabin heating poten- tialities of the installation above 25,000 ft., the heaters had to be ignited at a lower altitude and the outlet air temperatures kept below the overheat value (250°F.) above that altitude. To accomplish this the fuel metering controls were moved from the wings into the radio com- partment so that the fuel input to the heaters could be controlled in flight. Attention is called to the data of flight six in Appendix II taken at 30,000 ft, after heater operation to this altitude had been obtained by adjust- ment of the relocated metering controls. Although heat- er outlet air temperatures were held as close as possible to the overheat value during the climb, after leveling off at 30,000 ft. these temperatures dropped considerably. This was probably due to reduced ventilating airflow during the climb. D. Data taken on flight six shows that, with the ex- ception of the pilot’s compartment, sufficient heat was not supplied to meet winterization requirements. However, it should be noted that the heater outlet air temperatures were not as high as possible, and, therefore the capa- cities of the heaters were not fully utilized. It is possible that with an improved type of ignition and proper ad- justment of the fuel metering controls, sufficient heat could be supplied to meet winterization requirements. E. After approximately 100 hours operation of the right heater it was noted that the fenwal switch in the Stewart Warner Thermo Switch Control controlling the restricting solenoid valve was apparently not operating properly. This was indicated by the fact that the light on the control panel (See Photograph No. 6) in the overheat circuit would go out when the heater went out on overheat, while the light in the restricting solenoid circuit would remain on. Replacement of the Thermo switch resulted in proper operation for a short period of time, after which the same malfunction was noted. This malfunction also appeared in the left heater control after approximately 150 hours of operation. Because of this the heaters were operated in “Lo” above 25,000 ft. F. On a later flight after approximately one hours flight at 30,000 ft. and an outside air temperature of —-65°F. with both heaters inoperative, attempts were made to start the heaters after descending to 24,000 ft. Although the right heater ignited, the left heater would not, apparently due to improper operation of the fuel metering control. It was noted that when the heater was turned “ON”, the fuel pressure to the heater dropped to 0 psi. When the heater was turned off, the pressure to the heater rose to a value in excess of engine fuel pres- sure. Insofar as proper operation resulted when lower altitudes and warmer temperatures were reached, it is felt that the excessively cold temperatures encountered may have affected this control. Cold Weather Tests of Heating Oil and Batteries on Types C-13 and C-13A Auxiliary Power Units Prepared by: C. E. Wood, Capt., A. C., Equipment Laboratory A. PURPOSE 1. To report experimental tests of various methods of heating the subject power plants with Prefection Stove Co. engine coolant heaters. 2. To report the performance of the coolant heaters used during the experimental tests. B. FACTUAL DATA 1. GENERAL. a. The crank case oil and the batteries on the standard winterized type C-13 A. P. U. do not receive sufficient heat from the heated coolant to permit starting their engines by cranking electrically. b. Experiments were undertaken to find a simple means of supplying the necessary heat by utilizing; (1) Heat from the exhaust stack of the Super- fex Model 460 Coolant Heater (new blower type) ; (2) Warm coolant from the engine block in a heat exchanger located under the batery ; (3) A mixture of warm coolant from the en- gine block and hot coolant from a Model 454 (Modified Standard Model 452) coolant heater in a heat exchanger located under the battery. c. The experimental equipment was installed on two Type C-13 and one Type C-13A auxiliary power units described in Table I, page 125. d. New types of coolant heaters, Superfex^Model 460 and Perfex Model 454, were available and undergo- ing service testing by the Cold Weather Testing Detach- ment. The latter heater is a standard model 452 modified with a coil type coolant heat exchanger and electric igni- tion. Both models were used in these tests to study their performance. 2. BATTERY HEATING. a. Standard Winterized Type C-13 A. P. U. Unit No. 23. The following temperature measurements indicate typical results obtained with heat applied to the engine coolant only: 5230 123 Date* Average Period °F. °F. 1945 O. A. T.#* Hrs.-Min. Average Temp. Rise above O. A. T. Jan. °F. Cyl. Hd. Battery 18 —7 7:25 142 13 19 1 6:05 126 7 ♦Table I Exhibit A ♦♦Outside Air Temperature b. Exhaust Gas Heat Exchanger. Utilizing heat from the exhaust of the Model 460 heater provided a maximum temperature rise in the battery of 65 degrees at —39°F. with an average temperature rise of 57 de- grees during a period of 8 hours and 55 minutes. See Table HI, 13 February 1945 and Photographs Nos. 2 and 6, Exhibit B. c. Mixing Hot Coolant with Warm Coolant from Engine Block, Unit No. 86. The average temperature rise in the battery on Unit No. 86, which was equipped with the by-pass shown in Exhibit C, was 39 degrees dur- ing the same period quoted in Paragraph B 2.b. The bat- tery heater is shown in Exhibits D.l and D.2 and Photo- graph No. 8, Exhibit B. 3. CRANK CASE OIL HEATING. a. Standard Winterized Type C-13 A. P. U. Unit No. 25. The highest average temperature rise obtained in the oil of Unit 25 before application of the battery heater was 53 degrees at —7° F.O A.T., Table I, 18 Jan- uary 1945. The average in the cylinder head was 136°F. The actual oil temperature at —33°F. O. A. T. was 5°F., Table HI, 13 February 1945. The standard method, i. e., heating crank case oil by circulating hot coolant in the cylinder head of the engine, does not provide suffici- ent temperature rise to maintain the oil fluid at outside air temperatures below —40°F. b. Heater Exhaust Pipe under Crank Case Unit No. 79. The average temperature rise in the oil of Unit 79 was 77 degrees at —26°F. average O. A. T. The ad- ditional heat obtained from the exposed exhaust pipe on Unit No. 79 produced a satisfactory temperature rise in the oil, and it is obvious that hot air only without heated coolant in the engine block would accomplish the same re- sult. All considerations of housing the pipe to reduce fire hazard point to the advantage of using blast heat at lower temperatures. 4. CRANKING AND STARTING. a. The use of external heat for cranking and start- ing Types C-13 and C-13A A. P. U.’s is necessary at out- door temperatures below 10° F. A heating system should Coolant heaters mounted on auxiliary power units be developed to produce 70 degrees rise in the oil and bat- teries at —65°F. O. A. T. b. The Type R-l generator on the Type C-13 A. A. P. U. cranks the engine satisfactorily at approximately 0°F. oil temperature; whereas, the Type P-1 generators on the Type C-13 A. P. U. do not crank the engines satis- factorily at oil temperatures below 10° F. c. When operating at normal temperatures, the Type C-13A carries overloads of short duration with very little loss in speed of its engine. The type C-13 loses con- siderable speed and/or stalls. 5. HEATERS. a. The Model 460 heater has a number of features that warrant improvement: (1) Tilting affects the level of gasoline in the feed wick chamber, which, in turn, affects the rate of feeding gasoline to the burner and, therefore, the heat output. (2) The height of the wick is adjustable and marked LOW and HIGH. Proper wick adjustment can- not be determined without making several trial settings if the A. P. U.’s stand on rough ground. (3) The wire to the ignitor is not supported be- tween connections and is not protected against mechanical damage. (4) The wire is provided with a cord type con- nector but the using personnel do not always separate the TABLE I Identification No . 79 26 86 Manufactured by Unit Model A-APU The Wauhesha Motor Co. C-APU A-APU Unit Serial No 300148 306342 13289 Engine Model 1CK67-143 1CK67-C 1CK67 Engine Speed, rpm 1900 3000 1900 Order No 42-18505P 43-66385 42-1S50BP Crank Case Oil, Detergent, Spec. No 2-104B 2-104B 2-104B Capacity, KW 5 7.5 5 Volts - 28.5 28.5 28.5 175 263 175 Generator Type P-1 R-l P-1 Gen. Mfr Westing- house Jack and Heintz Westing- house 91A987GR3 R-l 91A987GR3 460 460 464 (462 modified) Wick Size 1/2" Standard Method of Battery Heating Heater Engine Coolant Engine coolant with hot coolant by-pass. Winterization Kit Applied yes yes Electric Starting (Std) yes yes 124 5230 connector when removing the ignitor resulting in break- age of the terminal lugs at the igniters. (5) Some evidence points to leaking needle valves as causes of fires with the Model 452 heater. The Model 460 heater incorporates a similar float operated needle valve. It is believed greater closing pressure on the valves would be beneficial. (6) Several operations are required to start or shut off the heaters, involving “wait periods” described in Appendix A, Paragraph B.3.a (6). Flight line per- sonnel do not always wait the required two minutes for gasoline to reach the burner when starting the heater be- fore pressing the ignitor switch. This overheats the ig- nitor element causing rapid deterioration. Likewise, when shutting off the heater, some persons fail to comply with one or another of the operations. This experience indi- cates the necessity for reducing the number of operations for starting and stopping the heaters. (7) When the heaters are allowed to stand idle for a considerable period of time with the gasoline ON and the wick adjustment in the feeding position, the gasoline syphons from the burner by capillary action and drips to the ground. Igniting one of the heaters in this condition failed to produce a fire, but this has been the cause of fires with the Model 452 heaters. (8) The condition mentioned in B.5.a. (7), causes an excessively high flame when the burner is ig- nited and flame emits from the stack. b. Model 454 Heater. (1) The coil type heat exchanger being of small diameter tubing with 3/8" I.P.T. connections causes re- striction to the flow of the coolant resulting in an excess- ively high temperature rise within the heater, (2) The electric ignition and associated modi- fication parts must be disconnected and the igniter must be removed to light the burner manually in the event the electric igniter fails. This is a difficult operation. Likewise, igniting the burner through the peep-hole is difficult. c. The capacities of both models of heaters are more than ample to heat the coolant and batteries of Type C-13 A.P.U.’s. d. The current drain from the battery to operate the blower on the Model 460 heater is negligible, l/10th amp. e. Wind had no noticeable effect upon the burner of the Model 460 heater when an A.P.U. was placed in the blast from the propeller of a Type B-25 airplane. The heater was approximately 6 feet from the propeller. /, The sizes of the pipe connections in the heaters and also in the engine blocks of the auxiliary power plants were found to be too small for good functioning of the thermosyphon system. C. CONCLUSIONS It is concluded that 1. The following modifications, if incorporated into the Superfex Heater Model 460, will accomplish de- sirable improvements: a. Incorporate the float and wick chambers in the base of the heaters, or as close to the burner as possible to reduce the changes in fuel levels that occur when the heaters are tilted. h. Equip the float valve assembly with “snap action” to operate the needle valve and provide as much spring pressure on the needle valve as possible. c. Provide a socket type receptacle for the igniter which will permit supporting the connecting wire on the heater and protecting it from mechanical damage. In this case, the igniter would have contacts to mate with the contacts of the socket and the cord connector would be unnecessary. d. Mount the control switch on a junction box with the main fuse inside. Provide a means of access to the fuse that does not require the use of tools. Provide armored wire for the main lead and eliminate the fuse holder type cord connector. e. Eliminate the “wait periods” in starting and stopping the heater. Each of these operations should be accomplished with one movement. f. Provide larger pipe connections for coolant lines, preferably not smaller than one inch I.P.T. In cases where kits are supplied with the heaters and coolant lines are of rubber hose, the hose and connecting fittings should be AN standards available in Army Air Forces stock. g. Provide flame quenching type smoke jacks. 2. The Model 460 heater has sufficient capacity to heat all components of the Types C-13 and C-13A A.P.U.’s and can be substituted for the Model 452 heaters now in service. The alterations to the heater bracket required to make the substitution can be ac- complished by the Services. 3. The advantage of the electric ignition feature of the Model 454 over the former manually ignited Model 452 is largely outweighed by the poor performance of the new coil type heat exchanger. The expenditure of man hours to make the conversion is not justified. 4. The use of external heat for heating the com- ponents of the types C-13 and C-13A A.P.U.’s is re- quired as follows: a. Coolant (60-40 mixture of ethylene glycol and water) at temperatures below —40°F.; b. Crank case oil, detergent, Specification 2-104B, at temperatures below 10°F.; c. Batteries, at temperatures below 10° F. 5. Since the oil and crank case require the greatest amount of heat, primary heating should be applied to them and secondary or waste heat allowed to heat the coolant. 6. The exhaust method of supplying heat to the oil and battery was tested as a possible immediate remedy, yet it was recognized as not being the most desirable method, due to Coolant heater used to heat oil and battery pf auxiliary power unit 5230 125 a. Fire hazard, from oil accumulation on the floor of the enclosure coming into contact with the hot exhaust pipe; b. Condensation from the products of combustion collecting in the exhaust pipe and battery heater. 7. The most advantageous method of accomplishing the conclusions of Paragraph C.5., would be with the use of hot air blasts under the crank case and battery. The winter enclosures for the Types C-13 and C-13A A.P.U.’s is sufficient insulation to maintain heat for warming the coolant. 8. Heaters, similar to the Model 460, could be de- signed with an air heat exchanger and a dual purpose blower; not only to provide forced draft to the burner, but also to force hot air through ducts to the crank case and battery. D. RECOMMENDATIONS It is recommended that 1. Battery heating kits be furnished to the services for application to winterized Type C-13 A.P.U.; the procurement to be on the basis of past procurement of winterization kits containing Model 452 heaters, and future procurement of kits containing the Model 460 heater. The battery heating kits to consist of the fol- lowing : a. Heater, Auxiliary Power Plant, Exhibit D-l; h. Case, Auxiliary Power Plant Battery Heater, Exhibit D-2; c. Necessary ED. rubber hose and fittings to connect the battery heater to the coolant heating system in the manner illustrated by the Schematic Diagram, Exhibit C. 2. The procurement recommended in Paragraph D.l. be considered an immediate remedy to improve the utility of the winterized Type C-13 A.P.U.’s. 3. Procurement of the Model 460 Heater be limited to necessary requirements for a. Replacing salvaged Model 452 heaters on ex- isting Type C-13 A.P.U.’s; b. Type C-13 A.P.U. winterization kits procured in the immediate future and until such time as an im- proved type heater is available. 4. The improvements suggested in Paragraph C.I., be incorporated into the Model 460 heater at the earliest date possible. 5. A project be initiated to develop a suitable hot air blast type engine and battery heater suitable for appli- cation in the field to Types C-13 and C-13A A.P.U.’s. Generator and Starter Failures During Cold Weather Tests Prepared by. C. E. Wood, Capt., A. C. Equipment Laboratory A. PURPOSE 1. To report failures of aircraft electric generators and starters that occurred during the Cold Weather Test Program of 1944-45. B. FACTUAL DATA 1. A list of all failures of the subject equipment is at- tached as Appendix I. Explanatory notes under “Re- marks’’ state briefly the cause of each failure; however, attention is directed to the following specific items: a. Item 4. All but one of the bolts holding the mag- net frame to the mounting flange were found broken and it is claimed, by those who removed it, that the paint at the joint was not cracked. It was believed that the bolts had been drawn too tight when the generator was assem- bled, resulting in their being over-stressed. Inasmuch as the generator was not damaged, new bolts were applied and tightened to 125 lb. in. torque after which it was tested and re-applied to the same engine at the next 100- hour inspection. The new bolts have not failed to date, substantiating the belief that the original bolts were over- stressed when applied. b. Item 19. None of the starters on the airplane were mounted on 1/16" spacers to prevent contact be- tween the meshing rod and the engine accessory shaft. There was evidence also of interference on No. 4 Engine, but no damage. There was no evidence of interference on Engines Nos. 1 and 2. Four starters, lubricated with special lubricants (Materials Lab. project) were install- ed, using the 1/16" spacers. There was considerable engine oil (synthetic) on the spline shafts and jaws of all starters. Also, the meshing mechanisms were stiff at cold temperatures. Two were set aside and tested after cold soaking at —37°F. (Avg. of previous 12 hrs.) : (1) Type 915, Model 4, Style F, Solenoid EA- 123228, Serial Nos. A2292 and A2293. No. A2293 was equipped with an improved type solenoid. (2) Both were very difficult to move by hand. Jaws would not return fully when released. Meshing operated satisfactorily with a warm battery, but would not operate with a 50% charged cold battery. No dif- ference in operation could be detected that might be attri- buted to the improved type solenoid on No. A2293. (3) The engine oil on the splines and jaw was judged to be the largest contributing factor to stiffness at cold temperatures. c. Item 20. It was noticed that the starter applied, and then removed on 30 January 1945, had not been mounted on a 1/16" spacer. This was due to the lack of T. O. authority to apply the spacers. d. Item 21. There was excessive oil in the gear case and in this instance, it had flowed into the motor r?.u„. outside of the bearing at the flywheel end (sliding fit). e. Item 8. While the primary cause of the failures was congealed engine oil on the splines, Serial No. 3113 126 5230 also had a worn solenoid valve sleeve which when meshed manually would cock and become immovable. The JH- 999 solenoid was replaced, the jaws and splines were cleaned and relubricated, and the starters were replaced on the same engines after which they operated satisfac- torily. 2. The failures resulting in burned out motors, broken jaws and spline shafts, except Item No. 19, occurred during attempted cold starts of engines. a. In the cases where parts were broken, Item 12, broken jaw, was not due to oil in the clutch. Apparent- ly, the clutch failed to function. The broken screw shafts, Items 17 and 18, may have been caused by oil in the clutches. h. Motors were burned out by holding direct crank- ing ON too long. Frequently the temperatures encoun- tered when cold starts are attempted are different from those anticipated when the engines were diluted, result- ing in the engines being unduly stiff when starts are attempted 3. The failures referred to in Par. 2 are a repetition of those encountered and reported during the cold weath- er tests of 1943-44. A large part of the testing activity this season was again devoted to making cold starts, and inasmuch as the primary object of the tests was to ascer- tain if the engines could be started, possible resultant damage to starters was of secondary consideration and resulted in the failures cited. 4. There were, in addition to the failures listed in Ap- pendix I, thirteen failures on Type P-63 Lend-Lease Aircraft wherein the JH-1729-35 bolts broke on Type JH5LR Starters. These, together with failures of the Jack & Heintz Equipment listed in Appendix I, were reported to the Jack & Heintz Company by their local representative. 5. All failures of Eclipse equipment were reported to Eclipse Pioneer Division of Bendix Aviation by their local representative. C. CONCLUSIONS 1. The use of the inertia feature of start- ers, for making cold starts, should be discontinued in order to alleviate breakage in the starters. 2. The number of burned out motors is indicative of the status of the progress of cold starting, and until such time as the technique is perfected, similar results can be expected with existing starters. D. RECOMMENDATIONS 1. That the information contained herein be referred to the project engineers for such action that they may deem necessary. Type D-2 Auxiliary Power Plants, Cold Weather Tests Prepared by. C. E. Wood, Capt., A. C. Equipment Laboratory A. PURPOSE 1. To report the general performance of the subject power plants during the cold weather testing program. B. FACTUAL DATA 1. There have been no electrical or mechanical fail- ures of the power plants during the season and minor malfunctions of that character were in the nature of fouled spark plugs and minor adjustments. 2. It was recognized that, like any gasoline engine, they would be difficult to start at low temperatures. This was true of a unit installed in E. T. O. U. Airplane No. 43-48088, Type C-47A, which was extremely diffi- cult to start at outside temperatures below 0°F. How- ever, reports indicated that the Type D-2 units on Type B-29 airplanes (standard installation) were started at various temperatures (not recorded) much lower than 0°F. 3. The matter was investigated in flight on Type B-29, Airplane No. 42-65214, which is equipped with a Model 906 Stewart-Warner Heater for warming the A. P. P. The unit was equipped with thermocouples at the loca- tions listed in Appendix A, and temperatures were re- corded for a period of approximately 6 hours. They are listed in the Log of Observations and shown in graph form in Appendix I. 4. The results indicate that air leakage from the pre- surized cabin maintains the adjacent compartment, in which the A. P. P. is located, approximately 10°F. higher than O. A. T. in the range from —20°F. to —36°F. The A. P. P. cooled rapidly and followed the compartment temperature closely. 5. During descent, the compartment and A. P. P. temperatures increased more rapidly than O. A. T. and the engine temperatures followed closely. This explains the somewhat better results that were obtained in start- ing the A. P. P.’s in Type B-29 airplanes. C. CONCLUSIONS 1. The results suggest possible modifications for warming the A. P. P.’s during flight. a. They should be housed in a sturdy but easily re- movable enclosure, and heated by : 5230 127 (1) Combustion type heater similar to the ex- perimental application on Airplane No. 42-65214, but one not dependent on rammed air as this type cannot be used on the ground, or (2) Waste cabin air conducted to the housing through a duct and controlled by a pressure relief valve at the duct entrance, or (3) Thermostatically controlled electric heaters in the crank case oil and at the cam shaft locations, and cabin air piped to the carburetor. D. RECOMMENDATIONS 1. That this report be referred to project engineers concerned for consideration in connection with studies of the subject now under way. Electrical Loads, Feathering Pro- pellers at Cold Temperatures and Hydraulic Pump Motors Prepared by. C. E. Wood, Capt., A. C. Equipment Laboratory A. PURPOSE 1. To report electrical loads encountered at low tem- peratures while feathering and unfeathering propellers actuated by hydraulic systems. 2. To report investigations of malfunctions of hydrau- lic pump motors used for propeller feathering. B. FACTUAL DATA 1. Equipment involved: a. Airplane Type C-47A-30-DK, No. 43-48088. Left Engine: Oil, Spec. 1100A. Propeller, Hamilton Standard (hydraulic). Propeller Fluid, Spec. AN-VVO- 366 (Test installation). Right Engine: Oil, Synthetic, Spec. PPO-265. Propeller, Hamilton Standard (hydrau- lic). Propeller Fluid, Engine Oil (Standard installa- tion). b. Hydraulic Pump, Motor Driven, Pesco Model AR-280BH; operating pressure, max. 1200 p.s.i. (The by-pass relief valve spring had been replaced to reduce the max. operating pressure to 100 p.s.i.) Duty-Lift pump for delivering hydraulic fluid AN-VVO-366B from bomb bay tank to standard propeller feathering pump in nacelle, B-24J airplane. (Test installation). c. Hydraulic Pump, Motor Driven, Pesco Model AR-280-BHC; B-17G Airplane; standard installation; engine oil, Synthetic Spec. PPO-265. 2. During propeller feathering tests while in flight on 29 December 1944, the main fuses for both engine driven generators were blown on the Type C-47 airplane de- scribed in Par. B.l.a. The propellers were feathered and unfeathered successfully. The airplane is equipped with a Type D-2 Auxiliary Power Plant which was used to restore power to the electrical system. The main generator fuses are 100 amp. capacity and located in the nacelles. 3. Electrical malfunctions in feathering systems of the hydraulic type have been fairly common during the test program. This is particularly true of the standard in- stallation on engines filled with Spec. 1100A oil wherein viscous oil at low temperatures imposes heavy electrical loads on the system when the propellers are feathered On two engine aircraft, if one engine fails and the main generator circuit protector of the other generator opens when the propeller is feathered, the airplane is left with battery power only unless the circuit protectors are ac- cessible to the crew. 4. To avoid repetition of the failure, 100 amp, circuit breakers (Spencer) were installed in place of the fuses in the Type C-47 A airplane. They have successfully withstood the overloads of subsequent feathering tests, but information is not at hand to determine if their in- verse time-current ratio is adequate to protect the cir- cuits on all overloads that might be encountered. 5. Personnel conducting the feathering tests ,were re- quested to observe the electrical loads while feathering. The observations, together with pertinent data, are listed in Appendix I. The installations using hydraulic fluid are for test purposes only. The synthetic engine oil, Spec. PPO-265 is still in its testing stage; however, it is in .use on A. T. C. airplanes, Type C-47, on regularly scheduled flights on the Alaskan Div. 6. Attention is directed to the current demand, Ap pendix I, with synthetic oil at —52°F. of 150 amps, and 125 amps, respectively, for the feathering and unfeather- ing operations, whereas, with regular Spec. 1100A oil at —26°F., the current demand was 190 amps, and 120 amps, respectively. With the latter oil, successful feath- ering is problematical at low temperatures. The results with the test systems using hydraulic fluid are quoted as a matter of interest only. 7. The motor described in Par. B.l.b. overheated while operating at the reduced load indicated and was stopped before complete burn out occurred. It had oper- ated satisfactorily at 10,000 ft. Alt., 20°F, and failed approximately 30 minutes later when operated at high altitude, 33 °F. The motor bearing at the pump end (sealed type ball bearing) was found to be rough and stiff. 8. The motor described in Par. B.l.c. was burned out and its corresponding bearing was found to be in the same condition. The motor and pump had operated sat- isfactorily on a previous flight at —56°F wherein the propeller feathered in 14 seconds and unfeathered in 7.3 seconds. It failed on the repeat test —59°F in 15 seconds, while feathering, by stalling. 128 5230 9. The inner races of both bearings were corrugated washboard fashion. The evidence points to differential expansion, and contraction—expansion of the inner race from heat in the armature while the outer race was con- tracted from cold. 10. Other pump motor failures have been due to over- loads while pumping viscous oil, principally the regular Spec. 1100A, during the propeller feathering tests. C. CONCLUSIONS 1. PROPELLER FEATHERING. a. Two-engine aircraft, equipped with main gen- erator fuses having less than 300 amp. capacity, should be modified to conform to latest specifications requiring circuit breakers. The circuit breakers should have an inverse time-current ratio suitable for the current-time loads quoted in Appendix I. h. The circuit breakers should be relocated ac- cessible to the crew to permit re-closing in the event they open. 2. MOTOR BEARINGS. a. The ball bearing failures described are 3ue to either: (1) Use by the manufacturer of contact fitied ball bearings, or (2) The tolerances for machining the bearing fit on the armature shaft are too great and, in some in- stances, the inner races of the bearings are expanded when pressed onto the shaft. D. RECOMMENDATIONS 1. That this report be referred to those concerned for such further action that they deem necessary. Main Generators - Type B-29 Air- plane, Cold Weather Tests Prepared by: C. E. Wood, Capt., A. C. Equipment Laboratory A. PURPOSE 1. To report on the operation of Type R-l generators of two manufacturers when intermingled on one airplane. 2. To report difficulties experienced in paralleling generators on the Type B-29 airplane. B. FACTUAL DATA 1. Three Type R-l generators, engine driven, G. E. Model 26M73B-6, were installed on a Type B-29 air- plane and intermingled with remaining J & H generators as follows: a. Airplane No. 42-24612 Engine No. 1—Outboard JH-2000 Engine No. 1—Inboard JH-2000 Engine No. 2— G. E. Engine No. 3— G. E. Engine No. A—Inboard JH-2000 Engine No. A—Outboard G. E. Date G. E. generators installed — 29 January 1945. 2. The G. E. generators, being interchangeable, were installed by the crew and allowed to remain in service without special attention. There have been no failures to date, nor malfunctions; however, it was reported that the adjustments for paralleling the generators were diffi- cult with either type. This had no relation to cold weather. 3. Since it would not be possible, while on a cruising flight, to obtain a large electric load that would remain constant and remit making the necessary adjustments for paralleling, observations were made on a flight during which numerous landings were made. The operation of the landing gear and the wing flaps imposes the largest single load on the generators. 4. A log of observations is attached as Appendix I, which indicates the adjustments made to the voltage regulators. Since it was not possible to obtain a large steady load, it was not possible to check the division of load between the generators under such conditions. C. CONCLUSIONS 1. It is not practical, nor is sufficient steady load available, to properly adjust the division of load between the generators on the Type B-29 airplane while in flight. 2. An external means should be provided for apply- ing an electric load to the generators. a. Preferably while the airplane is on the ground. b. While on test flights for the purpose of adjusting the generator regulators. 3. It is possible to operate the airplane engines during cold weather a sufficient period of time to accomplish the adjustments without overheating the engines. 4. Any external loading means developed should be compact, easily portable and preferably of a fold-up type. D. RECOMMENDATIONS That those concerned give consideration to the problem presented in the conclusions of this report with a view toward development of a suitable means of loading engine-driven generators externally. 5230 129 Power to Operate Landing Gear Retraction Motors at Low Temp- eratures, Type B-29 Airplane Prepared by: C. E. Wood, Capt., A. C. Equipment Laboratory A. PURPOSE 1. To report measurements of power input to land- ing gear retraction motors when operated at low tem- peratures. B. FACTUAL DATA 1. Those present: Major S. C. Britton, AC, Ma- terials Lab. Rep. Captain C. E. Wood, AC, Equipment Lab. Elect. Branch Rep. Mr. G. V. Roark, Tech. Rep., Texas Oil Company. 2. Equipment: a. Airplane Type B-29 No. 42-65214. b. Power Source—Type C-APU (Dual Unit). c. Ammeters, with shunts in main retraction motor circuits. d. Right retraction motor lubricated with Royco 6A and Royco 50, standard factory lubricants. e. Left retraction motor lubricated with Texas TG-204 (equivalent to proposed AN Spec, intermediate grease). 3. The primary purpose of the test was to ascertain differences in the lubricants at low tejnperature and this phase of the test is the subject of M/R, TSEAL-4- M4966-VII. It concludes that differences in operation of the landing gear that might be due to lubricants are not discernable at temperatures above —20°F. 4. Of interest to Dept. TSEPL-3, is the power re- quired to raise the landing gear: a. Airplane on jacks in hangar approximately 72 hours preceding test. Gear Test Volts Amps at Intervals Indicated Time Up Temp. at Seconds Seconds F A.P.U. Int. 5 10 15 20 25 30 40 1. Left 73 Low* 260 90 .... 180 196 186 164 155 38 Right 73 Low* 260 100 .... 185 200 210 203 180 46 2. Left 70 Low* 90 .... 168 185 192 185 150 46 Right 70 Low* 180 95 .... 175 193 202 205 200 51 ♦ Excessive voltage drop in long cables to A.P.U. outside of hangar. Volts at A.P.U. 30V. Insufficient power to raise gear simultaneously. b. Airplanes on jacks outside of hangar approxi- mately 24 hours preceding test. Length of wire to A.P.U. approximately 10 ft. Gear Test Volts at Amps at Intervals Indicated Temp, ret.mot. Seconds Time Up Seconds °F Int. Single—1st Operation 5 10 15 20 25 30 40 Left —3 30* 260 115 160 175 185 163 30 —3 30 295 115 170 204 205 195 180 30 Single—2nd Operation Left —3 30 240 105 153 182 175 155 28 Right —3 30 300 110 Simultaneous—3rd Operation 165 198 202 190 180 30 Left —3 30 95 120 170 190 165 150 28 Right —3 30 110 Total 205 * Volts at A.P.U. 28.5, no load. 160 280 195 "365 202 392 190 355 31 C. CONCLUSIONS 1. The data contained in this report is submitted as information and no action is necessary. Type C-12 Engine Driven Power Plant, Cold Weather Tests Prepared by: C. E. Wood, Capt., A. C. Equipment Laboratory A. PURPOSE 1. To report experiments in heating a Type C-12 Power Plant (Bardco) using a Superfex Model 460 Coolant Heater. B. FACTUAL DATA 1. Four Type C-12 power plants, two manufactured by Bardco and two manufactured by Buda were received by the Cold Weather Testing Detachment for service 130 5230 testing under cold weather conditions. This phase of the testing will be reported by the Cold Weather Testing Detachment. 2. Difficulty was experienced in providing a 240 V. 3 phase load and, after advice was received from the Base Engineer that it would not be possible to connect the power plants to any of the base facilities without exten- sive power line changes, it was decided to use a water rheostat. Although it was late in the season, one was con- structed locally and put to use but there was not suf- ficient time to complete life tests. 3. This made a Bardco unit available for an experi- mental installation of a coolant heater, which was started 10 February and completed 16 February. Photographs are attached as Exhibit A, showing the installation located on the back wall of the engine compartment. This location was the only space available inside of the unit housing. 4. A coolant type battery heater (similar to the type used on Type C-13 A.P.U.’s) was installed in the bottom of the battery box and connected between the engine block and the coolant heater inlet. The heater outlet was con- nected vo the coolant manifold on the engine with a *4" copper tube vent line to the radiator. 5. The location of the coolant heater proved to be too high for adequate circulation of the heated coolant and the installation was altered by providing a hot coolant stand pipe reaching to the roof of the canopy. ; The hot coolant line was then connected to the pump outlet. Re- sults were somewhat better, but circulation was still too slow. The experiments were discontinued as it was evi- dent that the coolant heater would have to be located near the base of the engine for good results, and this could not be accomplished within the probable remaining period of cold weather. 6. Attention is directed to the blank panel in front of the radiator shown in the photographs. The radiator is not provided with a means of closure. Likewise, the side panels of the housing contain louvers without a means of closing them and the bottom of the compartment is open. A makeshift means of closing the louvers was provided for the experimental tests. The bottom was left open. 7. The Buda unit has a bottom closure but no means of closing the side louvers and radiator. C. CONCLUSIONS 1. Reasonably tight enclosures should be provided for the engine compartment with a means of regulating the radiator and louver openings to: a. Control the engine temperature while the unit is operating, b. Permit closing the compartment while heating the engine. 2. A heater should be provided for cold weather operation to permit starting the engines after stand-by. The hot air blast type would be preferable to permit mounting in high location if necessary with the hot air conducted underneath the crank case, battery and carburetor through ducts. D. RECOMMENDATIONS 1. The conclusions of this report are recommended for the consideration of the project engineers and such action that they deem necessary. Oil and Fuel Pressure Gage Installations Prepared by: T. C. Warner, Capt., A. C. Equipment Laboratory A. PURPOSE 1. To report on the operation of various types of oil and fuel pressure gage installations in aircraft at Ladd Field, Alaska, during the winter of 1944-45. B. FACTUAL DATA 1. Airplanes assigned to Extreme Temperature Op- erations Unit were winterized at the Dayton Army Air Base in accordance with Technical Order 05-70-6. All pressure transmitter lines were serviced by TSEPL-3G personnel. A record of maintenance required and troubles encountered with these installations is contained in Appendix I. 2. The amount of servicing required on the A-l pressure transmitter on other aircraft at this field was more than that on Extreme Temperature Operations Unit aircraft. It was found that the old style, one piece caps (AN820-2) were still in use on many airplanes. They were replaced by the new style, two piece caps (AAF Stock No. 6300-541686) and the overall main- tenance required has been decreased. The A-l pressure transmitters have worked equally well at all temperatures encountered. The Technical Order requirement of ser- vicing lines on 50-hour inspection is adequate. There have been some cases, however, where more frequent servicing was required. Servicing at 50-hour inspection alone is considered to be too often under low temperature conditions. Every effort should be made to improve this condition, a. One trouble was encountered with fuel gage installations. On the P-61 the fuel gages consistently read below zero with engines off. Servicing of the lines would bring the gage back to zero but in a short time they would fall below zero again. This condition was also noted on other types of aircraft, the error varying from 0 to 3 psi. This was not apparent in oil gages due to the difference in the scale of the gages. 5230 131 b. One C-47B and one C-54 airplanes were modi- fied by installing a restricted gage fitting, Rochester Mfg. Co., Part No. 2162-R4A, in each oil gage line. Consid- erable trouble had been experienced with fluctuations in the C-47B and this was corrected by installation of the restriction. This installation has been satisfactory down to —37°C. (—35°F.) Fluctuations, to a lesser extent, were noted in the C-54 oil gages. The restriction has been an improvement and has been satisfactory; however, no low temperatures have been encountered with this installation. 3. The autosyn type pressure gage system has been satisfactory; only one indicator failed out of a total of 12 indicators and 24 transmitters in Extreme Temperature Operations Unit aircraft. 4. In the C-47A, considerable fluctuation has been present in the direct connected oil pressure gages. In an effort to correct this trouble, a restricted gage fitting, Rochester Mfg. Co., Part No. 2162-R4A, was installed. This restriction worked very well at moderate tempera- tures (down to —20°F.) but at —37°F. the oil pressure indication was oply 50% of normal indication in flight. The restrictor was removed from this airplane. a. From a winterization standpoint, direct con- nected gages are considered satisfactory except that they must be serviced frequently at low temperatures. A C-47A, operated by an Allied Government, was inspected and a new type of oil gage system noted. This airplane originally had an ordinary direct connected gage system. It had been modified to include a filler line from the tee, Part No. 43-A-14984, to the airplane hydraulic system. A needle valve installed on the instrument panel is pro- vided to allow opening of this line from the hydraulic system to the oil gage line. This installation allows ser- vicing of the line at any time without any equipment except that which can be permanently installed in the airplane. 5. P-63 aircraft, being ferried through this base, do not have the panel fitting installed in the cockpit for servicing the oiUines. The indicators are rear mounted and very difficult to remove from the panel for servicing. Consequently, maintenance personnel do not service the lines at the instrument but brake the line in the nose wheel well at an easily accessible connection. This clears the line from this point to the engine, but does not clear the line back to the gage. A-l pressure transmitters mounted on lejt engine support on all engines 132 5230 C. CONCLUSIONS 1. The autosyn type oil and fuel pressure gage sys- tems have been satisfactory in B-24 and B-17F aircraft. 2. The restricted gage fitting, Rochester Mfg. Co. Part No. 2162-R4A, operated satisfactorily in C-47B (type A-l oil pressure gage system) but was not satis- factory in C-47A (direct connected oil pressure gage system). 3. Maintenance requirements on type A-l oil and fuel pressure gage systems on service aircraft are higher than on either the autosyn (oil and fuel )or the direct con- nected (oil) type systems. D. RECOMMENDATIONS 1. It is recommended that the modification described in Paragraph B-4 be considered for use in Army Air Forces aircraft for extreme low temperature operation. 2. It is recommended that the comparative advan- tages and disadvantages of autosyn and A-l types of oil and fuel pressure gages be reviewed considering the infor- mation contained in this report in an effort to standardize one one type of remote indicating system for all combat aircraft. Tests of Cabin Heating and De- frosting Systems of P-59A Prepared by: W. H. Giedt, Lt., A. C. Equipment Laboratory A. PURPOSE 1. To report on tests conducted on the cabin heating and defrosting systems of P-59A No. 44-22610. B. FACTUAL DATA 1. Description of cabin heating system. a. The cabin is heated by regulated mixture of heated, pressurized air from the engines, and cold, am- bient air from an inlet ram (see Photograph No. 1), The air flows through a control regulator, intercooler and anemostat into the cabin. b. The cabin heating and pressurizing system is designed to maintain comfortable cabin temperature at a pressure greater than the equivalent of 25,000 feet altitude, up to 50,000 feet. From the pressure rings mounted on the front of each engine, hot, pressurized air bled from the engine compressor is conveyed inboard to a Y fitting on the centerline of the airplane. The reg- ulated mixture of air for the cabin is conveyed from the mixing chamber, forward around the pressure safety valve, to the anemostat installed in the cabin floor for- ward of the main instrument panel. If the air is too hot, instead of going directly to the cabin, it is automatically conveyed through the intercooler before entering the cabin. The cabin is ventilated by an exhaust duct in the floor, directly under the pilot’s seat. The exhaust air passes back to the regulator and through a valve out into the atmosphere. c. Cabin temperature is controlled by a thermostat which energizes a split field series motor. The motor operates a butterfly valve in the cold rammed air inlet line and the hot air by-pass line, and a shutter valve in the mixing chamber. The temperature control linkage on the regulator, actuated by the motor, is adjusted so that when the shutter valve directs all the air through the intercooler, the cold rammed air valve is open and the hot air by-pass valve is shut. Below 15,000 feet altitude, where ram pressure exceeds the cabin pressure, temperature control is obtained by proper mixing of hot and cold air. Above 15,000 feet, when the cabin is pressurized, only the hot air source remains and the cabin temperature is controlled by passing through the intercooler, whatever fraction of the hot air is necessary. d. Cabin ventilating airflow is determined by the size of all cabin openings and by the differential pres- sure between the cabin and the atmosphere. Part of this is cabin leakage; the remainder passes through the regu- lator exhaust valve. e. The pilot’s control of the system is mounted on the cabin floor just forward of the control column. This lever operates an emergency valve in the forward end of the engine air duct. Closing of this valve cuts off all hot, pressurized air, thus putting the heating and pres- surizing system out of operation. 2. Description of cabin glass defrosting system. a. The cabin glass and guns are heated by air taken from the tail pipe heater muff. Ambient air enters the heater muff through an inlet duct (see Photograph No. 2). It circulates completely around the tail pipe, gathering heat from the pipe and numerous thin steel fins. The heated air is conveyed out through the bottom of each tail pipe to a Y duct assembly, just inside the fuselage structure. A single duct conveys the heat forward through the fuselage to the gun compartment, where it flows to the cabin glass and guns (see Photo- graph No. 3). The control mounted underneath the in- strument panel actuates a damper in the duct which con- trols the airflow. Photographs Nos. 4, 5, 6, and 7 show the double panel construction of the cabin glass. 3. Flight test data is included as Appendix I to this report. 4. Flights 1, 3 and 4 were conducted with the cabin anemostat in place to determine temperature distribu- tion throughout the cabin. Preliminary flights had indi- cated that the venturi meter, installed for measuring cabin airflows and heat inputs during flights 5 and 6, interfered with the distribution of heated air throughout the cabin. Attention is called to the following: a. Temperatures throughout the cabin were within 10°F with the exception of the waist level. Tempera- 5230 133 tures at the right and left of the pilot at waist level were considerably lower than the temperatures near his foot or head level. It is likely that these were the result of the pilot, wearing heavy clothing, unintentionally pushing the thermocouples measuring these temperatures too close to the fuselage wall. b. Data taken on Flight 4 shows that the heating system comes well within winterization requirements at high altitudes. c. Because the the thermostat controls the cabin temperatures around 50° F and because sufficient low temperatures at low altitudes were not encountered dur- ing the testing period, it was not possible to check the maximum capacity of the heating system at low altitudes. However, comparison of heat inputs to the cabin at 1,500 feet and at 31,500 feet in Flights 5 and 6 indicates that the system has the necessary capacity to meet winteriza- tion requirements at low altitudes. This is further borne out by the fact that the average temperature rise in flight 4 reduced to the temperature rise at sea level and —65°F according to Low Temperature Require- ments Sheet No. 54-128 is approximately 85 °F. d. On all flights a gradual increase of temperatures resulted as the flight progressed. Because the length of each flight is limited in this airplane, it was not possible to determine if equilibrium condtions had been reached or not. e. During Run 3 of Flight No. 6 when the power setting was increased to high speed cruise conditions, the cabin airflow and heat input decreased rather than increased as anticipated. Cabin temperatures, however, did not drop. It is felt that this was due to improper regulator operation, insofar as irregularity in its opera- tion had been noticed by the pilot.« This would mean that more heat than was necessary was supplied by the heating and pressurizing system during Runs 1 and 2. 5. Flights 1 through 4 were conducted with thermo- couples installed to read the inside and outside surface temperatures of the windshield glass (thermocouples Nos. 11, 12, 13, 14, 15 and 16). Flight No. 2 was con- ducted with the cabin heating system off in order to determine the windshield surface temperatures resulting from the use of the defrosting system by itself. Atten- tion is called to the following points: a. Outside windshield surfaces. (1) Temperatures were maintained from 10 to 20°F above ambient air temperature. (2) The center windshield surface was from 4 to 6°F warmer than the left and right windshield surfaces. Because of the construction of the system more heated air probably passed between the panes of the center windshield than between the side windshields. (3) Slightly higher temperature rises were ob- tained at high altitude. h. Inside windshield surfaces. (1) Temperatures were maintained from 40 to 118°F about outside air temperatures and with one exception in Flight 2 and Flight 3, all surface tempera- tures were above 32 °F. (2) Higher temperature rises were obtained at high altitude. 6. Insofar as the windshield defrosting system de- pends upon rammed air for operation, ground defrost- ing was not satisfactory. On the relatively cold days (ground temperature —20°F) encountered during the testing period the moisture, which condensed on the inner surfaces of the windshield from the pilot’s breath, was not removed until the airplane was in the air. 7. At no time during the testing period were wind- shield defrosting difficulties encountered in flight. This includes several short runs through clouds, C. CONCLUSIONS 1. The cabin heating system as tested meets winter- ization requirements. 2. Windshield defrosting in flight was satisfactory under the conditions tested. However, more tests should be conducted in regions where the moisture content of the air is higher before the system is considered satis- factory. 3. Provisions should be made for windshield de- frosting on the ground. D. RECOMMENDATIONS 1. None. P-59 A turbine check-heater duct in use 134 5230 Type E-l, Artificial Horizon Indi- cators Type C-l, Directional Gyro Indicators Prepared by: T. C. Warner, Capt., A. C. Equipment Laboratory A. PURPOSE 1. To report results of a low temperature service test on subject instruments. B. FACTUAL DATA 1. The subject instruments are operated by 115 volt, 400 cycle, 3 phase alternating current. They were de- signed for low temperature use to overcome the difficulties encountered with standard air driven instruments. 2. Insofar as operation in flight is concerned, these instruments were designed to give the same indications as standard air driven Instruments. 3. Four airplanes were equipped with the subject instruments and only one failure was encountered. This failure was due to a defective erection mechanism. The instruments operated satisfactorily at all temperatures encountered. The lowest temperature at the instruments, in flight, was —38°C (—37°F). 4. Two sets of instruments were kept as spares. The directional gyros were used to make a bench test to see if the latitude corrector on this instrument was satis- factory. The instruments were originally set at 40°N. latitude and were changed to 65°N. latitude. The amount of drift, measured on a ground test stand, was decreased by this change. 5. A photograph of one set of instruments installed in an A-26B aircraft is attached to this report as Exhibit A. Installations in other aircraft were similar to this one. A record of the tests is included in Appendix I. 6. As these instruments require 3 phase alternating current power, it was necessary to provide a separate power source for each installation. Holtzer-Cabot, Type MG-153 Inverters, operating from the airplane’s direct current power supply, were used to provide power to the instruments. These inverters are too heavy (approxi- mately 30 lbs.) to be considered for service use and they required considerable maintenance to supply the proper power to the instruments. C. CONCLUSIONS 1. The Type E-l Artificial Horizon indicator and the Type C-l Directional Gyro Indicator operated satisfac- torily at all low temperatures encountered. 2. The dial of the type C-l directional gyro is unsat- isfactory and the cover glass on the Sperry Instruments become foggy. 3. A more practical source of power must be obtained for the subject instruments before they can be recom- mended for service use. D. RECOMMENDATIONS 1. It is recommended that the deficiencies in the C-l Directional Gyro and the power supply be corrected before the subject instruments be used in Army Air Forces aircraft. Type F-4 Airspeed Indicator Prepared by: T. C. Warner, Capt., A. C. Equipment Laboratory A. PURPOSE 1. To report results of a low temperature service test on one Type F-4 Airspeed Indicator. B. FACTUAL DATA 1. One Type F-4 Airspeed Indicator, Army Air Forces Specification No. X-27512, Kollsman Part No. 865CK-03 Serial No. 113, was received for tests in a P-5 ID airplane. As there were no P-5 ID airplanesavail- able for test work, the instrument was installed in a P-38L, Serial No. 44-24050. 2. Laboratory scale error tests, before and after installation, showed that the errors in the indicator remained almost constant during operation in low tem- perature conditions. Total time installed was 53 days and total flight time was hours. Test results are listed in Appendix I. 5230 135 3. Comments received from pilots were favorable. The maximum speed pointer, varying with altitude, is desired by pilots who have flown this airplane. One pilot who was asked to observe this instrument requested that additional markings be placed on the dial at every 10 mph increment. Another pilot, flying transition, who was not informed about the F-4 Indicator, did not notice that this instrument differed from the standard type F-2 indi- cator. It has been generally agreed that the markings are satisfactory, although some pilots are anxious to know their exact speed at times. C. CONCLUSIONS 1. The Type F-4 Airspeed Indicator is satisfactory for use in low temperature conditions. 2. The Type F-4 Airspeed Indicator is preferred to the Type F-2 for pursuit aircraft. D. RECOMMENDATIONS 1. It is recommended that the Type F-4 Airspeed Indicator be used in place of the Type F-2 on pursuit aircraft. Navigation Instruments Prepared by: T. C. Warner, Capt., A. C. Equipment Laboratory A. PURPOSE 1. To report results of tests on various items of navi- gation equipment. B. FACTUAL DATA 1. Project engineers requested that tests of various items of navigation equipment be made during the cold weather testing program at Ladd Field, Alaska. All items were tested by Equipment Laboratory personnel with the assistance of 1st Lt. Roger E. Wahlberg, navigator. Items, such as the A-6 Navigation Case and Inverted Astrocompass, were used by Lt. Wahlberg in his position as navigator on the C-54B, Serial No. 43-17157. Unless otherwise noted, the statements contained herein are based on experience obtained using this equipment to navigate the C-54 aircraft. 2. “Type A-15 Watch”. One watch, Serial No. AF44-249, was made available for tests. This watch was in use approximately two months before any tests were made. An average rate of —13 sec/day was obtained from 7 December to 7 January. An average rate of —15 sec/day was obtained from 22 January to 24 February. After approximately 3 months use, the stitching broke on the watch strap and the strap became badly worn at the hole which had been used for the buckle. The outer and inner dials were set on zero (1200 position) each day and observed for movement due to rubbing of heavy flying clothes on the watch stems. The outer dial moved a distance of 1 to 2 minutes each day while the inner dial remained on zero. The elapsed time dials were movable at a low temperature of —35°C (—30°F). Low tem- peratures were not encountered for a long enough period to make a rate test at any given temperature. 3. “Air Position Indicator”. One A.P.I. was installed as standard equipment in a B-29 aircraft. Tests con- ducted indicate that this instrument operated satisfac- torily. Results of tests are contained in Appendix I. 4. “Gyrosyn Compass”. One installation was made at the Dayton Army Air Base on 2 November 1944 in the C-54. This installation was found to be faulty and was removed by the Project Engineer at Wright Field. 5. “Inverted Astrocompass”. This instrument was used in the C-54, Serial No. 43-17157. Visibility is good, sufficient for all necessary observations. Compared to a standard astrocompass, it is much easier to set up and read operations. The slow motion drive mechanism makes it easier to move for a small change in reading and does not interfere with operation. As the astrocompass sits low in the dome observations cannot be made with body at a low altitude. In this airplane the instrument is very difficult to install when the plane is on the ground, and cannot be installed in the air. For test purposes, the instrument was left installed at all times. 6. “Polar Navigation Computer”. This computer is designed for use above 75° latitude. There were no flights made above 70° latitude, thus it was impossible to test this item. 7. “Gyro Flux Gate Compass”. Five standard in- stallations of this compass were observed in B-17 (2), B-29 (2), and C-54 (1) aircraft. a. In turns there was lag in some of the fluxgate compasses and over-reading in others. It generally took from 10 to 90 seconds before the compass would settle on desired heading. Otherwise, the compass was accurate. b. The compasses were swung by observing celes- tial bodies with the astrocompass in flight for true head- ings. The compasses were compensated by means of the compensating device around the face of the master indicator. c. The caging mechanism operated satisfactorily at all temperatures observed, + 18°C to —40°C ( + 64°F to —40°F). Only one installation (C-54) had a low temperature push button on the amplifier. The coldest temperature encountered on this airplane was —30°C (—22°F). At that temperature, there was no need for this additional power to erect the gyro. The standard installations without the push button operated satisfac- torily at —40°C (—40°F). d. The gain control had no apparent effect on the sensitivity of the flux gate compass. This control was left at the normal (No. 3) setting on all installations. The highest latitude encountered was 65° 50' and the shortest distance to the magnetic pole was approximately 2900 miles. 136 5230 e. The navigator flew with variation set in the master indicator on several flights, but it is not recom- mended, as the present navigation system is set up for using compass headings and pilots are accustomed to using compass headings. 8. “A-6 Navigation Case’’. The case does not pro- vide sufficient space to carry most types of sextants in their standard box. Without box, pockets are not pro- vided for batteries, extra bubble chambers and other sextant equipment. The space provided for books and watches is not adequate. In aircraft with navigator as crew member, there is space provided for navigation equipment. Except on C-46 aircraft, the navigator’s compartment is so compact that it is not possible to stow the A-6 case so it can be used conveniently in flight. The insert for plotting equipment is very satisfactory. Stands are provided, when necessary, in production aircraft, making it unnecessary to use the A-6 case as a stand. When completely loaded, the case is well balanced, but is very heavy and awkward to carry. The map pocket, when kept properly strapped, shows no appreciable wear over a six-months period. 9. “B-3 Driftmeter Installation C-54”, This instru- ment was installed by the Project Engineer at Wright Field in the early part of January 1945. The driftmeter works the same as the standard B-3 with the addition of a “gyro boost” mechanism, for low temperature starting. Weather encountered was not cold enough to require the use of the gyro boost mechanism. Ice and frost formed on the inside of the view plate at free air temperatures of 0 to —15°C (+32 to +5°F) and cockpit tempera- tures of +20°C (+68°F). It is not possible to de-ice in flight. C. CONCLUSIONS 1. There were no failures or excessive errors in Navigation Equipment due to exposure and use at the lowest temperatures encountered. 2. The mounting provided for the inverted astro- compass in the C-54 is unsatisfactory. 3. The Type A-6 Navigation case is too heavy and bulky, 4. The inside of the view plate on the B-3 driftmeter becomes covered with ice and frost at a free air tempera- ture of 0 to—15°Cand a cockpit temperature of +20°C. D. RECOMMENDATIONS 1. It is recommended that the project engineers on the various items of Navigation Equipment correct the deficiencies noted in Paragraphs C2, C3, and C4 of this report. Air Driven Gyro Instruments Prepared by: T.C. Warner, Capt, A.C. Equipment Laboratory A. PURPOSE 1. To report on operatioh of subject instruments in- stalled in aircraft undergoing cold weather tests at Ladd Field, Alaska, during the winter of 1944-45. B. FACTUAL DATA 1. Five installations of modified instruments were made in Various airplanes for low temperature service tests. These instruments are of two types; namely, Sperry Artifical Horizon Indicator (Flight Indicator) Part No. 646040 with Type 34-B grease lubricated bear- ings, and Type A-l 1 Turn and Bank Indicator with bear- ings lubricated with Spec. AN-G-3 grease. These in- struments were installed at the Dayton Army Air Base in September of 1944, and have been operating satis- factorily, with the exception that neither horizon would remain in the caged position in flight. Details of the test are contained in Appendix I. 2. Failures of Standard AN type Artifical Horizon Indicators is excessive. As established by reports from operating bases elsewhere, the life of this type instrument is exceedingly short, and failures are usually due to bear- ing troubles. In addition, it has been noted here that many gyros are replaced, due to troubles in the miniature airplane and the caging system. 3. There were several instances of Air Driven Direc- tional Gyros and Artificial Horizons becoming sluggish or inoperative at temperatures between -23 and -35°C. (-9°F and -31 °F. This low temperature failure is the same as noted last year under similar conditions. The normal application of heat before flight and the use of air- craft heaters in low altitude flight has minimized this problem during operations at this base. Air driven gyro instruments cannot be depended on for satisfactory op- eration when the cockpit is below -30°C. (-22°F). Some instances of satisfactory operation at instrument temp- eratures of -35°C. (-30°F) have been encountered whereas one failure occured at -23°C (-9°F). 4. Pilots of two B-29 aircraft assigned to this station complained about sluggishness of their gyro instruments, particularly the artificial horizon. The vacuum systems on these airplanes were thoroughly checked and found to be satisfactory. An additional vacuum gauge was differentially connected to the artifical horizon on the pilot’s panel in addition to the standard gauge which is connected to the co-pilot’s flight indicator. The vacuum reading was found to be correct at altitudes from 0 to 20,000 feet with and without cabin pressurization. Flight tests in both airplanes were made and it was found that the horizons (Ternstedt Part No. T-95100) were satisfactory on standard rate turns (180°/Min. - approximately 35° bank). In normal flight, however, the horizons appeared sluggish in that there was a short 5230 137 lag in the instruments when the airplane was brought out of a turn. According to representatives from the Sperry and Jack & Heintz Instrument Companies, ho- rizons are calibrated for a standard rate turn of 180°/min. at an airspeed of approximately 170 mph. In the B-29, in normal flights, turns are made at much higher speeds and slower rates of turn. In addition, turns are often made with considerable "sliding”. These features of flight in this airplane cause precession in the gyros, which gives them the appearance of being sluggish. The erection mechanism in the instrument corrects this error when straight and level flight is maintained. The erection rate for standard instruments is 8°/min. It is felt that an improvement can be made by designing the instruments for a higher airspeed (larger bank-angle) and means of overcoming precession of the gyro, and increasing the erection rate should be investigated. 5. Jack & Heintz Flight Indicators, Part No. JH6500, in B-17 and B-24 aircraft particularly, have been object- ionable due to excessive “spilling” of the gyro in flight, which required recaging of the instrument. This oc- curs when the gyro precesses more than 6° from the vertical causing the pendulous vanes (erection mechan- ism) to be ineffective. One new Jack & Heintz instru- ment, Part No. 6500A, was installed and operated satis- factorily. It is understood that all JH6500 instruments are to be modified to JH6500A at time of overhaul. This is believed important enough to require modification of all existing stocks of JH6500 instruments and granting of authority to organization commanders to order re- placement of all JH6500 instruments in the field where trouble has been encountered. This condition is par- ticularly evident in large aircraft where precession er- rors occur due to unbalanced forces on the gyros in long slow turns. 6. Type A-3A automatic pilot installations in C-47, P-61 and C-54 aircraft have been fairly satisfactory. Failures encountered are not attributed to low tempera- tures. In both the C-47 and P-61, intermittent trouble has been encountered with hunting in the rudder controls. On one C-47, one servo unit was continuously leaking and was changed after 74 ;25 hours. One pressure regu- lator was changed at 103 hours and the rudder control box changed at 113:05 hours. C-47B Lend-Lease Air- craft, processed through this station, have the A-3A pilot installed. The greatest amount of trouble in this installa- tion has been with air relays and the oil filter. Two air re- lays which were sticking were examined and a slight film of gray substance was present on the shaft. In one relay there were 3 particles of foreign matter present. In both cases, cleaning of the shaft was all that was necessary to make the unit operable. The housing is made of mag- nesium and the shaft is steel; possibly this is corrosion starting between the two dissimilar metals. One Skin- ner Oil Filter, Part No. 27400, Spec. No. 94-27983-A. was removed because it leaked excessively. This unit had 30 hours operation. Cause of failure was in the washer be- tween the case and the head of the filter. A photograph of this item is attached as Exhibit A to this report. This type of failure has been frequent, according to instru- ment maintenance personnel. However, only one case has been noted by the writer. The use of an “O-Ring” type washer in a recess in the head of the filter, similar to that employed in the gyro instrument filter, Spec. AN-F-9A, should correct this condition. C. CONCLUSIONS 1. Artificial Horizon Indicators, Sperry Part No. 646040, with Type 34-B rotor bearings and standard type A-l Turn and Bank Indicators with rotor bear- ings lubricated with AN-G-3 grease are as satisfactory for low temperature operation as present standard in- struments with oil lubricated bearings. 2. Failures of Artificial Horizon Indicators are ex- cessive. The reasons for these failures are mainly bear- ing failures and mechanical defects in the caging mech- anism and the miniature airplane. 3. Standard Air Driven Gyro Instruments, (with the exception of Turn and Bank Indicators) cannot be re- lied upon for satisfactory operation at instrument tem- peratures below —30°C. (—22°F). 4. The effect of precession and the slow erection rate (8°/min.) in standard instruments is more serious in large aircraft like the B-29 than in older, smaller types of aircraft. 5. Trouble encountered with "spilling” of Jack & Heintez Artificial Horizon Indicators, Part No. JH6500, has been corrected in Part No. JH6500A. D. RECOMMENDATIONS 1. It is recommended that Artificial Horizon In- dicators with Type 34B rotor bearings and Turn and Bank Indicators (Type AN5820) be procured with grease lubricated rotor bearings in place of present standard instruments. 2. It is recommended that instructions for re- lubricating instruments in service with grease at time of overhaul be prepared and included in applicable Technical Orders. 3. It is recommended that efforts be made to decrease the precession and increase the erection rate of artificial horizon indicators. 4. It is recommended that a new type sealing washer be developed for the Skinner Oil Filter, Part 27400, Spec. 94-27983-A. 5. It is recommended that laboratory corrosion tests be made on Jack & Heintz air relays to determine if the use of a steel shaft in a magesium housing is causing corrosion. Type T-l lifting bags used to raise zving of B-24 airplane 138 5230 P-59 Instruments Prepared by. T. C. Warner, Equipment Laboratory A. PURPOSE 1. To report on operation of instruments in the P-59 airplane, serial number 44-22610. B. FACTUAL DATA 1. One P-59 airplane was instrumented for low tem- perature service tests, at the Dayton Army Air Base. The following modifications and installations were made: a. Skinner Air-Oil Filter, part No. 27400-VS, was installed in the pressure line to the gyro instruments just ahead of the Schwien Vacuum Regulators. b. Pressure tubing was relocated from underneath the fuselage to the top, in rear of the cockpit, to make the Schwien Regulators, part Nos. 22500-1 and 22500-2, accessible. c. Filler Check Valves (AN5832-2, gauge fitting No. 43A14984 and cap AN820-2) were installed as shown in Fig. 3, Detail B of Technical Order 05-70-6, on the engine side of the General Electric, Selsyn oil pressure transmitters on both engines. On autosyn and A-l type pressure transmitters on other types of aircraft this is a standard winterization modification to enable servicing of the oil line with hydraulic oil to prevent congealing at low temperatures. d. A type A-l 1 Turn and Bank Indicator, with bear- ings lubricated with AN-G-3 grease, was installed in place of the standard instrument for service test. 2. Test data are contained in Appendix I and photo- graphs of the Skinner Air-Oil Filter, Schwien Regu- lators and the Instrument Panel are attached as Exhibits A, B and C respectively. 3. The Skinner Air-Oil Filter was designed to re- move the oil from the air by means of a system of baffles and also to cleanse the air by means of a phenolic im- pregnated paper filter element. After approximately 50 hours flight time, examination of the filter showed that it was ineffective, as oil had passed through into the regulators and had not collected in the bowd of the filter. 4. The Schwien regulators were unsatisfactory when the airplane arrived because correct pressure for gyro operation could not be obtained. The regulators were found to be contaminated with oil and the No. 1 regu- lator was damaged. The regulators were cleaned, re- paired and reinstalled in the airplane. Tests showed that there was one inherent feature of these regulators which was unsatisfactory; that was, the No. 2 regulator would not hold the pressure to 4" Hg. until the pressure had first reached a maximum of 8" Hg., at which time the regulator took effect and cut the pressure down to 4" Hg. As this regulation did not occur until an engine rpm of approximately 14,750 was obtained (take off rpm was approximately 16,500), it was considered dangerous, as a slight change in the regulators, due to contamination or wear, might cause this regulation never to occur and the gyros would be operating continuously on 8" Hg. pressure. 5. The oil pressure indication system should be modi- fied to prevent initial presures from giving faulty indi- cations. Additional troubles encountered with engine instruments are discussed in Appendix I. 6. The arrangement of flight instruments and the mounting of all instruments did not conform to Army Air Forces requirements. As all instruments were rear mounted, it was very difficult to replace any instrument on this airplane. A conventional type D-2 Airspeed Tube was mounted upside dowrn on the empennage con- trary to requirements of Army Air Forces installation specifications. C. CONCLUSIONS 1. The experimental Air-Oil Filter, Skinner Part No. 27400-VS did not remove the oil present in the air flowing to the gyro instruments. 2. The Schwien Pressure Regulators, Part Nos. 22500-1 and 22500-2, did not properly regulate the pres- sure to the gyro instruments. 3. The oil pressure indication system was unsatisfac- tory when surge pressures over 25 psi were encountered on “cold starts” at low temperature. 4. The use of filler check valves, AN 5832-2, as re- quired by Technical Order No. 05-70-6, was not neces- sary on this airplane. D. RECOMMENDATIONS 1. It is recommended that the deficiencies noted in this report be corrected on future aircraft of this type by: a. Modification of the oil pressure indication system by putting a stop on the transmitter at 25 psi or by adding sufficient restriction in the oil line to prevent surge pres- sures in the oil system from reaching the transmitter; b. Conformance to Army Air Forces requirements on mounting and arrangement of instruments; c. The use of a conventional vacuum system with air driven gyro instruments, electrical gyro instruments or a modification of the present pressure system designed to overcome the deficiencies noted herein; d. Conformance to Army Air Forces specifications on the location and mounting of air speed tubes. 5230 139 Cold Weather Testing of Type C-11A Electric Power Plant Prepared by: C. E. Wood, Capt., A. C. Equipment Laboratory A. PURPOSE 1. To summarize results of service tests performed by personnel of the Cold Weather Testing Detachment on the subject power plants. B. FACTUAL DATA 1. The power plants were service tested approximately in accordance with the contemplated test program, an extract of which was forwarded to the above addressee as Appendix D of Status Report, Electrical Branch, Cold Weather Tests, Equipment Laboratory, dated 5 Janu- ary 1945. 2. A complete report of the service tests will be sub- mitted through regular channels by Cold Weather Test- ing Detachment. 3. The following results of these tests are of immediate interest to the A. T. S. C. project engineers: a. The type of spark plugs (manufacture and no- menclature unknown) in the units were found to be unsatisfactory for making cold starts, believed to be due to oil deposit on the spark gap. These were exchanged for Champion Type HO-14S, which performed satisfac- torily, b. It was found that the units could be cold started at temperatures as low as 0°F. It was necessary to ap- ply external heat for starting at lower temperatures. c. The units operated satisfactorily at the lowest temperatures encountered, —43°F. d. Out of a total of 700 accumulated hours of oper- ation, there were approximately 60 man hours expended in maintenance. e. Malfunctions were primarily due to the spark plugs mentioned in par. 3a, and cleaning and adjusting of magneto breaker points. f. There was one failure—broken teeth in a mag- neto driving gear. The cause could not be diagnosed and it is considered an isolated case. C. CONCLUSIONS 1. It is concluded that the Type C-l 1A Electric Power Plant is generally satisfactory for operation in cold temperatures. a. Without the aid of external heat for starting, to a minimum temperature of 0°F. b. With the aid of external heat for starting, to a minimum temperature of —43 °F. D. RECOMMENDATIONS It is recommended that: 1. The type of spark plugs be changed to the Champion type HO-14S or equivalent having air gaps between the electrodes. 2. The project engineer investigate magneto perfor- mance with the adopted type of spark plugs. Cold Weather Testing of Lamp Assembly, Rigid Drum Type Rotating Beacon, 24" AN-L-4 Prepared by: C. E. Wood, Capt., A. C. Equipment Laboratory A. PURPOSE 1. To report the performance of subject lamp assembly under cold weather conditions. B. FACTUAL DATA 1. The complete assembly was mounted on a portable stand by personnel of the Cold Weather Testing De- tachment and operated in the normal manner in the local test area from 12 December 1944 to 9 Feburary 1945, when it was removed for installation on top of the Ladd Field control tower. 2. Cold temperatures as low as —30°F. had no effect upon its operation, except that there were two cases wherein the lamp changers, after normal operation caused by burned out lamps, did not complete their movements 140 5230 and stopped against the latch resulting in burned con- tacts. Increasing the rotating spring tension corrected the difficulty. It could not be ascertained whether these malfunctions were due to cold temperatures or original adjustment of the rotating springs. 3. Several of the rotating beacons are in service in this area and maintenance personnel have reported excessive maintenance of brushes and collector ring surfaces due to the collector rings either being out of round or mounted eccentrically. Collector ring surfaces become blackened causing sparking at the brushes and brushes wear rapidly in the brush holders. 4. Attention is directed to lubrication specifications in T. O. AN-08-20-33 which call for: a. Thrust bearings to be greased with Gr. 375, Spec. 3560. b. Worm gear to be greased with, oil, transmission, Spec. 2-28 or oil, mineral steam cylinder, Gr. 2, Spec. 2-32. 5. Advice from representatives of the Materials Labo- ratory indicates that: a. Gr. 375, Spec. 3560 has been superseded by Grease, Spec. AN-G-3. b. Oil, Mineral, Spec. 2-28, has been superseded by Grease, Spec. AN-G-10. 6. This report supplements letter from E. T. O. U. dated 7 January 1945 to Director, Air Technical Service Command, Attention TSEPL-3F, a copy of which is attached. (Exhibit I). C. CONCLUSIONS 1. The subject lamp assembly operates satisfactorily at the lowest temperatures recorded, —30°F., except for the mechanical defects described. D. RECOMMENDATIONS 1. It is recommended that: a. Mechanical defects be brought to the attention of the Inspection Division and the manufacturers. b. T. O. AN-08-20-23 be changed to specify the lubricants mentioned in Par. B5a and b. Lamp Assembly, Rigid Drum Type Rotating Beacon, 24 AN-L-4 1. The subject lamp assembly was placed in operation in the local test area 12 December 1944 for observation of its performance. 2. Performance has been satisfactory except the slip ring brushes became noisy (squealing) after 10 days of operation. The slip rings were found to have been machined with a sharp pointed tool, leaving thread-like ridges which resulted in poor brush contact and black- ening of the slip ring surface. 3. It was also reported that in warm weather, grease from the warm gears drops on the brush holders and soaks the brushes. 4. It is recommended that condition stated in Para- graph 2 be brought to the attention of the manufacturers for correction on future production units and that drip shields be developed for application by the services to units now in use as well as on future production units. Cold Weather Testing of Lamp Assembly, Type C-3 Acetylene Operated Flashing Beacon Prepared by: C.E. Wood, Capt, A.C. Equipment Laboratory A. PURPOSE To report an experimental test made to eliminate the accumulation of frost inside the Fresnel lens of the sub- ject lamp. B. FACTUAL DATA 1. The lamp assembly was condemned as an obstruct- ion marker or beacon for use with aircraft in M/R dated 6 January 1945, from ETOU to Director, Air Tech- 5230 141 nical Service Command, beacuse of the accumulation of frost inside the lens. 2. The lamp as received had no means for preventing the products of combustion from coming in contact with the outer lens, resulting the condition reported. 3. Consequently, it was modified after being service tested, by sealing the air passage between the inner globe and outer lens at the top, and again placed in oper- ation. 4. The alteration proved to be effective as there was no furthur accumulation of frost inside the lens. 5. Photographs Nos. 2 Appendix A, illustrate the extent of frost accumulation before the alteration was made, and Photograph No. 5 shows the baffle that was applied to correct the difficulty. 6. To determine if the baffle had any effect on the stability of the lamp in wind, an air speed indicator was installed on the lamp assembly, and it was placed in the blast of airplane propellers. The wind produced by the propellers was gusty and air speeds up to 75 mph were indicated with averages of approximately 40 mph. These winds failed to extinguish the pilot light, and the lamp operated satisfactorily. The lamp remained in a position where it was subjected to the propeller blasts from parked airplanes for a period of two weeks, and it operated satisfactorily during the entire period. 7. Light frost accumulated on the outside of the sun valve globe, but it had no noticeable effect upon the operation of the sun valve. 8. The flashing mechanisim operated satisfactorily at -48°F (measured at the lamp location) with factory installed diaphragms. The special low temperature dia- phragms, furnished substitutes for use in case the original diaphragms failed, were not installed. C. CONCLUSIONS 1. The lamp assembly, if provided with a means for preventing frost accumulation on the Fresnel lens, such as that mentioned in Par. B.5, will be entirely satisfactory Frost accumulation inside Fresnel lens for use as an obstruction marker or beacon light for air- craft. D. RECOMMENDATIONS It is recommended that: 1. The manufacturers develop modification parts to seal the air passage between the inner globe and outer lens of the lamp assembly. 2. Modification parts with instructions for installation be furnished to the using services for installation in the field, and that the modifications be incorporated in future production of the lamp assemblies. Cold Weather Test of Direct Cranking Starters, Power Input to Crank Cold Engines, Type B-29 Airplanes Prepared by. C. E. Wood, Capt., A. C. Equipment Laboratory A. PURPOSE 1. To report the performance of and power input to direct cranking type starters while cranking cold engines on a type B-29 airplane. B. FACTUAL DATA 1. Equipment. a. Location. Ladd Field. h. Dates of Tests. 13 and 14 February 1945. 142 5230 Airplane, Type B-29-ll-MO#42-65214. d. Engine Type. Wright Cyclone, R-3350-23A. e. Type of oil. Eng. Nos. 1, 2, 3—Synthetic, Spec. PPC-265. No. 4— Regular, Spec. 1100A. /. Starters. No. 1 Eng. J&H5E. No. 2 Eng. Eclipse 1416 Model 6, Style A, Serial #65. (Di- rect cranking type). Spline and jaw seal lubricated with Spec. AN-06-A oil. Installed 23 January 1945. No. 3 Eng. Eclipse 1416, Model 6, Style A, Serial #49. (Di- rect Cranking Type). Factory lubrication. Installed 23 Janu- ary 1945. No. 4 Eng. J&H5E. g. Engine Hours. No. 1 14 hr. No. 2 12 hr, 30 minutes. No. 3 86 hr. 45 minutes. No. 4 86 hr. 45 minutes. h. Power Source. Model C, Auxiliary Power Unit, (Waukesha dual type) Capacity, 15 KW, Volts 28.5 d.c. 2. Advantage was taken of the coldest temperatures encountered during the cold weather testing period to determine the power required to crank the R-3350 en- gines. The lowest temperatures occurred on 13 and 14 February 1945, and test results are attached as Appen- dices A and B respectively. 3. Attempts were made to evaluate engine tempera- tures vs. cranking power. On 13 February, the engines were considered too stiff to attempt to crank without un- due risk of damaging engine accessories and, further, that attempts to start would be unsuccessful and useless. Therefore, the engines were heated until, in the judgment of the crew, they were just free enough to attempt to start. Power input to starters was measured after which attempts were made to start the engines. These at- tempts were unsuccessful and the process was repeated. Immediately after starting, oil, carburetor air, and cylin- der head temperatures were recorded as shown in Ap- pendix A, Par. 9b. These and the measurements of oil dilution, were inconsistent and considered as not indicat- ing the true condition of the engines. Therefore, it was decided to repeat the tests, using available thermo- couples on No. 2 engine as an indication of engine tem- peratures ; however, the engine had not been thermo- coupled with this in view and it was recognized that they would not indicate temperatures within the engine. Nevertheless, it was the only means at hand of making any sort of comparison. 4. Procedures on 14 February 1945, as summarized in Appendix B, were repetitions of those summarized in Appendix A, except, due to the extreme stiffness of the engines, No. 1 (combination starter) was energized for 5 seconds only prior to meshing, and all three were direct cranked for 15 seconds only. No. 4 engine was “frozen” and no attempts were made to either crank or start it. 5. The engines cranked readily under the cold con- ditions summarized in Appendix B, Par. 5a, and crank- ing speeds were adequate for starting. It is believed the engines could have been started had it been possible to vaporize the fuel properly at these temperatures. Dur- ing the unsuccessful attempts to start after heat had been applied for 15 minutes, Nos. 1 and 3 fired instantly and then ceased, apparently due to the intake of cold air, No. 2 engine did not fire. All three engines were primed to the extent that gasoline flowed from the blower drains. 6. In all starting attempts, No. 1 starter was ener- gized for IS seconds before meshing to note differences, if any, in starting ability due to the faster acceleration from the inertia of the starter flywheel as compared to the direct cranking starters. There wras no apparent differ- ence in starting ability. In one instance, clearly definable, the inertia of the starter was dissipated in one quarter of a turn of the propeller, indicating that the stored energy was of very little assistance to the starting. 7. There have been no malfunctions of the direct cranking starters on the subject airplane, nor of those on B-29 No. 42-4612 (solid injection engines). The latter airplane is currently in the U. S. for engine mount changes precluding making tests. 8. There is little probability of additional cold weather and no further reports will be submitted except to describe any malfunctions of the starters during the remainder of the test period. C. CONCLUSIONS It is concluded that: 1. Neither the lesser cranking speed nor the lack of the inertia feature of the direct cranking starters has aay deleterious effect upon starting. 2. Direct cranking is advantageous in starting cold engines in that shock loading of starter and engine parts is less than wdth inertia starting. 3. Power input to the starters as ascertained by these tests does not represent the ultimate that will be en- countered in starting large size cold engines. 4. It is not practical to make accurate determinations of power for cranking cold enginess on airplanes in serv- ice, due to the time required for thoroughly cold soak- ing and the vagaries of the weather. 5. The slipping clutch protective feature is unneces- sary for cold starting as severe back firing does not occur, and that the feature is not more necessary in a direct cranking starter than in a generator or any other engine accessory. D. RECOMMENDATIONS It is recommended that: 1. Future test programs include the determination of cranking power for the largest sizes of engines after be- ing cold-soaked in cold rooms, and that such tests be given a high priority. 2. Tests recommended in par. a above be coordinated with the Power Plant Laboratory and the Bureau of Aeronautics with a view toward accomplishing the tests with fuels, lubricant and/or oil dilution methods that may be adopted as cold starting standards. 3. With view toward reducing weight, studies be made of a torsional elasticity means of reducing shock stresses due to back firing as a substitute for the slipping clutch protective feature. 4. A copy of this report be forwarded to the Bureau of Aeronautics through whose cooperation the direct cranking starters were obtained for testing. 5230 143 Instrument Hose and Fittings Prepared by: T.C. Warner, Capt, A.C. Equipment Laboratory A. PURPOSE To discuss performance of instrument hose and fittings on aircraft assigned to this activity during the period from October 1944 through February 1945. B. FACTUAL DATA 1. Standard instrument hose and hose assemblies in- stalled on production aircraft have operated satisfactorily under the conditions encountered. This hose is made to Specification AN-ZZ-H-626a, and the hose assemblies are made to drawings AN 855, AN 856 and equivalent Army Air Forces drawings. The fittings are crimped on the hose and are not reusable. The hose is marked with a white code line indicating winterization approval. This approval was given to hose manufacturers when they had obtained a product satisfactory down to temperatures be- tween minus 40 and minus 65 degrees F. The use of the yellow code stripe has been authorized some manu- facturers, indicating minus 65 degrees F. approval; how- ever, none of this was available for tests this winter. 2. White line hose with detachable (reusable) fittings, made by the Weatherhead Co., Cleveland, Ohio, and the Areo-Quip Corp., Jackson, Michigan, was installed in the instrument lines on one 'P-38 and one B-17G air- plane. A total of 21-quarter inch I D and 2-three-eights inch I D assemblies was installed in pitot-static, oil, fuel, vacuum and fuel vent lines. The lowest ground temp- erature encountered was minus 40 degrees F. and the lowest free air temperature in flight was approximately minus 65 degrees F. There were no failures of these assemblies and they are still in use. From an engineering standpoint, hose assemblies with both the permament and the detachable end fittings have been satisfactory. The detachable end fittings were developed to enable hose replacements to be procured and stocked by large rolls of hose and seperate fittings instead of individual assemblies of varying lengths. However, experience here indicates that there is very little replacement neces- sary of instrument hose. The hose assemblies with de- tachable ends were installed on the P-38 and B-17 in October 1944 and have approximately 100 and 140 hours flying time, respectively, Exhibit “A”, attached to this report, pictures the subject assemblies. C. CONCLUSIONS 1. Detachable fittings manufactured by the Weather- head Co. and the Aero-Quip Corp. for use with instru- ment hose are satisfactory for service use. 2. Low pressure instrument hose installed on pro- duction aircraft is satisfactory for low temperature operation. D. RECOMMENDATIONS It is recommended that either crimped on, permanent type fittings (AN 855 and AN 856) or detachable fit- tings as shown in Exhibit “A” be accepted with low pressure hose for instrument installations in Army Air Forces aircraft. Instrument Vacuum Selector Valves and B-29 Vacuum System Part I Prepared by: T.C. Warner, Capt, A.C. A. PURPOSE To report results of tests on Winterized Vacuum Se- lector Valves and Modified B-29 Vacuum System. B. FACTUAL DATA 1. Installations of experimental valves were made in production airplanes as follows: B-17G Ser. No. 43-38221 B-24J Ser. No. 42-51660 B-29 Ser. No. 42-65214 Dole Valve Co. Part No. EXP-2165 Johnson Service Co. Part No. SA-12304 Dole Valve Co. Part No. Q-2770-OV installations were completed in September of In addition, the Vacuum System was modified on the B-29 to provide: a. Better operation at low temperature; h. Decreased weight of the system; c. Elimination of Deicer Shut-Off Valve necessary in production installations to provide satisfactory instru- ment operation in case deicer boots are punctured. 2. Production installations of Vacuum Selector Valves in B-17, B-24, B-29 and A-26 aircraft were tested in comparison with the experimental installations. 3. Extreme low temperatures have not been en- countered but tests made to date have shown that the valves listed in Paragraph B-l of this report are superior to the production installations. Ground and flight tests of the Modified B-29 Vacuum System have shown that the Vacuum Selector Valve is superior to the production installation in addition to the elimination of the Deicer Shut-Off Valve and the saving of weight. (A weight saving of approximately 20 pounds was realized.) 4. This report is submitted at this time to present recommendations for changes in production aircraft. Any additional information obtained on the operation of the experimental valves and at extreme low tempera- tures during the remainder of the cold weather tests program this winter will be submitted as an amendment to this report. 5. Check valves installed in B-29 Aircraft Vacuum Systems have operated satisfactorily but do not have winterization approval. Valves installed are (1) Eclipse Aviation, Teterboro, New Jersey, Part No. 525 and (2) Kenyon Instrument Co., Huntington Station, Long Is- land, Part No. 19-100-3. 6. Test data are contained in Appendix I, and sche- matic diagrams showing the differences between the standard and modified B-29 Vacuum Systems are con- tained in Appendix II of this report. Details of this modification have previously been submitted by letter from the Equipment Laboratory to the Bombardment Branch, Procurement Division, Air Technical Service Command. C. CONCLUSIONS 1. Vacuum Selector Valves installed in production aircraft are unsatisfactory for sub-zero operation; whereas, the experimental valves listed in Paragraph B1 are satisfactory. 2. The Vacuum System as modified on B-29 Ser. No. 42-65214 is superior to production installations. D. RECOMMENDATIONS 1. It is recommended that only approved winterized vacuum selector valves be installed in production air- craft. 2. It is recommended that B-29 aircraft incorporate the vacuum installation as modified on Airplane Serial No. 42-65214. 3. It is recommended that check valves, Eclipse Part No. 525, and Kenyon Part No, 19-100-3, be considered for Winterization Approval. Instrument Vacuum Selector Valves and B-29 Vacuum System, Part 2 Prepared by: T. C. Warner, Capt., A. C. A. PURPOSE 1. To present additional information obtained on sub- ject valves. B. FACTUAL DATA 1. Original Memorandum Report (Ref, No. 54-28) dated 5 February 1945, was prepared recommending the use of the experimental vacuum selector valves in pro- duction aircraft, on the basis of tests in the temperature range from 0 to —25 °C. 2. Additional tests have been completed at a ground temperature of —39°C. The three test installations, Dole Valve Co. Part Nos. EXP-2165 and Q-2770-OV and Johnson Service Co. Part No. SA-12304, were satisfactory; whereas, the production installations which were tested were not satisfactory. C. CONCLUSIONS 1. Vacuum selector valves installed in production air- craft are unsatisfactory for sub-zero operation; whereas, the experimental valves tested are satisfactory. D. RECOMMENDATIONS 1. It is recommended that the valves listed in Par. B-2 be granted winterization approval. 2. It is recommended that only approved winterized vacuum selector valves be installed in production aircraft. 5230 145 Final Report from TSEPL-3G Representatives on Temporary Duty at Ladd Field, Alaska Prepared by: T. C. Warner, Capt., A. C. Equipment Laboratory A. PURPOSE 1. To present final results on instrument operation. B. FACTUAL DATA 1. Representatives from TSEPL-3G were present at Ladd Field from approximately 2 December 1944 to 6 March 1945. 2. The major portion of the test work has been reported by individual items or groups of items, refer- ence : a. “Report on Service Tests (No. 2)” (Conducted by the C.W.T.D.) dated 27 Feb. Ref. No. 54-34. b. “Instrument Vacuum Selector Valves and B-29 Vacuum System”, dated 5 February, Ref. No. 54-28 and Amendment No. 1 dated 2 March, Ref. No. 54-35. c. “Instrument Hose and Fittings”, dated 14 Feb- ruary, Ref. No. 54-29. d. “Air Driven Gyro Instruments”, Memorandum Report No. TSESE-4-17, dated 26 February. e. “P-59 Instruments”, Memorandum Report No. TSESE-4-16, dated 26 February. f. “Navigation Instruments”, Memorandum Re- port No. TSESE-4-19, dated 27 February. g. “Type F-4 Airspeed Indicator”, Memorandum Report No. TSESE-4-20, dated 27 February. h. “Type E-l, Artificial Horizon Indicators’ Type C-l, Directional Gyro Indicators,” Memorandum Report No. TSESE-4-22, dated 28 February. i. “Oil and Fuel Pressure Gage Installations,” Memorandum Report No. TSESE-4-29, dated 5 March. 3. The following items were tested and have not been reported before: a. Manifold Pressure Drain Valves. (1) Nine manifold pressure drain valves, made by the Weatherhead Mfg. Co., Cleveland, Ohio, were received on 24 January 1945. These valves were tested for leaks with an air pressure of 25 psi and a vacuum of 8 psi for a period of one minute. Two of the valves leaked under pressure and, therefore, were not used for test purposes. Six valves were installed in Extreme Temperature Operations Unit aircraft and one retained as a spare. The temperatures encountered were from +4°C. to —40°C. (+40°F. to —40°F.) The valves were used approximately 15 times in each airplane. The number of hours of flight time on each installation was: P-38L (1) 25 Jan to 1 Mar—56 hours B-29 (2) 27 Jan to 1 Mar—37 hours B-17G (2) 30 Jan to 1 Mar—60 hours C-47A (1) 31 Jan to 1 Mar—22 hours (2) The valves operated satisfactorily at all times. The valves were installed in accordance with Army Air Forces Drawing No. S45B6557-1 or S45B6557-2. On the B-29 and C-47A, where the mani- fold pressure gages are mounted from the front of the panel, installation of the drain valve in accordance with Army Air Forces Drawing No. S45B6557-2 makes it very difficult to remove the gage from the front of the panel without first disconnecting the hose line (AN856-4) from the rear of the instrument. This de- stroys the advantage of front mounted gages and can be remedied by teeing the drain valve into the instrument line about 14 inches from the instrument (as shown in Army Air Forces Drawing No. S45B6557-1) instead of at the rear of the instrument. A photograph of the instal- lation in the B-17G aircraft is attached to this report as Exhibit A. h. Carbon Monoxide Signal Assembly. (1) One type K-l Carbon Monoxide Signal Assembly was installed as standard equipment in B-24J Serial No. 44-41378. The glass tube in the vacuum sup- ply gage was broken when the airplane arrived at this base. As no replacements were available, the gage was removed and a type F-4 vacuum gage installed. In addi- tion, the “A” lead was broken at the female receptacle (Amphenol No. AN-3102-14S-6S) at the top of the instrument. This was repaired by Sgt. J. Fox (TSEPL- 3G) and the instrument was reinstalled for low tempera- ture tests. There were no known concentrations of carbon monoxide available to test the accuracy of the instrument. Operation was tested by holding a lighted cigarette to the sampling tube in the cockpit. The signal assembly was located aft of the bomb-bay. (2) On 1 March the airplane had 204:25 hours flying time. The instrument was tested at temperatures between 0°C. and —30°C. (+32°F. and —22°F.) The instrument operated satisfactorily at all times. Lowest ground temperature was—45°C. (—49°F.) and lowest free air temperature in flight was approximately —55°C. ( 66° F.) During warm-up period the alarm relay always closed and the instrument stabilized in less than five minutes. On several occasions the instrument gave an alarm on or shortly after take-off. The pilot opened the windows and after a few minutes the alarm would stay off when the reset button was depressed. The longest period necessary to shut off the alarm was approximately ten minutes. 4. The mean temperature from 1 December to 1 March was approximately —16.5°C. (-f3°F.) The ground temperature encountered was —43 °C. ( 45 F.) and the lowest mean temperature for one day was 38.4 C. ( 37.1°F.) Lower free air temperatures were encountered in many cases at altitude for short periods of time. Lnder these conditions only two failures, due to low temperatures, were encountered. One was air driven gyro flight instruments and the other, standard 146 5230 installations of vacuum selector valves. Experimental installations of electric flight instruments and new types of vacuum selctor valves, designed to overcome these difficulties, performed satisfactorily at the low tempera- tures encountered (reference, paragraphs B-2b and B-2h of this report.) 5. The maintenance required on standard equipment in production aircraft can be reduced considerably by stricter adherence to Army Air Forces Installation Speci- fications and Requirements. Items observed during test work and investigation of problems encountered by other organizations are listed below. These items are not to be construed as winterization or low temperature prob- lems buf are a source of trouble under any conditions. Where maintenance is involved, the troubles were much jnore noticeable here because of the difficulty of working in low temperature conditions. a. Front mounting of instruments is not complete by any means. P-63, P-38, B-24 and B-29 airplanes are particularly difficult to work on because the instruments are rear mounted. h. Suction gages on B-25 (G, H and J) and C-46 aircraft do not have a vent connection to the air inlet of the gyro instruments as required by Specification AN-I-5. c. The A-l pressure transmitters on the B-17G and C-54 aircraft were relocated to make them accessible for servicing. The pressure gage (oil and fuel) lines cannot be reached in the wing of the B-29 as there are no access doors near the lines. On one occasion it was neces- sary to heat the wing section between the engine and the firewall from the outside in order to free a line which had frozen. d. Front mounting of oil and fuel pressure gages on the A-26 and P-61 airplanes is ineffective because of insufficient flexible hose on the instruments. In the P-61 the instruments could be serviced from the front but to remove an instrument it was necessary to disconnect the hose lines from the back of the panel. In the A-26 it was Typical installation—thermocouple selector switch and bracket for potentiometer 5230 147 necessary to service the line and to disconnect the hose lines from the back of the panel. e. As noted in Memorandum Report No. TSESE-4-17 dated 26 February, the number of failures of Gyro-Horizon Indicators is excessive. /. There were many failures of cylinder head tem- perature gages due either to cracked cover glasses (at the adjusting screw) or broken leads. C. CONCLUSIONS 1. Except as noted in Paragraph B-4, aircraft instru- ments operated satisfactorily at the lowest temperatures encountered. D. RECOMMENDATIONS 1. It is recommended that Electric Gyro Flight In- struments be installed in aircraft for use in extreme low temperature conditions. 2. It is recommended that approved winterized vacuum selector valves be installed in production aircraft. 3. It is recommended that project engineers take steps to correct the items in Paragraph B5 to decrease the maintenance requirements on Army Air Forces aircraft. Cold Weather Tests of the Type A-5, 35 mm Motion Picture Camera Prepared by: W. G. Straube, Ijf Lt., A. C. Photographic Laboratory A. PURPOSE 1. To determine the functioning characteristics of the Type A-5 motion picture camera in sub-zero weather, B. FACTUAL DATA 2. The Type A-3 camera was operated with film at temperatures varying from 0 degrees to minus 45 de- grees Fahrenheit and at altitudes as high as 30,000 feet. The following malfunctions were noted; a. Difficulty was encountered in threading the camera with brittle film. b. The motor became too stiff at extreme low tem- peratures to satisfactorily operate the film driving mechanism. c. Improper tolerances in the shuttle mechanism caused perforations to be torn and as a result film buck- ling occurred which caused the breakage of film. d. The governor fails to function properly at low temperatures due to the breaking design apd lubrication difficulties. e. Tachometer fails to operate consistently at low temperatures due to improper type of lubrication. 3. Detailed engineering test data are available in the files of the Photographic Laboratory. C. CONCLUSIONS 4. The Type A-5 motion picture cameras previously produced are not satisfactory for extreme low tempera- ture operation. D. RECOMMENDATIONS 5. That future additional cold weather tests be con- ducted on Type A-5 cameras now being procured in ac- cordance with Specification No. 75-2468, dated 2 No- vember 1944. Cold Weather Tests of Stereo- Mounted K-35 (35 mm) Cameras Prepared by: Carl B. Balcom\ Photographic Laboratory A. PURPOSE 1. The purpose of this Report is to report results of tests of Stereo-mounted (35 mm) K-35 camera as- sembly during the 1944-1945 cold weather tests con- ducted by the Photographic Laboratory. B. FACTUAL DATA 2. Subject experimental assembly, (see Appendix A), was designed for the making of three dimensional stereoscopic photographs of details of mechanical de- vices or planes in flight, for training or identification purposes. 148 5230 3. Two standard commercial K-35 cameras were so mounted, with prisms, as to make possible the varying of interocular distance to produced natural depth effect in three dimension photographs of objects ranging in distances of from approximately four feet to fifty feet from the camera assembly. Means are also provided for the use of synchronized flash equipment. 4. Tests indicated that the full power of five bat- teries . operating at approximately 70°F. was required to operate all elements of the assembly and that batteries mounted as a part of the assembly exposed to extremely low temperatures would not function. a. The mounting of the solenoids were found to be unstable because the plastic body of the cameras failed to hold the mounting screws securely. b. The triggers in the gun-grip handles required too great a pressure to effect contact which made it difficult to hold assembly level at moment of exposure. C. CONCLUSIONS 5. It is concluded that for proper cold weather op- eration, a special battery case should be provided. This case could be hung !from belt or shoulder straps near the human body and under heavy outer garments, and with an extension cord which could be plugged into the camera assembly. 6. That the solenoids should be mounted with bolts, washers and nuts in place of screws in threaded holes in the plastic body of the camera. 7. That “microswitch” triggers be used in place of the heavy spring action triggers now used. D. RECOMMENDATIONS 8. It is recommended that when modified as sug- gested above, further tests of subject assembly be made under similar conditions. Cold Weather Tests on the Types B-I and B-1A, 1G mm Motion Picture Cameras Prepared by. W. G. Straube, 1j/ Lt., A. C. Photographic Laboratory A. PURPOSE 1. To determine the functioning characteristics of the Types B-l and B-1A motion picture cameras in sub-zero weather. B. FACTUAL DATA 2, The Types B-l and B-l A camera were operated with film at temperatures varying from 0 degrees to minus 45 degrees Fahrenheit and at altitudes as high as 30,000 feet. The following malfunctions were noted: a. The 12 and 24 volt motors supplied with the Type B-1A camera became too stiff at extreme low temperatures to satisfactorily operate the film driving mechanism. b. The peep-sight type of viewfinder, which is usually furnished as a standard finder with both types B-l and B-1A cameras is unsatisfactory for aerial utilization due to the danger of having the eye bruised or frozen when coming in contact with the finder eye- piece. c. Both types of cameras as manufactured, are produced with tolerances which are too tight for cold weather operation and unless the film driving mechanism and moving parts are properly winterized, the camera does not function satisfactorily at low temperatures. d. Difficulty is encountered in accomplishing the proper film take-up on the Type B-1A when 400 foot capacity magazines are used due to the spring belt sys- tem of take-up. 3. Detailed engineering test data are available in the Photographic Laboratory files. C. CONCLUSIONS 4. The Types B-l and B-1A motion picture cameras as delivered to the using activities is not satisfactory for extreme low temperature operation. D. RECOMMENDATIONS 5. Types B-l and B-l A motion picture cameras to be issued from supply depots to the using activities con- cerned with cold weather operations should be winterized in accordance with latest existing information by motion picture maintenance repair activities prior to shipment of cameras for cold weather utilization. 149 5230 Cold Weather Tests on the Type A-7, 35 mm Motion Picture Camera Prepared by: IV. G. Straube, Lt., A. C. Photographic Laboratory A. PURPOSE 1, To determine the functioning characteristics of the Type A-7 motion picture camera in sub-zero weather. B. FACTUAL DATA 2. The Type A-7 camera was operated with film at temperatures varying from 0 degrees to minus 45 de- grees Fahrenheit and at altitudes as high as 30,000 feet. The following malfunctions were noted: a. The 24 volt motor supplied with subject camera becomes too stiff at extreme low temperatures to satis- factorily operate the film driving mechanism. b. Due to the design of the spider turret difficulty is encountered at low temperatures in rotating and seat- ing the desired lens mount to the proper taking position. c. The peep-sight type of viewfinder which is usually furnished as a standard finder with the Type A-7 camera is unsatisfactory for aerial use inasmuch as the eye cannot be placed close to the eyepiece without being endangered by freezing or bruising. d. The camera as manufactured is produced with tolerances which are too close for cold weather operation and unless the film driving mechanism and moving parts are properly winterized, the camera does not function satisfactorily at low temperatures. e. Difficulty is encountered in accomplishing proper film take-up when 400 foot magazines are utilized due to spring belt system of take-up. 3. Detailed engineering test data are available in the files of the Photographic Laboratory. C. CONCLUSIONS 4. The Type A-7 .motion picture camera as delivered to using activities is not satisfactory for extreme low temperature operation. D. RECOMMENDATIONS 5. The Type A-7 motion picture cameras to be issued from supply depots to the using activities concerned with cold weather operations should be winterized in accord- ance with latest existing information by motion picture maintenance repair activities prior to shipment of cam- eras for cold weather utilization. Water Repellent Jacket for K-17 or K-22 Camera Prepared by: E. Leger, Capt., A. C. Photographic Laboratory A. PURPOSE 1. To report the results of tests conducted to de- termine the value of a water repellent jacket for K-17 or K-22 camera for Army Air Forces use. B. FACTUAL DATA 2. Several jackets were fabricated by Troy Sun- shade Company, Troy, Ohio, in accordance with Army Air Forces Drawing No. X45G14761 for preliminary test purposes. See Photographs Nos. G-5168 and G-5170. 3. One jacket was subjected to extreme cold tests and wrater repellency tests in the laboratory. The results of both tests were favorable in determining flexibility of material at —60°F. and water repellent character- istics after being exposed to running water for 18 hours while fitted on a camera. 4. Two jackets were sent to the Tropical Test De- tachment in Panama for tests. These tests were in- complete due to insufficient time available after the jackets had been received. However, as a result of these tests, the thread used in making the jacket was found to be unsatisfactory and has been changed to nylon to prevent attack by fungus. The seam has been treated to make it more water repellent. 5. Two jackets were sent with the cold Weather Detachment to Alaska and subjected to normal winter 150 5230 operations in that latitude. It was not expected that the jacket would be used in extreme cold operations, but several minor changes have been accomplished as a result of these tests. a. The binding has been made stronger around trunnion holes. b. The drawstrings will be tacked to the material so that they will not be pulled out and become ineffective. c. A heavier grade of material would be better, but not obligatory. C. CONCLUSIONS 6. As a result of numerous laboratory and field tests, the jacket has been improved considerably over the original design. The jacket is now deemed satisfactory for the purpose for which it was intended, namely as a water repellent jacket for use with all focal length cameras of either the K-17 or K-22 type. D. RECOMMENDATIONS 1. It is recommended that the subject jacket be listed in the Army Air Forces stock list and made available for the use of service activities. Cold Weather Test of Color Film Prepared by: B. D. Merrill, Capt., and S, P. Balcomb, C/WO A. PURPOSE 1. To report on the cold weather test of color film conducted at Ladd Field, Alaska, during the winter of 1944-45. B. FACTUAL DATA 2. Three rolls of aerial Kodacolor were exposed and processed, and the following observations recorded: a. The required color balancing filter tests were made with little difficulty and the processed film demon- strated that the recommended filters gave the best results. b. There were some difficulty in the handling of the gelatin filters required for the tests, as they became quite brittle and cracked easily at low temperatures. c. There was no apparent loss of color film speed at the average temperature of approximately 25 °F. found inside the aircraft. However, more exposure meter data will be necessary to definitely establish aerial film speeds under the rapidly changing light intensities found at extreme latitudes. d. There was little difficulty encountered in processing aerial Kodacolor with the color kits. How- ever, because of the difficulty in securing large water supplies, it was necessary to substitute successive rinses where the processing instructions called for washing in running water. 3. Some comparative tests were made using cut-sheet Ansco Color film and Kodachrome. Both types of film were generally under-exposed and the resulting photo- graphs were too dark for accurate comparison. C. CONCLUSIONS 4. It is concluded that aerial color film can be exposed and processed successfully under cold weather field con- dition with only the minor change of substituting suc- cessive rinses where the processing instructions called for washing in running water. 5. It is concluded that although the excessive changes of the gelatin filters required by the filter tests eventually caused cracking at low temperatures; these filters did perform satisfactorily when used in the recommended standard manner. 6. No conclusions could be made as to the compara- tive merits of Ansco Color film versus Kodachrome under cold weather conditions. 7. It is concluded that in extreme latitudes, where the sun shines for short periods only and then at very low angles, it is extremely important for good quality color photographs to secure reliable exposure data from dependable exposure meters. D. RECOMMENDATIONS 8. It is recommended that personnel using color film in regions of extreme latitude be impressed with the im- portance of correlating the readings of a dependable exposure meter with test exposures on the type of color film they are using, and then strictly adhering to the use of that exposure meter. 9. It is recommended that instruction sheets for processing color film be amended to include data for successive rinses to replace washing in running water wherever the latter is unavailable. 10. It is recommended that further exposure meter data closely correlated to film exposure series be secured on future cold weather tests. 5230 151 Cold Weather Test of the Type N-5 Kit, 16 mm Motion Picture Film Field Processing Prepared by: R. D. Fullerton, 1st Lt. and S. P. Balcomb, C/WO A. PURPOSE 1. To report results of cold weather tests conducted on the 16 mm Field Processing Kit, Type N-5, to de- termine its compliance with the requirements as 3et forth in Specification No, 31394 (Type K-2 Developer) and Specification No, 31395 (Type C-4 Prmter). B. FACTUAL DATA 2. One Type N-5 kit manufactured by the Houston Corporation, Los Angeles, California, was submitted to the Photographic Laboratory for cold weather tests 27 November 1944. 3. The kit, as submitted, consisted of one Type K-2 developer with accessories, one Type C-4 printer, one 16 mm editor and splicer with comparator, and one darkroom cabinet, 4. The tests consisted of operation of the kit in normal room temperatures of from -)-550F. to +750F. in a Jamesway Shelter when the outside air tempera- tures ranged from —51°F. to -j-20°F. 5. Due to an inadequate water supply, it was neces- sary to operate the developer without the benefits of running water. The wash tank was filled with Al/2 gal- lons of water and was drained and refilled after the processing of each 200 feet of film, 6. Table I shows the temperature range in which both negative and positive film was developed: a longer developing time, it was not possible to develop this film at plus 55°F. 8. All solutions were allowed to freeze in the tanks of the developing machine for a period of 12 hours. Thawing out of the solutions was accomplished by using immersion heating elements. Because the hydroquinone of the developing solution had crystallized, it was neces- sary to heat the solution to -(-100oF. to completely re- dissolve it. The solutions were then used without ap- parent harm to the film. A thorough inspection and subsequent operation of the developing machine revealed that no damage was caused by the freezing. 9. Due to lack of running water, it was necessary to siphon the tanks by manual means. 10. Lacking the necessary tool, considerable trouble was experienced in making tight water-proof connec- tions between the various water hoses and the developer. 11. Poor packing and crating of the kits,,resulted in broken plastic knobs on the risers and a loosened tacho- meter on the control panel. 12. The printer, Type C-4, performed satisfactorily at all room temperatures. However, due to the peculiar design of the aperture plate block a uniform lack of absolute contact was noted on all printed film. 13. The darkroom cabinet of the kits ultimately became a storage locker for miscellaneous items. Ade- quate darkroom facilities were available at all times and it was not necessary to use the cabinet for loading or rewinding. C. CONCLUSIONS 14. It was concluded that; a. The Type N-5 kit is satisfactory for field use in cold weather climates if the operating temperatures are maintained above -f-60°F. This is possible if the darkroom is only a Jamesway Shelter with outside tem- peratures as low as —51°F. D. RECOMMENDATIONS 15. That the darkroom cabinet be excluded from the Type N-5 kit. 16. That a suitable wrench be made a part of each Type K-2 developer. Table I TEMPERATURE RANGE, PROCESSING SOLUTIONS, TYPE N-5 KIT Negative Film Positive Film Temperature Minutes Development Temperature Minutes Development Plus B6°F. 17 Plus 62°F. 17 60 17 66 16 62 16 68 13 66 18 70 12 68 12 72 11 70 10 72 9 7. Seventeen minutes development was the maxi- mum processing time possible with the K-2 developer. Although the film was somewhat under developed at 4-55°F., it was possible to make a print of satisfactory quality from the negative. Because positive film requires 152 5230 Cold Weather Tests with F-5E Airplane Prepared by: A. C. Olson, Capt., and S. P. Balcomb, C/WO A. PURPOSE 1. To report on the camera compartment heating, and window defrosting tests, conducted at the Cold Weather Test Detachment, Ladd Field, with an F-5E airplane, during 1944-1945. B. FACTUAL DATA 2. An F-5E airplane No. 44-23602 was used for the camera compartment heating, and window defrosting tests. Several flights were made with the normal camera compartment heat; several flights were made with ducts to conduct the hot air to each window, and two flights with no heat provided to the camera compartment. 3. During each of the flights, the free air and camera compartment temperatures were recorded at each 5,000 foot level up to 30,000 feet and likewise on descent (See Appendix I). Three (3) pictures were taken at each of these altitudes. 4. The film from these flights was inspected with regard to window frosting or fogging. No signs of these were found at any altitude or under any of the compart- ment heating and window defrosting conditions. This was due to the low relative humidity of the atmosphere where the tests were conducted. 5. From the values of the temperatures in Appendix I, it can be seen that the general compartment heat pro- duced the greatest difference between free air and camera compartment temperature. This is further illustrated in Figure I, which shows the plotted averages of four (4) flights with compartment heating and four (4) flights with defrosting ducts used. In both cases, the averaged free air temperatures are also plotted. This higher com- partment temperature makes a better condition for camera operation. It has been found necessary, however, in other theaters of operation, to use the window defrost- ing ducts in order to keep the windows clear. In these areas, the relative humidity of the atmosphere is quite high and the windows fog easily, if the air is not blown across them. C. CONCLUSIONS 6. In a theater of operations such as Alaska, the use of either window defrosting ducts or general camera compartment heat in an F-5E airplane is satisfactory for successful photography. 7. General camera compartment heat in an F-5E air- plane affords a better camera operating temperature, D. RECOMMENDATIONS 8. None. Low Temperature Tests on Aerial Photographic Cameras Prepared by: A. A. Koepjer A. PURPOSE 1. To report on tests conducted at Ladd Field and at this Laboratory on experimental modifications of stand- ard equipment, and also by the Proving Ground Com- mand on standard equipment winterized in accordance with Technical Order No. 10-1-96, dated 20 October 1944. B. FACTUAL DATA 2. Three experimental modifications were made on standard aerial camera equipment in an effort to improve operating performance at extreme low temperatures. The modifications were as follows: a. The standard Type K-24 Aerial Camera was modified to incorporate thermostatically controlled in- ternal heaters with fiber glass insulation. b. A Type K-17 24" shutter assembly housing was constructed of steel instead of the usual bronze to mini- mize binding and contractual interference caused by different rates of contraction between the bronze casting and the steel shutter links. c. A Type K-22 24" cone was modified to provide for circulation of hot air between the filter and the rear 5230 153 and front lens surfaces, and also the internal surfaces of the cone to prevent condensation from gathering at these places. 3. Tests on the internally heated Type K-24 camera revealed very satisfactory operation under all conditions experienced throughout the tests. The lowest tempera- ture encountered was —55°F. Laboratory tests of this camera revealed satisfactory operation after storage at —65 °F. for a period of 24 hours. One K-24 camera modified in this manner has been sent to England for tests to determine if the British concur in this method of insuring proper low temperature operation. 4. The steel shutter housing in the Type K-17 camera performed very satisfactorily at all temperatures down to —55 °C. Laboratory tests at temperatures as low as—65°F. also indicated satisfactory operation. 5. Test on the hot air heated Type K-22 camera did not prove too successful. The definition on the negative is affected by turbulence caused when hot air passes across the lens surfaces. Also during test the passing of the hot air over the cold lens surfaces caused the lens to check. In view of these factors, this method of heating is not recommended and instead electrical heated filters and internal electrical heaters are to be provided. 6. Several cold weather tests were conducted by the Proving Ground Command on all standard type aerial photographic cameras which had been winterized in accordance with Technical Order No. 10-1-96 prepared by this Laboratory. Results of these tests were very good as satisfactory performance was obtained under all conditions at temperatures down to —62°F. Complete reports covering the tests on each type of equipment are available in the cold weather test file of this Laboratory. C. CONCLUSIONS 7. The above information relative to performance of aerial cameras operating at temperatures as low as —65 °F. indicates that the problem has been greatly alleviated in the past two years. The prime factors con- tributing to reliable operation at low temperatures were: a. The development of a new type of grease and oil each having excellent low torque characteristics at extreme low temperatures. b. The elimination of contractual interferences between mating parts constructed of different materials by using similar materials and providing for additional clearances. D. RECOMMENDATIONS 8. It is recommended that modification (a) and (b) of Factual Data Paragraph 2 be incorporated in future production of K-24 and K-17 aircraft cameras respec- tively. Installing cameras—P-38 154 5230 Ground Cameras Prepared by: L. Woloshin & Y. P. Balcomb, C/WO A. PURPOSE 1. To report the results of the Cold Weather Tests of 1944-1945 insofar as they are applicable to ground cameras. B. FACTUAL DATA 2. THE CAMERAS TESTED DURING THE WINTER OF 1944-1945 WERE; a. Kodak 35 mm with rangefinder. b. Type C-l Ground Camera. c. Type C-3 Ground Camera. d. Type C-4 Ground Camera. 3. TYPE C-l GROUND CAMERA. a. The Type C-l Ground Camera tested this winter is one that had previously been used during the tropic tests of 1944. b. It was observed, upon unpacking the camera at the start of the cold tests, that the glued joints of the camera bed had become unfastened. c. It is believed that this was due to the tropic tests in view of the fact that the malfunctioning occured prior to the time cold tests were conducted. d. Tests were conducted at —14 degrees Fahrenheit on the shutter and lens assembly and it was observed that the cement between the elements of the lens had cracked. This malfunctioning of the Gundlach lens was also re- ported during the cold tests of 1942-1943 and 143-1944. Mechanical operation of the shutter was satisfactory at —14 degrees Fahrenheit. e. Shutter speed tests were conducted on the shutter assembly at room temperature and at —7 degrees Fah- renheit. The marked 1 /50th second speed was actually 1 /25th second. It appeared that the cable release for this shutter was approximately l/16th inch too short. It is not known if the contraction of the metal of the shutter was responsible or whether the difficulty was due to the particular cable release used. However, the cable release worked satisfactory at room temperatures, but inoperation of cable release at low temperatures were no doubt due to contraction of both release and shutter assembly. /. Shutter speeds tests were made using a Mark Hurd shutter tester. 4. KODAK 35 MM CAMERA WITH RANGE- FINDER; a. The Kodak 35 shutter became inoperable shortly after the start of the test program. Examination re- vealed that the spring operating the blade controller latch (Part No. 56840) had become free. The camera was repaired but did not operate perfectly. Of the two Kodak 35’s used for stereo photography, one operated satisfactorly. The source of difficulty in the second cam- era was that the spool assembly; film take-up, (Part No. 77275) was not being released when pulled up. Ex- amination revealed the bushing remained in the take-up position. After repair, the camera operated properly. b. Continued operation of the camera revealed that the K-35 is not constructed rugedly enough for ardous usage. 5. THE TYPE C-3 GROUND CAMERA: 4 a. The camera used, (Serial No. 43-31248) with a Graphex Shutter, had been used during the cold tests of 1943-1944, and the tropic tests during the summer of 1944. At the coldest temperatures recorded during this year’s tests (—51°«F.) the Type C-3 camera performed well. The winterized flash unit made possible proper flash synchronization. b. After continued use of the camera where a long series of successive photographs were taken, the back of the camera and rangefinder eye piece frosted and caused inconvenience to the camera operator. No tests were conducted to determine the value of placing felt or chamois on the metal parts of the camera back for pro- tection of the photographer’s face. It may be possible to avoid this difficulty by extending the length of the range finder eye piece about 1 or 1-1/2-inches. However, an increase of length may interfere with camera storage in the carrying case and, also, the eye piece may project too far from the protection from breakage offered by the camera body. However, a telescoping eyepiece might be designed which would eliminate this factor. c. The Graphex shutter of the Type C-3 Ground Camera was checked at —7 degrees Fahrenheit using the Mark Hurd shutter tester. These speeds were: Nominal Speed Actual Speed 1/200 1/100 1/100 1/50 1/50 1/16 1/25 Too long a duration to be measured. During the Cold Weather Tests of 1943-1944, the same shutter was tested at —30 degrees aFhrenheit and at —43 degrees Fahrenheit. At these temperatures the shutter operated more slowly. A comparison cannot be made in view of the fact that during 1944-1945, no tests were made at temperatures lower than —7 degrees Fah- renheit. d. Focal plane shutter operated satisfactory at temp- eratures down to 10 degrees above. Below this point the curtain did not release properly. 6. TYPE C-4 GROUND CAMERA: a. Remarks applicable to the proper performance of the Type C-3 Ground Camera? apply to the tests con- ducted on the Type C-4 camera. This is due to the simi- larity of design and construction of the cameras. b. Shutter speeds checked at —7° Fahrenheit with the Mark Hurd Tester were: Nominal Speed Actual Speed 1/200 1/200 1/100 1/100 1/50 1/50 1/25 1/100 Reason for the failure of the l/25th second during this test is unknown. 5230 155 7. Some difficulty was encountered with the range- finder on the C-4 Camera. This apparently was due to tension of the cam spring. 8. Before shipment to Alaska, all camera parts re- quiring lubrication were cleansed in naphtha gas and relubricated with Specification ANG-3a, Grease; Lubri- cating, with special camera lubricants added and Speci- fication AN-0-6, Oil; Lubricating. C. CONCLUSIONS 9. It is concluded that if properly winterized, the subject cameras will operate at temperatures down to the lowest encountered (approx. —43°F.) 10. It is also concluded that further study should be made of rangefinders with reference to cold tempera- tures and the frequency with which they become out of synchronization. 11. It is further concluded that lenses manufactur- ed by the Gundlach Optical Company are not suited for cold temperature operation. D. RECOMMENDATIONS 12. It is recommmended to TSBPR-4L and TSSEQ-8, that procurement of additional lenses for the Type C-l ground camera be made only of those lenses whose lens elements are cemented with a cement that is known to be capable of withstanding tempera- tures as low as —65 degree Fahrenheit. 13. It is further recommended that only limited use be made of the K-35 mm (with rangefinder) when low temperatures are existant. Report to Chief, Maintenance Division Prepared by: P. E. Shanahan, Col., A. C. 1. PURPOSE The purpose of subject temporary duty was to act as liaison officer between CWTD, Ladd Field, Fairbanks, Alaska, and Maintenance Division. Headquarters, ATSC, to observe CWT methods, procedures and re- sulting maintenance problems. 2. FACTUAL DATA a. A brief description of the Cold Weather Test Detachment’s organization, purpose and scope will be given in order that a clear picture may be obtained of the entire program. For your information, attached as Ex- hibit “A” is chart showing the latest proposed organi- zation of CWTD. (1) Cold Weather Test Detachment operates under the jurisdiction of the Commanding General, AAF Proving Ground Command, Eglin Field, Florida. Its reports are submitted through him to the AAF Board, Orlando, Florida, where recommendations concerning the results of the winter’s testing are made and submitted to the Commanding General, AAF. (2) Directives for the operation of CWTD ema- nate from Headquarters, AAF. and are based in part on recommendations submitted by the AAF Board. CWTD is in reality composed of two (2) main parts, CWTD proper, which tests first-run production equipment for cold weather operation, and Extreme Temperature Oper- ating Unit (ETOU), which is a part of the Engineering Division, Headquarters, ATSC, and which operates under the Commanding Offiicer, CWTD, while technical control rests with Engineering Division, Headquarters, ATSC. In reality, ETOU operates almost independently. It has its own directives, its own methods and procedures, and operates under the Commanding Officer, CWTD, only in that it conforms to CWTD’s policies which govern its operations at Ladd Field. Whereas CWTD tests first-line production equipment, ETOU is* engaged in testing experimental equipment. (3) CWTD utilizes and operates Watertown AAB, Watertown, South Dakota, as a staging field for CWTD operations in that CWTD personnel, both offic- ers and enlisted men based at Ladd Field, are returned to Watertown AAB during the spring and summer months. While there, troop training is conducted, air- planes are prepared for the coming winter’s tests and shake-down flights on them are accomplished. The com- ing winter’s cold weather test programs are drafted, and supplies are gathered which will be needed at Ladd Field for those tests. These supplies are then in the main flown to Ladd Field, though some are shipped by other methods. Watertown originally was a Second Air Force heavy bomber base and has fine runways for heavy air- craft. It has one (1) medium size hangar and adequate control tower and weather facilities. It also has ample housing facilities for the entire CWTD personnel of ap- proximately seventy-five (75) officers and four hundred (400) enlisted men. During the winter months a house- keeping detachment only is stationed there, and occasion- ally airplanes from Ladd Field fly there for emergency supplies. (4) CWTD has available for its use when needed several satellite fields in the area adjacent to Ladd Field, including Nome, Point Barrow, Galena, Tanana, North- way, Tanacross, Big Delta and Satellite. These fields are located anywhere from 25 to 500 miles distant, and while they were not built for cold weather activities, they are readily accessible and available when the temperatures at these fields are enough lower than those prevailing at Ladd to make it worth while for CWT airplanes to go there. They are also used as refueling stops for CWT airplanes which in the course of their testing may be out on extended flights away from Ladd, such as gunnery missions out over the Bering Sea. As an example of how these fields may be used, Ladd Field very, very seldom 156 5230 Ladd Field, Alaska Fairbanks, Alaska has high winds, and normally when extremely low' tem- peratures predominate there the wind is dead calm, or almost so. Big Delta, on the other hand, is very often subject to high w'inds, 15 to 20 mph, with sub-zero tem- peratures, and the winds go as high as 50 to 60 mph gusty. A 30 to 40 mph wind w ith temperatures of near zero or even slightly abo’-e presents a terrific ground handling and ground maintenance problem, even w'hen compared with temperatures of —50° with calm conditions. Nor- mally most of interior Alaska gets those low temperatures because the cold air collects in the valleys and plains which are protected by mountains and where calm condi- tions prevail at the surface. Usually fields subjected to these very low temperatures always have a temperature inversion 1000 to 2000 feet over the field. Then, some- where between the 5000 and 10,000 foot levels, the normal decrease in temperature with increase in altitude is en- countered so that temperatures at the 25,000-35,000 foot levels are about the same as encountered anywhere. (5) As previously mentioned, CWT conducts tests on latest production equipment. To do this, they have approximately seventy-five (75) officers and four hundred (400) enlisted and civilian personnel and about thirty (30) to forty (40) production aircraft of all types (see attached list, exhibit “B”). The organization has Headquarters and Headquarters Staff and various oper- ating sections, including Heavy Bombardment, Medium Bombardment. Cargo, Fighter and ground equipment, w'hich conduct the actual tests and prepare necessary reports. (6) ETOU has approximately twenty (20) air- craft (see attached list, Exhibit “C”), most of which are late model production items. These aircraft are equipped with latest experimental equipment. Maintenance per- sonnel are furnished ETOU from the CWT pool. Test pilots and engineering personnel are from the Engineer- ing Division, Headquarters, ATSC, and are usually from that Laboratory concerned wdth the particular equipment on which tests are being conducted. Aircraft and accessories manufacturing concerns are invited to participate in cold weather tests by both AAF Proving Ground Command and Engineering Division, and their representatives are sent to Ladd Field for these tests. (7) Since all existing cold weather test directives are w'ritten around temperature ranges from —65° to + 165°, there has of late been considerable discussion as to the merits of interior Alaska as a suitable field of operations for cold wreather testing. Army Service Forces have done considerable testing in the neighborhood of Fort Churchill, Canada, located on the west shore .of Hudson Bay, and there have been suggestions made that Churchill would be more suitable than Ladd for AAF cold weather testing because of temperature as low as those prevailing at Ladd with much higher wind velocity which certainly increases the cold weather maintenance problem. However, a careful analysis of the conditions prevailing in both localities would seem to indicate that there is very little difference between the two. Average wind velocity at Churchill for the winter of 1943-44 was a trifle higher than at Ladd proper but no higher than at some of the satellite fields. Temperatures, on the other hand, were also a bit higher, both as to maximum and mean values, while minimum values were definitely lower at Ladd. There also is the fact to be considered that the AAF have many expensive, well equipped installations in the interior of Alaska while Churchill is Canadian. By summer of ’46 it is expected that the climatic-hangar now under construction at AAF Proving Ground, Eglin Field, Florida, will be completed, and this hangar should be ample to handle the Air Force’s cold weather test pro- gram. The building is 200'x240', 70' high in the center. It will be equipped with refrigerating machinery capable of lowering the temperature to —70°. There are also provisions for artificial snow, sand, rain and sleet storms, as well as wind machines. There will be arctic, desert, and jungle test rooms. b. Operations for the winter of 1944-45. Cold weather testing of both production and experimental equipment has been considerably hampered this season by unusually mild weather. Temperatures, —35° to —50°, were rare at both Ladd and its satellites, so all testing was of a necessity conducted in only moderately low temperatures. Results of the past three (3) winters’ testing have indicated that the Air Forces have brought all equipment to that standard of perfection where it can probably operate satisfactorily down to —30° or —35°. There are still problems to be solved in —40° to —55° range. (1) Current problems include hydraulic fluids, oils and greases, engine preheaters, control cables, pulleys and movable surface hinges. Problems encountered in these last three (3) items are not only those of lubrica- tion but binding caused by misalignment due to unequal expansion and contraction. Hydraulic seals have been bad this winter, particularly on P-47 type aircraft. Greases and oils, especially the former, are not yet satisfactory for extreme low temperatures. Tests on synthetic lubricating oils have been promising. Also synthetic tires versus natural rubber tires are being tested, but the results are not available as yet. (2) Snow and ice tires. These items of equip- ment are controversial. Some pilots do not believe they pay for themselves, especially on heavy aircraft. Other pilots claim they would not operate without them. Yet, one engineer, an officer of ETOU, stated that one pilot who was very strongly in favor of these tires did not know that his own airplane was not so equipped. The old “beer bottle cap” style tire has been supplanted by a conventional non-skid type tire with the non-skid ele- ments strengthened and bolstered by small steel inserts. In general, pilots of Cold Weather Test activities did not seem to think that there was enough noticeable increase 5230 157 general very little photographic trouble is being encoun- tered this year. They have received photographic equip- ment improperly winterized, that is, lubricating agents had been improperly applied and gumming of shutters and other delicate moving parts had resulted. This mat- ter has been reported to Photographic Maintenance Branch, Associated Equipment Section. The Base Photo- graphic Officer, Ladd Field, stated that some balsam cemented compound camera lenses were still being re- ceived and that in extreme temperatures the compound lenses separated due to failure of the cement. Field de- veloping laboratories still experience some difficulty in getting sufficient supplies of suitable water for use in their activities. Otherwise, photographic cold weather test problems are normal. (5) Communications equipment. Maintenance difficulties with communications equipment available at Ladd Field, which included radar as well as radio, were slight. (6) Clothing, Emergency Kits and Survival Rations. There is considerable evidence that these items of Air Force equipment are not completely satisfactory as yet for cold weather usage. Mr. Washburn of Per- sonal Equipment Laboratory, Engineering Division, Area “B”, contacted the undersigned and requested com- ments relative to the shortcomings of clothing, kits and rations. A copy of these comments is attached as Ex- hibit “D” and contains representative complaints made not only at Ladd Field but at other stations from Ed- monton north. (7) Ground testing of engines. At the present time there is no means at Ladd Field for operating air- craft engines on the ground under cold weather condi- tions. However, there is now nearing completion test blocks which were made from the old concrete structure originally set up for engine running stands by the 6th Air Depot Group. These testing stands were never com- Ice grip tire with steel spring inserts in performance of the snow and ice grip tires on heavy, high performance aircraft to warrant their use. The Aircraft used by the undersigned was equipped with the old “beer bottle cap” style tires. The airplane was light and of low performance, and on glare ice runway, with a very light film of water over the ice, they were a help in taxiing . However, such runways were encountered only three (3) times, twice in Alaska and once at Pat- terson Field. The only noticeable difference was that a great deal more care had to be exercised in taxiing. Snow and ice grip tires are difficult to manufacture, thereby slowing production, and are more expensive. The mild weather prevailing at Ladd Field during the latter part of January gave excellent opportunities to test these tires, and Cold Weather Test personnel were making every effort to obtain information on this equip- ment during the mild weather period which caused slip- pery runways. (3) Observations of the undersigned indicate that one of the biggest problems encountered in cold weather operation is the difficulties encountered by ground personnel in performing their duties. Field maintenance shelters are not yet adequate for use under all low temperature conditions, especially when low tem- peratures are accompanied by high wind velocities. Wherever adequate hangar facilities are available, cold weather problems are greatly reduced, but the moment primitive field conditions exist, ground crews get into trouble—the level of preventive maintenance drops, man- hours to accomplish a given job increase enormously, and there is far more tendency for work to not be up to high standards. It is believed that more emphasis should be placed on ground handling equipment, mechanics’ clothing, field shelters, etc. (4) Photographic. Cold Weather Test Photo- graphic Project-Officer was contacted and stated that in Ice grip tire with steel bottle-cap inserts after 67 landings 158 5230 pleted other than pouring the concrete tor the basic struc- tures. Working from this as a base, the new cold weather test stands are being made and should be in full operation by next fall. These stands will then permit mounting both production and experimental type engines, either jet or conventional type, and running them under very low temperatures. Also, believed to be more important on a cold weather test angle, ground maintenance problems arising from cold weather operations may then be thor- oughly exploited. In cold weather operation good main- tenance is a major problem because of the severe condi- tions under which personnel must operate. 3. CONCLUSIONS AND RECOM- MENDATIONS a. If all Air Force equipment is to operate satis- factorily down to the extreme temperature range of —65°, which has been set up by directive from Head- quarters, AAF, as the goal, then considerable work still remains to be done. b. When the climatic hangar, AAF Proving Ground Command, Eglin Field, Florida, is completed and in operation, it should prove a very valuable tool for use in solving extreme cold weather problems. c. If the Air Forces expect to operate in ground temperatures from —30° down to —65°, a great deal more emphasis must be placed on the development of suitable equipment for use on the ground. The efficient handling of aircraft, starting of engines, and, above all, the achievement of high maintenance standards will be factors of prime importance. d. It is recommended that representatives of the Maintenance Division participate in the drafting of Cold Weather Test Programs in the same fashion as they now participate in 689 Inspections and Mock-Up Boards. e. It is recommended that very close Liaison be maintained between the AAF Proving Ground Com- mand and the Maintenance and Engineering Divisions, Headquarters, AT SC. Report of Visit to Ladd Field, Alaska Prepared by : R.C. Johnson, Capt, A.C. Maintenance Division 1. In compliance with par. 1 of Letter Orders No. 10-31-37 dated 31 October 1944, the undersigned pro- ceeded to Ladd Field, Alaska, for the purpose of liaison on matters pertaining to maintenance in cold weather operation. 2. A representative of the Supply Division visited Ladd Field at the same time as the undersigned; there- fore, no mention of the supply problems will be made in this report. 3. Base personnel contacted were the Adjutant, Air Inspector, Chief, Maintenance and Supply, Maintenance Officer, Technical Inspector and the enlisted personnel performing the maintenance. 4. Cold Weather Test personnel contacted were the Commanding Officer, Adjutant, Engineering Officer, Maintenance Officers, Technical Inspector and enlisted personnel performing the maintenance. 5. The maintenance in Cold Weather Test is broken down to types of aircraft-fighter, medium bomber, etc. A Maintenance Officer is assigned to each type aircraft and he is responsible to the Engineering Officer for their status. This system operates very satisfactorily, and the percentage of aircraft maintained in flyable status is very high. 6. A complete picture of the difficulties encountered when performing cold weather maintenance was not ob- tained, since —25°F was the lowest temperature regis- tered. However, listed below are some approximate figures received from maintenance personnel making in- spections on the aircraft. a. The approximate time necessary to accomplish a normal 50 hour inspection at different temperatures is as follows: Type Aircraft Temperature* 0°F —20°F —40°F —60°F C-46 12 hrs. 16 hrs. 24 hrs. 40 hrs. C-47 12 hrs. 16 hrs. 24 hrs. 40 hrs. B-17 14 hrs. 18 hrs. 26 hrs. 46 hrs. B-24 14 hrs. 18 hrs. 26 hrs. 46 hrs. B-25 12 hrs. 16 hrs. 24 hrs. 40 hrs. B-26 12 hrs. 16 hrs. 24 hrs. 40 hrs. P-47 12 hrs. 16 hrs. 24 hrs. 40 hrs. P-51 12 hrs. 16 hrs. 24 hrs. 40 hrs. P-63 12 hrs. 16 hrs. 24 hrs. 40 hrs. b. The approximate time alloted the crew chief to ready the airplane for flight is two hours. 7. Attached hereto is a list of Pre-flight and Daily Inspection items. This list was coordinated with both Base and Cold Weather Test maintenance personnel and approved. 8. The following recommendations were received by the undersigned: a. That adequate tire tools be provided. The present Firestone Kit as issued is very unsatisfactory. b. That T.O. 01-1-50 be revised to eliminate the necessity of requiring a man in the cockpit of an airplane when towing bars are being used to tow the airplane. c. That T.O. 19-1-105 be revised to take care of activities operating from snow and ice covered fields (in process of revision). d. That additional Aircraft Maintenance and In- spection Guides for The C-46, C-47, and C-54 be for- warded. (Being accomplished). 5230 159 e. That T.O. distribution be expedited. (Checked with TSSEQ6C and was informed that they now have Overseas priority, which is the highest priority possible). 9. Information on Radar equipment is being forward- ed to TSMTE5. 10. Recommendations: a. That orders for all personnel visiting Ladd Field this winter specify that A.C. clothing will be issued at Great Falls instead of Q.M. clothing. h. That the approved list of Pre-flight and Daily Inspection be included in all Aircraft Maintenance and Inspection Guides. Report of Temporary Duty at Ladd Field Prepared by: H.F. Helbig, Major, A.C., Maintenance Division A. PURPOSE The purpose of the subject temporary duty was to act as liaison officer between CWTD, Ladd Field, Fairbanks, Alaska, and Maintenance Division, Headquarters, ATSC, to observe CWT methods, procedures and re- sulting maintenance problems, with particular emphasis to engine maintenance problems. B. FACTUAL DATA 1. A brief description of the CWDT’s organization follows: a. The Cold Weather Test Detachment operates under the jurisdiction of the Commanding General, AAF Proving Ground Command, Eglin Field, Florida. All reports are submitted through him to the AAF Board, Orlando, Florida, where recommendations concerning the results of the winter’s testing are made and submitted to the Commanding General, AAF. b. All directives for the operation of CWTD ema- nate from Headquarters, AAF and are based in part on recommendations submitted by the AAF Board. The Cold Weather Test Detachment is composed of two main parts, CWTD proper, which tests first run production equipment for cold weather operation, and an Extreme Temperature Operations Unit, which is part of the En- gineering Division, Headquarters, ATSC. Basically ETOU operates almost independently under its own directives, methods and procedures, conforming only to CWTD’s policy which govern its operation at Ladd Field, Alaska, and is engaged primarily in testing experimental equipment, as compared to testing of production equip- ment by CWTD. c. There are several satellite fields available for both ETOU and CWTD in the area near Ladd Field, includ- ing Nome, Point Barrow, Galena, Tanana, Northway, Tanacross, Big Delta and Satellite. These fields are located anywhere from 25 to 500 miles distance, and while they are not built for cold weather testing they are readily accessible and available when temperatures are lower than those prevailing at Ladd Field. An example of how these fields may be used is indicated by the fact that Ladd Field very rarely has any high winds when temperatures are low. Big Delta, on the other hand, is subject to high winds with low temperatures; therefore, presenting a greater ground handling and ground main- tenance problem than is encountered at Ladd Field, making it advisable to run various tests at this activity. d. Since all existing cold weather directives are written around temperatures of —65° to -j-165°F., it is found that Ladd Field very rarely encounters tempera- tures below —35° ; therefore, it would be advisable to select another location where lower temperatures prevail a greater percentage of the time for cold weather test. Attached is Engineering Division Technical Note TN- TSESE-1, (Exhibit #1) governing the design of Aero- nautical Equipment for Operation in Extreme Climatic Conditions. 2. Operations for the winter of 1944-45. Cold weather testing of production and experimental equipment was hampered considerably the months of December and January by unusually mild weather. Temperatures of —35° to —50° were rare at both Lacfd and Satellite Fields, so all testing was conducted only at moderately low temperatures. Observation, however, indicated that the AAF has brought all equipment to a standard where it is possible to operate aircraft with a reasonably amount of success at temperatures down to —30° or 35° ; however, at lower temperatures there are still many problems which will have to be solved before satisfac- tory operation can be accomplished. a. Current problems at extremely low temperatures include hydraulic fluids, oils and greases, engine pre- heaters, control cables, pulleys and movable surface hinges. Problems encountered in the last three items are not only due to lubrication but also are affected by the large amount of expansion and contraction, and mis- alignment in large surfaces and cables. It was noticed that the hydraulic seals on P-47 airplanes are entirely unsatisfactory, and tests on synthetic lubricating oil PPO- 265, at the time the writer was in Alaska, seemed to be very promising. b. Ground testing of aircraft engines. At the pre- sent time there are no means at Ladd Field for operating aircraft engines outside of aircraft on the ground under cold weather conditions. There are, however, test stands being constructed at the present time for testing both conventional engines and gas turbine type engines. At- tached are photos of both conventional and gas turbine test cells which have been constructed at Ladd Field. (Exhibit #2, pages 2A and 2B). 3. The following is a brief resume of some of the engine difficulties experienced at Ladd Field: a. Oil hose failures on P-51 aircraft is prevalent during cold mornings. Inspection of the hose in the field disclosed that it was aromatic non-self-sealing hose. In 160 5230 Maintenance using heated nose hangars accordance with existing Technical Orders, this type hose is not recommended for oil systems but may be used if the regular hose is not available. For cold weather operation, it is recommended that only specified oil hose be used on these aircraft. b. Attached is an estimated oil dilution schedule used by CWTD and ETOU for use with synthetic oil in various combat aircraft based on zero per cent dilution required for —15°F. and 20% required for —65°F. This schedule appeared to be satisfactory. (Exhibit #3, page 2C). c. On 6 December 1944 the B-29 aircraft descended from 33,000 ft. at an outside air temperature of —46°C. and found that when 2,000 ft. altitude was reached the two propellers on engines using regular grade 1100 oil did not govern for approximately one minute. The pro- pellers using synthetic oil performed satisfactorily. Dilu- tion on B-29 aircraft was accomplished in accordance with Technical Order 02-1-29, and table shown below. The above data is preliminary data, however, it is con- sidered that variations in oil tank level will not greatly effect the above dilution times. airplane on 16 December during the feathering test of hydraulic propeller feather system on #3 engine. The engine was feathered at 20,000 ft. and —30°C. Feather- ing was accomplished in seconds, however, the oil system was not diluted. After l/2 hour flight in this condition the propeller was unfeathered smoothly in eight seconds with RPM set at 1500, however, it increased gradually up to 2500 RPM and found that the governor had no control over the RPM. It was then noted that the oil pressure was zero. As the result of the failure to dilute prior to feathering the propeller during flight, the oil had become stiff and when the engine was turned over had caused failure of the supercharger blower bear- ings and supercharger cases. It is recommended that all future flight instructions for cold weather operation stress the importance of dilution prior to the feathering of pro- pellers to prevent similar failures. e. The attached photo, (exhibit 4, page 3A) shows ice which was removed from the fuel line of a B-25J. The line and ice was located in the bomb bay on the discharge side of the right wing fuel boost pump. The fuel drains had been checked the day before and the ice was located below the condensate trap. The reason for this condi- tion was not determined. f. Attached are photos showing P-38 aircraft after 30% dilution. This aircraft lost approximately seven gallons of oil in three minutes during take-off powers. This problem had not been solved at the time the writer left Ladd Field. (Exhibit #5, pages 3B, 3C). Anticipated Dilution Tima Approx. % Free Air Temp. °F. in Minute* Dilution 25 a 5 10 4 lO — 9 15 d. An engine failure was experienced on the B-17G 5230 161 C. CONCLUSIONS 1. If all AAF equipment is to operate satisfactorily in accordance with extreme temperature operation goals set up by the AAF, a great deal of additional development is necessary during cold weather testing. 2. Maintenance records available in this section, taken over four months at the ETOU, indicate a definite in- crease in maintenance required on aircraft proportional to the increase in temperatures. 3. Present shelters used by maintenance personnel are highly unsatisfactory under windy conditions. 4. From the maintenance viewpoint the P-59 aircraft with 1-16 units installed operated very satisfactorily. Starting problems were at a minimum on this aircraft. D. RECOMMENDATIONS 1. It is recommended that representatives of the Main- tenance Division participate more actively in formulating cold weather test programs and are made a part of the test program, rather than acting as liaison representatives with no power or authority in the program. 2. It is further recommended that close liaison be kept between AAF Proving Ground Command and Mainten- ance and Engineering Divisions of this Headquarters. 3. It is the belief of the writer that aircraft engine starting problems would be greatly lessened by the use of hot circulators of coolant and oil prior to starting of tests. Such circulators are available but were not tested at Ladd Field during the 1944-45 season. Heat circu- lators would perform two functions; that of heating the oil, which in turn will heat the engine. It was definitely found that by applying heat to accessory case and air in- take starting could be accomplished more easily. Hot oil and coolant circulators would heat the accessory sec- tion making far better volatilization of fuel and prevent excessive wear on parts due to stiff oil. 4. It is strongly recommended that guards for the fans on Herman Nelson heaters be furnished to prevent in- jury to personnel. Several mechanics at Ladd Field lost fingers due to the fact that there is no guard provided on these heaters. A simple screen over the fan would pre- vent this. 5. It is further recommended that CWTD advise this Headquarters immediately upon discovery of corrective measures on engines and equipment during cold weather operation. At the present time this information is not disseminated to this Headquarters until after it has cleared through the AAF Board and Headquarters, AAF. It is felt that this wastes much time in getting effective fixes disseminated to other operating activities. Under the present plan no definite decisions, only recom- mendations, are made by the CWTD, and action on re- commendations must be taken by the AAF Board. By giving CWTD, which is right on the spot, power of decision, operating units in the field could benefit more quickly from the work being done at Ladd Field, and receive these benefits during the same winter. Report of Visit to Ladd Field, Alaska Prepared by: E. E. Murphy, Capt., A. C. A. PURPOSE 1. The purpose of this travel was for liaison on matter pertaining to supply in cold weather operations. B. FACTUAL DATA 1. At the time the undersigned arrived at Ladd Field, there was little flying activity. Planes and crews were just arriving and continued to arrive all through Novem- ber. Practically the only flying being done at the time was routine local flights. All of the various sections of cold weather tests were engaged in setting up shop, and most of their buildings were still in the construction stage. 2. This was particularly true of the Cold Weather Test Supply Section. During the testing season 1943-1944, Supply had been located in the Main Hangar, and had been well organized. For some reason, in July of this year, it was moved out of there and the supplies left out in the open or in small Stout houses until the new techni- cal supply buildings were completed. By early Novem- ber, the two buildings were complete. However, bins were still being built, and there was no heat other than that furnished by a few small coal stoves and Nelson heaters operating outside the building. Use of Nelson heaters for this purpose was universal throughout. Steam heating equipment is on hand, but at the present rate of progress, will not be installed until late December or January, if then. Supplies were piled indiscriminately in both warehouses, in Stout houses, and in the open. A large quantity of project material was being held at Depot Supply until technical supply was organized. 3. Personnel in Cold Weather Test Supply consisted of two (2) officers and seventeen (17) enlisted men. However, of the 17 enlisted men, only four (4) were qual- ified supply men, the other thirteen (13) consisting of clerks and handlers, none of whom were familiar with supply procedures. This placed a heavy burden on the regular supply men. Conversation with the officers in charge of Cold Weather Test Supply and Depot Supply revealed that a rotation policy, as it is now set up, works to their disadvantage. Enlisted men who have become qualified supply clerks during the last two years are ro- tated to the United States. Their replacements, even though they have an M.O.S.of 826, are not supply clerks, and considerable time is lost in training these new men. In addition, many of these replacements have high enlist- 162 5230 Snow Jeep Fuel dump af a typical small Alaskan Air Field ed grades, which limits the chances for promotion of the remaining qualified clerks. This situation has a deci- dedly disturbing effect on morale. 4. During the testing season 1944-1945, approxi- mately fifty (50) of the latest models of fighters, bombers, cargo and liasion aircraft will he used. Special projects had been written in August, and by November approxi- mately two-thirds of the material had reached Ladd Field. Projects as written seemed to be fairly complete, with a few exceptions. No project had been written for B-29 planes, three of which will be used. No class 03-E material was included, even though approximately twenty-five (25) of the ships now at Ladd Field are turbo super- charged. This was brought to the attention of Capt. Hamlin, the supply officer, and immediate action was taken by him, through Major Stratten, Proving Ground Command Liaison Officer at Wright Field, to secure delivery of the necessary supplies. 5. Supplies reach Ladd Field by several routes— by air from Edmonton, by boat and rail from Anchorage, and by the Alcan Highway. Considerable time is lost on routine shipments, due to trans-shipment at Tacoma and Anchorage. Such shipments take from three to five months to reach their destinations. Air and highway ship- ments are quicker, time running from two days to six weeks. One complaint made is that ATC often arbitrarily removes priority cargo destined for Ladd and routes it via Alcan Highway. The assertion was made, without any proof being offered, that priority Cold Weather Test shipments and routine ATC shipments, requisition- ed much later, often arrive at Ladd on the same plane. 6. During the month of November, most requisitions were being filled by Depot Supply. This was due to the fact that very little material was available in Cold Weather Test Supply, since the buildings had just been completed. Only a small portion of available material had been unpacked and binned, and bin cards and locator files were non-existent. If material was not in Depot Stock, it was requisitioned by radio directly through the Theater Branch in this Headquarters. Late in the month, this procedure was changed and requisitions were forwarded to Pacific Over- seas Air Technical Service Command. The effect of this change is not known as yet. Personnel at Ladd Field were of the opinion that it would materially lengthen the time required to complete action. 7. The condition of the material arriving at Ladd Field is generally good. This, however, is due more to good luck than to good packaging. The following points were noted: a. Of the larger assemblies, starters, generators and magnetos were originally well packed. However, shipping tickets on the outside container were lost, neces- sitating breaking open the moisture barrier in order to identify the material. Coolant radiators, oil coolers and test stands were not protected by moisture barriers and boxes were so poorly braced that several were damaged by rough handling. h. Smaller assemblies, such as pumps, governors, relays, induction vibrators, were usually poorly packed. Pliofilm packed assemblies generally had moisture indi- cators showing red. In general, pliofilm seems to become brittle in cold air and cracks. In a large number of cases, assemblies packed in pliofilm evidently had been taken out of the original carton at the shipping activity and shipped separately. Rough handling naturally broke the pliofilm bags. c. Numerous cases of over and under packaging were observed. One shipment of small gaskets, screws and fittings, weighing about four (4) ounces, came in a wooden box weighing ten (10) pounds. Another instru- ment occupying one(l) cubic foot was packed in a box occupying sixteen (16) cubic ft. On the other hand, many delicate instruments come packed only in the original cardboard container. d. Rubber goods, such as inner tubes, expander tubes, and accumulator diaphragms, are frozen stiff when unpacked and must be thawed out. Supply men say this folding and freezing causes cracks that eventually lead to failure. e. There is no cargo moving equipment available at Cold Weather Test Supply, and as a result, material is often damaged from rough handling. Labor crews un- loading trucks in below zero weather are not apt to be too careful in their handling equipment. 5230 163 8. Major Hunter, Cold Weather Test Enginering Officer requested that some type of tire demounting equipment be furnished. At present, tires on C-46, B-17, B-24 and B-29 planes are demounted by laying the wheel flat on the ground, laying a twelve (12) inch plank on top of the tire, and driving a Cletrac or, in one case, an 18-ton earth mover, over the tire. This usually breaks the bead loose—and usually ruins the casing. 9. Equipment specified in Table of Allowances No. 1-1697 is generally inadequate. Requirements for equip- ment on this table, with the exception of heavy equipment, are greatly in excess of table quantities. This is particu- larly true of Class 05, 08 and 17 material. 10. Excess experimental equipment is causing a se- vere storage problem. At the present time, there are several carloads of excess skis, heaters and other types of equipment for which there is no foreseeable use. Some of this could be sold to commercial Alaskan Airlines, particularly the skis. C. CONCLUSIONS It is believed that Cold Weather Test Supply should be operating with reasonable efficiency by the end of De- cember. Although hampered considerably by the change in warehouse location, untrained personnel, and poor working conditions, progress is being made towards the proper organization of that Section at Ladd Field. Cir- cumstances beyond the control of depot personnel will, however, continue to impede progress. These include shipping delays, improper packaging, untrained replace- ments, and, to a certain extent, over-classification of doc- uments relating to cold weather test, which has very defi- nitely interfered with proper advance planning for the current testing season. In spite of these limitations, Sup- ply is functioning effectively. To date, no aircraft have been grounded for parts for more than two (2) days. D. RECOMMENDATIONS 1. That blueprints for tire demounting equipment be furnished Cold Weather Test Detachment. 2. That action be taken to obtain either Class 2 air priority for shipments to Ladd Field or to insure that present Class 3 air jpriorities now issued are adhered to. 3. That more attention be given to methods for packaging overseas shipments. While corrosion is not a problem in the Alaskan theater, if the condition in which material arrived in this theater is indicative of the con- dition in which it arrives in others, then iserious attention should be given his problem. 4. That steps be taken to insure that replacement per- sonnel are actually skilled in the M.O.S. that is assigned them. E. ACTION ON RECOMMENDATION Recommendations b, c, and d have been brought to the attention of the proper offices in this Headquarters by R & R. Action has been taken on recommendation (a) by supplying blueprints of tire demounting equipment currently used at FATSC to the Cold Weather Test Detachment. Cold Weather Tests of Radio & Radar Equipment Prepared by: P. D. Langrick, Capt., A. CAircraft Radio Laboratory. I. EQUIPMENT SUBMITTED BY NAVIGATION LABORATORY A. This Laboratory submitted the following Airborne and Ground equipment to be subjected to Cold Weather Testing for the winter season of 1944-1945. AN/ARN-7 Radio Compass. Army Air Forces Instrument Ap- proach System is composed of the following units: AN/CRN-10 Localizer Equipment, AN/CRN-2 Glide Path Equipment and AN/MRN-1 Marker Beacon Equipment, and AN/MRN-2 VHF Radio Range Equip- ment. B. AN/ARN-7 RADIO COMPASS. 1. The winterized version of this equipment did not arrive until the season was nearly over. After it was installed in the B-24, the equipment operated satisfac- torily as the temperature did not drop below —25 °F. 2. The regular production model AN/ARN-7 Radio Compass equipment, installed in the majority of airplanes used in conducting this season’s cold weather tests, was checked daily and it was found that the loop was sluggish and at times hard to turn at temperatures below —25 °F. 3. At temperatures below —30°F. a larger number of these sets of equipment would fail to function until the cabin temperature was raised to +40°F. or more. The causes for this malfunction could never be absolutely determined. In some instances, ,the replacement of con- trol boxes from stock kept at room temperatures would cause the equipment to operate satisfactorily. In other instances, it was necesary to wait from 10 to 20 minutes for the sets to warm up sufficiently to raise the tempera- ture of the electrolytic condensers to the point of func- tioning properly. 4. After being warmed up on the ground, the radio compass operated properly throughout the season, with the exception of a few malfunctions attributed to defec- tive tubes, condensers and resistors. 164 5230 5. In conversations with the Communications Officer of the U.S.S.R. Mission stationed at Ladd Field, it was found that the equipment installed in Lend-Lease air- planes was functioning substantially as reported in the above paragraphs. 6. CONCLUSIONS It is concluded, from an aver- age taken from several hundred pre-flight checks on the AN/ARN-7 Radio Compass, that the equipment will operate satisfactorily in temperatures above —20°F. and in most instances will operate after waiting 10 to 20 minutes for the set to warm up when the temperatures are in the region of —30°F. 7. RECOMMENDATIONS a. It is recommended that an investigation be under- taken to determine if the sluggish loop condition at —25 °F. and below can be attributed to the lubricant used or if other malfunctioning is causing this sluggish condition of the loop mechanism. b. It is recommended that all the electrolytic con- densers in Receiver BC-R5/ARN-7 be replaced with paper or oil immersed condensers. It is the desire of the Communications Officer of the U.S.S.R. Mission that this be accomplished at the earliest possible date, as it will eliminate a constant source of trouble in Lend-Lease airplanes during the winter months, which prevail over the greater part of each year in Russia and Siberia. C. AN/CRN-10 LOCALIZER EQUIPMENT. 1. This equipment did not arrive at Ladd Field until February, thereby missing the coldest part of the winter season. No difficulties were experienced with the equip- ment which could be attributed to the effects of the equip- ment being exposed to cold weather conditions. 2. It was necessary to replace several sets of rectifier tubes and one set of final amplifier tubes during the time this equipment was in operation. 3. The power supply Type PU-25/CRN operated satisfactorily throughout the testing period without be- ing overhauled at any time. a. The total time of operation was approximately 500 hours. b. The equipment was installed 2000 feet from the west end of the north runway, which is the principal run- way at Ladd Field. 4. CONCLUSIONS It is concluded that this equipment operated in a satis- factory manner throughout the testing period. 5. RECOMMENDATIONS None. D. AN/CRN-2 GLIDE PATH EQUIPMENT. 1. This equipment did not arrive at Ladd Field until February, thereby missing the coldest part of the winter season. It was set up on 24 February 1945, 1400 feet from the approach end of the runway with the glide path set at degrees. Flight checks disclosed the course to be straight and flyable with sufficient clearance over the hill at the approach end of the runway. The glide angle was later raised to 3 degrees to give an added safety factor in clearing the hill. 2. It was necessary to move the equipment back to 2000 feet from the approach end of the runway and lower the glide angle to degrees due to the rapid rate of descent of airplanes of the B-26 and B-25 class. 3. In the five weeks that the equipment was under- going tests, the only trouble encountered was caused by Type 8025 transmitter tubes and Type 836 rectifier tubes. Investigation of the first failure disclosed two fuses to be blown and the contacts on the center arm of Relay No. 1007 to be melted off. A new relay contactor arm was fabricated by Cpl. Westwick, to replace the damaged arm, as it was impossible to secure a replacement relay. 4. Further investigation of the equipment disclosed the failure to be caused by the simultaneous failure of two 8025 tubes, one in the driver and the second one in the final amplifier stage. In testing this equipment after the failure, Test Meter No. 2 became defective. This was attributed to the shorted elements in one of the de- fective 8025 tubes. a. As it was impossible to secure a replacement meter, a two-inch meter of the same range was secured from the Alaska Air Depot. b. On the last day of the tests, the equipment failed to function properly. Investigation disclosed the Type 8025 tubes in the final amplifier to be defective. This was attributed to a surge of higher than normal voltage from the 60-cycle alternator, caused by the gasoline en- gine driven power supply becoming defective, after run- ning approximately 450 hours without a major overhaul. It was found that the gasoline engine was running at normal speed without a load, and that when the load was applied, the gasoline engine would run above normal speed for a short time and then slow down, causing the voltage to surge well above its normal value and then drop down to a lower value. No attempt was made to repair the gasoline engine, as the tests were concluded on this equipment and negotiations were being completed to turn over the Army Air Force Instrument Approach System equipment to Ladd Field. Total time of oper- ation was approximately 450 hours. 5. CONCLUSIONS It is concluded that the AN/CRN-2 equipment worked in a satisfactory manner throughout the testing period, with the exception of tube failures, which could not be attributed to the effects of cold weather. 6. RECOMMENDATIONS a. It is recommended that a fuse for the protection of Meter No. 2 be installed. b. It is recommended that the Type 8025 tubes with the magnesium getter be recalled and the new high vacuum type tube be used for replacement of the recalled stock and for all future uses of this type tube. c. As the Type 8025 transmitting tubes and the Type 836 rectifier tubes have been a constant source of trouble this season, due to the fact that no test equipment was available to properly check these tubes, it is further recommended that either a tube checker capable of 5230 165 checking the two tube types be supplied with each set of equipment using these tubes, or some provision be made in the equipment for the proper checking of these tubes. E. AN / MRN - 1 MARKER BEACON EQUIP- MENT. 1. When this equipment was not undergoing cold weather testing, it was used as a Boundary Marker Beacon as an integral part of the Army Air Force In- strument Approach System. 2. Due to the necessity of placing the Boundary Mark- er Beacon in an exposed location between the road at the eastern end of the field and the Chena River and Field Regulations prohibiting vehicles from being parked in this area, it was necessary to remove the chest contain- ing the transmitter and power supply from the jeep. 3. It operated in a satisfactory manner without any failures for a number of weeks. 4. The total time of operation was approximately 375 hours. 5. CONCLUSIONS It is concluded that this equipment is entirely satis- factory for its intended purpose. 6. RECOMMENDATIONS None. F. ARMY AIR FORCE INSTRUMENT AP- PROACH SYSTEM. 1. The three sets of equipment, namely, the AN/CRN- 10 Localizer Equipment, the AN/CRN-2 Glide Path Equipment, and the AN/MRN-1 Marker Beacon Equip- ment, were set up to be used as a unit composing an Army Air Force Instrument Approach System, less the outer and middle Marker Beacons, 2. The only difficulty encountered wras of a minor nature, due to the metal construction of Hangar No 1. At first there were two pronounced bends in the course of the Localizer Path in front of this hangar, 3. The two bends in this course were eliminated when the antenna array was moved a short distance and more precise measurements were made to center the Localizer Path on the runway. 4. After the equipment was set up and flight-checked, it was run on a 24-hour-a-day basis and the airplanes with the proper installation of equipment made use of this system for the duration of the test period. 5. Several pilots, who had had no previous experience with this system, were very enthusiastic about it and were of the opinion that they could now bring in their airplanes in zero-zero weather at the fields equipped with Airmy Air Force Instrument Approach Systems. 6. CONCLUSIONS It is concluded that this equipment is entirely satis- factory for its intended purpose and will work in a satis- factory manner throughout the temperature range it was exposed to for the duration of the cold weather tests for the winter of 1944-1945. 7. RECOMMENDATIONS None. G. AN/MRN-2 VHF RADIO RANGE EQUIP- MENT. , 1. This equipment arrived at Ladd Field on 13 Janu- ary 1945 and was processed through the Cold Weather Testing Detachment Ordnance and Garage Sections. The K-53 truck was only partially winterized as it was not contemplated to move the equipment once it was set in position. 2. The truck and equipment were accepted from the above-mentioned sections on 18 January 1945. 3. Trouble immediately developed in the Onan power supply; the gasoline engine would run for from one to two minutes and then stop, and could not immediately be started again. a. It was necessary to request assistance from the Maintenance Branch of the Cold Weather Testing'De- tachment Auxiliary Equipment Section to correct the fault that had developed in the PU-3 CRN/5 Onan Power Supply. Investigation by expert repairmen dis- closed that the spring in the automatic choke had been reversed. b. After this error had been corrected, the power supply was run for 48 hours, when trouble again de- veloped. Considerable time was spent in finding the source of trouble, which was finally traced to the disrib- utor cap, which is made of cast bakelite and which had developed a crack that allowed the high voltage energy to leak to ground, causing the engine to fire on one cyl- inder only. A new distributor cap was obtained and the PU-CRN/5 power supply operated in a satisfactory manner. The cracked distributor cap was directly attrib- uted to cold weather, the lowest temperature at the time of failure being —15°F. c. The coolant in the radiator of this equipment, as shipped from the factory, was inadequate for this region as it offered protection only to a temperature of —20°F. Therefore,4-1/2 quarts of Prestone were mixed with an equal amount of water and placed in the radiator; this mixture will not freeze until the temperature has dropped below —6G°F. d. It was our intention to install this equipment at a point approximately 2000 feet from the west end of the south runway and have the constant signal zone of the Eastern quadrant centered on the runway. This was im- possible to accomplish, due to the inaccessibility of this portion of the clearing, which is across the river from the ends of the runways. Therefore, the equipment was set up approximately 2500 feet from the ends of the run- ways and centered between them. It should be pointed out that the instruction book does not contain adequate information regarding the keyer and bridge circuits and how to set up the cams in the keyer circuit, with partic- ular emphasis on the phaser cams. e. This was found to be true, as the equipment had been on test for only a short time when trouble developed in the keyer circuit and sufficient information could not be found in the instruction book to be of assistance in correcting the faulty keyer action. At about the same time the following facts developed: The plate voltage on the final amplifier stage dropped from a value of 420 volts to 100 volts. Investigation revealed no failure of any corn- 166 5230 ponent parts. Several sets of rectifier and final amplifier tubes were tried in an attempt to discover whether the low voltage were caused by defective tubes; this failed to bring the plate voltage to its normal value. f. It was found that the “D” and “U” quadrants had a lower output than that of the other quadrants. The “Line Voltage” position of the switch on the meter panel was found to be defective as it would not cause the meter to indicate the voltage unless the switch was held to one side. Fortunately, Mr. Wedin, an engineer from the Nav- igation Laboratory who has had considerable experience with the AN/MRN-2 VHF Radio Range Equipment was in the vicinity and his assistance was obtained to cor- rect the faults which had developed in the equipment. Mr. Wedin’s investigation disclosed that the low plate voltage to the final amplifier stage was caused by a de- fective 836 rectifier tube; further, that the major portion of these tubes from the Spare Tube Kit were defective. It was impossible to check properly the rectifier tubes, as there were no tube checkers available that would accomo- date this tube. g. The low output in the “D” and “U”‘ quadrants was finally traced to a manufacturing defect in one of the antennae, as the connections were reversed. The antenna pattern became normal after this defect had been cor- rected. The defective keyer action was corrected when one set of cams was reversed. It is quite apparent that none of these defects can be attributed to the action of cold weather. This equipment operated in a satisfactory man- ner 24 hours each day for the rest of the test period. The total time of operation was approximately 650 hours. 4. CONCLUSIONS It is concluded that this equipment will operate in a satisfactory manner 24 hours a day over the tempera- ture range to which it was exposed during the test period. It was the consensus of opinion that this equipment left the factory without inspection. 5. RECOMMENDATIONS a. It is recommended that the coolant in the radiator of the power supply PU-3 CRN/5 be changed from the present mixture, which will freeze at —20°F. to a mix- ture of Al/2 quarts of Prestone and an equal amount of water, which will not freeze until the temperature has dropped below —60°F. h. It is recommended that the amount of information on the keyer and bridge circuits and especially on how to set up the cams in the keyer circuit, be increased in the Instruction Book. c. It is recommended that a tube checker capable of checking all the types of tubes used in the AN/MRN-2 equipment be supplied with each set of equipment. d. After having experienced the great amount of difficulty before this equipment could be successfully placed under test, it was quite obvious that the equipment had left the factory without being properly tested and in- spected. Therefore, it is recommended that steps be taken to see that the production AN/MRN-2 VHF Radio Range Equipment be properly inspected and tested before it leaves the factory. II. EQUIPMENT SUBMITTED BY THE SPE- CIAL DEVICES LABORATORY. A. This Laboratory submitted one Type AN/ANQ-2 Airborne Recorder and one Type AN/GNQ-2 Ground or permanent station type recorder, to be subjected to Cold Weather Testing for the winter season of 1944- 1945. 1. Both recorders are of the rotating disc type, the turntable and disc turning at the unusually low speed of 10 to 11 revolutions per minute; this low speed is neces- sary to obtain 30 minutes of recording time on each side of an 8-inch disc. 2. With this low turntable speed, the intelligibility of the recorded speech is of a low order. B. AN/ANQ-2 AIRBORNE RECORDER. 1. The original installation of this equipment in the Radio B-24 was made so that the radio operator had con- trol over the equipment, which was plugged into the Interphone System so that voice recordings could be made by the pilots and engineers to assist in keeping' records of their work. 2. As some flights were being made without a radio operator and the turntable is placed in motion by pressing the microphone switch, extensions were made from the pilot lights in Control Box C-99/ANQ-2 to a position on the instrument panel so that the pilot could tell when the turntable was in motion and when the recording time had elapsed. 3. Preflight checks made in temperatures down to —34°F. disclosed that the recorder operated in a satis- factory manner; the turntable started without difficulty and the speed was constant at 10 to 11 rpm. 4. A record was made while flying between an altitude of 10,000 and 15,000 feet. Upon returning, when the record was played back on the ground equipment AN/GNQ-2, it was found to be full of “wows”, causing the speech to be unintelligible. Since, upon investigation, the speed of the turntable appeared to be constant, it became apparent that the “wows” were being caused by the vibration set up by the motors and the roll and pitch of the ship in turbulent air. By changing springs, more pressure was applied to the cutting stylus and with a new stylus the “wows” disappeared. The recorded speech quality is very poor with throat microphones, in fact, un- intelligible at times, increasing in intelligibility with mask and hand-held (T-17) microphone. 5. CONCLUSIONS: It is concluded that this re- corder operates in a satisfactory manner for its intended purpose and throughout the temperature range to which it was exposed during the cold weather testing of the winter season 1944-1945. 6. RECOMMENDATIONS: None. C. AN /GNQ-2 GROUND OR PERMANENT STATION TYPE RECORDER. 1. This recorder will operate satisfactorily when kept at a minimum room temperature of -(-65° to -f-75°F. When exposed to lower temperatures, the turntable was very slow in picking up speed. After being subjected to 5230 167 room temperature of —10°F, overnight and warming up to -)-550F. in two and one quarter hours, the speed was one revolution in two minutes and ten seconds. A hot blast of air was applied for five minutes and the speed increased to eleven revoultions per minute. This was at- tributed to the lubricant used in the gear box and motor bearings. Major Britton was to have worked on the prob- lem of finding a satisfactory lubricant, but left Ladd Field before doing so. 2. CONCLUSIONS: It is concluded that the AN/GNQ-2 Recorder will operate satisfactorily when kept at a minimum room temperature of +65° to +70°F. 3. RECOMMENDATIONS: It is recommended that a satisfactory lubricant be found for this equipment so that it will operate satisfactorily in temperatures down to 0°F. Ill EQUIPMENT SUBMITTED BY THE COM- MUNICATIONS LABORATORY. A. This Laboratory submitted one Type AN/ARC-3 VHF Radio Set, to be subjected to cold weather testing for the winter season of 1944-1945. B. AN/ARC-3 VHF RADIO EQUIPMENT. 1. This set of equipment is composed of an eight- channel crystal controlled transmitter, an eight-chanel crystal controlled receiver, associated dynamotors and control boxes. 2. One of its unique features is the automatic tuning that takes place upon changing channels. 3. It was thought by a number of persons that this par- ticular feature would not stand up under arctic tempera- tures. The equipment was placed in operation several hundred times, during the winter season in tempera- tures ranging from -j-70°F. to —35°F. In every respect it is superior to the SCR-522 VHF equipment, having greater output, a more sensitive receiver with better audio quality, and ease of maintenance. 4. CONCLUSIONS a. It is concluded that the AN/ARC-3 VHF equip- ment operates in a satisfactory manner for its intended purpose throughout the temperature range to which it was exposed during the cold weather testing of the winter season of 1944-1945. 5. RECOMMENDATIONS a. None. C. The following facts were noted during the winter season and are recorded here for the information of per- sonnel of the Communications Laboratory. D. AN/ART-13. RADIO LIAISON EQUIP- MENT. 1. This equipment works well under arctic conditions. Two or three instances of slipping autotune units were noted. Several high vacuum switches were found to be shattered. The above two items were attributed to low temperatures. Several instances of Resistor No. 215, 250 ohms being burned out were reported. Several complaints of variations in antenna current and output, with varia- tions in temperature, were received. 2. A test set-up was made m an exposed location to investigate the variations in antenna current and output. In a temperature change from —34°F. to 0°F. the cur- rent as indicated on the Radio Frequency Ammeter varied 90% from the original set value when the antenna network was tuned at a certain temperature. It was fur- ther noted that the antenna current and output would return to normal when the equipment was subjected to the same temperature as that at which the original tuning adjustments had been made. E. SCR-578-B SEA RESCUE EQUIPMENT. 1. Under the program of the Base Cold Weather Testing Detachment, the SCR-578-B and the newer two- channel set were subjected to cold weather tests. It was noted that the base unit had the same experience as the writer. Signals were received up to five miles without a ground; using a river ground, the signals were received up to eleven miles. 2. Counterpoises were tried, varying in length from two hundred to three hundred feet and were laid on top of the snow. The signals were received at distances up to 75 miles, on a few occasions up to 100 miles and reported one time as being received at 150 miles. 3. The balloons used were manufactured in May 1942 and would develop pin holes after being inflated from two to four hours. Only about one balloon in ten would stand up over a period of three or four days. 4. The lithium hydride generators would take well over an hour to inflate a balloon in temperatures below 0°F. For use in the arctic regions, it is recommended that a more rapid means of inflating balloons be found. Chaff dispenser installed on P-38 airplane 168 5230 IV EQUIPMENT SUBMITTED BY THE AUDIO LABORATORY. A. This Laboratory supervised the installation of an AN/AIC-2 Interphone System in the Radio B-24 to be subjected to Cold Weather Testing for the winter season of 1944-1945. B. AN/AIC-2 INTERPHONE SYSTEM. 1. This system worked satisfactorily throughout the winter season in temperatures as low as —56°F. 2. Early in the season the output transformer in the audio amplifier became defective. This occured at a time when some work was being done on the ship at the Alaska Air Depot, and without the knowledge of the writer a new output transformer was installed in the amplifier AN/26-AIC. 3. The defective transformer was requested from the Alaska Air Depot so that it could be returned to the Laboratory for investigation, but could not be recovered. 4. One complaint of low output was received. In- vestigation disclosed that the pilot was using high im- pedance earphones instead of low impedance earphones. A new set of low impedance earphones was installed in the pilot’s helmet which corrected the difficulty. 5. CONCLUSIONS It is concluded that this equipment operated in a satisfactory manner throughout the testing period. 6. RECOMMENDATIONS None. V EQUIPMENT SUBMITTED BY THE RADAR LABORATORY. A. RADAR SET AN/APN-9 (LORAN). 1. Due to the distance between Ladd Field and the closest Loran Station, reception was dependent upon sky waves. Reception was found' to vary considerably with time of day, as is characteristic of sky wave propa- gation. Signals were rarely seen above the noise level when the AN/APN-9 was operated in the air; a 200-foot “flat-top” antenna on the ground gave more consistent results. Good aerial results were obtained when later flights were made around the Aleutian Islands, within “ground wave” range of the stations. All islands and prominent land marks checked against the charts after applying appropriate corrections to the readings as ob- tained from Loran Correction Chartlets. Maximum ground wave reception obtained was 600 miles at 10,000 feet over water in the Radio B-24, using the “flat-top” antenna and no loading coil. 2. The set was checked and operated at temperatures down to —46°F. At this temperature the starting cur- rent with a 105.6 volt input was 2.4 amperes. All func- tions were normal after a 30 second warm-up period. 3. It was necessary once to replace the 3 BPI indi- cator tube because of a loose element in the tube. It is impossible to determine if the defect were a result of exposure to extremely low temperatures or faulty tube construction. 4. The receiver became intermittently insensitive due to a loose connection between the socket and cathode pin of Tube V-102. The socket construction was the cause of the fault. 5. After 20 hours of operation, it became necessary to adjust the grid voltage of V-131 in order to stop sweep jitter which had developed. This adjustment was done by means of adjusting variable resistor R-260. All tubes checked satisfactorily; as no circuit diagram was avail- able, it was impossible to analyze the circuit for possible causes of the sweep jitter. 6. CONCLUSIONS: It is concluded that the opera- tion of Radar Set AN/APN-9 was not adversely affected by the temperatures encountered during the cold weather testing at Ladd Field for the winter season of 1944-1945. 7. RECOMMENDATIONS: None. B. RADAR SET AN/APN-12 (XA-1). 1. The wide band antennas normally used with this set were not available for cold weather tests. An SCR- 729 type antenna installation was made in the B-24 “Radio Test" airplane for the test operation of the Radar Set AN/APN-12 (XA-1). This situation limited the useful operation of the set to the frequency band covered by the first three positions of the frequency selector. 2. Inspection of Receiver-Transmitter RT-ll(XA) APN-12(XA-1) upon arrival revealed that the shield on the suppressor output cable had broken loose where it was soldered to J-106. The single spot of solder applied at this point gave insufficient mechanical strength and apparently broke from vibration during shipment. 3. The receiver became insensitive during a flight test. The failure was caused by a break in the B-f- lead where it connected to R-128. Cause of the break was believed to be a nicking of the wire in the insulating stripping process during manufacture. B-29 Radar dome damaged by ejected shell cases. Low temperatures caused embrittlement of dome 5230 169 4. The center leaf of switch S-104 shorted to ground on the tuning mechanism mounting. This occurred when the follower was on the high point of the cam and momentarily grounded the 24 volts D.C. No ill effects were noted upon the operation but arcing each time the tuning mechanism ,was operated had extensively des- troyed the rivet holding the bakelite follower to the switch leaf when discovered. Figures 23 and 24 show the damage caused by the arcing. 5. The modulation lead from X-202 to L-207 was badly frayed from chaffing at the point where it passes between the chassis and the vernier tuning mechanism. Figure 25 shows the amount of chaffing on this lead. 6. A flight test was made using the AN/APN-12 (XA-1) as a beacon at 176 Me. It was interrogated by an SCR-729 operated in another aircraft flying at the same altitude (5,000 feet). The maximum range ob- tained of the front of both antennas was 85 miles. 7. The set was flight tested against an SCR-695 oper- ated as a beacon with the antenna mounted 25 feet above the ground level. The maximum range was 55 miles at 10,000 feet. IFF in other aircraft whose elevation was unknown were received from 85 miles at the same time. 8. The set was used in connection with test flights against the AN/CPN-7 (BABS) and gave satisfactory results. 9. The pre-set frequencies remained within 0.5 Me throughout the total set operation time of approximately 60 hours and a period of 70 days. The set arrived at Ladd Field late in the season (20 January 1945). Tem- peratures below —15°F. were experienced only once for a short period after the arrival of the set, during which period the set was undergoing repairs; thus, no significant temperature-frequency drift data is available. 10. CONCLUSIONS: Due to the limited scope of the available data, no definite conclusions as to the set’s ability to function properly over long periods at low temperatures can be made. 11. RECOMMENDATIONS: It is recommended that the mechanical difficulties noted above be remedied before continuing production of the set. 12. It was noted during flights on the AN/APN-12 that the simultaneous operation of the Interrogator and the IFF Receiver (SCR-695) in the same airplane caused the Marker Beacon Indicator to light. The indi- cator came on once every 2)/> seconds, or once each cycle of the IFF frequency sweep. Marker Beacon Receiver BC-1033-A receives 75 Me signals. A quarter wave open stub was attached across the antenna input terminals of the marker beacon receiver. Adjustment of the length of this stub eliminated the interference but did not detract from the normal operation of the receiver, VI FINAL REPORT ON COLD WEATHER TEST OF THE AIRFLOW TYPE RADOME. 1. This radome was developed for use on the B-29 airplane, to replace the older round-type radome. which in its retracted position extended down farther than the new airflow type, which is of the fixed type. The older type offered greater wind resistance and at low tempera- tures had a very short life. 2. Tests. In the first test to determine the amount of damage to the radome caused by shell cases and links Airflow type rodome damaged by ejected shell cases ejected by the forward lower guns, 850 rounds were fired, scoring approximately 125 direct hits on the radome with five of sufficient force to tear several layers of canvas. The radome was exposed to a temperature of —40°F. for five hours and the firing occurred at a temperature of —34°F. at an altitude of 18,000 feet. Figure No. 26 is a general view of the radome, showing the damage caused by the ejected shell cases and links. Figure No. 27 is a close-up view of the section of the 'radome in which the shells and links struck with sufficient force to tear several layers of canvas. 3. Further tests were conducted in an attempt to find the number of rounds that could be fired from the lower forward guns, before the ejected shell cases and links punctured the radome. A total of 2175 rounds were fired at a temperature of —40°F. without inflicting fur- ther damage to the radome, other than scratches and small indentions. 4. Unfortunately, mechanical failure of the B-29 used for these tests made it necessary to discontinue the tests. Before the photographers arrived to take pictures of the sustained damage to the radome caused by the ejected shell cases and links, the crew filled in the large indentions with plastic compound and painted the radome, making it impossible to secure photographs of the sustained damage. Figure No. 28 is a head-on view of the radome. Figure No. 29 is a close-up view of the forward right side of the radome. Figure No. 30 is a close-up view of the left side that originally sustained the greatest amount of damage. 5. CONCLUSIONS; It is concluded that the new Airflow Type Radome is greatly superior to the older type and will stand a larger number of combat missions. After looking over the last three photographs, it is con- cluded that if the indentions caused by ejected shell cases and links are filled in with plastic compound and painted, that the radome may have an indefinite life. 6. RECOMMENDATIONS: It is recommended that some maintenance procedure as outlined in the above conclusions, be inaugurated. 170 5230 VII EQUIPMENT SUBMITTED BY THE RESEARCH LABORATORY 1. Cold Weather Tests on Chaff Dispenser A-2 and Chaff CHA-28(3) were started by the Base Cold Weather Testing Detachment Radar Section. Due to circumstances beyond the control of this Section, it was impossible for them to complete the tests. At the request of Lt. Caldwell, the Aircraft Radio Laboratory represen- tatives agreed to complete the tests. 2. Chaff (CHA-28[3]. Late in January a mission was flown to determine the amount of “bidnesting” of Chaff CHA-28(3) and to test the Dispenser A-2 under cold weather conditions. The Chaff was released at 500 feet in a free air temperature of -j-14°F. and the “bird- nesting” was estimated to be in excess of 50%. The dispenser worked perfectly at this temperature, both in the air and in preflight checks on the ground. Figures 31 and 32 are views .of two types of “birdnesting” of Chaff (CHA-28[3]) that were encountered. 3. Chaff Dispenser A-2. In an attempt to test the dispenser at lower temperatures, a mission was flown at 29,000 feet and a free air temperature of —53 °F., the gears in the stripper unit in the A-2 Dispenser apparently failed,,allowing only four packages to be dispensed in about two minutes, when set up for dispensing forty packages per minute in the preflight check prior to take- off on this mission. Investigation disclosed that one of the gear pins was sheared off and the rachet bar badly worn. A new set of gears was requested from the Labo- ratory. When the new gear assembly arrived for the stripper unit, it came with a motor attached; as this motor was physically smaller than the older motor, it did not fit into the mounting brackets. Therefore, it was necessary to use the old motor and gear assembly and change the new gears to the old assembly. After this had been accomplished, and the dispenser had been at- tached to the P-38, it was set up to dispense sixteen packages per minute in the preflight check just prior to take-off on a missionAo 30,000 feet. At this altitude, the dispenser was turned on for a two minute period and only two packages were dispensed. The temperature was —56°F. The unit was again made operative, and as no packages were dispensed after four minutes, the mission was considered to be a failure. Investigation disclosed the gear pin to be sheared off; no attempt was made to repair the damaged pin, as the P-38 was not available for further test work. This unit will be returned to the Laboratory for investigation of the failure. Figure 33 is a rear view of Dispenser A-2 installed on the P-38. Figure 34 is a view of the P-38 with the Dispenser in- stalled. Note the auxiliary gas tank attached to the right wing. This is filled with a sufficient amount of water to rebalance the plane, wrhich was thrown off-balance by the additional weight of the dispenser on the left wing. 4. CONCLUSIONS: It is concluded that the Dis- penser A-2 will not function properly at low tempera- tures. 5. RECOMMENDATIONS: It is recommended that this unit be modified to work at high altitudes and low temperatures. 5230 171 SECTION V Reports off Manufacturer's Technical Representatives This Section consists of reports of special or general interest written by the various Technical Rep- resentatives attending the cold weather tests. They are, in most part, excerpts or partial reproductions of the reports written, and the bulk of the supporting data has been omitted. Allison Division of G.M.C. H. S. Hanson Until February 12, the weather was comparatively mild for cold weather testing, and, as a consequence, I have been spending considerable time with the Alsib ferry planes, trying to help with minor difficulties. Following are items of general interest and results of cold weather testing; 1. Just a few days ago the first P-63C Alsib airplane, with V-1710-117 engines, began coming through this base. Most of them thus far have been leaking a slight amount of oil through the cylinder block hold down stud seal. In my opinion, this condition is not a serious one, but immediate action to correct this trouble should be taken at the factory. The U. S. S. R. does not care to accept the planes if the leakage is too great. This condition has also been noted on some of the V-1710-111 and -113 engines at this base. 2. We have been keeping a record of the P-63 air- planes, passing through this base, from which RP43S spark plugs have been removed to correct engine rough- ness. Any indication of spark plug malfunctioning is corrected by replacing an entire set—intake or exhaust— as the case may be, rather than correcting any individual cylinder. Thus far, the rate of replacement of the RP43S plug has been about the same as that for the spark plugs pre- viously used. The cylinder most generally found to have the faulty plug has been number 6, right or left. By far the majority of plugs changed has been on the exhaust side. After removal, the spark plugs are tested under 480 pounds of air pressure, and with 10,000 volts at the terminals. Complete reports of our findings are being turned in to the service department, 3. On February 12, the temperatures took a rather sudden turn for the better and were down to —34°F at 8:00 A. M. The only airplane on which successful cold starts were made was the P-59A with 1-16 gas turbine engines. However, because of excessive oil pressure, it was necessary to shut down after about one minute of run- ning. Cold starts were tried on one C-47 airplane with R-1830 engines, both with normal butane and with regu- lar gasoline, but were unsuccessful. However, both engines had been insufficiently diluted, and were quite hard to turn over. All other airplanes on the field, which were in com- mission (32 out of 51), were either insufficiently diluted or were otherwise unable to start cold at this tempera- ture. 4. On this same day, a flight was made in a P-38L airplane which had no provision for applying carbure- tor heat. The pilot maintained flight under 10,000' to obtain coldest carburetor air temperature. Extreme engine roughness was reported at powers below military rated, although at 2,000 R.P.M. and 30" Hg manifold pressure the engine ran more smoothly in the auto-rich mixture position than it did in the auto- lean mixture position. The roughness was most noticed in the cruise power range, but roughness was noted even at take-off. P-38J airplanes, with identical engines but with shut- ters in front of the intercooler, were able to take off without engine roughness. As provisions for heating the carburetor air were also installed, very good opera- tion could be obtained at all other power settings. 5. On February 13, outside air temperatures were at —42°F for starting trials. Both oil systems of the P-38L airplane equipped with the Allison cold starting kit had been diluted to permit the propeller to be pulled through by hand. Two un- successful starting trials were made with regular 130 grade aviation fuel on the right engine. No firing what- soever was noted during this period. The Allison cold starting kit was then connected to the airplane. The engine fired intermittently for three 20 second cranking trials, and on the fourth trial began to run well. Evi- 172 5230 dently the engine had been badly flooded with 130 grade fuel during the first trials. The left engine was started in the first few revolutions by using the Allison kit. Normal butane was used in the kit during these trials. However, after the engine was switched over to regular fuel it ran very poorly, and could not be kept running without excessive use of the primer. Successful cold starts were also made on both of the 1-16 engines in the P-59A airplane, but after a brief time lack of fuel pressure necessitated a shut down. I believe these were the only cold starts made on the field on this day. 6. On February 14, at an ambient air temperature of —33°F, successful cold starts were made on both engines of the P-38L, and on both of the R-1830 engines in the C-47 airplane. These starts were made using normal butane as the priming fuel. Again the engines of the P-38L were rough when the switchover to regular grade fuel was made and constant priming was necessary to keep them running. Considerable preheating was applied to the engines of three of the other P-38 airplanes at this base, and all were able to take off satisfactorily. 7. Comparison of a number of cold starting trials at this base has convinced me that field starting demonstra- tions can be made at from 10°F to 20°F colder than those possible in a cold room when good laboratory practice is adhered to. In my opinion, there are two possible reasons for this difference. These are : a. Ambient air temperatures noted at the time of a field starting demonstration are not necessarily indica- tive of the temperatures throughout the engine and in- duction system. Examination of ground temperatures since the last flight usually reveal that the airplane has not been subject to the temperature at starting time, for a very long period. Sometimes it has been subjected to a colder temperature than that noted at starting time, but more often the opposite is true as the coldest tem- peratures are generally recorded in the early morning hours. Cold room experience has shown that after only five to ten minutes of running at idling load, even an uncowled engine requires a very considerable period of cooling before an even low temperature base line is reached. A cowled engine, which has been run at high powers for several hours, must surely require longer to cool, even if constant low temperatures were obtained. b. When cold starts are anticipated, the engine oil is usually diluted plentifully enough so that the propeller can be easily pulled through. No torque data is available for the starts made at this base, but comparison with my work in Detroit convinces me that it is usually a good deal less than that called for in the cold starting require- ments of Specification AN-9500c. 8. To care for all contingencies and field variations, I advise that we recommend the use of special priming fuel on our engines for all cold starting below 0°F. 9. D. P. Heath, of the Socony-Vacuum Oil Com- pany, has plotted curves to show the vapor pressure versus temperature of several fuels suitable for cold starting. The curve for normal butane is very nearly the same as that for the mixture of 60% iso pentane and 40% iso butane, which we found necessary starting at —70°F. Both cold room and field tests have shown that fuel of this composition can also be used for starting at temperatures near 0°F. In view of the desirability of having a single, easily obtained fuel for all cold starting, rather than a blend for each temperature, I think that normal butane might be considered for use in our engines. ♦ ♦♦♦♦♦ A considerable amount of trouble has been experi- enced in the past week. This was seemingly initiated by the installation of RP43S spark plugs for service testing in two of the P-38L airplanes at this base. Sum- mation of the difficulties is as follows; 1. Airplane P-38-1, No. 44-24697. At 150 hr. inspection, new RP43S spark plugs were installed in both engines; intake and exhaust, and new jets were installed for T. O. compliance on K-8 carbu- retors (—6 setting). On the first run-up after inspection, the magneto check at 2300 rpm and 27" Hg showed a 300 rpm drop, which cleared up after a brief period of running. The first flight, of forty minutes duration, was made by Col. R. Stewart, who reported the right engine as running rough. This roughness began after he had been flying for some time and could not be eliminated by carburetor heat or mixture setting. It seemed to increase in degree as the power increased. When the ship was landed a magneto check on the right engine indicated a loss of 150 rpm on the exhaust distributor. The intakes checked ok. The left engine operated satisfactorily throughout the flight. A check flight of fifteeen minutes duration was then made by Captain R. Accord, who reported both engines as being rough, with the right engine excessively so. RP43S plugs were removed from both engines and replaced with new LS87 plugs. During the removal of the RP43S plugs, an abnormal amount of carbon and/or lead chunks was noted in several of the spark plugs and in most of the spark plug wells on both engines. On the first flight after installation of the LS87 plugs. Capt. Accord reported smooth operation of the left engine, but the right engine was so rough that it was necessary to feather the propeller after a short time in the air. After landing, inspection showed No. 2R cylinder to have no compression, as only the stem of the No. 3 ex- haust valve remained in this cylinder. Analysis indicates that several factors might have been the cause of the reported roughness and engine failure, such as: a. Loosening of the combustion deposit, caused by installation of the new plugs or by the leaner operation of the new K-8 carburetor setting. At removal of the RP43S plugs, an abnormal amount of these deposits, in chunk form was noted in the spark plugs and wells. Those in the right engine of this ship were decidedly grayer and more metallic looking than those in the left engine. This was probably due to the use of synthetic oil, Spec. PPO-265, in the right engine. (See my report, 1/20/45, Paragraph 7). The abnormal amount of combustion deposit might have been caused by long operation of the engine with the excessively rich original setting of the carburetor. b. The stems of all the exhaust valves on the re- moved engine seemed to be very dry and lead coated. It is possible that the failed valve may have been sticking open, thus causing inadequate heat transfer from the head of the valves. The engine will be sent to the Power Plant Laboratory at Wright Field. I strongly urge that we have a com- petent inspector there at the tear-down. The manu- 5230 173 facturer’s number on this engine is A-056232, and the Model No. is V-1710-111. There were 141:10 hours on the engine at removal, and the last 112:15 hours were with synthetic oil in the system. 2. Airplane P-38L-1, No. 44-24696. As on the other P-38 airplane, smaller carburetor jets and new RP43S spark plugs were installed in both en- gines at the 150 hour inspection. The first flight, of three hours duration, was made by Captain Accord, who reported both engines somewhat rough and a drop of 100-120 rpm on both right mag- netos at the conclusion of flight. A second flight of one hour and ten minutes was made by Major Allerdice, who reported essentially the same condition of operation. The RP43S spark plugs were removed, at which time the same conditions of combustion deposits in spark plugs and wells as in the other P-38 were observed. LS87 plugs were then installed, and the pilot reported satisfactory operation after the first flight. I do not believe that the plugs have been adequately tested. They should be reinstalled at a later date, when the test program permits. Most of the P-63A Alsib planes are now coming through with RP43S spark plugs, and no abnormal spark plug difficulties have been re- ported. The V-1650 Rolls-Royce engine utilizes a spark plug somewhat similar to the RP43S in appearance. The original gap on these plugs was .012", at which setting a great deal of lead fouling occurred. This gap has been increased to .022", and the engines are reported as op- erating satisfactorily, with no excessive fouling. If the RP43S plugs are reinstalled, I believe it might be well to run a comparative test with a larger gap set- ting. Please let me hear your objections to the use of a larger gap. 3, Two flights have been completed in the P-38L air- plane, at long range cru;se power settings. These tests are being conducted to determine the effect of carburetor air temperature upon fuel consumption. Although the results of the test were nullified by a leaking fuel se- lector valve, several interesting facts were noted. These point to the desirability of using carburetor heat in this installation. Test number one was conducted under the following conditions: 1600 rpm Manifold press, adjusted to give 170 I.A.S. start, Hg finish) Altitude 1000' Carburetor heat off Carburetor air temp = 0 to —12°C. (Average —8°C.) Oil temperature 62-64°C. Coolant temperature 96-98°C. The airplane was flown for four hours under the above conditions. At the end of two hours, a magneto check was made. Both engines were very rough on the right magneto, so they were brought up to maximum cruise for two minutes, and to normal rated power for another three minutes before resuming the long range cruise power setting. After two more hours, the engines were advanced to normal rated power. Both engines were very rough, and the right engine actually cut out at 2300 rpm and 30"Hg. The exhaust spark plugs were removed from both engines at the conclusion of this flight. The plugs from the right engine, which had been using Spec. AN-VVO- 446 oil. Grade 1100, were very sooty as compared to those from the left engine, which had been operated on PPO-265 oil. The only deposit noticed on the plugs from the left engine was tiny beads of lead. Flight number two was conducted under the same conditions as number one, except for the following: Carburetor heat on. Manifold press, adjusted to give 170 I.A.S. (25" Hg start, 24" Hg finish) Carburetor air temperature = 9-12°C, left: 18-21 °C, right. The magnetos were checked at the end of two hours flight and again at the end of three hours flight. They were found to be satisfactory both times. At the end of four hours of flight, the carburetors air heat was turned off, and the engines were suddenly ac- celerated to war emergency power and held there for one minute. The left engine accelerated very smoothly. The right engine coughed once on the way up in power. 4. I believe that this test is an adequate indication that carburetor air heating is an advantage, or even a necessity, for long range operation at low temperatures. Also, you will note that a slightly higher manifold pres- sure was required to maintain a given air speed wdth cold carburetor air, as compared to warm carburetor air. This information, plus that sent in my report of 1/20/45, indicates that a loss in power for a given rpm and mani- fold pressure might be expected as the carburetor air is decreased below some optimum temperature. Mr. Lee Chambers, of the Lockheed Aircraft Co., has long been working to develop an adequate carburetor air heating system for this airplane, and I believe that we should be able to furnish adequate information as to the best operating temperature for this heating sys- tem. We are especially interested in obtaining mixture control data for the following range of operating con- dition (roughly) : 1500 to 2200 rpm —30°F to -j-50°F carb air temperature. 20" Hg to 34" Hg manifold pressure. In other words, we believe that a duplication of the lower portiton of curve 0-259-A, dated 10-24-44, will show appreciably different results if run at the tempera- tures indicated above. There are a comparatively large number of P-38L airplanes now being ferried through this base. As it is entirely conceivable that they will be used in long range work, I think that it will be to our immediate advantage to have this informaton. Please let me hear from you. 5. In company with M. K. Wood, of Bell Aircraft Company, Engineering Department, a short visit was made to the Alsib ferry base at Nome, to interview the pilots, crew chiefs, and engineering officers in regard to difficulties experienced with the P-63A airplanes going through that point. All parties interviewed seemed to regard the airplane with a good deal of favor. As far as engines were con- cerned, the major complaint was “rough” engines. The U. S. S. R. does not accept the airplane if the mag- neto drop exceeds 35 rpm, or'at the most, 40 rpm, from an original setting of 2200 rpm and 28"Hg manifold pres- sure. It is my personal opinion that this criterion is too criti- cal. This seems especially true as pilots and crew chiefs do not always get the same results on successive run-ups of a given engine. 174 5230 Bell Aircraft Corporation Marvin K. Woods. 1. The remainder of this report will be devoted to general commentary and a concluding summary. Regard- ing the P-63, the oil dilution tests must be considered of first importance. Both the V-1710-93 and V-1710-117 engines were operated without spewing on oil diluted to 30%. The vapor separator in the breather lines was proven to be very helpful by reason of the fact that when it was removed, spewing occured on the dash 93 engine with oil diluted 15%. During the time when dilution is necessary the amount of oil service into the oil tank should be limited to 10 gal. A certain amount of trouble was experienced along the ferry route when two or three gallons of gasoline was added to the oil system which had already been filled to the 13 gallon tank level with the result that the system was overloaded and oil was forced out of the breather lines. 2. I was surprised to find that the ferry pilots have been instructed to use 90°C. as the desired coolant tem- perature. This lower temperature has a serious effect on the amount of heat available for cabin and carburetor heat. 3. In running some of our reduction gear box tests we were required to operate at rated horsepower i. e., 42.5 inches H. G. 2600 R. P. M. As our synchronized schedule gives 40 inches 2700 R. P. M. it was necessary for us to install an old P-39 quadrant. I checked several pilots, some of whom had combat experience, for their opinions regarding the synchronized quadrant. All agreed that it was very desirable during actual combat but they wanted to be able to select a schedule which would give them best specific fuel con- sumption when going to or returning from a mission. The new selective-synchronized quadrant should fill these requirements perfectly, 4. Carburetor heat is rapidly becoming an important consideration in cold weather operation. In the past, car- buretor heat has only been appreciated during icing con- ditions. Fuel vaporization tests have established the effect of controlled induction temperatures on specific fuel con- sumption. Regulated heat also makes it possible for escort fighters to operate at low powers with a minimum of plug fouling. I predict that within a short time the pro- vision to automatically control carburetor heat between 15°C and 20°C will become a requirement. 5. During the winter I was able to visit several of the ferry bases. The airplanes seem to be moving along with a minimum of trouble or complaint. The nearest approach to a chronic ailment was relative to RP-43S plugs. Whereas the rate of replacement for LS-86 plugs ran about one in every twenty airplanes, the replacements on RP-43S averages about one in every six. The biggest fault seems to be engine roughness on the exhaust bank. The bases I visited lacked a supply of RP-43S plugs so LS-86’s were being used for replacements. The usual amount of leaky oil coolers and struts were being encountered but at the time the extent was consid- ered only that which can normally be expected. The main criticism of the airplane itself was the lack of controllable aileron trim tabs which imposes consider- able strain on the ferry pilot. 6. United Aircraft Products conducted a series of oil dilution tests on their automatic control valve which was installed on the P-63. The operation of their valve is based on the viscosity and pressure of the circulating engine oil. A selector switch opens the dilution valve. When the oil viscosity and pressure drops to the desired amount, the valve will automatically close. In checking their valve we found that when 10% dilution was de- sired the “Y” drain sample showred 16%. 20% desired gave 22% and 30% checked out correctly. These results prove that valve could be made to work satisfactorily because it is a simple adjustment to change the base line for the 10% requirement. 7. It appears as if the ultimate solution to cold weather engine operation lies in the development of a synthetic oil. These oils have the desirable character- istics of higher viscosity at high temperatures and lower viscosity at low temperatures. In other words, these oils have a flatter viscosity curve than natural crude oils. PPO-265 which was being tested in several airplanes this year still isn’t the final solution but where the dilution period for regular oil was seven minutes, only three minutes were used with PPO-265. Some further advantages being claimed for synthetic oil are: a. has greater “creeping” or power to wet metal surfaces b. not as injurious to rubber compounds for seals and gaskets c. lower inflammability. 8. The following are the main points of interest brought to light on the P-59. The first and foremost weakness lies in the engine accessories. Several starter fuel pumps had to be re- placed, one had a broken coupling shaft, another had leaking seals. There were two other pumps that were removed and showed no visible defects wrhen dismantled but the installation of new pumps corrected the starting troubles. On our attempted cold starts at —40°F. both units started satisfactorily but wc could only get 30# to 40# fuel pressure and a speed of .8,000 R. P. M. The main fuel pump was replaced and the unit ran satisfactorily. The following day under the same conditions the fuel pressure and R.P.M. again failed to build up sufficiently. This time the condition was corrected by replacing the barometric. The main fuel pump we had removed ap- peared in good order when inspected so the conclusion is that the barometric must have stuck both days. The operation of the barometrics was especially bad. Several replacements were made. The last set used #T8902718 and #T8439317 were supposed to be of the 5230 175 latest design but there was no noticable difference in any of them. As the accompanying over-speeding curves show, the barometrics failed to regulate R. P. M. with changes of altitude. The curves also indicate the inability of the governors to keep the R. P. M. below 16,500 R. P. M. However, we did not replace or attempt to ad- just the governors. I deem it highly advisable to cold room test all the engine accessories. 9. The elevator trim tab control gave trouble starting at about —30°F. To localize the trouble we disconnected the actuator and made another flight. The control was still a’most impossible to move so this time the system was disconnected at the rear sprocket. This eliminated the trouble so we had proof that low temperature was affect- ing the system somewhere between the sprocket and ac- tuator. From these tests we were not able to tell definitely whether or not the actuator might also be causing trouble and as we did not eliminate the cause in the sprocket, that question still exists. 10. The cabin heating system seems to be adequate. At 28,000 feet and 15,000 R. P. M. with an ambient tem- perature of —55°F. the lowest recorded cabin tempera- ture was 24°F. My first C.W.T. report mentioned a pilot’s complaint of cold feet. At the time the anemostat was out and a venturi installed in the cabin intake air duct. After the venturi was removed there were no more complaints. 11. When the ground temperature went down to —40°F the cabin seal tube became very hard and yet we encountered no pressurization difficulties attributable to excessive leakage. After about 75 hours the pressure regulator showed signs of erratic operation. In cycles of approximately five minutes duration the cabin altimeter would jump five to eight hundred feet and then surge back to normal in a few seconds. An inherent weakness in the regulator lies in its inability to instantly compensate for any change in conditions. For example, at 25,000 feet when R.P.M. was reduced from 16,500 to 15,000 a momentary 1,000 foot rise was noted on the cabin altimeter. The same thing happens when one unit is stopped and started in flight. These sudden changes of cabin altitude are very unpleasant to the pilot. 12. Several types of oil were tried out in the lubri- cation system. 3580 which is called for in the specification was removed before any very cold weather was encount- ered. It is primarily a hydraulic oil therefore a substi- tute is being looked for among the lubricating oils. When ground temperatures of —40°F were encountered the airplane was serviced with AN-O-6 in the left unit and WS-804 a synthetic development in the right. After the first cold start both oil pressure gages regis- tered 25 lbs which is the limit of the gage. The units were stopped and when the oil was found to run out of an open petcock the units were started once more. The oil pressure again went overboard. After about a minute the left gage dropped back to normal but the right gage became inoperative. As 3580 is considerably heavier than AN-O-6 it is safe to assume that 3580 would not be suitable for tempera- tures down to —40°F. My recommendation is that we get permission to use AN-O-6 instead of 3580 and further that we replace the present 25 lb. gage with one that will record up to 100 lbs. pressure. 13. There was no canopy cover available for the P-59 and as a result the windshield became covered with frost several times. This was easily removed by directing a heater duct into the cockpit for a few minutes. Although none of the AAF airplanes I know of are able to defrost while standing still, our pilot was anxious to have this provision. His proposal was to tap a line into the compressor ring and lead it back to the intake of the heater muff. As the need did not seem to warrant such an elaborate installation we added a metal scoop to the muff hoping there would be enough increased ram to permit defrosting while taxiing. Due to the lack of suitable weather it was not possible to judge the effectiveness of the scoop. 14. The P-59 may require ground defrosting more than most fighters for the reason that it has no clear view panel and because the pilot is restricted from open- ing the canopy far enough to enable him to see out during take-off. If some simple means for producing forced draft at the muff could be devised it would be a definite improvement. 15. We had hoped to collect data on the current draw of various electrical units but we were not able to cali- brate and install a shunt in the various systems. The closest approach made was to record the ampere increase on the instrument panel when the flaps and landing gear were operated. These readings are given in flight No. 10 of the Temp. Survey. 16. The following observations were made on the P-59, (a) the booster coils would burn out after several unsuccessful starting attempts, (b) the generators would successful starting attempts, (b) the generators would not parallel especially at high altitude, (c) the air filters became soaked with oil after a few hours operation but with no apparent ill effects to the lubricating system. Bell Aircraft Corporation Lee Mclntoch. Along with numerous bombers, transports, and other fighters, two Bell Aircraft products, a P-59A-1, and a P-63 A-10, were tested for cold weather operation this past winter by the Extreme Temperatures Operations Unit of Wright Field. Among the numerous aircraft represented, it can be stated without prejudice that the record of the P-63 and P-59 was outstanding in both cold weather operation and in the small amount of general maintenance necessary to keep them in commission. The record of the P-63 is in large part due to the fact that nearly every winetrization item that gave trouble on the P-39 has been modified or improved on the P-63. 176 5230 The record of the P-59 is due to several factors, includ- ing the fact that it is a good airplane, as evidenced by a 3,486 mile flight from a warm temperature to a cold temperature with only one stop that demanded any main- tenance beyond refueling. Also, the jet propulsion engine was found especially adaptable to cold weather operation in that this engine will start at forty degrees below zero F with as much ease as it starts at 70 degrees above. This report is not to be construed as a eulogy from the preliminary remarks, which are included solely to give credit where credit is due. No airplane in existence is yet ready to operate normally at —65 °F, which is the present ultimate requirement. Though ground temper- atures of only —40°F were reached this winter, it was sufficiently cold to prove the need for winterization modi- fications on present production models and cold room tests on items to be included on experimental models. P 59A-1, No. 44-22610 It is the writer’s intention to emphasize that cold weather data collected on the P-59 should be utilized both for winterizing the P-59, and, perhaps more important, winterizing the experimental aircraft and 1-40 engine in- stallation. Since these aircraft are of the same type, it is believed that winterization problems on the former will more than likely apply to the latter, and if proper steps are taken, the number of difficulties the new models might experience in cold weather can be held to a minimum. It is recognized that some of the items are directly the responsibility of General Electric. They are installed on an airplane bearing the name of Bell Aircraft, however, and since an accumulation of maintenance difficulties almost invariably accrues to the aircraft manufacturer, it is considered a not unwise step to do all possible to ex- pedite improvements wherever improvements are needed. A. FUEL SYSTEM 1. Barometric. Although this item will not prevent an airplane from being flown in cold temperatures, it is inadequate and undesirable for cold temperatures for two specific reasons: a. The thrust from an 1-16 unit is dependent on RPM and air density. The critical or maximum RPM is 16,500. This is the RPM to operate the engine at for greatest thrust at any air density. Since at ground tem- perature below 35°F, and base altitude (455 feet), the barometric by-passes too much fuel, maximum RPM and thereby maximum efficiency are not attained for take-off. At —20°F, maximum RPM averaged 15,750 and at —40°F, only 15,600. Due to this inadequacy of the barometric, on the 1-16 test stand unit, it was of necessity removed and replaced with a needle valve for thrust measurement tests. Using the needle valve to regulate fuel pressure, 2500 lbs. thrust was measured at 16,900 RPM and 795 lbs. fuel pressure. Contrast this to 15,600 RPM and 250 lbs. fuel pressure at —40°F on the P-59 with the barometric adjusted to maximum RPM. Providing an increased range of adjustment on the barometric would only partially answer the problem as it would then require adjustment at each change in tem- perature. If the barometric is to continue in use, it will require an automatic temperature control. b. A number of test climbs were made, as the barometrics continuously allowed overspeeding in ex- cess of 16,500 rpm at altitude. Starting at base altitude 450', with the throttle set at 15,000 rpm, rpm would increase to 16,500 at 14,000 feet, though the temperature decreased by 54°F during the climb and the throttle setting remained constant. It is not known how much overspeed in excess of 16,500 rpm could have been at- tained due to danger involved, though the pilot reported unintentional overspeeding to 17,000 rpm two or three times. 2. Governor. In conjunction with b above, it is noted that the gover- nor does not perform its function of preventing over- speeding. It is the understanding of the writer that a new type governor is being tested which will eliminate the need for a barometric. This new type governor should be adequately cold room tested before its pro- duction in quantity. Items of this type should not prove difficult to test in a cold room. It is suggested that in testing them, the following be taken into consideration— Fuel temperatures. From thermocouple reading taken on 22610, fuel temperatures remain at ground tempera- tures, i.e., if an airplane is on the ground for several hours at 0°F, this will be the approximate fuel tempera- ture. Though the airplane go to —65 °F at 30,000 feet, the fuel passing through the fuel governing system will still be at approximately 0°F. 3. Starter Fuel Pump. A total of seven starter fuel pumps failed at Ladd Field. These included one failure due to a sheared shaft, two pumps with vanes binding on the dural pump casing, and four seal failures. The cause of these pump failures cannot be definitely assigned to cold weather, as these failures occurred at not unusual temperatures. No failures occurred at —40°F. The Pesco CWT Rep- resentative at Ladd Field informed me that G.E. is now being supplied with a modified starter fuel pump that has a seal designed for kerosene, a bronze pump casing, and that this modified pump has passed cold room tests at —65°F. B. OIL SYSTEM 1. Engine Oil. Of the three principal engine oils tested, WS804, AN-O-3 Light, and AN-O-6 Light, only AN-O-6 is recommended for use. Tests on WS804 and AN-O-3 showed high oil consumption, averaging up to two quarts per \l/2 hour flight. Oil consumption using AN-O-6 was negligible. AN-O-3 has the additional disadvantage of causing high bearing temperatures. Tests on AN-O-3 oil were run in the hope that the same oil could be used in the thrust unit as is used in the P-63 reduction gear box. AN-O-6 oil shows good flow characteristics at —40°F and can be further tested in the cold room for flow at lower temperatures. 2. Engine Oil Pressure Gage. This gage is inadequate for cold weather as high oil pressures are encountered at starting. The gage on the P-59 only goes to 25 lbs. It can become damaged by starting the engines at —40° F. The following specific recommendation is made: An oil gage mockup using a restriction in the oil line or a 100 lb. gage should be cold room tested using AN-0-6a oil at —65 °F to determine an installation that will meet this —65 °F requirement. 3. Lagging. At engine change on 22610, all lagging was removed 5230 177 from the left engine oil lines and tank. This was ac- complished prior to the occurrence of the coldest tem- peratures encountered at Ladd Field this season. Since no differences in engine operation could be noted fol- lowing the removal of lagging, the need for lagging in cold weather operation is questioned, and the recom- mendation is made that future cold weather tests be made with lagging removed. C. COLD STARTING The cold starting procedure for cold weather is dif- erent in one respect from starting at warm temperatures. Greater starting fuel pressures are necessary. A normal start may be made at 70°F with 50 lbs. fuel pressure. At —40°F, 75 lbs. fuel pressure is necessary. The P-59 starting fuel pump will build up 150 lbs. pressure which provides a generous factor for starts at temperatures below —40°F. It is the writer’s understanding that the 1-40 engine also provides a generous factor in this respect. The barometric will sometimes stick when starting cold at low temperatures. The engine will start but rpm will not go above 8000 when this occurs, until heat is applied to the barometric, or it is removed and cleaned. D. IGNITION The only ignition trouble encountered was the need for replacement of six booster coils. The life of these coils can be lengthened considerably if the existing starting procedure is strictly adhered to. Some pilots, however, will take longer than others to start the engines and the insulation on the coils will melt down, resulting in shorting out. Although the C-l booster coil is an easily procurable item and simple to replace, it would be advantageous from the standpoint of reliability and a concession to differences in pilot’s alertness to incorpor- ate a heavier booster coil. E. CABIN HEAT No definite requirements known to the writer have been set for cabin heat on a fighter aircraft. This, I believe, is an oversight, as cabin heating equipment seems to be dependent on whether or not pilots complain of being too cold in flight. I is my opinion that available cabin heat of room temperature (68°F) is not especially desirable or necessary on a fighter aircraft. Excessive cabin heat can encourage pilots to fly without cold weather clothing, which could result in serious conse- quences should an emergency arise. Pilot on the P-59 did not complain of cabin heat. He stated the cabin was comfortable for him and that he could fly with his gloves removed. Thermocouples installed at various points in the cabin showed good heat distribution and an average of 35 °F in the cabin at 16,500 rpm with the heat control full on. Unless specific cabin heat requirements are set up, no recommendations other than modifying the cabin pressure regulator to increase its life. This regulator on 22610 was good for over 60 hours before it began causing pressure fluctuations. F. WINDSHIELD DEFROSTING Until a canvas hatch cover was fabricated (a required item of cold weather equipment), the pilot complained of frosting windshields at ground run-ups and at taxiing out for take-off. With the nightly use of the canvas cover, frosting was in large part eliminated. On take- off and in flight, windshield defrosting was exceptionally good. No frosting was evident at any altitudes on any temperatures including —70°F at 32,000 feet. As an experiment, small scoops were attached to the heater muff intakes to see if they would pick up any rammed air during taxiing. The installation of these scoops made little difference, however, as the rear im- peller intake sucks air from the back of the engine nacelle and around the engine until speed is attained. The present heater muff intake is located at the bottom of the muff where it can pick up dirt and any oil or kero- sene leaking onto the inside of the engine cowl, and carry this matter to the inner surfaces of the windshield. Unless the engine installation is kept free from leaks and the cowl kept clean, this will occur. It is felt that this is a maintenance problem. The windshield defrosting system adequately meets cold weather requirements for —65 °F when the required canvas hatch cover is used to prevent frost from forming whenever the airplane stands outside overnight. G. CABIN HATCH The operation of the cabin hatch grew increasingly stiffer the colder the temperature. An attempted cor- rective remedy was tried by filing and smoothing metal surfaces wherever they appeared to be grooving or scraping. This did not decrease stiffness. After this attempt, it was noted that the rubber pressure seal tube became less and less pliable the colder the temperature and it exerted a pressure against the hatch wherever it was not securely and properly recessed in its mounting channel. Rubber was found on the hatch scraped from the lower rear right corner of the tube where the greatest pressure was exerted at low temperatures and where the tube was most noticeably not properly recessed. Proper installation of the pressure seal tube at the factory will eliminate hatch stiffness at low temperatures. An im- proved rubber which will remain pliable at low tempera- tures would also be advantageous. H. CONTROL SYSTEM 1. All surface controls, with the exception of the trim tabs, operated satisfactorily on the ground and in flight. The main surface controls were slightly stiff on the ground at—40° F, but loosened up quickly after being moved a few times and after the engines were started. 2. Elevator Trim Tabs. Stiffness of these units was excessive in flight at low temperatures. By the process of elimination, first dis- connecting the flex cables from the actuators and finding the installation still stiff, and then disconnecting the rearward trim tab chain, and finding no stiffness, the trouble was isolated to the actuators and flex cables. Testing was discontinued on this unit when a 90° drive on the right actuator was accidentally broken during a T. O. change of the flex cables. Concurrently, a report was received from the Central Offices stating trim tab stiffness had been eliminated at the factory by succes- sively cold room testing each item in the installation and taking corrective action on each item until the stiffness was eliminated. 178 5230 3. Rudder Cable Tension. The P-59 has the longest rudder cables of any pro- duction fighter produced by this company. An accurate check was made to find exactly how much temperature affected cable tension. The rudder cables were set at 175 lbs. tension at 60°F. At —35°F, the tension had dropped to 83 lbs.; at 0°F, tension was back up to 118 lbs., and at 12°F, 130 lbs. This shows a drop of approxi- mately a pound per degree, F. Standards has informed me this drop in tension is not excessive. Should still longer cables be used on the later models, a cable tension regulator manufactured by U. A. P. is available. This item has been used successfully on the B-24, I. FLAP INSTALLATION At —40°F, ground temperature, it was noted that the flaps would not operate until after the engines had been run up, thereby causing some heat to be absorbed. This indicated a grease problem and several attempts were subsequently made to cause stiffness in the flaps so that the grease could be changed and the corrective action recommended. Flights were made to 30,000 feet and —65°F. The pilot flew as long as fuel would allow and then tried operating the flaps. In each case, the flaps operated normally. Since it was found impossible to cause the flaps to again become stiff, no corrective action could be taken which would show positive results. It is recommended that a mockup of the flap installa- tion be cold room tested at —65 °F to again induce stiff- ness in order that the corrective action needed to elimi- nate the stiffness may be discovered. J. LANDING GEAR No winterization problem occurred on the P-59 land- ing gear. The shimmy damper did not leak, nor did the struts, which had the old type V-ring packing. K. GENERAL RECOMMENDATIONS Since airplane No. 42-22610 was the first jet-propelled aircraft to ever be tested in cold weather and it was never subjected to temperatures below —40°F, and it was also the only jet-propelled airplane tested, additional cold room testing of accessories and items which might require winterization would be desirable. It is recom- mended that all accessories on both the 1-16 and 1-40 engines, which have not been cold room tested, be sub- jected to temperatures of —65°F, and operated. .. Any modification found necessary should be effected by the proper manufacturer. Bendix Products Division Caesar Benassi. P-38L. Using PD12K8 carburetors PL 395270-6. We made the setting change to —6. I received your serv- ice bulletin on this and many new flow sheets. Plugs were changed at the same time that —6 setting was made Spark plugs installed were RP-43. Reference my report No. 4 of January 18, 1945. These plugs replaced after some three hours and very badly messed up. It looked like gum carbon and lead deposits. It may not be the fault of the plug but due to the lever setting, the engine may be burning out accumulation of gum and carbon formations. Regardless, the plugs were an awful mess and had much of these bricates or pieces of formation which was grounding them out. LS87 plugs were in- stalled. After some 17 hours, these have been replaced on the exhaust side of both engines as they fouled out. Some of them were not firing. These are much cleaner and show small amounts of this gum carbon or lead de- posits. The story on the LS87 plugs was this. They started fuel consumption tests after installing them. First test was a four hour run wdth carburetor heat on, pulling low powers 1600 RPM and 24" MP to 25". This was to simulate bomber escort mission cruising approxi- mately 170 MPH. The idea wras to find out the effect and improvement that carburetor heat had on engine performance and fuel vaporization. The pilot flew four hours with carburetor heat on +9 to 12°C on left engine, +18 to +21 °C on right engine at 1000 feet. After two hours of flying a mag check was taken and found O. K. At the end of four hours a mag check was again taken and found O. K, Carburetor heat was taken off and war emergency power was pulled in cold air. Both engines took it fine, excepting the right engine coughed once but immediately caught and went on. The exhausts were clean all the time. No torching has been reported at any power setting since —6 setting has been made. Left engine is using synthetic oil and right en- gine 1100 oil. Fuel consumption end of test was spoiled due to leaking fuel selector valves. The next day the same kind of test was made with carburetor heat off with a temperature of approximately —10°C. At the end of two hours a mag check was taken and both right mags were very rough. A power run was attempted but engines were very rough. Back on test run for two or more hours. At the end of four hours, the pilot advanced the throttles to pull rated power but the. engine was so rough that he was unable to. Both right mags were very rough. Pilot said, “the turbos were very black and when he increased power a carbon layer like foil peeled off turbo waste gates.” From this preliminary test it seems that carburetor heat can be used to good advantage on long range high altitude cold temperature flights. More tests are being conducted on this. Lockheed is ahead of other turbo installations on carburetor heat tests and seem to be on the way to making it a success. They get their heat from a shroud around the exhaust pipe and dump it into the turbo air inlet side. At the same time close off ram cold air and have a nose shutter in front of intercooler to shut off intercooler air. They get the best effect by having this shutter in front of intercooler rather than after. They also have a pressure differential controlled unrammed cold air door in wheel well that opens up and allows cold 5230 179 air to mix with this hot air at high powers so that when pilot begins pulling high power this door will open to keep carburetor heat from going too high. But at the present time, the valve he is now using is set to open at approximately 3.9" Hg pressure differential which is too high and he estimates it will be necessary to have it open at 1.5" to 2.0" Hg for correct operation. He is using an Airesearch valve. Republic has a carburetor heat control on the P-47D but it is not satisfactory. The heat rise is negligible on ground operation and low powers. They just take the heat from a shroud around the exhaust pipe and put it into the turbo air inlet. We may get some low power tests on these airplanes. The Wright Field E.T.O.U. Unit have some carburetor heat installations to make on B-17 and B-24 for test. I believe that when the value of carburetor heat for fuel vaporization is realized for long range, high altitude, low power missions rather than just removing ice, that more work will be done in this direction. It is a bad deal for the fighter pilots when they get to their destination after a long cruise at low powers and are unable to pull high powers due to plug fouling. It seems that the advantage of carburetor heat for such use has been very much neglected and I hope that we can gather enough information with further tests to prove its value in improving engine perform- ance and efficiency. In the past, carburetor heat has been looked upon only as medium of carburetor ice prevention or removal, and very little attention has been paid to its effects on engine performance and fuel consumption in long range cruise. Very definite indications have been observed which leads one to believe the tactical advantages resulting from the use of carburetor heat have not been fully explored. It is my firm belief that with low power, long range, oper- ation a noticeable fuel saving may be effected with the use of carburetor heat, when low cearburetor air temp- eratures are normally encountered. Furthermore, engine performance is definitely improved in low power cruise, in that spark plug fouling is reduced to a minimum. This also makes it possible to pull high powers from the engine even after several hours of long range, low power oper- ation. In other words, a tactical aircraft could make ex- treme long range missions, pulling lower power for fuel economy, and yet the engines would remain “clean” enough to make safe operation at high powers possible. It is believed fuel economy will be improved due to the increased vaporization effected by the use of carb- uretor heat. It is to he remembered excessive heat is also, therefore any carburetor heat system must have “controlled heat”. For example, in a P-38 (Allison Engine) a minus 20°C carburetor air temperature is undesirable when pulling low power (1600 RPM— 25") and any carburetor air temperature above plus 25 °C is also undesirable. For 1600 RPM—25" MP it is be- lieved a plus 20°C carburetor air temperature is the most economical for fuel consumption, and is also high enough to prevent spark plug fouling. Spark plug fouling is prevented by improving fuel vaporization and conse- quent combustion. We left for the 11th Airforce contact in the Aluetians on March 4th, and returned to Fairbanks on March 19th. Before departing we had the pleasure of meeting Gen- eral Johnson as he passed through here. It was he who requested our assistance. Thus we got an idea of what he expected to accomplish. On the way out we spent a half day at the 11th Air- force Depot at Anchorage, where we advised them on the P-38 work. We then proceeded on to Attu and Shemye. On this trip I had the pleasure of being associated with two very capable men—Captain Accord, C.W.T., P-38 project officer for the last two winters; and Lee Chambers, Lockheed, CAV.T. Representative for the past three winters, who have done a grand job. Captain Accord has had two P-38L’s on test this winter. Besides being a very good pilot, who knows every part of his airplane thoroughly, he also has considerable engineering ability. Lee Chambers has worked very hard on the P-38 winterization and carburetor heat installation. It is due to his good work that Lockheed can now claim a satis- factory controllable carburetor heat installation on the P-38L. Because of the close cooperation of Mr. Cham- bers and Capt. Accord and the free hand given them by Col. Stewart and the C.W.T. Detachment, they were able to gather some very valuable information. By im- proving fuel vaporization and reducing plug fouling, this will go far toward improving low power, long range operations, thus allowing the P-38 to pull war emergency power after long range, low power escorts. So far, this carburetor heat control is installed only on 115 airplanes, most of which are being sent in this direction. While in the islands, we lectured to mechanics, day and night, seven days a week. Mr. Chambers covered the heat control; Capt. Accord discussed the P-38L in gen- eral; and I dwelt on carburetion. The lectures were three hours long with a ten minute break each hour. We imparted much information, which, I am certain, will help them with these airplanes. Capt. Accord and Mr. Cham- bers assisted them in starting the modification of the carburetor heat control so that it would be held at any desired temperature. The way it is now hooked up, the carburetor air filter lever, which was not being used, now controls the carb- uretor heat and cold rammed air valve. By moving this lever, which is near the mixture control in the cockpit, the cold ram air valve can be closed and hot air can be taken in from around the exhaust shroud and put in on the suction side of the turbo. The hot air shroud can stand enlarging for its restricts air flow as much as 8" of manifold pressure when used. This doesn’t matter too much at low airflow, but can be corrected for altitude work by using partial heat. Also, an Airesearch,relief valve should be put in this system to allow cold rammed air to automatically begin entering at approximately 2300 RPM 32.0" manifold in case a pilot forgets and starts pulling high powers with carburetor heat on. This would be a safety factor and so avoid damage to the engine. They also installed two B9A switches in the cockpit just below the prop feathering switches to control a nose shutter in front of the intercooler. This shutter can be controlled by a small screw jack at any given position to give desired carburetor air by controlling the efficiency of the intercooler. This can be used alone or in conjuction with the hot air valve. The pilot’s operation of these ships was very poor as they had acquired many bad habits, such as: L Ground operation in auto-lean to keep plugs from fouling. This could have been accomplished in auto- rich and the use of the higher RPM after the engine started; also by having the idle mixture properly set 180 5230 and by the use of carburetor heat. This resulted in two ships taking off in auto-lean position beacuse the pilot forgot to go to auto-rich for take-off One ship was damaged. The other pilot found his eror in time to save the ship. 2. Starting by using manual mixture control instead of primer. This is a serious fire hazard. 3. After using carburetor heat for ground run-up, forgetting to take it off for take-off. 4. High power operation, overworking and damag- ing engines. This was very unnecessary as they were not going anywhere, and it resulted in throwing rods and having entirely too much maintenance. I just received your Field Service letter of March 22, 1945 of comments by George Strobridge as to their findings in England on lead fouling and his comments on Ostrander’s memo. I felt that if they go out and do as we have in the past three winters up here, operate engines at low RPM with -|-20 to +30° centrigrade carburetor air temp- erature that they will eliminate plug fouling. We have fouling. We have operated P-38’s as much as 115 hours on same plugs. We also found that rich cylinders get most of the lead. We have operated as long as 4 hours at one time, 1600 RPM and 25" MP without fouling plugs and carburetor heat on, then pulled war emergency pow- er with heat off , However, at above setting without carburetor heat, the plugs would foul out in two hours with temperatures only—12° centrigrade. Then at the end of four hours, the plugs would be fouled so badly that it was impossible to pull even rated power as the plugs would not clean off and had to be changed. Might suggest they try some carburetor heat test to improve fuel vaporization, distribution and reduce plug fouling. I have been a booster for carburetor heat for cold op- eration for three years, and I believe that it is finally coming into play and that you will see a definate trend towards its use in the near future. After my first winter’s operation up here, I returned to the plant and advised our engineering department to install carb- uretor heat on our test stand Allison engine and to work on a means of automatic carburetor heat control. I never received any information, so supposed it was never done. If so, we have missed much valuable data. Allison has much information on carburetor heat and distribution. At one time, they did not recommend the use of carburetor heat, but in the past year, have learned much and have changed and are for it. I would appreciate it if Wally Knopp could acquire for us this data from Allison. Cold Weather Carburetor Heat Test, Report A2-127, Experimental Dept, by G.M. Grabbe, 4/1/44 to 4/30/44. Yesterday, I attended a meeting with Major Anderson and Captain Alexander of A. T. C. and Bud Shaw of Allison. The discussion was on P-63 plug fouling. They changed 850 spark plugs last month and none of these had over 25 hours. The planes have been coming up op- erating at 2000 RPM and 30" of MP in auto rich posi- tion. I suggested the use of carburetor heat to -f-20 to -f-30° centigrade not to exceed 2250 and 32" of MP in autolean position. Auto lean being quite lean on this installation, I suggested, if they find it so, to operate towards or in auto rich as they found it necessary. They are going to put out a letter to this effect and train all pilots and mechanics to do this by having them fill out a check sheet with their operating information and if neces- sary check out pilots and mechanics on proper procedure for operation. Auto rich will be used on the ground at all times. Thus they expect to eliminate most of this plug fouling and rough engine operation. They have found some plugs improperly set in stock and will check all these before installation as well as torquing plugs when installing. The carburetor situation has been very good, only one being removed that was causing rough operation in A. I. This will be flow tested and I will get results. Trouble was in cruise range so I suspect idle spring setting. On my B-29 reports, I stated that the primer is essential for cold starting with fuel injection engines. Since studying my repdrts, I would like to add a few words of explanation. I feel satisfied that the primer can be eliminated for warm operation. For instance, we started engines at -f-20°F. in less than 70 seconds without priming, time after time. However, under the same conditions, with the primer we could start them in 15 to 30 seconds. We really don’t know how low we could start without the primer, but we did get better starts with it. With direct injection, cranking speed makes a dif- ference, and the faster the engine can be cranked the better. It is desired to crank at least 25 RPM for suc- cessful starts. We should also consider the method we used for starting and the lack of knowledge on our part. It did seem that % to 1" throttle opening was best, and sometimes cracking the engine 1 prop, RPM mixture A. R. before turning ignition on helped. This seemed like the best method, and we started in 25 to 30 seconds with it. Better warm up operation was had when engine was run up to 1200 RPM as soon as oil pressure hit 40 lbs. It is sometimes necessary to hit the dilution solenoid slightly to maintain the above oil pressure. Auto lean operation at this time does reduce the exhaust torching, but does not seem to smooth out engine operation very much. While I was in the Aleutians a meeting was held by the C. W. T. Cargo Section. It was attended by the P. & W., Wright Aeronautical, and Curtiss airplane representa- tives. The discussion was about the C-46 low power, rough engine operation and cutting out. I haven’t been able to get the minutes of the meeting, but will do so or discuss the same with those who attended. From what little information I gathered, it was more of a sudden cutting out and it happened mostly to the right engine, although it has happened on the left. It happened on a straight level flight, low cruise, or let down in A. L.— usually at 1900 RPM, 25" M. P. A. R. or lower, and could be corrected by using carburetor heat or A. R., or by increasing manifold pressure to 27.0". High blower was not tried. ANF-28-130 grade aromatic fuel was being used. C-34S plugs were used. It also happens when the temperature is 0°F. or colder. I am satisfied that it is a distribution problem due to this type fuel at cold temperatures, using low powers, and not getting enough heat from the blower to help vaporize and dis- tribute this fuel properly to each cylinder. I feel that this combination of low cruise at low temperature and this fuel is creating quite a distribution problem, and that the use of carburetor heat with this fuel is the answer. I had the pleasure of meeting the Phillips 66 repre- sentative. He advised me that they ran into RPM fluctuation at low powers such as 1460 RPM and 2020 RPM, and 25.0" of M. P. in A. L. As near as he knew 5230 181 A. R. carburetor heat or 27" to 28.0" of M. P. would eliminate this. After listening to my thoughts on this subject he invited me to take a ride some time, and see for myself what happens. This I will do if I have time. There has been much said in regards to synthetic oil PPO-265. I have made it a point to discuss this oil with various ATC officers, enlisted men, and factory repre- sentatives attached to the Army. In practically all cases they feel that this oil is the cause for rough engine oper- ation after a few hundred hours; and they can in most cases clear up the engine roughness by changing oil. Please do not get the idea that I am criticizing this oil or condemning it, for I have no such intentions. In fact, if it is given the right chance, I believe that it is the an- swer to some of our dilution problems. I feel that in most cases it was put into an engine and just allowed to carry on. It was expected to create wonders and wasn’t given a fair chance. For instance, it is the opinion of most people I talked to that this oil will do the following things: 1. It will flow freely and penetrate more than ll60 oil. 2. It will clean an engine of sludge and gum. 3. It will burn cleaner at the exhaust. Now let us consider the above comments or opinions: 1. If it flows freely and penetrates, it will reduce the necessity of oil dilution and should improve cold weather operation. 2. If it cleans the gum and sludge from the engine, in time, this gum and sludge will be flowing throughout the engine in the oil. This is not desirable as it will finally deposit this residue in the prop dome (Hydromatic), and, as the oil penetrates, more probably in the valve guides. For this reason we are bound to get engine roughness. Also, for this reason, this oil should be used only in a new engine that doesn’t already have a quantity of gum and sludge accumulation. If used in an old engine, it should have some type screen to catch this sludge, or the oil should be run through a clarifier after the first 50 hours, and probably every hundred hours thereafter to eliminate the sludge and gum. This would be giving the oil a fair chance and might he an answer to all the trouble being encountered. 3, Since it burns cleaner, it would be more desirable. This is only my opinion; but I would like to see it tried to see if it would eliminate the troubles encountered, as I do think that this oil could answer many problems. I have been told that draining the synthetic oil and replacing it with 1100 oil has cured engine roughness; and that at times they have flushed engines with diesel oil and put in new synthetic oil and cleared up rough engines. If so, why wouldn’t a clarifier do the same thing ? I hope that this may be of help to some one. While in Anchorage, checked on the P-38L situation and it is coming along quite satisfactorily. In fact, some of the news was very satisfactory and made me very happy. I met Colonel Semway who is Commanding Officer of the 54th Fighter Squadron at Attu and he said he had some information for us from the chain. He gave us what he knew about it and it amounted to this. A group of the P-38L’s had simulated a bomber escort with B-25’s for 9 hours and fifteen minutes using approxi- mately 64 gallons of fuel per hour. This was done at 1600-25" one way with a twenty minute' scramble of high powers at the supposed target, then returning at 1600-30" to the home base with 270 gallons of fuel left in the tanks which was a good four hours reserve. They used carburetor heat on this mission. They had one 300 gallon belly tank and one 165 gallon belly tank and did not drop the tanks which would give them a slight loss in air speed. Being that they were worrying about fuel on a 9 hour mission, I feel that this will cause them to realize that Capt. Accord knew what he was talking about when he advised them of the powers to use to get 13 hours flying time from their fuel. I am certain this will give those pilots the confidence they needed and that they will learn more as they go along. Now I feel that the combination of Accord-Benassi and Chambers did much good on that trip, and feel that the trip was worthwhile. Chandler Evans Corporation H. H. Wallace 1. No report of malfunctioning of B-29 carburetors have been received by this writer to date. The complaint on B-24 carburetors is the same on all ships—difficulty in getting the engine to fire in the carburetor alone during cold starts. After a sufficient warm-up period, ground and flight operation are normal in all cases. However, during cold starts, at temperatures lower than —10°F., the engine will fire on prime but will not run with the carburetor alone until it has been running about three minutes or longer on the primer. 2. This was observed by the writer on the morning of January 19, 1945, on airplane No. 44-41377, when starts were made at —19°F. Each engine showed the same trouble with No. 3 engine, the worst offender. 3. The capacity of the primer was such that the engine would not go above 500 RPM with continuous priming. 1 his is to be investigated by the writer this week. 4. Investigation of the load compensator balance line drip from the gurgle tubes showed No. 3 engine to flow the least. It was therefore decided to change this carbu- retor and install one of the four carburetors I brought from Ceco, Dayton. This was done and on cold start the next morning this engine ran on the carburetor as soon as it was put in auto-rich after starting. 182 5230 Consolidated Vultee Aircraft Corporation D. ,M. Moore D. M. Moore 1. On a trip to Anchorage in November, airplane B-24J, Serial No. 44-41377 encountered ice. The crew chief reports the propellers and empennage iced while the wings remained clear. The alcohol system was not ef- fective in eliminating the ice. When the engine speed was increased to 2400 RPM, the ice was thrown off; the numerous dents in the skin on the right side of the fuse- lage in line with the plane of propeller rotation are verifi- cation of the crew chief’s story. A similar condition has been noted on a Model C-46 airplane at this base. Also observed ice on 'the leading edge of the blades of a Model B-29 airplane when it had been run in the hangar. The ice extended approximately eighteen inches beyond the end of the slinger outlets. Sandy suggests we extend the outlets to the hump on our blades, increase their diam- eter and incorporate fluid nozzle outlets to increase ejec- tion velocity, and install icing strips to avoid denting the fuselage. Ice research was conducted on an instrumented Model B-25 hot wing airplane at Minneapolis least year. Cam- eras were installed so photographic evidence could be obtained in flight. The North American Engineering Representative at Ladd Field this season is the engineer who covered the tests at the Ice Research Base. The results of the test indicate wing and empennage icing is is not nearly as critical as formerly believed; indicated air speed was reduced approximately 4 RPM when IV2 inches of rime ice was formed on the leading edge or the run back formed 3 inches high over the single spar. Landing characteristics were not impaired appreciably by these formations. On the other hand, numerous tests indicated propeller ice is critical. Prior to entering known icing areas the power setting, altitude and indicated air speed were recorded. The first warning of propeller ice was excessive vibrations of the engine ; throw-off follow- ed and the indicated air speed dropped—in some in- stances as much as 35 MPH. The engines were speeded to about 2300 RPM to throw-off the ice; when the origi- nal power setting was resumed at the same altitude, the indicated airspeed returned to the initial reading. When part of the ice is eliminated the unbalanced propeller produces vibration, ensuing rapid flexing and hunting of the blades in pitch change attitude, noted in strobo- scopic observations, appeared to be responsible for the loss of throat rather than the change in blade contour produced by the ice. Rime ice predominated in acclumulations on the blade at low propeller speed while glaze ice predominater at high speed. Ic accumulates faster at the low speed but the rime is much more easily eliminated by increasing engine speed; it may be impossible to eliminate glaze ice accumulated at higher engine speeds and still remain within recommended operating limits. Consequently, the North American representative suggests operation at the lower speeds and reving up at intervals to remove the ice. Operation in the lower range of engine speeds may hinder development of high power for carburetor deicing. Discussion revealed that pilots and personnel engaged in ice research attribute the excessive empennage flutter encountered in our Model B-24 airplane at Minneapolis primarily to propeller ice rather than empennage ice; disturbance in the air stream and vibration originating at the propeller are believed responsible for resonant flex- ure in the tail. 2. Sandy has received information that Aleutian pil- ots are encountering carburetor ice on Model B-24 Series airplanes. Increasing power and/or changing altitude as recommended in the 1 September 1944 issue of the Standardization Handbook for B-24 Pilots published by the Second Air Force necessitates fuel consumption in excess of minimum cruise requirements. The additional consumption could easily be critical when icing weather prevails for several hours during a bombing mission. We are planning to build some experimental muffs to cover part of the exhaust tail stacks; the muffs will be just below the carburetor ram air inlet passage so the inter- connecting hot air ducting will be short. A valve to close the interconnecting duct and exhaust the muff air into the slip stream can be controlled by a cable from the in- tercooler shutter actuator. The temperature can be con- trolled by adjustment of the existing butterfly for selec- tion of filtered air or rearrangement for selective setting of the intercooler actuator, A simple design that can be fabricated in any sheet metal shop would provide a quick and dirty solution for the Aleutian area without penaliz- ing fuel economy. The muffs should also reduce the duration of rough engine operation when cold starts are desired. CARBURETOR HEAT BY EXHAUST GAS INJECTION 1. Carburetor heat is supplied by exhaust gas injec- tion on the Model B-25 airplane. Excessively rich oper- ation was traced to stratification at the top deck; tests revealed a stream of cold air surrounded the altitude compensator, which also corrects for temperature. In addition, theory indicates richer operation can be antici- pated when exhaust gas is dumped into the inlet air stream; fuel is injected in proportion to the mass density of the entering gas whether it be oxygen and nitrogen or carbon dioxide, water vapor and partial products of combustion. Further, the water vapor might conceivably augment the icing in the event of leakage of a small quantity of exhaust gas into cold air. Solid residue from exhaust gases may restrict impact tubes and change the carburetor metering characteristics. The foregoing reasons indicate carburetor heating by exhaust gas in- jection is not desirable. OPTIMUM AIR TEMPERATURE FOR MAXIMUM RANGE 2. Tests are being conducted on the Model P-38 air- plane to determine the optimum carburetor inlet air tem- 5230 183 perature for maximum cruising range. Preliminary data recorded so far indicates approximately 3 percent econo- my can be affected by operating with air heated to 30°C. instead of using 0°C. inlet air. The 3 percent is believed conservative; fuel selector valves, inspected for elimina- tion of internal leakage, have been requested so the test ca*1 be continued. The improvement in economy is at- ti ibuted to increased fuel vaporization. It is recommended provision for carburetor heat be incorporated on our experimental airplane, the bomb bay cells can be used as containers for fuel for a similar test. Take-off and landing can be effected with fuel in the wing tanks so the difference in weight of the bomb bay cells will show the fuel consumed during the test runs. The data is desired in the event we incorporate automatic control of carburetor air or intake manifold temperature; the warm air can be obtained from the manifolds in the heat exchanger system as outlined in my previous Cold Weather Test Reports. The effect on range should be noted on our cruise control charts. INTERCOOLER SHUTTER EFFICIENCY 3. Cold Weather Tests on Model P-38 airplane, which has an intercooling system similar to ours, indi- cated circulation occurs in the cooling air duct when the aft side of the intercoolers is sealed; a similar conclusion was derived from tests on a Northrop Model P-61 A airplane. Minor leakage through the butterfly located forward of the intercooler on one of the Model P-38 air- planes under test this season produces cooling of major magnitude; a shutter that will exclude all cooling air is found to be necessary. Our failure to obtain appreciable heat rise, when turbo boost is applied on the Model B-24 airplane, indicated the carburetor air was being cooled almost as fast as it was heated; this condition exists with the intercooler shutters closed. Tests were conducted to support this contention and supply data for redesign by B-24 Project Engineering. A review of results reveals additional ex- planation is unnecessary. It is suggested work on the re- design be scheduled to coincide with our modification for carburetor heat. A cracked throttle is not desirable because tempera- tures below the butterfly valve may be in the neighbor- hood of 60°F lower than is indicated on the carburetor air temperature gauge. The data covering the Model B-17 airplane is submit- ted to indicate the characteristics of a muff around the tail stack. This experimental installation might prove adequate if the intercooler shutters were redesigned and relocated so 100% efficiency could be obtained. This in- stallation is simple and can be incorporated easily on our airplanes in service which are not equipped with heat ex- changers. SURFACE CONTROLS 4. Shortly after the B-24J airplane arrived at Ladd Field the control cables were discovered materially looser than is specified in the Erection and Maintenance In- structions ; they were tightened so a basic tension could be established for test purposes. Data recorded this winter indicates the tension variation in aileron control cables is greater than in either the elevator or rudder cables. The maximum tension noted in the aileron was approximately 79 pounds at -{-65° F when the aileron was in the hangar. The minimum tension was 61 pounds at —40°F. The variation amounts to 18 pounds over a temperature range of 105°F. A recommendation will be submitted to obtain test results covering a wider range of temperature. At —62°F the tests show the tension in the aileron thermal control cables in airplane B-24J, Serial No. 42-51660 was 47.5 pounds and 50 pounds. At -|-10F, the tension on the same cables was 52.5 pounds and 57.5 pounds respectively. The maximum variation is, there- fore, 7.5 pounds for a temperature change of 63°F. No evidence of unsatisfactory performance was noted. This cable is standard 7x19 extra flexible construction; co- efficient of expansion is 8.73 x 10-6; ultimate strength 3670 pounds; yield strength 1900 pounds. The specialists from the Aircraft Laboratory think the tension regulator may prove ultimately superior to the thermal cable when the interior of the airplane is thoroughly insulated. ENGINE OIL SYSTEM 5. Enclosure (C) shows the results of dilution tests on airplane B-24J, Serial No. 44-41377. The results indicate the hopper in our latest tank design is unsatisfac- tory ; the diluted mixture in the circulating system over- flows into the top of the reservoir. Enclosures (D) and (E) are the results of boil-off tests; they confirm the dilution of the reservoir outside of the hopper. In spite of the low dilution requirements to provide for starting in mild weather this season, evidence of spewing has been observed on all Model B-24 airplanes at this base; maintenance is increased because the oil must be cleaned off of the nacelle fairing aft of the breathers. The quantity of oil lost in this manner is low as the oil consumption of the engines is considered norm- al. Discussion with Mr. William Hoffman, Chief Engi- neer for United Aircraft Products Corporation, reveals breather spewing has been eliminated by modification of the design of the oil system on a Lancaster airplane with a Packard built Rolls-Royce engine at dilution per- centages as high as 25 to 30. Tests conducted by United Aircraft Products Corpora- tion on one of our reservoirs with the 3 inch diameter hopper show deareation of the oil is inadequate; entrain- ed air by volume in the inlet oil is approximately 20 per- cent and entrained air in the line to the engine pump is approximately 18 percent under the test conditions. Mr. Hoffman was requested to forward copies of the test results to Mr. W. Ring, Chief Service Engineer, for my attention. United Aircraft Corporation has designed an oil sys- tem for the Lancaster airplane which provides satisfac- tory performance for (1) dilution (2) deareation (3) warm-up (4) propeller feathering (5) spewing. The de- sign is predicated on elimination of the feature where clean reserve oil is fed into the circulating system when the hopper supply diminishes; the reserve oil as well as the hopper oil is used in the circulating system. A discussion with the Specialist from the Fuels and Lubricants Section of the Power Plant Laboratory reveals Wright Field tests indicate the reserve oil in tanks of current design circulates in the system and invalidates the design theory. As the United Aircraft Products investigations and tests are subject to constant surveillance by the Engineering Division at Wright Field, a change in design specifica- tions is anticipated. I also requested a copy of the draw- ing of a modified oil tank be included with the test results noted above. The data is desired to assist our engineers in modifying the oil system. 184 5230 NOSE COMPARTMENT AND CABIN HEAT 6. On 10 February 1945 Sergeant Outlaw was bom- bardier in airplane B-24J, Serial No. 44-41377, during a bombing mission at 20,000 feet altitude when the out- side air temperature was —40°F. He froze the little finger on his left hand ; he considered it necessary to wear a mask to avoid freezing his face. This instance is cited to illustrate the consequences of inadequate heat in the nose compartment. Inquiry reveals the crews of all Model 24 Series Airplanes avoid riding in the nose, when possible, during Arctic flights on account of prevailing low tem- peratures. Heating tests were conducted in airplane B-24J, Serial No. 44-41377 by means of thermometers secured to per- sonnel ; thermometers were located just outside of the clothing on top of the head at the waist and slightly above the ankle on the inner side of the leg. The pilot’s ankle thermometer was on the left leg while the co-pilot’s was on the right leg where they would not receive direct blast from the registers. The radio operator stood erect in the center of the compartment just f©reward of the top turret; the bombardier stood erect in the nose compart- ment just aft of the bomhsight; the pilot and co-pilot occupied their seats. Readings were recorded when sufficient time had elapsed for temperatures to stablize. Enclosures (F) and (G) show data obtained when all the floor registers in the pilot’s compartment and the radio compartment were in the closed position—which does not shut off the hot air. The damper far the flexible top turret defrosting duct in the radio compartment was closed. The pilot’s windshield defrosters were half open. The em- pennage deicing was off. The dampers in the right and left cabin heat ducts and the three miscellaneous equip- ment dampers in the nose compartment were wide open. Preliminary trials indicated these settings yielded the most even distribution of heat in the pilot’s and radio compartment as well as directing the greatest possible quantity of warm air to the nose. The foregoing tests reveal temperatures a few degrees above that of free air prevail around the bombsight and the air emerging from the pilot’s and co-pilot’s registers is too warm for comfort especially when wearing muk- luks. The results of a bombing mission are dependent on the performance of the bombardier; best performance can not be obtained when he is cold—especially if his eyes are watering or his nose is running. In Arctic flying, it is just as essential not to become over-heated as to be sufficiently warm; excessive perspiration in foot gear may be the cause of frozen feet. A study is suggested to locate and stop leakage of all outside air into the nose compartment—especially the leakage above t,he bombardier in the turret after-door sill. Additional heat is recommended for the nose compart- ment and better distribution in the pilot’s compartment to eliminate the blast effect on the feet. A modification is already in processing, I believe, to provide heated air for the tail section. It is recommended investigation for nose section leakage be included in the airplane spot check schedule because of possible subsequent development as a result of changes and variations in production. ♦ ♦ ♦ ♦ 1. The ensuing article, describing a proposed Heated Air System for the model B-24 airplane, is based on (1) observations of cold weather tests during the winter of 1944-1945 at Ladd Field, (2) discussions of operational and maintenance problems with personnel assigned by both the Army Air Forces and the aircraft manufacturers to participate in the Cold Weather Test Program and (3) a review of several previous reports on cold weather test, data in Technical Orders pertaining to Arctic operation data in Engineering Division Technical Note Serial No. TN-TSESE-1 covering design for extreme climatic con- ditions and data in manufacturer’s publications covering cold weather operation. The article is prepared in an effort to consolidate problems incident to cold weather tactical operation and provide a solution adaptable to in- corporation in short range production ; the specialist from the Power Plant Laboratory has suggested this article may be of interest to personnel at Wright Field. Heat exchangers are incorporated in the tail pipes on the four engines of production model B-24 airplanes so energy in the exhaust gas can he utilized to warm air for wing and empennage deicing, windshield, astrodome and turret defrosting and cabin heating. Scoops located in the oil cooler ram air ducts supply cold air to the ex- changer intake ports. Insulated ducts convey a portion of the heated air from the inboard exchangers to a common junction in the fuselage, longitudinal ducts from the junc- tion distribute the air fore and aft to the cabin and tail. The balance of the air flowing through the inboard heat exchangers is conveyed to the center section leading edge for deicing. The outboard exchangers supply heated air for outer panel deicing only. Thermostatically con- trolled dump valves at the exchanger heated air exhaust port divert the hot air to the atmosphere in the event the temperature becomes excessive. A carbon monoxide de- tector is incorporated in the airplane as a precautionary measure to warn the pilot in the event of heat exchanger leakage. A redesign of the foregoing heated air system and some equipment is proposed to provide for the following functions: 1. Immediate Ground Starting. 2. Propeller Deicing. 3. Propeller Feathering and unfeathering at Low Temperature. 4. Engine Starting on Flight. 5. Attenuation of Engine Roughness During Warm- up. 6. Carburetor Deicing. 7. Improvement in Fuel Economy by Vaporization. 8. Short warm-up Period Prior to Take-off. 9. Wing and Empennage Deicing: 10. Cabin Heating. 11. Defrosting. 12. Altitude Operation of Auxiliary Power Unit. IMMEDIATE GROUND STARTING An auxiliary fuel burning heater in conjunction with a blower and heat exchanger on the auxiliary power unit would be designed to supply warm air to the heated air ducts in the proposed system. Part of this air would flow through a manifold, common to the four engine heat exchangers, and into the accessory compartment of each engine; a compartment temperature in excess of —20°F should be maintained when the free air temp- erature is —65°F. Critical locations such as oil and fuel drains would be protected with sumps or electrical ele- ments to prevent ice from blocking the lines. The re- mainder of the warm air would be routed to the cabin to keep the battery and instruments at temperatures equiv- alent to those in the accessory compartment and provide 5230 185 a warmer atmosphere for Maintenance personnel. Warm air would be diverted to the carburetor intake of each en- gine during starting to insure adequate vaporization of fuel. Following procedure specified in existing Tech- nical Orders should result in easy starting. When the airplane is inoperative, the auxiliary power unit and heater would be in continous operation; design for operation at partial throttle would he expected to decrease maintenance. Continuous operation of the auxiliary power unit insures energy to supply localized electrical heating equipment. It is estimated one fire guard could attend to five airplanes. PROPELLER DEICING, PROPELLER FEATHERING AND UNFEATHERING AT LOW TEMPERATURE AND ENGINE STARTING IN FLIGHT Heated air deicing is reported to he under deve’opment at the Ice Research Base. Discussion reveals a feature in the design is a fairing over the propeller dome to pro- vide for distribution of heated air to the blades; the heated air is also expected to warm the oil in the dome sufficiently so the propeller can be feathered and unfeath- ered at extreme low temperatures. The duct design provided for immediate ground starting should maintain sufficient temperature in the accessory compartment, while the engine is stopped, to insure starting when the propeller is unfeathered ; dilution would he required prior to feathering to avoid congealing in the feathering line. The heated air supply to provide for the foregoing operations would be obtained from the heat exchanger manifold in the proposed system. ATTENTUATION OF ENGINE ROUGHNESS DURING WARM-UP CARBURETOR DEICING AND IMPROVEMENT IN FUEL ECONOMY A mixing valve, thermostatically controlled by the intake manifold fuel-air mixture temperature, would be incorporated in the ducts leading from the common manifold to the individual turbo intake air ports; the cold air supply to the mixing valves would he obtained from the existing carburetor inlet air ducts. An override, controlled from the pilot’s compartment, would be in- corporated in the mixing valve as a safety precaution so the heated air supply could he blocked in an emergency. The optimum fuel-air mixture temperature would be determined by tests; results of previous tests indicate it bears no uniform relation to the carburetor inlet air temperatures under various combinations of power and throttle settings. Based on current available informa- tion, it is expected to correspond roughly with a car- buretor inlet air temperature of 70°F. Too low a tem- perature is detrimental to distribution of fuel in the fuel-air mixture resulting in exhaust smoking and loss of power; too high a temperature is detrimental to volu- metric efficiency and depresses detonation limits. The thermostat governing the mixing valve would he adjusted to maintain the optimum fuel-air mixture temperature which would insure deicing of the carburetor. The foregoingarrangement would attenuate roughness during warm-up, eliminate the problem of carburetor deicing and assist in obtaining maximum fuel economy under cruising operation. It would also eliminate the necessity for readjusting the carburetor idle setting when major changes occur in the free air temperature. SHORT WARM-UP PERIOD PRIOR TO TAKE-OFF The soaking period and temperature differential are the dominant factors which influence congealing of un- diluted engine oil in the reservoir. A temperature in excess of —20°F in the accessory section is believed adequate to avoid congealing in the reservoir during soaking encountered in usual Arctic operation. Incorp- oration of decongealing fins on. the hopper should insure feed of the diluted oil by the time it was required in the system. Dilution requirements for this temperature are not drastic so excessive breather spewing would not he anticipated. Test data indicates this temperature is adequate to avoid vacuum pump failures. A cabin temperature in excess of —20°F combined with available electrical energy for localized heating would attenuate or eliminate the warm-up period for erection equipment and insure immediate operation of inverters. Continuous heat in the pads on the servo motors would eliminate control stiffness that might originate in these units. A review of the foregoing considerations indicates the warm-up period prior to take-off at low temperatures can be materially reduced by adoption of the integral heating system. WING AND EMPENNAGE DEICING, CABIN HEATING AND DEFROSTING The application of heated air to wing and empennage deicing, cabin heating and defrosting is a recognized solution of these problems; further discussion is con- sidered unnecessary. ALTITUDE OPERATION OF AUXILIARY POWER UNIT The blower incorporated on the auxiliary power unit would be designed to supply air under sufficient pressure for operation at altitude; this provision would ensure availability of an additional source of electrical energy and heat in emergency. Discussion with the representative of the manufac- turer of the heat exchangers incorporated on production model B-24 airplanes indicates a low percentage of heat available in the exhaust gases is utilized and heat ex- shangers of larger capacity can be procured. Inquiry reveals no unsatisfactory reports pertaining to the heat exchanger on the model B-24 airplane have been noted in spite of their use on airplanes in service for nearly a year. The results of cold weather tests this season indicate the carbon monoxide detector is easily checked by holding a lighted cigarette at the mouth of the pick-up behind the pilot; it is considered reliable by operating personnel. The integral heating system is applicable to airplanes of other manufacture as well as to the Model B-24 air- plane. It is hoped the foregoing article will stimulate further development of the heated air system and pos- sible result in an experimental installation for better evaluation of its merits. 186 5230 Curtiss-Wright Corporation A. H. Nisita 1. BTRY. CART RECEPTACLE LOCATION T. E. Battery cart receptacle in location of prop blast. a. On glare ice, collisions with horizontal stabilizer have been narrowly avoided. b. Very inconvenient for personnel in prop blast, especially at sub-zero temperatures. Rec. & Cone. a. That relocating the receptacle forward on the center line of the fueslage alleviates the aforementioned conditions and places the subject item in the most advan- tageous spot on the subject and other conventional twin and four engine airplanes. b. That the ATSC should increase the car battery take off line by three feet, so that on convential gear air- craft (C-47, C-46) it would not be necessary to enter the propeller rotation area, c. That the change be considered and acted upon by the contractor in the light of the above mentioned reasons. 2. MODIFIED JANITROL IGNITION PLUGS (56A97) The subject plugs have been recently installed, one in each of the three subject aircraft operating at this activity, along side of the 438-MA—MB & MC series. Crew chiefs have been instructed to replace failures (if and when they occur) with the same type, so that compara- tive time may be adequately substantiated by a record of test on at least two units. The Janitrol plug is the best design the writer has seen. In view of past experience, however, it remains for service life to tell an accurate story. Rec. & Cone. It is recommended that the contractor design a plug along similar lines, using the same diameter and material in the electrodes; but protect and clean the porcelain by adding vent holes around the outside case and moving the porcelain down approximately one inch. 3. HEATER IGNITION PLUGS T. E. a. A 438MA and a —16 standard production plugs were removed at 35 hours for a comparative check at this period. The MA center electrode had already begun to deteriorate. b. A set of —16 plugs with 125 hours were still firing when removed from 24720. Note location of porcelain failure. A. T. Replaced with one MB and one 56A97 plugs. Rec. & Cone. a. That the present production plug porcelain design is unsatisfactory and should be elimi- nated in favor of a small stub type center electrode porcelain protected by a vented steel shield as previously recommended in this and other reports, closely modeled after the Champion D-8, which should be in the con- tractor’s possession by this time. 4. CLEAR VIEW PANEL Since the contractor is contemplating going to a flat glass windshield in the near future, photographs of the C-54 installation is submitted for engineering study. Note simple locking mechanism and method of heat application. 5. PILOT’S SIDE WINDOW T. E. Innumerable complaints about the ineffectiveness of the subject airplane’s pilot’s side window in all types of weather have prompted this writer to investigate two of the best designs on the field. The B-29 subject unit was commented on my Report No. 3. For the contractor’s evaluation, photographs of the C-54B installation are submitted. Rec. & Cone. a. The present design is totally unsatis- factory for its intended purpose, b. That the contractor consider the advantages of the above mentioned designs and incorporate similar features in a new or modified design of the subject aircraft’s installation. 6. WINDSHIELD DEICING AND ANTI-ICING In view of a projected flat glass windshield for future subject aircraft and in view of the fact that flat glass shields have bad anti-icing and deicing characteristics, photographs of the Douglas 3 way method of anti-icing and deicing on the C-54 are herewith submitted. Note the hot air blast aft in conjunction with a double pane, the wiper in the center and the alcohol nozzles at the apex of the windshield “V”. Each unit is very efficient in itself and in severe icing do a very effective job of coordinated anti-icing or deicing. 7. HEATED CABIN AIR DISTRIBUTION T. E. a. Stratification of ventilating air throughout the main cabin aft of the navigator compartment is distinctly noticeable in readings taken to date and last winter (1943-1944). b. Stagnation of cold air masses from the forward side of the main cargo door, Sta. 501. to Sta. 704, is also evident and was reported last winter. c. The above conditions are attributed to positive pressure of cold air masses radiating through the floor of the J compt. bulkhead 704, and through the ventilating louvres on the riser of the step into the J compt. This cold air is sucked out through the door openings that were heretofore mentioned. A. T. Relative data will be submitted to the contractor in the very near future. Rec. & Cone. a. In view of the subject aircrafts use as a troop and litter carrier, it is advised that the con- tractor improve the ventilating characteristics of the subject airplane. 5230 187 b. Since it is understood that the contractor is con- sidering thermostatic heater control, complete insulation of the main cabin is mandatory, as is a redesign of the ventilating system. INSULATION is not the ultimate answer. Thermostatic control will be very ineffective without a definite improvement in distribution. c. Photographs 17' 18 show the selective heater out- lets (spread and center) and the recessed floor return vents used on the C-54B. Note in Appendix 5, page 1. THE ELIMINATION OF ALL BENDS in the transition and flow ducts by placing the heater overhead in the main cabin (bunk compt.) and employing a single straight run. Appendix 5 also may be referred to for additional information on thermostatic control as suc- cessfully employed in the C-54B airplane. 8. PARKER FUEL SELECTOR VALVE T. E. a. External leaks around the shaft have been noted below —30°F. b. Internal leaks on three sides have been noticeable at any temperature for some time. A. T. a. Original valve removed and a new winterized Parker valve, P. W, C56-4177 was installed. This also leaked externally between —30 and —50° F. b. Th e original valve was returned to the Power Plant Lab. at Wright Field for investigation. Rec. & Cone. a. That the subject units are entirely unsatisfactory for their intended purpose, and do not justify yellow dot approval. b. That the old Adel selector valve gave no similar trouble for some time before they were removed in favor of the Packer, nor WERE THEY (ADEL) AS TROUBLESOME IN QUANTITIVE PROPOR- TIONS FROM THEIR INCEPTION ON SUB- JECT AIRPLANES. c. That the contractor consider the use of the Adel valve once again since it is recognized that the Packer unit is extremely critical. d. That the new Packer units above 656-301 series will replace the present valves as soon as they arrive at this activity. Douglas Aircraft Co., Inc. J. F. Hill, A. Zimmerman, A. A. Hershfield. C-54 Airplane The heater installation, both nose and main cabin, gave excellent results, operating satisfactorily at all conditions of temperatures, altitude and speed within the operational range of the airplane on which they were installed. Test data makes possible calculations which prove the heater capacity to be in excess of the heat requirements of the airplane with insulating blanket installed. The method of control by cycling the heaters gave excellent results in cabin temperature control. Temperature distribution was very good within the operating range of the airplane under all conditions of flight and loading configuration. The placement of cargo in relation to air outlets and inlets had a marked effect on the temperature Control. The litter installation proved exceptionally good for temperature distribution. Ventilation rates were satisfactory, averaging 19 CFM/person at normal cruising speed. The pilot’s and co-pilot’s cold air inlets are unsatis- factory, as is the side window defrosting system due to high pressure drop in the delivery ducts; also, valves in the duct system intended to shut off do not do so. The following recommendations are made: 1. That all C-54’s, A’s and B’s be brought to this general configuration to insure the best performance of the heating and ventilating system. 2. That the side window defrosting system be revised to obtain adequate flow. 3. That the shut-off valves be revised to incorporate positive shut-off. 4. That the foreward cabinstat be re-located from behind the bunk curtains. 5. * That the nose heater exhaust be extended approxi- mately one inch in length. 6. That the existing 5 gallon nozzles be replaced by gallon fuel spray nozzles. 7. That the control amplifier relay be changed to one of a larger capacity. 8. That the cold air inlets be revised for satisfactory operation. 9. That the forward toilet vent be revised to prevent odors from entering the crew’s compartment. 10. That a school be inaugurated to instruct crew chiefs and operators in the operation of the Heat and Vent System. 11. That further study be devoted toward humidi- fying cabin planes. INTRODUCTION Service reports have indicated considerable dissatis- faction with the heating and ventilating system as in- stalled in previous C-54 series airplanes in regard to tem- perature control, temperature distribution and reliabil- ity. The “E” system was designed to embody satisfactory solutions to all of these problems. A series of tests was therefore run to prove the satis- factory operation of the heating and ventilating system, under moderate and extreme temperature conditions, as installed in the C-54E airplane, and with any additional improvements deemed necessary to better performance. A C-54B airplane, Army Air Forces No.43-17157, was modified at the Santa Monica plant of the Douglas Aircraft Company, Inc. to incorporate the latest design features in the heating and ventilating system concurrent with present knowledge and proposed service changes 188 5230 The following items were installed, changed or noted; 1. New ignition system embodying special spark plug and high tension spark ignition. This insures in- stantaneous ignition at all altitudes and temperatures. 2. Air bleed around spray nozzle. This moves the combustion area forward in the heater keeping the plug and spray nozzle clear of carbon. 3. Fuel flow regulator and new fuel system in place of the air flow regulator. This controls the air fuel ratio without introducing pressure drop in the combustion air stream, allowing high altitude operation. 4. New ductstat compensator in the control system circuit for the main heaters. This reduces the tempera- ture swing in the ventilating air stream to the cabin to a negligible quantity. 5. Variable Fenwall control for the nose heater. This permits the pilot to control the heat output of the nose heater and thus control the temperature of the crew’s compartment. 6. Canvas bulkhead below the floor at fuselage Sta- tion 858. This prevents ventilating air loss into the tail cons, and controls temperature distribution in the cabin. (Refer to report No. SM10936). 7. Jet—or—spread-type Anemostats. These Anem- ostats give the cabin attendant control over the tempera- ture distribution in the cabin. 8. Cabin air exhaust grilles. The Great Falls modi- fication center installed a cabin insulating blanket which covered the intended air outlets. Therefore, exhaust grilles were necessary to obtain proper ventilation and temperature distribution. 9. Felt pad under cabinstat. This aids in elimination of error in the control system by lessening conduction losses from the cabinstat to the outside skin. 10. Army modification for windshield deicing and cabin insulation. 11. Valve handle on valve aft of cabin heaters. This allows operator control of air flow and is for use in case cargo only is being hauled in the cabin. Following these modifications at the factory, the airplane was flown to Minneapolis, Minnesota to the Ice Research Base, and the instrumentation for the test was installed. Tests were then conducted while the ship was flown to Ladd Field, Fairbanks, Alaska, where the test program was completed. 1. All configurations of seating arrangements, litter installations and cargo loads were investigated for tem- perature distribution in the occupied areas. 2. Operating characteristics of the heaters were ob- tained at various flight altitudes and speeds within the operating limits of the airplane on which the system was installed. 3. Ventilating system characteristics were obtained under various flight altitudes, speeds and attitudes. 4. Functional characteristics of the Army modifica- tion windshield deicing were observed and operational details of the side window defrosting system were checked. 5. Data were obtained to prove the satisfactory op- eration of the heater cycling control system as applied for temperature control in the occupied areas. The airplane was flown in the most extreme tempera- ture conditions obtainable, and data taken which would permit calculations to prove that the system as installed was capable of satisfying the most stringent conditions ever likely to be encountered. CONCLUSIONS 1. Heaters— Satisfactory operation of the heaters in this installa- tion can be expected under any condition of speed, tem- perature or altitude within the operational range of the airplane on which they are installed. If the installation is to be used in other C-54 series airplanes with higher operational ceilings, consideration should be given to the installation of \y2 gallon spray nozzles in place of the 5 gallon nozzles now in the main heaters. Ample heat capacity is available from the installation to maintain comfortable temperatures in the cabin and crew’s quarters under the most extreme conditions of speed, temperature and altitude likely to be encountered with the airplane. A 4]/2 gallon nozzle in the main heaters will supply ample heat to meet requirements. 2. Control— a. The variable Fenwall control on the nose heater functions satisfactorily. However, a lower temperature setting control would improve the operational charac- teristics of the installations. b. Cyclic control as applied to the main cabin heaters on the test installation gives very good results in cabin temperature control. The success of the system is probably the result of the combination of the following items: (1) New ignition system insuring instantaneous ignition. (2) New ductstat reducing the time lag in the control circuit. (3) Air bleed around the fuel nozzle insuring continued instantaneous ignition by prevention of carbon deposits on the electrodes of the spark plug. (4) Fuel flow regulation insuring proper air fuel ratios at higher altitudes. Although no failures occurred in the control system, inspection of the relay contacts in the amplifier, after the test, indicated a larger capacity relay might be desirable. Fairchild Camera and Instrument Corporation IV. C. Edwards On 13 January I arrived at Ladd Field, Fairbanks, Alaska, to observe the results of cold weather tests being conducted by the Army Air Forces on aircraft camera equipment manufactured by the Fairchild Camera and Inst. Corp. Immediately upon my arrival, I reported to the Corn- 5230 189 manding Officer of the Cold Weather Testing Detach- ment, and then visited the photographic huts which served as headquarters for the camera test. Here I met Captain Lewis, Lt. Schwartz, W/O Goodnight of CWTD, Prov- ing Ground Command, and W/O Balcomb from Wright Field, who were actively engaged in testing procedures. My stay at Ladd Field was to be limited to two weeks. During this period I intended to look over the aircraft camera and correct any possible mechanical troubles, discuss the operation of the equipment during the period prior to my arrival, offer suggestions to remedy any current failures during operations, and generally to observe the behavior of the cameras while they were used in extreme sub-zero weather. EQUIPMENT BEING TESTED The Fairchild cameras being tested included the K-22-6", 12", 24", and 40" models; the K-17B-6" and 12" models; K-18A; K-19B; and K-20 cameras; A-5A magazines; and the B-3B intervalometers. PREVIOUS PERFORMANCE OF EQUIPMENT In discussing the weather prior to my arrival with the Cold Weather Testing Detachment, I was told that to date the average temperature has been approximately 10° below zero. However, at one time for a few days the temperature was 54° below. Flights have been scheduled to different parts of Alaska where the tempera- tures were well below —50°. Today’s flight at 30,000 feet was 64° below. In discussing the equipment prior to my arrival with Captain Lewis and W/O Balcomb, they said compara- tively few complaints have been registered against the Fairchild camera. The majority of complaints were due to their being disassembled and reassembled incorrectly after leaving the Fairchild factory. The disassembly had been done by the Army Depot to relubricate and win- terize the cameras. The A-5A magazine had to be dis- assembled by the Cold Weather Testing Detachment to clean the grease from the metering clutch spring before the magazine could be used. The magazines brought in from stock that I checked were found to have the meter- ing clutch spring packed with grease. INFORMATION RESULTING FROM OBSERVATIONS 1. Power cable from A-5A magazine to camera body should be three inches longer, 2. Photocell cable K-19B. In extreme low tempera- tures the cable will freeze making it next to impossible to handle, also outside rubber cover will crack. 3. When cameras are winterized, all grease should be removed from the power receptacle and cable plug. 4. Focal plane curtain on K-22 camera should be made from more pliable material. The material now being used tends to stiffen in sub-zero weather and retards the action of the curtain. 5. There seems to be a question as to which of three greases is the beter; ANG-3a, TG-223, or TG-455. a. ANG-3a has proven satisfactory in sub-zero weather. b. TG-223. K-22, 24", No. 42-58490, was greased by Wright Field, with TG-223 and sent to Panama last summer for the test, then sent direct to the CWTD at Ladd Field without winterization or changing the grease. To date the camera has operated satisfactorily in sub- zero temperatures, c. TG-455 is being tested; however, not much seems to be definitely known about it as yet. General Electric Co. J. M. Robertson P-59 AIRPLANE I checked the oil in both units before removal from the plane and found that both starting fuel pumps were leak- ing kerosene through the seals. This brings the starting fuel pump failures to a total of nine. Removed Unit numbers are: L.B. 734119; R.H. 734136. Saturday, February 10, the plane was removed from the hangar with the two new units installed. A trial run was made to check for leaks and any other possible mal- function. This trial run proved very satisfactory, with one small fuel leak found in the L. H. unit. After ground run up and check, Captain Markey made a one hour flight and was satisfied with the operation of both units. No report of fumes in the cockpit was reported after this flight. Sunday, February 11, an attempted start was made on the units. Due to burned out booster coils this start failed. Proposed flight for Sunday was cancelled with prospects of cold weather for tests on Monday, February 12, 1945, with estimated outside air temperatures forecast for be- low —20°, Monday, February 12, 1945, new booster coils were installed and cold starts were made on both units. The outside air temperature was —35°. The P-59 airplane was left outside on the line all weekend through Monday for these cold starts. There were a number of planes on the line, but the P-59 airplane was the only plane to start without heat application to the units or any part of the system at this —35° start. During these starts, we were using AN06 oil as a lubricant. High oil pressures were encountered on both units. These high pressures exceeded the range of the gauge, which is a 25 pound gauge. Oil flow checks were made through petcocks installed in the left hand unit oil system. Oil flow was considerably slower in com- parison to normal conditions or even a —5° temperature*. The bearing temperatures remained normal during these starts and runs. 190 5230 We were unable to build up fuel pressure on the L. H. unit. The highest pressure reached was between 70 and 95 pounds. Due to the lack of fuel pressure, our R.P.M. was limited to 5000 R.P.M. A new main fuel pump was installed on the left hand unit. This new pump solved our problem, and we were able to get the necessary fuel pressure. Since there was no malfunction with the right hand unit, an hour’s flight was made. During this flight the pilot took thermocouple readings and checked landing gear, etc. Upon completion of this flight, the oil was drained from the right hand unit and WS804 oil was used to replace the AN06A that was removed. Tuesday, February 13,1945, cold starts were attempted again with a —38° temperature. The left hand unit, which is our instrumented unit, has all lagging removed from the lines. At this —38° temperature we were un- able to start the left hand unit again. We encountered the same trouble as in the previous day, namely low or in- sufficient fuel pressure. Pressure registered at this attempted start was 35 lbs. I recommended that heat be applied to the gear casing accessories, dump and drip valve, fuel manifold ring, and also the throttle and barometric. I believe that there were ice formations in the fuel system, and that by apply- ing heat to the system this theory could be checked. How- ever, since changing main fuel pumps the previous day had solved our problem, those in charge decided to change another main fuel pump. Since this change over- took place outside, heat had to be applied to enable the crew to work under the extreme cold temperature. 1 believe that this heat application solved our problem, because on disassembly of the first main fuel pump re- moved it appeared to be in good working condition with no visible defects. The number of the pump removed is Newpert No. 12 587-B, Serial No. PE242, R 62-19895”. Tuesday afternoon, the second main fuel pump was installed. Another start on this left hand unit, with a second new fuel pump installed, was not attempted until Wednesday, February 14, 1945. Wednesday, February 14, 1945, a start on the left hand unit was attempted at a 34° outside air temperature. This was the first start attempted with the second new fuel pump on this left hand unit. We were able to get only 35 to 40 pounds fuel pressure, thus starting of this left hand unit failed again. I then recommended that heat be ap- plied to the system, as suggested before. Heat was ap- plied and attempts were made to centralize the heat on one accessory at a time. This failed because the equip- ment available was not adequate for such an application. The barometric from the test stand was installed on the plane, and another start was attempted on the left hand unit. The left hand unit started this time. How- ever, we had a temperature rise from —34° to —7°. I believe that this rise of temperature along with the heat application to the unit could have thawed out and broken up any ice formations in the system. To further prove this theory and eliminate the fact that changing of barometrics was the solution to our problem, I installed the baro- metric that was removed from the plane on to the unit on the test stand. The barometric, which was removed from the plane, worked fine on the test stand and no malfunctions were noticed. On starting the left hand unit on the plane, we had 40 pounds fuel pressure for about 5 seconds. Under the same throttle setting as the 40 pounds were observed for five seconds, a sudden change of pressure was noted, at which time the fuel pressure surged to 75—to 100 pounds at which time the unit fired. This sudden change of pressure could have been ice formation in the system breaking loose. In the starting of the left hand unit the starting motor turned out and the starting fuel pump failed. Failure of the starting motor was not mechanical failure and was no fault of the motor or unit. The starting motor burned out because a great deal of kerosene got into the motor from fuel pressure out put checks on the starting pump and main fuel pump. Failure was caused by the starting motor insulation catching fire and burning out. Failure of the starting pump was caused by pickups On the pump casing uhder the gears. Results of these pickups and casing score were that the pump froze and could not be turned. Two flights have been made since a new starting motor and starting pump were installed on the left hand unit. Both flights went off very well and no further troubles were encountered. Arrangements are being made for the P-59 airplane to fly back to San Bernadino, California, instead of back to Dayton. No definite date has been made as to just when all the tests will be completed. However, I expect to leave here some time between the 3rd and 17th of March, at which time I will accompany the P-59 to its destination in the States as requested. Monday, February 12, a calibration run was made on the test stand with the outside air temperature —35° This calibration run was made with the barometric dis- connected, and a needle valve was used to replace it as mentioned in a previous report. AN03L light oil was used as a lubricant for the first start. This oil was very unsatisfactory at this —35° temperature. A flow check showed us it poured like a heavy molasses, and the oil pressure registered on this first start was 175 pounds. Due to this extreme oil pressure, we did not attempt to run the unit over four or five minutes. During this time our bearing temperature remained normal. AN03L light oil was drained from the system and an approximate 2y2 hour calibration run was made. Reading and data from this run are attached to the re- port. Monday, at midnight, we drained the AN03L light oil and replaced it with PPO-280. Tuesday, February 13, 1945, a start was made. The outside air temperature was —38°F. The oil used on this start was PPO-280, and the oil pressure on this start was 90-100 pounds. We ran the unit for 4 minutes on this first start. A second start, on which the indicated oil pressure registered 80 pounds at start, was made. Following this start, a 2 hr. 40 min. calibration run was made dur- ing the run. Oil pressure registered from 45 to 75 pounds, and the bearing temperature remained normal. Wright Field Power Plant representatives requested an overspeed run during this calibration run. We reach- ed top R. P. M. of approximately 16,925. In order to reach this R. P. M. we registered an indicated fuel pres- sure of 795 pounds. Thrust from this R. P. M. was 2522 pounds, which is the greatest amount of thrust re- corded on any of the tests made to date. On completion of this run we disconnected the gover- nor from the system and connected the in and out line of the governor together. The reason for this was to decrease our fuel pressure on the overspeed runs, as shown on the attached data sheets. We also removed the PPO-280 oil and replaced it with AN06A. February 14, a calibration run was made with AN06A oil, and the governor was disconnected as explained. 5230 191 This was a one hour run, during which five sets of read- ing, including an overspeed run to 17000, were taken. There was a noted decrease in thrust as our outside air temperature had reached —14° when our last reading was tawen. However, at 17,000 R. P. M. we did get 2351 pounds thrust. With the governor disconnected from the system and the fuel in and fuel out lines con- nected together, our main fuel pressure dropped from 795 pounds to 625 pounds. The lube oil pressure remained normal throughout the run. 10 to 12 pounds lube oil pressure remained constant with this AN06A oil in the system. Lockheed Aircraft Corporation Lee C. Chambers 1. I wish to call your attention to a recent Technical Order issued concerning “Oil Diluent Boil Off”. In a previous report (C. W. T. Report No. 4), I remarked that the V-1710-11 & 113 engines would not scavenge diluted oil as well as the -89 and -91 engines. It is as a result of this reported condition that T. O. -75FF-44 was written. However, I believe the T. O. in question paints a blacker picture of the situation than actually exists. All scavenging test are conducted by pulling military power during take off and for a period of 5 minutes, then power is reduced to maximum continuous for 15 to 20 minutes. If excessive spewing occurs during this run, then the en- gine is considered unsatisfactory for dilution at the per- centage tested. Since very few P-38’s will ever be actually operated under the above described conditions the situation looks worse than it really is. 2. It is also posible to dilute to 30%, take off, and maintain military power for five minutes without spew- ing—provided the pilot uses manual oil temperature con- trol, maintaining oil temperatures at 40°C. or below. 3. The P-38 Project Officer, Capt. Accord, contended that he could scavenge 30% diluted oil by using the method described above. To give a practical demonstra- tion, a test was conducted on one of the C. W. T. P-38’s. A summary of the test and results are presented herewith: a. Dilution—• (1) The oil tank dip stick was checked before dilution began, and 9 gals, of oil was indicated. After 7 minutes dilution, the tank level was found to be gallons. This amounted to 3j4 gallons gasoline added, or approximately 30% dilution. b. Warm Up— (1) The engines were started and the oil tem- perature regulator shutters were placed in the full closed position. The oil temperature read 30°C. and the oil pressure indicated 65#, c. Take Off—Flight (1) Just prior to take off the oil temperature regulator shutters were partially opened. Take off was made at 54" MP and 3000 RPM. This power was maintained for 5 minutes, all during the run careful check on oil shutter position was made to assure an oil temperature between 35° to 40°C. Oil pressure remain- ed at approximately 70 P. S. I. A check was made at this power to see the relationship between oil pressure and temperature. The oil were fully opened momentarily, and the temperature dropped to 20°C. and the pressure increased to 80 P. S. I. The shutters were immediately returned to a position which maintained a 35° to 40°C. oil temperature. After 5 minutes of military power the settings were reduced to 30"—2200 RPM. This power was maintained for 25 minutes, and the oil temperature was manually controlled at 50°—60°C. Oil pressure in excess of 60 P. S. I. was maintained at that temperature. The oil shutters were then placed in “Auto- matic” and an additional 30 minutes of flight was main- tained at 2200—30". Oil temps, ranged from 77° to 81 °C. and oil pressure read above 60 P. S. I. No oil spewing occurred during any part of the flight. d. Conclusions— (1) It is apparent that in an emergency, military power may be held for five minutes on a P-38L aircraft, which has been previously diluted to 30%, providing the engine oil temperature is manually controlled at 35°— 40° C. It is also believed that max. continuous may be held for an additional 25 minutes in place of the 30"— 2000 RPM, as described above, since oil spewing general- ly begins during or immediately after take-off (as soon as high oil temperatures are reached). (2) It is believed that no harmful effects to the engine may result, since 30% diluted oil at 40°C. is still O. K. from the viscosity standpoint. The satisfactory oil pressures obtained would indicate this. (3) Of course the above procedure could not be considered as a permanent fix for “oil spewing” problems, but until Allison corrects the trouble it could be used whenever it is necessary to pull military power for five minutes, and maximum continuous for fifteen minutes after take-off. If power is reduced immediately after take-off, no serious problem exists. (4) After the above described test run, there was more oil at the secondary drive seal vents than at the en- gine breathers, and neither was abnormal. 1. The subject trip was made at the request of Brig. General Harry Johnson, and was for the purpose of acquainting the 11th Air Force personnel with the use of carburetor heat as a means for preventing spark plug fouling while operating in extreme long range power cruise. It was requested that Capt. R. K. Acord, C. W. T. P-38 Project Officer; Mr. Caesar Benassi, Bendix- Stromberg C. W. T. Representative; and myself make the trip and assist in lowering the existing P-38 Fuel Consumption rate. 2. Our first stop on this trip was at Anchorage, Alaska. There we visited the Alaska Air Depot. At this base all of the PD12-K8-5 carburetors on the P-38L’s were being changed to K8-6 settings before delivery to the 11th Air Force. It was noted that several turbo-supercharger bearings had already been damaged by turbo torching as a result of operation with the excessively rich K8-5 192 5230 carburetor setting. These turbos were being replaced or repaired. 3. Considerable trouble was also noted with regard to Paul Henry Switch and Airesearch Screw Jack Con- trols on the Carburetor Heat System. I instructed the mechanics concerning Screw Jack Load Switches, their operation, and the importance of having the shutter stops properly set to avoid burning out the electric screw jack motors as a result of exceeding the screw jack travel limits before sufficient load is applied to trip the load limit switch. The inter cooler nose shutter stops can be very satisfactorily adjusted to eliminate the above de- scribed condition. However, the Turbo Inlet Elbow- Butterfly Screw Jack Actuator Linkage is very difficult to adjust to eliminate excessive screw jack travel limits, and all cases of Paul Henry switsch malfunctioning can- not be entirely eliminated without replacing switches or overhauling them as trouble is encountered. Enclosure (A) lists the number of malfunctions and failures en- countered thus far with Airesearch screw jack, Paul Henry carburetor heat switches, and also windshield defroster motors and heaters. Failures of the latter named item have been inconsequential and may be con- sidered nothing more than routine service difficulties. However, the abnormally high rate of failures and mal- functions of the screw jacks and carburetor heat switches, along with other operational difficulties, prompted me to take action as outlined further along in this report. 4. Upon reaching the 11th Air Force operational theater it was learned that the “three point carburetor heat control” (1) “OFF” (2) “INTERMEDIATE” (3) “FULL ON”, was unsatisfactory for their oper- ations. Both the “OFF” and “INTERMEDIATE” positions resulted in carburetor air temperatures which were too low for extended operation in long range, low- powder cruise; and the “FULL ON” position resulted in a carburetor air temperature which was too high. Thus, it was apparent that steps need be taken to give “complete control” of carburetor air temperature between the ex- treme of heat “OFF” to “FULL ON”. 5. The Fighter Group Commanding Officer was well aware of the fact that long range fighter escort missions are utterly impossible when low carburetor air tempera- tures exist, as he was in charge of the simulated escort mission tests conducted last winter, wherein all of the P-38’s used were forced to land 520 miles short of their objective as a result of spark plug fouling and poor engine efficiency. Consequently, he was very desirous in ob- taining satisfactory operation of the carburetor heat system. 6. I suggested that it was possible to modify the carburetor heat control system and' obtain the desired control of carburetor air temperature; that is, providing he could obtain Air Force approval on the necessary changes. I was requested to outline these changes for purposes of obtaining Air Force approval. The following outline of changes is presented along with comments as to the reason for suggesting the change. It will be noted that the final carburetor heat configuration is identical to John Pinaive’s original design proposal before Wright Field insisted that we sacrifice complete carburetor air temperature control for the advantages to be gained by having both intercooler nose shutters and turbo inlet controls on one unit control system. Carburetor Heat Control System Changes a. Turbo INLET (Hot or Ram Air) Controls 1 Change: (a) Remove Airesearch screw jack actuators. (b) Substitute standard P-38L manual con- trols (Desert Air Filter Controls). 2. Reason for change; (c) To eliminate the dangers attendant with Airasearch screw (jack and Paul Henry switch malfunc- tioning. (b) To allow independant operation of turbo inlet air valve, and intercooler nose shutter operation, which makes a complete control of carburetor air tem- peratures possible. h. Intercooler Nose Shutter Controls (1) Change: (o) Rework travel limit stops to eliminate overtravel of screw jack actuator before load switches can operate. (b) Remove Paul Henry switch and substitute two B-9A switches to control intercooler nose shutter positioning. (2) Reason for change: (a) To eliminate possibility of burning out screw jack motors. (b) To eliminate danger of having an inoper- ative carburetor heat switch. (c) To make complete control of carburetor air temperature possible. c. Alternate proposal for intercooler nose shutter operation in the event kits are made available as shown in P-38/SB 290, which links the intercooler nose shutter to the exit flap and allows positioning of the nose shutter by varying the amount of closure on the exit flap toward the end of its travel. 7. The changes outlined above were submitted to Air Force and were approved for installations on the 11th Air Force P-38L’s. Work has begun to accomplish both items A and B as outlined. These modifications must be completed before any long range fuel consump- tion tests can be accomplished. I would like very much* to return to the Aleutions to assist in completing these modifications and be present during the fuel consumption tests, for I feel that I could assist still further in this problem; but, since my draft board will not extend my leave of absence beyond April 1st, I guess I will be re- turning very shortly. 8. Using as a guide the results of long range low power tests conducted at this station, and a report by the Allison Experimental Division titled “Effect of Cold Air on Engine Roughness”, the following carburetor air tem- peratures were submitted as desirable for long range operations: Engine R. P. M. Desired C. A. T. —°C. 1600—2000 +20° to +30° 2000—2300 + 10° to +20° 2300—3000 — to-(-10o DO NOT EXCEED -f 40°C. A. T. AT ANY POWER Should these carburetor air temperatures be maintained, it is this writer’s firm belief that excessive spark plug fouling will not occur within the time limit dictated by fuel capacity and range. 9. One of the main factors contributing to the ex- cessive fuel consumption experienced by the 11th Air Force on their P-38’s was the pilot’s limited knowledge of proper power selection, R. P. M. vs. M. P., and a ten- dency to operate at extremely high R. P. M. After 5230 193 talking with the pilots, it was learned that the high R. P. M. was used in an attempt to prevent spark plug fouling. However, I believe they were using even higher R. P. M’s. than necessary for that purpose. Neverthe- less, improper power setting were an outgrowth of the necessity to eliminate plug fouling. Capt. Accord gave the pilots instructions on proper selection of economical power, using lof R. P. M.’s. and high manifold pressure, and at the same time warned them against exceeding the B. M. E. P. limits of the engine. 10. Mr. Benassi explained the dangers of leaky carbu- retor vapor floats as concerns the loss of gasoline through excessive vapor (gasoline) return to the reserve tank and its possible loss by flowing out the tank vents. He also suggested a check be made on these vapor returns and the altitude compensators before each long range mission. 11. The officers and enlisted men of the 11th Air Force were very cooperative, and I’m sure appreciated the as- sistance we were able to render. 12. While checking over the P-38L’s fuel system the following points were discerned; a. The PD12-K8-6 carburetors have a wide angle poppet valve and therefore do not have a #70 drill hole in the clover leaf. b. The two check valves in the fuel system ( (1) outer wing tank to strainer, (2) selector valve to strain- er) will not allow bleed off of fuel pressure in the carbu- retor. c. Due to the check valves and the absence of a drill hole in tht clover leaf, high pressures are built up in the carburetor after a flight and resulting accumulative heat from the engine warms up the carburetor. This condition may cause trouble in very warm clim- ates, in that the high pressures may stick even the wide poppet valves. A drill hole in the clover leaf is unsatis- factory, especially with high boost pump pressures, in that a great deal of fuel may be dumped into the engine supercharger scroll and thus create a backfire hazard. Therefore, I recommend a combination check and relief valve be installed in the system which will by-pass the main system check valve and thus allow bleed off of carburetor fuel pressures while on the ground. 13. While in the Aleutians, some interesting effects were observed with regard to windshield deicer panel operation. Due to the high relative humidity in that area, the deicer panel made a wonderful rain chamber. Moisture in the air, passing through the intensifier tube and hence to the double paned windshield, would con- dense and collect between the two panes of glass. This would occur only on take-off, but the situation was ex- tremely dangerous for visibility was greatly impaired. It was found necessary to take off with the right hand cockpit heater, valve in the “FULL OFF” position to prevent fogged windshield. In flight, the windshield became clear again. Carburetor Heat Test Report PURPOSE: 1. To determine whether sufficient carburetor air heat rise may be obtained with the P-38L carburetor heat configuration to satisfy requirements as outlined in the "Aircraft Designers Handbook”. 2. To determine the effect of carburetor air tempera- ture on engine performance in long range cruise. 3. To determine the effect of carburetor air tempera- ture on fuel consumption in long range cruise. 4. To determine the effect of carburetor air tempera- ture on engine warm up. METHOD OF TEST: 1. “Aircraft Designers Handbook” Requirements. a. Due to the lack of extremely cold weather this test was conducted with —18°F. outside air temperature in lieu of the —40° F. O. A. T. as required by the Design Handbook. b. The aircraft was flown at 2,000 feet M. S. L. altitude, with 65% power (2300 RPM—35" M. P.), carburetor heat "on” and “off” ; the carburetor air tem- perature was recorded for both conditions. 2. Engine Performance in Long Range Cruise. a. The aircraft was flown at long range cruise power on four separate flights, each of four hours duration. Two flights were conducted with carburetor heat "on” and two with heat "off”. b. These flights were conducted at 1600 RPM and manifold pressure was adjusted to maintain 170 IAS to simulate a bomber escort mission 3. Fuel Consumption. a. It was planned to conduct comparative fuel con- sumption tests with carburetor heat “On” and "Off”, however leaky fuel selector valves prevented accurate tests in this respect, so the idea was necessarily aban- doned. However, sufficient evidence was collected to indicate appriciable saving in fuel may be made by proper control of carburetor air temperature. This evidence is pointed out in the conclusions of this report. CONCLUSIONS: The P-38L carburetor heat configuration will meet the requirements as out lined in the "Aircraft Designers Handbook”. An outside air temperature of —40° F. was not possible for this test, however, a heat rise of 122°F. was recorded at 65% power (2300 RPM—35" M.P.), 2000' M.S.L. altitude, and with an outside air temperature of—18°F.; therefore it was concluded the carburetor heat system is capable of creating a 90°F. heat rise with an O.A.T. of —40®F. 2. Engine performance is greatly improved by the use of carburetor heat when operating in long range cruise power, a. Spark plug life may be lengthened by as much as 70%. b. Engine roughness due to low carburetor air temp- erature and attendant vaporization and distribution diffi- culties may be eliminated with the application of carb- uretor heat. 3. Indications that an improvement in specific fuel consumption may be expected with proper control of carburetor air temperatures was observed. a. An increase in I.A.S. was affected only by in- creasing the carburetor air temperature, (RPM and manifold pressure remained constant). It is also logical to assume the mixture became leaner as the tempera- ture increased since the air density was less at equal 194 5230 RPM and manifold pressures. In other words a greater air speed was obtained with identical RPM and MP, but with less fuel consumption. b. Another fuel saving, resulting from the use of carburetor heat, may be anticipated when flying long range escort missions, due to the fact that periodic high power engine run up for purposes of cleaning out spark plugs is not necessary when sufficient carburetor heat is applied. c. For reasons as stated above, it is concluded that a minimum carburetor air temperature of plus 20°C. should be maintained when operating in long range cruise. The amount in excess of 20°C. should be kept to a mini- mum in order to avoid any loss in engine volumetric efficiency. d. It is concluded the tactical advantages which may be made available through proper carburetor air temp- erature control should be more throughly investigated. 4. Cold starting and engine warm up are considerably improved with the use of carburetor heat. a. The tactical advantage is considerable since a minimum of 50 per cent engine warm up time may be saved, and service life of the engine and accessories will be lengthened also. b. By utilizing carburetor heat, low power ground operation may be performed for an extended period of time without danger of spark plug fouling. This allows lower taxi RPM and reduces the danger of taxi acci- dents on icy runways; for the same reason, brake life may be lengthened. Northrop Aircraft, Inc. C. IV. Harris, Leo Callings. Object This report is written to summarize the data and re- sults obtained from the operation of P-61B airplane AC 42-39402 by E.T.O.U. of Wright Field. Procedure All test data contained herein was obtained at the re- quest of Northrop personnel and through the efforts of the pilot Project Officer, Capt. H. J. Andre. The dis- cussion is segregated into sections dealing with the engi- neering design groups affected. Conclusions 1. The temperatures prevailing during this year’s cold weather operations were not low enough to pro- vide for test data which would allow definite predictions as to operations at —65°F. 2. The intercooler shutter installation on this airplane is not entirely satisfactory in that it does not completely seal off the flow of air through the intercoolers. 3. Satisfactory operation of the engine breather lines can be obtained by lagging or insulating the full length of the breather line providing that the production routing of the line is changed to exit aft of an exhaust stack similiar to the installation used on the R.H. side of sub- ject airplane. 4. Rerouting of the oil tank vent lines .to avoid traps eliminated diffculties encountered last year on these installations. 5. Incorporation of insulated engine breather lines and elimination of traps in the oil tank vent lines elimi- nated low temperature difficulties to the extent that it is no longer considered necessary to install intercooler shut- ters on the P-61 A and P-61B airplanes. 0 The Simmonds-Corsey propeller control operated entirely satisfactory at temperatures as low as —54°F. 7. All drain cocks used on subject airplanes are entirely satisfactory for temperatures encountered during this winter’s test. 8. Water tank immersion heaters are not of sufficient capacity to maintain water temperatures above 32°F. 9. The heated line and pump system for maintaining satisfactory operation of War Emergency power, under low temperature conditions, is entirely unsatisfactory. 10. The cabin heating system is entirely inadequate for O.A.T. below -|-50F. 11. The defrosting and defogging system is unsatis- factory. 12. Operating condition resulting from the proximity of the cabin heater exhaust port to the ventilating air inlet make it impossible to use the heating system for ground operation due to the presence of exhaust gas in the ventiliating air. 13. Oil temperature maintained by the automatic flap control resulted in entirely satisfactory operating con- ditions. 14. It is concluded that the most practical way of main- taining adequate gun breach temperatures on this air- plane would be through the use of electrical “spot” type heaters on the gun. Packard Motor Company C. R. Jones 1. OIL DILUTION TESTS Enclosures—Oil Dilution Tests: Tests com- pleted on aircraft P-51D, No. 44-14476; engine V-1650-7, No. 330964, equipped with new type of scav- enger screen and 1scavenge lines, failed to properly handle any premixed diluted oil above 11%. Further 5230 195 tests were continued with 17% and 22% premixed diluted oil, and, from the pilot’s reports and observations, the engine showed an excessive amount of oil spewing. Enclosures—Oil Dilution Tests with Thompson Centrifuge Separator: Tests completed on aircraft, P-5 ID, No. 44-14476; engine V-1650-7, No. 330964, equipped with an experimental test unit, type known as Thompson Centrifuge Separator, successfully scavenged the gasoline vapors of 15%, 20%, and 30% premixed diluted oils. Recommendations: If higher premixed dilu- tions than 30% are contemplated, further tests with the Thompson Centrifuge Separator should be continued. Pilot’s report and samples taken indicate that 30% is close to the maximum of premixed dilution that the pres- ent unit will properly scavenge as now installed. Crankcase gases from the Thompson Centrifuge Separator were expelled below and aft of the experimen- tal test unit. Would suggest that further tests be con- ducted to determine the most advantageous position to release these highly volatile gases, due to fire hazard ; and to prevent the possibility of any gases or fumes entering the pilot’s compartment. a. Tests completed on aircraft P-5 ID, No. 44- 14484; engine V-1650-7, No. 324373, failed to properly handle premixed diluted oil of 11% and 20.5%. Further tests were concluded, and from past records 10% was taken as the maximum premixed dilution the engines, as now equipped with N. A. A. type of breathers, will prop- erly scavenge without too much loss of oil. 2. SYNTHETIC OIL AND COOLANT HOSES a. Aircraft P-51D, No. 44-14476; engine V- 1650-7, No. 33-964. Type of hoses installed: E 30, E 40 and E 80. Installation has been made on the following oil and coolant lines: 3 pieces, 2" E 30 Header expansion tank to coolant line (R. H.). 2 pieces, 2" E 30 Header expansion tank to coolant line (L.H.). 1 piece, 2~y2" E 30 Coolant pump to radiator. 2 pieces, 1 ~y2" E 40 Oil pump to Y drain. 1 piece, 1 ~y2f R 80 Oil tank to oil pump. The first 25 hours of operation, using the above hoses, gave no visible appearance of any cold flow, though noticeable was the continued loss of hose clamp torque value for the first 25 hours. Apparently it takes this pe- riod of time for the hose and hose clamps to become set. Original hose clamp torque was tightened to 25 inch lbs. and torque values as low as 5 inch lbs. have failed to disclose any coolant or oil leaks. The coldest weather these test hoses have been subjected to, as of to date, is —46° F.- Left side hose connection between expansion tank and coolant line was flown for 25 hours with a 2-inch space between expansion tank metal outlet and the metal coolant line. No defects were noticeable upon exam- ination, and the hose was reinstalled. Aircraft P-5 ID, No. 44-14484; engine V-1650-7, No. 324373, and air- craft P-51D, No. 44-14513; engine V-1650-7, No. 327381, have several test pieces of E 30 and E 80 hoses installed and tests as of today seem most promising. 3. COLD WEATHER STARTS a. Starting of a V-1650-7 or -3 engine at tempera- tures of —10°F. or less gives considerable trouble, due to very litt’e if any fuel vaporization and unequal manifold distribution. Results of this condition makes a very rough engine, due to spark plug fouling. After the engine has started running, this condition continues for 8 or 10 min utes, then several minutes of 1500 to 1800 R. P. M. is needed to burn sufficient residue from the spark plugs before the engine will run smoothly. Opening the spark plug gap setting to .022 has helped the spark plug fouling to a fair degree, with no noticeable difference between an .018 spark plug gap setting and a .022 setting, relative to making a cold start. Flight tests made with this spark plug gap setting have operated satisfactorily at altitudes of 35,000 ft. Heat rise by carburetor warm air is not sufficient to assist much during the warm-up period. The application of warm air through filter air ducts, prior to starting and during the warm-up period, decreases spark plug fouling and gives a smoother operating engine during warm-up. However, 8 to 10 minutes are necessary before engine oil and coolant temperatures become high enough for full power operations. Engines, during take-off at low temperatures, smoke and torch badly and continue to do so for some length of time. Recommendations: When using 100 to 130 Octane rated fuel at low temperatures, operating in this Arctic area requires more carburetor heat to assist in vaporiz- ing the fuel. Flow bench one P. D-18C1A carburetor at the min- imum fuel air ratio for test flight. This would assist toward drawing some definite conclusions as to the cause for so much smoke to be present in the exhaust. 4. COOLANT LEAKS Aircraft PS1D, No. 44-14484; engine V-1650-7, No. 324318; Coolant pipes inlet, part No. 608758, on both A and B cylinder block, show coolant leaks at center and end connections from seal, part No. 608782. New seals were installed, and shortly afterwards leaks developed at the same locations. Tape was placed over the tubing where the leaks occured and the aircraft is still flying. a. A check made on two other engines, No. 32736S and No. 327381, revealed that the coolant pipes, Part No. 608758, were free and could be easily turned by hand. More noticeable at temperatures below —20° F. Recommendations: Further tests to be conducted with present seal and coolant pipe O. D. tolerance. 196 5230 Perfection Stove Co. E. J. Althouse A. Object of Trip The object of this trip was to observe annual winter tests conducted by Cold Weather Testing Detachment, Army Air Forces Proving Ground Command at Ladd Field, Fairbanks, Alaska, with particular reference to performance of Superfex Engine Heaters supplied by Perfection Stove Company, including 26 of the latest Model 460. At the conclusion of the tests at Ladd Field, all Army Air Force bases between Nome and Edmonton were visited ; at most of these bases the Motor Transpor- tation Officer and personnel using Superfex Engine Heaters were interviewed and at many, heaters were lighted and inspected. Several hundred heaters have been installed at these points. Returning home from Ladd Field, travel as far as Edmonton was with an Army convoy. Included in the convoy was an FI Tractor (Federal) upon which we had installed a 12 volt Model 460 Superfex Engine Heater. B. Test Set Up by Air Technical Service Command The specific test in which we had been invited to par- ticipate was one involving the installation and actual use of 25, 24 volt Model 460 Superfex Engine Heaters on as many C-13 Power Plants. We also had opportunity to observe the performance of 31 Model 452 heaters being used on the same work for the second winter, two of which were converted to Model 454 by the addition of electric ignitor kits. In addition to the 12 volt Model 460 heater used on the Federal Truck shown in Figs. 1 and 2, a second 12 volt Model 460 heater was installed on a C12—50 K.W. generator. Test procedure by Air Service Technical Command requested “ that in general, modified units (C13 Power Plants) be used in the normal manner on the flight line for starting and testing aircraft and that .... items .... be observed as to general operating character- istics with particular emphasis on the following: a. Perfection Heater (1) Flame extinction by wind or propeller wash. (2) Fire hazard. (3) Inspection and service periods. (4) Ease of out-of-doors -maintenance. (5) Coolant temperature rise obtained. (6) Other malfunctions and causes. (7) Effect of fan load on battery. Below are my observations on these items: 1. Lighted heaters were drawn through or left stand- ing in propeller washes repeatedly but none was ever extinguished by them. None was ever seen extinguished by winder even suspected of having been so extinguished. Heaters were occasionally found with lever and switch in operating position but this was not due to extinction by wind or propeller wash but to having run out of fuel. 2. No fires were caused by the Model 460 heaters but I did see two fires on C13 Power Plants caused by sparks in the engine control box igniting gasoline spilled during refueling of the supply tank, common to both the engine and the heater. One fire occurred on a Model 452 and was due, in my opinion to the shut-off cock having been left open, permitting gasoline to capillary over the burner and burner housing; this gasoline being ignited by flame blown from the bottom of the burner, probably by a down draft. The fire thus started, quickly consumed the combustible gasoline line and added two gallons of gasoline to the fire. Such a fire could not occur with the Model 460 because fire cannot be blown out of the housed- in burner, and forced draft makes a down draft into the heater practically impossible. 3. I observed no regular inspection and service peri- ods. On February 28th I removed the burner from No. 79 which is the unit Captain Wood and I had used most extensively for testing and which saw service on the line before and after we worked with it. Our records show 469 hours of use and with several weeks use on the line the unit probably had burned in the neighborhood of 600 hours, or well over half the burning time to be expected during a severe winter. The half of the burner away from the fuel inlet was as clean as though used for only a day; the other half had a coat of carbon and lead varying in thickness up to 1 /32" with here and there a projection of 1/16". On either side of the fuel inlet was a ridge about 1/8" high. The igniter looked like new. The igniter wick had its original shape and height and looked as though it would capillary gasoline as well as a new one but had lost some of its mechanical strength. This in- spection would indicate that the Model 460 need to be serviced only at the end of the season. 4. No out-of-doors maintenance was attempted but no repairs were required that could not have been accom- plished out-of-doors. 5. Coolant temperature rises were more than ad- equate ; we were obliged to operate the heater at under capacity to avoid boiling the coolant at around zero tem- peratures. We reduced the burning rate on 23 heaters by cuting away two-thirds of the width of the control wick and on the other two by cutting way one of the two layers of the control wick. Both systems worked satis- factorily but the one-layer wick is recommended for pro- duction. We found that tilting the heater might in- crease or decrease the heat output so it is recommended that heaters be kept reasonably level during operation. 6. • Other malfunctions and causes are: a. Three broken igniter wire terminals. The new connector now used at the igniter will correct this trouble. b. Three shorts in as many fused connectors which melted down the wiring; these probably were due to loss of the insulating sleeve. This trouble has been corrected by locating the fuse in the switch box. 5230 197 c. One float collapsed, due probably to cold shrink- ing the air in the float. This is an unusual occurence that could happen to any metal float. d. One burned out igniter, due to a short caused by its not being properly reinstalled in the burner; one ig- niter lost, probably for the same reason. Later type igniters seat more readily and are less likely to be found out of position. e. Clips holding control wicks in place broke off in changing wicks. This is not a normal service operation but has been corrected by bending clips with a radius in- stead of at right angles. /. Clips holding igniter wicks catch igniter. Our Engineering Department is studying this matter and will make necessary changes. g. Fire would go out at low fire setting. This has been corrected by changing the position of “low” on the guide. h. The most common cause of heater failure was a dead battery. While such failures cannot be charged to the heater, it is recognized that it would be more useful if the frequency of dead batteries could be reduced. The same thing could be said about the C13 Power Plant itself which depends upon the same battery. Therefore, we recommend that, the installation of some such instrument as the Hickok Electrical Hydrometer be considered for each C13 Power Plant This would enable a crew member to quickly and easily determine when to allow the unit to run to recharge its battery. 7. Tests showed that the effect of the fan load on the battery was negligible. C. Other Tests, Suggestions and Recommendations 1. No provision for warming the battery had been made in designing the C13 winterization kit. We ran battery warming tests, first using exhaust gases from the heater (see Figure 4), and later coolant circuits. The exhaust gas method not only did a better job of warming the battery but also added desirable warmth to the oil and used less fuel. Then too, the exhaust gas method eliminates the need to watch shut-offs to the battery cir- cuit in warm weather, since coolant from a running en- gine could overheat a battery. In designing any new kit, provision should be made for warming the battery. 2. A canvas cover is hard to handle, may catch fire or get lost. An all metal engine compartment with louver covers that can be slid to an open position or removed during the summer is preferable. The engine compart- ment floor should be made of metal rather than plywood. 3. A Zenith sediment trap was included in the fuel line of each 452 and each 460 installation; no stoppage of fuel line due to ice or any other cause was experienced. The yarn filter on the inlet fitting is preferred over the screen formerly used. 4. An all-metal fuel line, not too rigidly installed, should be used wherever possible because of the addi- tional fire hazard experienced with combustible feed lines. It a flexible, non-metallic section of fuel line is necessary, it should be at a point remote from the heater. 5. The fuel tank should have a gauge and be installed outside the engine compartment and away from the heater. Great care should be exercised in connecting fuel tank to heater to avoid possible leaks. 6. Screw holes on combustion chamber used to se- cure top cover should be moved 45° from their original location so as to be more accessible after heater has been installed. This change will be made in design of heater. 7. Four or five feet of 12 gauge wire should be fur- nished with each heater to avoid the necessity of requi- sitioning small amounts at the time of installation, and the possibility of installing heater with wire having excessive resistance. 8. A more rigid switch support was suggested, and the Office of Chief of Ordnance, Detroit has suggested that motor vehicle controls be on the dash rather than on the heater. For the C13 Power Plant it is recommend- ed that controls remain on the heater. A new control is being developed so that it may be mounted in either lo- cation at time of installation. This control will be more rigid than the one tested at Ladd Field. 9. Shake tests conducted by Office of Chief of Ord- nance showed a tendency for operating lever to shake down. No such tendency was observed on Cl3 Power Plant Installations nor on the FI Tractor on the twenty- one hundred mile trip from Ladd Field to Edmonton, much of it over exceedingly rough terrain. 10. Test of the two types of resistors used to reduce the ignitor voltage from 24 to 6 volts showed that one of the one-ohm resistors built into the igniters burned out. We did have trouble with the external one-ohm resistor used with the Model 454; coolant ran into the wiring and shorted it. It is therefore recommended that the original built design be retained on the 460. 11. Redesigning the Model 460 so that a single motion would start it and another would stop it was sug- gested. Our Engineering Department is working on this idea and is of the opinion such a modification of the Model 460 could be made available for next year; this modifica- tion would probably involve but little more than replac- ing the present igniter and control unit. 12. To install the 25 Model 460 heaters on the C13 Power Plants we made use of kits designed originally for the Model 452 heater. To do this we were obliged to: (a) modify the heater and the mounting bracket, (b) procure wire, clips, and terminals, (c) procure a few pipe fittings, (d) procure an additional length of l/ copper tubing or else an entire new fuel line. We did the latter so as to eliminate the combustible fuel line. The first two installations each required the time of one man for two days. Less than one day for one man was required for each of the remaining 23. This experience leads us to believe that any other kit originally designed for the Model 452 or 454 could be quite readily used to install a Model 460. 13. We found that difficulty in cold starting the engine of Cl3 Power Plants began to be experienced at around 10° above zero. We recommend that heaters be lighted when temperatures drop to that point. 14. Inasmuch as sustained temperatures of less than —50°F are rarely experienced anywhere in North America or in any part of the world held by the enemy at any time during the present conflict, and inasmuch as no Ethylene Glycol and water mixture will remain liquid at temperatures lower than —56° F, it is recommended that cold room tests of cold starting equipment be held at temperatures not below —50° F. Tests such as those attempted at Wright Field by soaking at —65°F are entirely impractical. 198 5230 15. Engine Heater kits should be designed so the oper- ator can light and extinguish them without raising the hood and without kneeling on the ground, preferably performing all operations from the cab. Consideration should be given to making kits already in use comply with these requirements; this work probably could be done in the field with materials already at hand. D. Conclusions Models 452 and 454 Superfex Engine Heaters have done the job for which they were designed; engines start in cold weather when the heater has been lighted. Model 460, with its forced draft and other convenience features is a better heater; it was received enthusiastically everywhere it was shown. Especially liked were electric igniter, elimination of the long flue, its ability to burn in any kind of wind condition, freedom from fire hazard, and the easy access to its various parts. With the addition of the refinements outlined above, suggested by various people at Ladd Field, it will be still more convenient and practical. Pratt & Whitney Aircraft Dlv. C. F. Blakely 1. Free air temperatures during the past week have ranged between 30°F and —10°F. Because of these relatively mild temperatures, cold weather tests and engine operational difficulties due to cold weather have been held to a minimum. 2. The E.T.O.U. group at Ladd Field have com- pleted some of the preliminary propeller feathering tests at low free air temperatures using an auxiliary non- congealing oil and electric pump for feathering the propeller. One test conducted on a B-17 at 20,000 feet altitude and —30°F free air temperature resulted in an engine failure. The propeller was feathered for one- half hour, and when the pilot endeavored to restart the engine, apparently the governor did not function because the engine speed increased to 2,500 RPM. The engine will not be completely disassembled at this base, however, visual inspection indicates that due to the oil congealing, several of the lower cylinder valve rocker arm push rods were bent and the engine impeller was split. This test indicates the need of using adequate oil dilution at low free air temperatures prior to completely feathering the propeller should the pilot have any intention of un- feathering the propeller in flight. One of the reasons for the necessity of unfeathering the propellers is that a bomber with a feathered propeller is the one which enemy planes will readily attack. 3. Another A.T.C. C-47 has landed at this base with peculiar operational characteristics. This phenomenon occurs as follows; o. Usually after a few hours of flying or after the engine is thoroughly warmed up. b. Has been described as a beat, burb, shake, surge, cut-out, vibration, etc. c. The intensity may be anywhere from very violent to mild. d. The vibration is usually noticed only in the cockpit. e. There have been a few reports of yawing due to an apparent loss of power. /. The frequency of this phenomenon varies from a few seconds in the case of the violent surges, to a continual vibration in the case of the mild periods. The very severe surges, which have been reported, have lasted only 2 seconds or more. g. The phenomenon may occur once in a flight, several times, continually, or not at all for several flights and then suddenly re-occur. It usually starts out mild, builds up and then ceases. 4. The vibrations occur at the following conditions: a. Any combination of manifold pressure and engine speed. b. Oil, cylinder head, and carburetor air tempera- tures remain constant. c. Air speed, altitude and free air temperature do not appear to materially affect or determine the condi- tions which bring on the above malfunctioning. d. Carburetor setting, A.R., A.L., or Full Rich does not appear to influence this condition. Carburetors have been changed with no improvement noted. e. Airplane installations with the above charac- teristics have had their magnetos and all spark plugs changed with no improvement noted. Magneto checks in flight or on the ground do not indicate fouled spark plugs or malfunctioning magnetos. 5. The first impression of anyone hearing these re- ports is to say “cockpit trouble” with perhaps a little ignition and carburetor malfunctioning. However, the stories of the trouble are too numerous to entirely dis- credit and they all follow the same pattern. a. All cases reported have been with engines using synthetic oil which had been put into the system after several hundred hours of operation with regular oil. b. No trouble of this sort has been reported on installations which had comparatively little or no running time prior to the adding of the synthetic oil. c. In installations which were reporting this trouble, and which were then switched back to the regular oil, the trouble apparently cleared up. d. Since the synthetic oil is a detergent oil, large amounts of carbon, lead, and sludge are released when the synthetic oil is added to a system which has completed several hundred hours on regular oil. e. Probably not all of the foreign material released will find its way out of the engine. 6. Whether using synthetic oil in an engine which already has had several hundred hours with regular oil will definitely cause the above malfunctioning can only be proven by extensive laboratory tests. However, one way to correct the condition at this time appears to be the adoption of the policy of only using synthetic oil in new installations. 5230 199 7. The only theories which sound at all plausible as to why this malfunctioning may occur with synthetic oil are as follows; a. The adverse effect of using synthetic oil on spark plugs which have been specified for operation with regu- lar oil. b. A large amount of foreign material is removed from the engine a short time after the synthetic oil is added. An excess amount of this material may collect in the torsional vibration damper chamber in the rear crankshaft counter-weight. The “puck” may be break- ing loose some of the material when the violent vibration occurs which causes the engine to smooth out. The frequencies of this vibration are not the same as those of the torsional damper, however, since the DC-3 cockpit is critical at some engine frequencies, the beats felt in the cockpit may represent the composite resonance of several units in the installation. 8. We are anxiously waiting for a tear-down inspec- tion report from one of the engines which have been pulled for the above reasons. In the meantime, we will check all rumors of the above operational characteristics which appear at this base. 9. Any information on the effect of lead, carbon, and sludge deposits on synthetic oil will be appreciated, ♦ ♦ ♦ 1. A trip was made to the Army Air Base at Edmon- ton, Canada, for the purpose of attending the Army Conference on Operation with Synthetic Oil. The con- ference was conducted for the purpose of reviewing engine operation difficulties attributed to the use of the PPO-265 synthetic engine oil. The following persons were present: (1) Reports of engine malfunctioning generally occur during the warm spells preceding the cold periods in which oil dilution has been used with synthetic oil. (2) The effect of fuel dilution on synthetic oil is more severe than with regular oil. (3) Western Airlines are using synthetic oil in winter operation, but are changing the oil every 100 hours with much better success than other operations which do not change oil. (4) The lead compounds formed in the engine when synthetic oil is used are not the same composition as the sludge compounds formed with regular oil. 3. At this time it is next to impossible to select an oil which is best for all parts of the engine. From the oil manufacturer’s viewpoint, the modern engine should be built to use two different oils. One oil would be specified for lubricating the high temperature surfaces, such as cylinder walls; and the other oil would be specified for lubricating the comparatively lower temperature but higher pressure surfaces, such as main bearings, etc., low 4. Other items of note are: a. Tests indicate that the inter-facial tension of this synthetic oil is not as good as with the regular grade oils, i.e., the oil has a greater “creeping” characteristic. b. The oil has a slightly different effect on rubber compounds than the regular grade oil. There was an approximate 5% shrinkage of the rubber seals tested by soaking them in the synthetic oil. c. Engines with 600 or more hours of running time appear to be giving the most trouble. There have been five or more instances where engine malfunctioning has cleared up when the power plant installation was switched back to the regular grade oil. d. In one installation the trouble was cleared up by switching to LS-87 spark plugs, which is a hotter spark plug than the LS-86. This is not conclusive, how- ever, since a Carburetor Automatic Unit was changed at the same time, and several automatic units were inadvertently shipped from the factory with oxygen sealed in the bellows. e. Engine oil consumption usually increases when the synthetic oil is used, especially when the oil has been used for some time. 5. Synthetic oil has the following advantages: a. Low temperature advantage for cold weather starting, since it requires less dilution, b. Keeps the engine cleaner. c. Oil is less inflammable. Reports from the the- aters of combat indicate that most power plant fires are caused by oil leaks rather than fuel leaks. 6. At this time synthetic oil has the following dis- advantages : a. Lead sludge from this oil forms a type of putty, which may become heavy enough to cause malfunction- ing of the propeller and governor assembly. b. Although not conclusive, off-schedule engine changes appear to increase where operators have switched to synthetic oil. In some cases maintenance has increased as much as fifty percent where synthetic oil is used. c. The occasional so called “cut out”, occurring only in engines using synthetic oil, seems to be the chief complaint against its use, d. Since the oil has a greater tendency to “creep”, there is reason to believe that this oil is leaking past the impeller shaft oil seals in greater quantities than the regular grade oil. Lt. Col. Williams Captain Zimmerman Major Woodard Lieutenant Parker Major Britton Warrant Officer Olsen Major Anderson Major Gill Warrant Officer Everest William Weitzen Captain Miller Roger Savery Irvin Perras 2. Synthetic oil is fundamentally a vastly different oil than regular grade oils, i.e.: a. The slope of the synthetic oil viscosity index curve is less than the regular grade oil viscosity index curve. (1) The viscosity of the two oils is matched at 3000°F, (2) At 210°F the regular grade 1100 oil is a 100 second oil while the synthetic oil is an 88 second oil, (3) At 0°F the spread of the viscosity index of these two oils is terrfic. (4) At —20°F the regular grade engine oil becomes solid and the synthetic oil becomes a 35,000 to 50,000 second oil. b. The general lubrication qualities of the synthetic oil are believed to be approximately 50% better than regular oils. The oil should be far superior to regular grade oils at extreme high temperatures. c. Chemical composition of this oil is very complex and completely different from regular oil. The ignition temperature is higher than the ignition temperature of regular oil. d. The effects of the T. E. L. and gasoline on the lubrication qualities and spark plug fouling of engines using a synthetic oil have not been thoroughly investi- gated. 200 5230 Socony-Vacuum Oil Co. D. P. Heath In the operation of conventional aircraft engines at low temperatures, rough engine performance is fre- quently encountered. This roughness is sometimes caused by uneven distribution of the fuel to the various cylinders resulting from incomplete vaporization of the fuel. At the present time sufficient data are not available to estimate accurately the temperatures at which diffi- culties will be encountered with a given fuel and engine installation. Flight tests are now being conducted in an attempt to obtain this information. However, the gen- eral principles of fuel vaporization are well known and can be used to make a qualitative analysis of the problem. The basis most widely used in analyzing the effects of fuel volatility on engine operation is the equilibrium air distillation (EAD). An EAD is obtained by supplying a definite fuel-air mixture to an equilibrium-air-distilla- ton apparatus and determining the percentages of fuel evaporated for the various temperatures at which the apparatus is maintained. Since the determination of an EAD curve is a difficult task, a correlation for determin- ing such a curve from the ASTM distillation curve has been developed by Bridgeman (Nat. Bur. Standards, Research Paper 694, 1934). The effects of fuel volatility on engine operation can also be estimated from the vapor pressure relationships of the fuel. The following 2 “rules” are used in this interpretation: 1. The fuel vapor occupies all of the space available at the vapor pressure of the fuel. The available space in this case is governed mainly by the engine displace- ment and speed. 2. The fuel vapor pressure is a function only of the temperature and the percentage of the fuel evaporated. Inasmuch as the necessary vapor pressure data are not normally available, and a trial and error computation is involved if the vapor pressure relationships are used, the calculation of equilibrium fuel vaporization conditions in an induction system is usually based on an EAD. However, the two “rules” given above are quite useful in the interpretation of vaporization problems. The EAD curves of an average aviation gasoline are given in Figure 1 for a supplied fuel-air ration of 0.065 and absolute pressures of 20 and 28 in. Hg. and for 0.095 F/A and 20 in. Hg. From these curves it appears that at a manifold pressure of 20 in. Hg. and a fuel-air ration of 0.065, rough engine operation would be en- countered at mixture temperatures below 52°F. How- ever, the EAD curves represent equilibrium vaporization, a condition that probably does not exist in an induction system. In addition some induction systems can probably distribute a limited amount of liquid equally among the cylinders making complete vaporization unnecessary for satisfactory engine operation. If equilibrium vaporization is obtained, an EAD curve alone will not give a complete picture of the con- ditions existing in the intake manifold. Computations must be made using the EAD as a basis to show the effects of mixture ratio and manifold pressure. A set of these computations effects of mixture ratio and manifold pressure. A set of these computations for a 1710 cu. in. engine are given in the table at the bottom of the page. The amount of unvaporized fuel at equilibrium is an indication of the amount of liquid fuel the manifold will have to distribute and therefore may serve as a criterion of how rich the richest cylinders will operate. Similarly the fuel vapor-air ratio will indicate conditions in the leanest cylinders. Cases I and II in the above table show the effects of mixture ratio on equilibrium vaporization. Richer mix- tures cause a smaller percent of the fuel to be vaporized but cause a larger amount of fuel vapor to be formed. This brings about an increase in both the amount of unvaporized fuel at equilibrium and the fuel vapor-air ratio at equilibrium. The effect on engine operation of richening the mixture when vaporization difficulties are encountered would be to decrease the danger of detona- tion in the lean cylinders and to increase the amount of smoking and torching from the rich cylinders. The effect of manifold pressure on equilibrium vapor- ization is shown by Cases II and III in the above table. Higher manifold pressures cause a smaller percent of the fuel to be vaporized at equilibrium, but cause slightly more fuel vapor to be formed. This brings about an increase in the amount of unvaporized fuel at equilibrium and a decrease in the fuel vapor-air ratio at equilibrium. The effect on engine operation of increasing the mani- fold pressure when vaporization difficulties are encount- ered is to increase both the danger of detonation in the lean cylinders and the amount of smoking and torching of the rich cylinders. Increasing the mixture temperature by either increas- Case 1 Case 11 Case III Manifold Pressure, jn. Hg 20 20 28 Engine Speed, r.p.m 1800 1800 1800 Mixture Temperature, °F 40 40 40 Air Flow*, lbs. /min 47.3 47.3 66.1 Fuel-Air Ratio, supplied 0.095 0.065 0.065 Fuel Flow, lbs. /min 4.49 3.07 4.30 Fuel Evaporated at Equilibrium, % 66 87 69 Fuel Vapor Formed at Equilibrium, lbs./min 2.96 2.67 2.97 Unvaporiied Fuel at Equilibrium, lbs. /min 1.53 0.40 1.33 Fuel Vapor-Air Ratio at Equilibrium 0.063 0.056 0.045 'Estimated from the displacement, speed, and temperature. ing the engine speed or applying carburetor heat will help to alleviate vaporization troubles. Care obviously should be used in the application of carburetor heat in view of the resultant effect on volumetric efficiency and the tendency to detonate. However, it has been shown that a moderate use of carburetor heat, when vaporiza- tion difficulties are encountered, will lower the specific fuel consumption. Sperry Gyroscope Co. R. J. Pearson 1. The E-l electric gyro horizon, Serial No. AF- 43-0760, and the C-l electrical directional gyro, Serial No. AF-43-0020, installed in a C-47A, Serial No. 43-48088, except for trouble with the horizon caging mechanism, have operated satisfactorily at the minimum temperature encountered. The minimum temperature at which a test was made occurred on Febru ary 13, 1945. The plane had been out over night at ground temper- atures of —40°F. to —45 °F. The inverter was turned on at a cabin temperature of —42°F. and the instruments started and erected correctly. In flight, the temperature at the instruments was —37°F. To date, the instru- ments have had about 1230 hours of operation. 2. At —37°F,, it became impossible to turn the cag- ing knob on the gyro horizon, A stiffness in the caging mechanism can first be noticed at about -(-5 to +15°F. 3. On Dec. 26, 1944, the Holtzu Cabot inverter used as a power supply for these instruments burned out three amp. fuses. The inverter was removed and checked. No trouble was discovered. It was put back in the plane and has operated satisfactorily since that time. (This same thing has occurred on the C-54 installation. Report of Feb. 20, 1945.) 4. When the C-l was installed at the Dayton Army Air Base on October 15, 1944, the instrument glass fogged up as soon as the instrument was started. The plane was still on the ground. This condition persisted throughout the first flight. A 3/16" hole was then drill- ed in the bottom of the case to correct the trouble. The fogging has not been noted since. There has been no difficulty of this type reported on any of the electric flight instruments in use at Ladd Field. The majority of them have not been drilled as mentioned above. 5. Considerable objection has been raised to the di- rection in which the C-l dial rotates. The following is quoted from Capt. B. Barrett’s December Progress Re- port of the C-47. “All pilots who have used the directional gyro object strenuously to its dial arrangement. On a standard air gyro, when the aircraft heading is being increased the numbers move from left to right relative to the lubber line. The electric gyro has a vertically mounted cir- cular mounted card, which rotates in the opposite sense to the air driven gyro. No one can see any justification for this difference, which causes considerable confusion to pilots who are used to the standard gyro. It is recom- mended that this instrument be modified so the card is numbered and rotates in the standard manner.” 6. There appears to be marked increase in the relia- bility of electric driven gyro instruments relative to air driven gyros at low temperatures (below —20°F.), and it is felt that this increased reliability would justify the use of electric instruments in regions where cockpit tem- peratures below —2°F. are anticipated. Lausen Engine Co. L. R. Pierce Five units—Stewart-Warner heaters—three “D-l” types and two “904-A” were used. UNIT NO. 1 The “904-A” job, No. 1, with no engine changes ex- cept the use of a heavy valve spring operated continous- ly under conditions as close to actual conditions experi- enced on the “line” for 623 hours. To the best of my knowledge an oil change was made only three times during that period—oil being added at various times to maintain level in sump. Some valve trouble was experienced at 232 hours. Old valves were removed—new ones installed and ground in were doing good work at time tests were stopped at 623 hours. During this period of 623 hours very little trouble was experienced with magneto and parts. It was necessary, however, to adjust and dress breaker points only once during this run. Lubricating oil used was No, 20 detergent. Fuel used was 73 octane gasoline for approximately 400 hours and 100/30 octane was used exclusively for 202 5230 balance of run. Official record was kept by Sgt. Wm. O. King, C.W.T. Detachment, Wright Field, Dayton, Ohio, which will show accurately all details. During the period from February 5th to February 12th temperatures daily ranged between —15° and —20°F. This unit started very easily without applica- tion of heat. On February 12th temperature dropped to —41 °F. On that morning very little heat, applied for a two minute period from a similar heater was all that was required to start the engine with two pulls on the rope. UNIT NO. 2 —‘904-A’' (Rotating valve and modi- fied cam). The engine used on this unit was standard in every re- spect except that the valves were modified in such a way as to permit them to rotate while off the valve seats and the cam contour was changed to permit a more rapid closing action to occur. The valve seat angles were cut to 47°, the valve face was left at 45°. A gear type oil pump was installed in place of the plunger type pump. This engine was not equipped with the latest style mag- neto which has a felt wiper for lubricating the magneto cam. TEST This engine was started on a test run on February 9th and ran continuously for 150 hours at which time it was necessary to readjust the points due to excessive wear of the breaker arm fiber caused by lack of sufficient lubri- cation. (Note: This trouble has been remedied in later design magnetos through the use of an oil impregnated felt wick for lubricating the cam.) Points were re-checked and lubricated and lubri-plate ignition point trouble again occurred at about 150 hours due to lack of lubrication on the cam. At this time the ignition or heat exchanger was faulty due to plug failure. No replacements were at hand and the run was discon- tinued. UNIT NO. 3 Gear oil pump was installed and priming cup was used on restriction elbow at point of priming plug. This unit started readily with use of primer at —41 °F. Heat from “904-A” applied to both engine and Roots blower for two minutes period. It was impossible to keep the above unit running until overheat switch was disconnected. No further trouble in operation was encountered. The unit was used at various places where heat was required and performed satisfactorily until tests were discontinued. The entire running time was 232 hours—good performance in general. UNIT NO. 4 Modifications on this unit consisted of gear oil pump, rotating valves, intake and exhaust ports reamed out to and polished exhaust lead was pipe. Starting qualities, with primer, were excellent requir- ing not more than three pulls on rope. Heat application previous to start did not exceed two minutes, also from a unit already in operation. The overheat switch on this unit disconnected on account of being faulty. Uninterrupted operation of jabove unit 176 hours. HEAT EXCHANGER COMMENTS Due to an air leak around the heat exchanger ignition plug warm air from the heater was forced onto the engine causing excessive frost accumulation to form on the gov- ernor mechanism thus preventing it from functioning properly. To remedy this trouble a baffle plate was placed on the engine to deflect the air flow away from the engine, KICK STARTER—(Supplied by the Stewart-War- ner Company). Too much lost action and continual failure of clutch spring. Summary of tests run this past season at Ladd Field is a definite opinion that very satisfactory engine per- formance over a period to exceed 200 hours without maintenance is available under present conditions—much better performance is anticipated from developments now in process. The Texas Company C. V. Roark A. General Statements 1. The 1944-45 Cold Weather Tests conducted by units of the Army Air Force revealed that satisfactory petroleum products are available for operation of air- craft at ground temperatures as low as •—40 to —45 °F. When compared with previous experience the infre- quent difficulties encountered reflect a considerable im- provement in low temperature performance of airplanes that had been winterized and were accorded currently accepted servicing procedures such as dilution of engine oil and application of external heat to facilitate cranking and fuel evaporation when engines were started. 2. Atmospheric temperatures were considerably above normal for the locality, during the period 1 December through 17 February there were only a few days colder than —30° F. The few failures and instances of border- line performance indicate some further investigations should be given consideration in the effort to develop air- craft, accessories, equipment, and supplies, that can be used throughout the temperature range of —65 to —160° F. with the minimum of special servicing. The purpose of this review is not to detract from the present state of perfection of the airplanes but to suggest addi- tional studies that may lead to their improvement. 5230 203 3. A major problem in low temperature performance of aircraft is the tendency for manually operated and power driven parts to freeze or to become sluggish in action and require excessive force. There is a very wide spread habit to attribute such failures or borderline per- formances to inadequate lubrication but experience gain- ed in low temperature test work has revealed that other factors are more often responsible than the specialized lubricants now available. These factors are usually in- volved in improper design or insufficient clearances in manufacture of parts and assemblies, unnecessarily com- plicated mechanisms or systems, excessive stresses and misalignment of parts during assembly, and inadequate provision for lubrication. The problem of proper clear- ances at extreme temperatures is of particular impor- tance. It gains in significance when materials with dif- ferent coefficients of expansion are involved. Some in- stances where the above factors contributed to unsatis- factory performance will be discussed later. 4. The frequent modification of airplanes and occasion- al revision of lubricant specifications have in some in- stances lead to misapplication of the latter. Develop- ment of all purpose oils and greases will mitigate this problem but continued effort should be given to dis- semination of instructions and equipment so that proper servicing practices will be followed. Consideration could be given for holding periodic lubrication orientation classes so that engineering officers, pilots, crews and supply men will be kept abreast of developments. 5. Experimental work and service testing of lubri- cants involved performance of new experimental pro- ducts compared with that of materials now in use, and trial of present products in new applications where speci- alties have been used in an effort to reduce the total number of items that must be carried in stock. Both types of work will be discussed under the subject of an experimental material where one was involved. B. Products Tested Ultra Low Temperature Greases 1. The experimental product, TG-455, meets all the requirements of Specification AN-G-3a for Low Tem- perature Lubricating Grease and has other attributes including ability to withstand extensive working, as in a very high speed ball bearing, without significant soften- ing. Its resistance to torque (stiffness) at —67°F. is about one fourth that permitted and it can be cooled to —90°F. without exceeding torque limit at only —67°F. established in Specification AN-G-3a. 2. Five trim tab systems and a surface control lock system were completely lubricated with TG-455 to com- pare their performance with others carrying regular AN-G-3a Low Temperature Lubricating Grease. Past experience has pointed to the possibility that while AN- G-3a grease has satisfactory low temperature torque when new, it has insufficient margin of safety to allow for alterations in its composition that later occur and reduce its ability to remain sufficiently soft as low temperatures. If his possibiliy is verified the ultra low temperature type of grease with greater margin of safety is available. 3. Test data taken at ground temperatures down to —45°F. show a slight advantage in favor of the ultra low temperature grease. It is significant that only a few of the AN-G-3a lubricated main surface control, trim tabcontrol, and surface control lock systems were rated F (frozen) or VS (very stiff but operable). The grease apparently was able to cope with the ground temperatures experienced. When unsatisfactory performance did oc- cur there were usually similar systems in other airplanes of the same type and approximate serial number that could be manipulated without excessive force; this points toward lack of uniformity between the mechanisms that should receive further attention, 4. In view of past experience more data were taken on heavy bombers than any other group of airplanes. Increase in stiffness as ground temperatures dropped suggests that at extreme temperatures one type of heavy bomber would have inoperable aileron trim tabs before other control system difficulties. In another type the surface control lock system is most critical followed by aileron and rudder trim tab and the elevator system. In a third heavy bomber type aileron and rudder trim tabs and the elevator and rudder systems were sensitive to cold weather. 5. Readings made on the ground coupled with reports of pilots indicate that at extreme temperatures aileron trim tabs may freeze and other trim tabs may become very stiff in one type of cargo ship. 6. Freezing of elevator trim tabs of a pursuit ship at high altitude and low temperature was traced to a portion of the system consisting of a chain running over three sprockets. 7. Main surface and trim tab controls of another type of pursuit ship that is the outgrowth of a now discon- tinued type, against which many complaints had been lodged particularly because of aileron trim tab stiffness, were found to function satisfactorily at the lowest tem- peratures encountered. The aileron trim tab system of the old model embodied a complicated coordinating ar- rangement with several chains and sprockets and has been eliminated in the currently produced airplane. How- ever, the other control systems reflected considerable im- provement. Data were taken on one of the airplanes with aileron and rudder trim tab systems lubricated throughout with ultra low temperature grease and on several airplanes lubricated with AN-G-3a grease. 8. Most of the difficulties were encountered in heavy airplanes with dual controls. It is suggested that con- sideration be given to simplifying the means of coordinat- ing dual installations. Each individual control system usually involves in addition to final actuators one or more of the following: cables over drums and pulleys, chains and sprockets, torque tubes and gears, thrust rods and bell cranks, and flexible drive cables. A study of the different mechanisms might lead to the elimination of those least desirable with respect to friction, ease of lubrication and sensitivity to temperature changes and still permit the control system to have satisfactory weight, strength and tautness. General Purpose Aircraft Lubricating Grease 1. The experimental Grease, TG-404, meets all re- quirements of Navy Aeronautical Specification M-675 for General Purpose Aircraft Lubricating Grease that was issued on 15 January, 1945 while the Cold Weather Tests were still in progress. Requirements include water 204 5230 resistance, ability to lubricate very high speed ball bear- ings at elevated temperature for an extended period of time, and low torque at moderately low temperature; temperatures specified are 250°F. and —40° F. respec- tively. This type of grease is intended for use in anti- friction bearings, gear boxes, and plain bearings where both reasonably low temperature operation and high tem- perature stability are required. Suitable applications would be electric motor and generator bearings, wheel bearings and landing gear or other parts with pressure grease fittings. It is not intended to replace ultra low or AN-G-3a grease for factory lubricated, sealed bearings of control systems required to operate at extremely low temperatures. 2. The general purpose grease was applied to bear- ings of two starters to compare their performance with the regular grease Specification 3560-E, Medium Grade, High Melting Point Grease in two identical starters. None of the four starters experienced bearing trouble at relatively moderate ground temperatures encountered this past winter when the Cold Weather Tests were con- ducted. However, except when special starting fuel was tried out, external heat was applied to engines and ac- cessory compartments. The four starters were scheduled for limited service tests inasmuch as bearings were not to be examined until Cold Weather Tests are completed. 3. The general purpose grease, TG-404, was placed in bearings of main wheel retracting motor or a heavy bomber to compare its performance with that of a similar motor in which bearings carried grease applied by the manufacturer, Royce 6A. Neither of these motors, nor four others in other airplanes of the same type failed to function at ground temperatures experienced during the 1944-45 Cold Weather Tests. It was noted, however, that the motor carrying general purpose grease raised the wheels in shorter time and consumed less current. 4. There was insufficient good test weather to switch motors and determine to what extent any excessive fric- tion or binding of reduction gears, screw jacks or other units in the wheel retracting mechanisms may have in- fluenced the load on these two motors. Experimental Graphite Grease 1. The experimental graphite grease consisted of TG- 404 in which 5% of graphite had been incorporated. It was applied to gears of the two starters carrying TG-404 in the bearings. Gears of the comparative starters were lubricated with ordinary Specification AN-G-6 Graphite Lubricating Grease. As stated before the four starters functioned satisfactorily. The gears were to be examined after completion of the Cold Weather Tests. 2. Specification AN-G-6 does not include low tem- perature torque nor high temperature stability require- ments. Consideration might well be given to a study of these qualifications with reference to possible improve- ment of starter performance and life. Aluminum Soap Grease, Specification AN-G-4, Grade AA 1. Specification AN-G-4, Grade A A grease is now designated for only a few uses on airplanes. It was formerly used on gears and blade bearings of some types of propellers but has been displaced by AN-G-3a grease for this application. Both products were tried out the past winter and performed without complaint, but at ground temperatures approaching —65°F., the alumi- num soap grease may be too stiff. During the colder weather there was some grease leakage from a few pro- pellers, this is a problem involving seal composition for low temperatures. With the advent of general purpose grease of the TG-404 type it is possible use of AN-G-4 Grade AA can be discontinued for the few pressure fitting applications where it is now called for. Grease Summary 1. The field of greases for anti-friction bearings, plain bearings and gears can now be covered by the following available products; Usable Temperatures Product Low °F High °F Ultra low temperature grease —90 160 (approx) Lom temperature grease —67 160 (approx) General purpose grease —40 250 High temperature grease • 300 ♦AN-G5a, High Temperature Grease was not scheduled for cold weather testing; no low temperature torque is specified. 2. In order to determine value of the ultra low tem- perature grease as an all weather lubricant it is suggested that it be given a field service test including moderate and extreme summer temperatures. Servicing and oper- ation of the airplanes involved should be carefully super- vised to prevent inadvertent mixing with other lubricants. C. Experimental Oils General Purpose Oil 1. The Texas Company supplied a product identified as TL-534, which was developed to meet Specification AN-0-6a for investigation as a General Purpose Low Temperature Lubricating Oil. This is a well refined moderately light oil with ultra low pour point and it carries a rust inhibitor. It is intended for use in plain and anti-friction bearings but not to displace hydraulic and gear oils. The AN-0-6a Oil was used in several applications for comparison with performance of the regularly employed lubricant and of oils normally used for other applications. Two experimental synthetic oils were also tested. 2. The above applications and results obtained are summarized below: Satisfactory Operating Product Temperature, °F. Turbosupercharger Lubrication AN-VV-0-366b Hydraulic Oil —70 AN-0-6a Below —46 WS-804 Synthetic Incomplete data PPO-280 Synthetic Incomplete data Jet Engine Lubrication •AN-VV-0-366b .OK at —45 AN-0-6a Borderline at —36 WS-804 Somewhat above —34 AN-O-3, Light Incomplete data Aeroproducts Feathering Propeller, Flight Tests AN-0-6a —70 PPO-280 —50 AN-O-3, Light, Low Temperature Gear Oil....Borderline at —36 WS-804 —10 • Product regularly used during very cold weather. 3. Altho AN-0-6a Oil proved satisfactory in turbo- superchargers and jet engines at ground temperatures experienced this winter another specification, Army No. 3606, has been drawn up to cover a similar oil but with- 5230 205 out the rust inhibitor and with lighter viscosity at low temperatures. This new oil may be even more satisfac- tory in the above services. On basis of tests made during the winter AN-VV-0-366b remains the preferred oil for Winterized Aeroproducts propellers. 4. The AN-0-6a oil satisfactorily lubricated bearings of a number of gyroscope motors but in one type several bearings failed. All the bearings are self-aligning, double row ball bearings with fibre cages. The failed bearings differ from those in other gyros in that their cage is wider than the inner and outer race and can act as an oil slinger for the light AN-0-6a oil. The bearings ran dry and showed evidence of excessive thrust loads on the out- board rows of balls. 5. It is desirable to use light low pour test oil in these gyros to obviate use of heaters now required because of higher pour test of the more viscous oils now used. One or more of the following steps may be advantageous: eliminate overhang of ball cages, add seals to act as oil reservoir, substitute single row ballbearings with greater thrust capacity, lock both bearings and allow shaft to float within one of them, increase clearance between bearing and housing to accomodate temperature differ- ential and expansion coefficient of the dissimilar metals. Lubricating Oils—Suimnary 1. The 1944-45 Cold Weather Tests revealed that progress is being made in the development of oils for low temperature operation of airplanes. It is not so necessary, as in the case of greases, that these products be suitable for warm climates because oils are usually employed in circulating systems that can be quickly drained and refilled with heavier oils. 1 D. Fuels Aircraft Engine Fuels (Gasoline) 1. Definite progress was made in the study of gas- oline volatility requirements and application of carbure- tor heat. 2. External heat is now applied to engines and ac- cessories to facilitate starting at temperatures below approximately 0°F. for radial air cooled engines and below —10 to —20°F. for in-line liquid cooled engines. Oil dilution facilities including gasoline scavenging capa- cities of the oil systems and improved low temperature greases for accessories would permit cold starting at lower temperatures. Problems that should receive fur- ther investigation include diluting the vacuum pump crankcase oil. or arrangement of a separate system with light oil, and use of a more volatile starting fuel. Because of the higher vapor pressure of volatile fuels and sub- sequent greater fire hazard use of droppable tanks or special ground facilities should be considered. Western Electric Co. E. IV. Brinkerhoff A. INTRODUCTION This report contains a general summary of the per- formance obtained and experience encountered with radar equipment of Western Electric manufacture during the 1944-45 Cold Weather Tests. Western Electric was represented in these tests for a period of six weeks commencing January 16, 1945 ending March 3, 1945. B. SUMMARY All of the following information was obtained from routine operational flights and early morning pre-flights. a. Radar Equipment (1) Cold Weather Operation Both SCR-717C and AN/APQ-13 radar equip- ments operated very satisfactorily during the cold weather experienced. The PE-218 C & D Inverters both em- ploying the carbon pile type regulator reacted identically to that experienced during the Cold Weather Tests last year. For ambient temperatures of —30° to —40°F. the inverters started at a high voltage of approximately 125-f- volts. The radar equipment suffered no damage during this initial high voltage period. However, the varying of the AC voltage which is characteristic of these inverters during variations in temperature around 0°F. render the operation of the AFC as unsatisfactory. Focus control is also very difficult during the AC voltage variations. It is still impossible to operate the ON and OFF buttons of the Control Unit with the use of regulation flying gloves or mittens. (2) Test Equipment and Employment (a) Signal Generator (TS-35/AP)—this unit was available hut dummy load (TS-231/AP) and T section (B41456) or CG98B directional coupler essential for accurate power measurements were lacking. The stiffness, in sub-zero temperature, of the AN/RG-8/O wave guide to wave guide patch cable used in conjunction with the TS-35/AP for frequency measurement made extremely difficult working condi- tions. The two spring clips which are employed to fasten the patch cord to the test set are not strong enough to support the stiff patch cord. (b) Power Meter (TS-36/AP)—this unit was also available but TS-35/AP was used when needed. (3) Propagation of Microwaves At no time during these tests which in this season involved over 600 operational hours were unusual ranges evidenced or atmospheric data obtained which would indicate the presence of anomalous propogation. h. Availability of Airplanes Absolutely no trouble was experienced this season in conducting radar test flights. A Douglas C-47B equipped with SCR-717C was available exclusively for 206 5230 radar test flights. A B-17 and two B-29’s equipped with AN/APQ-13 were also available. Operation of C-47B aircraft: the radome slows the C-47B down to unreliable single engined performance characteristics which is especially dangerous for cold weather operation. c. Weather Compared to last year the season had been equally as mild. The lowest recorded temperature for 1943-44 was—45°F. wherein—40°F. was the lowest for 1944-45. The temperature tables for the winter months 1944-45 are attached, C. ORGANIZATION OF COLD WEATHER TEST DETACHMENT The organization for CWT was essentially the same for this season as it was for the last with the exception of no civilian specialists from Aircraft Radio Labs also a sharp reduction in the officer personnel representing ARL. a. RADAR EQUIPMENT (1) System Performance and Operating Time (a) SCR-717C This equipment was installed in a C-47B and operated normally for a total time of 175 hours thereafter no attempt was made to keep further records of the time. The equipment was operated on the average of 5 hours a day continuously for a three-month period. The system was flown to and operated under various weather condi- tions experienced down to —45 °F. Echoes with the ship docked in the bay were continually and reliably re- ceived every day from the Alaskan Range approximately 90 miles south of Ladd Field. (b) AN/APQ-13 1. System in B-29—#768—this equipment was operated for approximately 100 hours of which 20 hours it operated at 30,000 feet and with air temperatures of —60°, —65°F., and 2j4 hours with the air at altitude pressure in the cabin. Photographs of the PPI scope on 2,500 mile flight at 30,000 feet ground speed 300 miles per hour air temperature —61 °F. are included in Appendix I. 2. System in B-29—#214—this equipment was operated for approximately 171 hours of which 5 hours it operated at 30,000 feet with air temperatures of —60°, —65°F. 3. System in B-17—#587—this installation was mocked-up by and installed under Lt. E. E. Cald- well’s CWT supervision at Ladd Field, Alaska; its oper- ation was normal for over a period of 100 hours. 4. System as ground spare—operated for a period of 25 hours, system was “cannibalized” whenever necessary. (2) Operational Notes The following notes and operational difficulties are briefed: SCR-717C 1. Couldn’t pressurize RF or Modulator units, maintaining seal on units is extremely difficult at low temperatures, no work was done to determine what could be accomplished as extra gaskets were not avail- able. 2. Loss of signals due to faulty 6AC7 in Synchronizer, 3. PE-218C Inverter carbon disc of voltage regulator burned, also burned brushes. AN/APQ-13 1. Two crystals replaced in B-29’s #214 and #268. 2. PE-218D inverter on B-29 #768 burned a set of brushes. 3. Search switch on B-29 #768 defective, icing believed cause of this trouble. 4. Radome on B-29 is serious problem at low temperatures, as material used is very brittle and fails when hit by shell cases, links and frag bombs ; during a gunnery mission, one antenna was seriously damaged by shell cases and links which had penetrated the radome. At time of the writer’s departure a new streamlined radome was being put through cold weather tests. Inverters PE-218 C & D PE-218D inverters were employed with AN/APQ-13 system. PE-218C was used in the SCR- 717C system. The starting voltage of these inverters at —30° —40°F. was generally higher than 125 V. Con- sequently as the cabin temperature varied, the AC volt- age accordingly varied. Test Equipment Patch cables becoming extremely stiff in sub- zero temperatures presented the major problem. (See Photographs Appendix I) (3) Tests—Pre-flight Checks (a) During the month of February, pre-flight data was taken on AN/APQ-13 installed in B-17 #587 to determine as close as possible the information desired in BTL letter dated January 3, 1945. For pre-flight data reference is made to Appendix II. (b) Lack of Proper Test Equipment and Modification Kits. Of the four AS54A/APQ-13 an- tennas, two were of the X66170A variety, one X66170G and the other we were unable to determine since the radome in which it was mounted was never removed. All four antennas lacked the rotary joint heater unit modification which would supply power and tem- perature control to the heater. Modification kits were requested but never re- ceived. A TS-35/AP test set wras available but dummy antenna (TS-231/AP) and T section (B41456) or CG98B directional coupler essential for accurate power measurements were not available. Since the rotary joints were not heated, no spare gaskets were available and the equipment had con- siderable operating time. Checking for leaks in the transmission line was extremely difficult; two antennas were found, however, with audible air leaks in the plugs of the wave guide to coaxial transformer on the input side of the rotary joint. These leaks were due to im- proper soldering. At temperatures of —40°F. it was possible to operate the sweep delay switch only under considerable hand presure. With the varying AC voltage which apparently is a normal characteristic of PE-218D inverter during low temperature changes the AFC does not function properly. Variations in filament emission may have contributed much to this AFC condition. Pre-flight data shows the variations—revolu- tions per minute of antenna in search and continuous rotation position. variations—looks per minute in sector scan, variations—antenna tilt time, degree of tilt variations—in frequency of magnetron, variations—of AC output of PE-218D inverter with tem- perature changes. 5230 207 D. CONCLUSION In so far as the radar equipment is concerned, the nature of these tests were purely operational. Owing to the fact that the weather was extremely mild, the cold weather data taken is of little consequence. The Army CWT program for Western Electric radar equipment was merely the performance of the gear while under as- similated combat operations. There was no planned pro- gram and no test data was desired. No test gear was available to subject the radar equipment to vibration tests. The excellent performance of the gear for over 600 hours of cold weather operations during which time gunnery tests and various other sources of shock and vibration were subjected to the equipment may be considered as a criteron of the equipments shock ability at sub-zero temperature. 208 5230 LADD FIELD, ALASKA Hr. Day 0100 0200 0300 0400 0500 0600 0700 0800 0900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 Max. Min. Mean 1 27 29 28 28 27 26 23 23 21 21 22 23 24 25 26 26 21 21 22 25 25 25 24 24 30 21 24.4 2 23 23 22 22 21 20 18 16 13 12 12 14 16 18 20 23 22 20 20 16 13 12 11 11 25 10 17.4 3 10 10 9 8 8 8 7 7 10 9 13 15 19 19 20 19 19 19 14 13 11 8 8 8 20 7 12.1 4 7 7 6 6 5 5 6 6 5 6 6 12 14 19 22 19 16 15 12 13 15 15 12 11 22 4 10.8 5 8 8 5 5 4 4 4 4 4 2 4 5 11 13 16 17 15 12 8 7 6 6 4 3 18 2 7.3 6 3 3 0 1 4 2 2 3 3 2 12 12 15 17 16 17 17 17 17 16 15 12 9 7 18 0 9.2 7 5 4 3 4 4 4 3 3 2 1 3 6 6 8 9 9 10 10 10 10 10 11 11 11 12 1 6.5 8 11 11 11 11 11 10 10 9 10 12 12 15 18 17 17 17 16 16 15 15 14 14 14 13 19 10 13.3 9 12 11 11 9 9 9 9 9 9 9 10 10 12 12 13 12 10 8 6 5 5 5 6 5 13 5 9-0 10 3 2 2 3 2 0 0 0 1 3 3 5 5 7 7 7 7 5 5 5 5 5 5 5 8 -1 3.8 11 3 2 2 -2 -3 -8 -10 -9 -9 -12 -9 -7 -7 -2 2 2 1 -5 -9 -9 -11 -11 -13 -10 5 -13 -3.7 12 -11 -11 -13 -11 -9 -9 -10 -14 -14 -16 -16 -14 -14 -8 -3 -3 -6 -6 -8 -10 -10 -10 -10 -10 -3 -16 -10.2 13 -10 -11 -11 -10 -11 -12 -12 -11 -11 -10 -9 -7 -5 0 -1 -2 -4 -5 -5 -5 -5 -4 -2 0 3 -13 -6.7 14 2 3 4 4 4 4 5 5 6 6 7 7 8 9 9 8 8 5 5 5 5 5 1 2 10 -1 5.3 15 0 2 5 7 11 11 12 12 15 17 17 17 15 15 14 17 17 17 17 15 16 14 16 18 21 0 13.2 16 19 20 18 12 10 10 10 10 10 12 12 14 16 18 18 17 18 18 16 15 13 12 9 9 22 ' 9 14.0 17 9 8 8 9 9 8 9 8 8 9 8 8 13 15 15 14 12 10 8 9 8 6 6 5 16 5 9.2 18 5 6 5 5 4 3 3 2 4 8 4 6 8 10 15 16 14 13 10 7 9 9 10 10 18 2 7.6 19 10 9 9 8 11 10 8 8 8 5 5 9 10 11 14 14 12 11 11 14 15 15 16 16 18 2 10.8 20 18 18 16 15 11 9 9 8 10 14 14 15 15 15 15 14 14 12 12 11 9 9 14 14 18 7 13.0 21 14 15 14 14 15 16 16 16 17 17 17 16 18 16 16 18 18 17 15 15 15 14 14 14 19 12 15.7 22 13 12 11 11 11 11 11 11 12 12 12 13 13 13 13 14 14 14 15 15 14 14 14 14 15 11 12.8 23 12 12 12 11 10 8 8 6 6 5 5 4 5 5 5 5 5 3 4 2 -2 -3 -3 -5 13 -9 5.0 24 -6 -6 -6 -6 -5 -4 -1 2 1 1 0 0 0 2 2 0 -2 -3 -3 -3 -3 -3 -4 0 2 -8 2.0 25 1 1 -1 -2 -3 -2 -2 -2 -2 0 -1 -1 0 2 1 1 0 0 0 1 -3 -3 -5 -4 2 -9 -1.0 26 -9 -9 -8 0 2 3 2 3 1 -1 0 4 6 7 7 6 6 0 -6 -6 -1 0 -2 -3 9 -9 0.0 27 -2 -2 -3 -4 -6 -5 —8 -5 0 0 -1 0 5 6 6 7 6 6 6 8 10 11 11 11 14 -10 2.4 28 12 12 12 12 12 11 9 9 8 7 7 5 4 4 3 3 3 4 5 5 6 6 6 7 14 3 7.2 29 7 7 8 8 8 8 11 10 7 6 6 6 6 6 6 6 5 5 4 3 2 2 2 1 11 0 5.8 30 1 2 4 3 2 2 1 3 3 1 0 -2 -2 -2 -5 -7 -8 -9 -11 -11 -11 -12 -11 -12 5 -14 3.4 TIME IS A. W. T. TEMPERATURES ARE IN DEGREES FAHRENHEIT MEAN FOR MONTH +7.3 Appendix TABLE I SURFACE TEMPERATURE NOVEMBER 1944 5230 209 LADD FIELD, ALASKA Hr. Day 0100 0200 0300 0400 0500 0600 0700 0800 0900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 Max. Min. Mean 1 -13 -14- -14 -15 -16 -16 -16 -15 -17 -17 -16 -18 -14 -12 -10 -9 -8 —8 -7 -6 -6 -8 -8 -7 -6 -20 -11.8 2 -9 -10 -10 -10 -10 -8 -7 -7 -7 -5 -4 -4 -4 -3 -4 -2 -2 -2 -1 -1 0 0 1 1 1 -10 -4.5 3 0 1 1 1 1 1 1 1 2 2 0 -1 -3 -3 -4 -5 -4 -5 -6 -6 -6 -6 -7 -7 3 -8 -2.2 4 -7 -9 -9 -9 -9 -9 -9 -9 -9 -9 -10 -9 -10 -10 -10 -10 -10 -10 -11 -12 -14 -16 -18 -21 -7 -21 -10.8 5 -24 -24 -25 -26 -27 -28 -28 -31 -31 -28 -30 -30 -29 -32 -34 -33 -32 -32 -34 -34 -34 -34 -34 -34 -24 -34 -30.3 6 -35 -36 -36 -38 -41 -39 -38 -37 -39 -39 -37 -37 -37 -36 -36 -35 -35 -37 -35 -37 -37 -38 -38 -38 -35 -41 -37.1 7 -38 -38 -36 -35 -36 -38 -37 -38 -37 -35 -34 -32 -30 -29 -25 -23 -23 -23 -22 -23 -22 -21 -19 -19 -19 -40 -29.7 8 -19 -19 -18 -18 -17 -16 -15 -14 -12 -12 -11 -11 -10 —8 —8 -7 -8 -9 -9 -9 -12 -14 -14 -15 -7 -19 -12.7 9 -15 -15 -16 -17 -15 -15 -15 -15 -14 -14 -12 -13 -14 -13 -14 -13 -13 -14 -14 -16 -13 -12 -12 -11 -11 -18 -14.0 10 -12 -9 -6 -5 -2 5 7 8 10 34 35 36 38 39 39 38 35 35 33 33 33 34 33 30 39 -13 21.7 11 27 24 24 27 32 33 33 22 23 20 16 18 20 22 27 36 35 38 34 34 35 30 30 32 40 15 28.0 12 35 34 33 36 34 36 36 35 35 38 36 35 35 31 32 31 32 31 25 22 19 18 18 16 39 16 30.5 13 12 12 15 17 18 17 17 13 15 18 19 18 17 15 15 15 15 16 16 16 14 19 21 26 26 12 16.5 14 27 25 25 27 28 28 29 26 26 29 27 28 28 30 27 25 21 18 14 13 12 12 15 15 34 11 23.1 15 15 15 14 16 15 17 17 16 17 18 19 19 19 20 21 22 22 19 17 17 19 23 23 21 23 14 18.4 16 30 30 32 29 29 31 34 35 35 35 38 38 38 38 35 35 34 34 34 33 33 29 31 31 39 29 33.4 17 31 30 31 24 27 24 24 26 27 20 20 20 20 20 20 21 19 19 18 18 12 9 7 7 33 7 20.6 18 6 5 6 6 6 9 10 13 13 14 13 17 18 21 20 19 18 18 18 19 20 20 15 13 21 5 14.0 19 16 17 18 15 14 13 13 12 17 18 19 19 20 20 20 20 20 19 19 21 21 23 22 21 24 12 18.2 20 20 22 22 20 20 22 23 22 20 22 19 17 14 14 12 8 8 6 6 3 1 2 10 6 24 1 14.1 21 12 13 14 14 11 9 8 9 9 9 4 4 2 3 5 4 2 2 0 -1 3 0 -1 -2 15 -2 5.5 22 -2 -4 -5 -2 -3 2 2 7 9 11 11 12 10 10 6 4 1 1 -2 -4 -6 -6 -4 -4 12 -7 1.8 23 -5 -5 -6 -7 -8 -8 -9 -9 -8 -5 -6 -6 -2 -1 -1 -3 -4 -4 -2 1 -3 -2 -2 -2 2 -11 -4.4 24 -4 -6 -7 —8 -8 -7 -6 -7 -8 -9 -8 -10 -11 -10 -10 -12 -12 -13 -11 -11 —8 -7 -7 -10 -4 -15 -8.8 25 -11 -11 -11 -14 -12 -13 -13 -13 -13 -11 -12 -12 -11 -10 -10 -12 -12 -12 -15 -16 -16 -17 -18 -19 -10 -19 -13.1 26 -19 -20 -20 -21 -23 -23 -24 -24 -24 -23 -23 -21 -20 -15 -11 -9 -9 -7 -6 -2 -4 -11 -11 -11 -1 -25 -15.9 27 -11 -12 -16 -14 -12 -12 -8 -3 -1 -2 -4 -5 -4 -8 -5 -4 -5 -5 -6 -2 0 1 3 2 4 -17 -5.5 28 1 1 -2 -6 -7 -8 -8 -12 -12 -13 -14 -15 -17 -16 -18 -19 -20 -21 -24 -21 -22 -28 -28 -25 1 -30 -14.6 29 -15 -26 -29 -26 -27 -28 -28 -29 -28 -22 -26 -25 -13 -13 -11 -14 -15 -14 -16 -15 -14 -12 -13 -13 -9 -30 -19.7 30 -13 -10 -6 -4 4 5 5 7 8 8 9 10 10 10 10 10 10 10 10 10 9 8 8 4 11 -13 5.5 31 -1 -1 -3 -3 -4 -5 -5 -4 -4 -6 -14 -17 -18 -16 -15 -15 -18 -19 -20 -20 -24 -25 -25 -24 -1 -25 -12.8 TIME IS A. W. T. TEMPERATURES ARE IN DEGREES FAHRENHEIT MEAN FOR MONTH + 1.1 TABLE I SURFACE TEMPERATURE DECEMBER 1944 LADD FIELD, ALASKA Hr. Day 0100 0200 0300 0400 0500 0600 0700 0800 0900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 Max. Min. Mean 1 -22 -20 -16 -15 -14 -9 -7 -10 -10 -10 -9 -9 -10 -11 -9 -11 -11 -10 -10 -12 -12 -11 -8 -7 -7 -22 -11.4 2 -3 -3 -3 -3 -4 -4 -3 2 2 6 6 0 3 5 5 11 11 9 5 0 0 -5 -5 -7 12 -8 1.0 3 -7 -9 -11 -11 -13 -12 -13 -12 -14 -13 -11 -11 -10 -7 -8 —8 -8 -9 -10 -9 -10 -9 -9 -7 -15 10.1 4 -7 -7 -5 -4 -5 -7 -9 -11 -12 -9 -9 -9 -7 -6 -6 -6 -7 -9 -10 -9 -8 -8 —8 -8 -4 -13 -7.8 5 -12 -12 -7 -13 -14 -11 -9 -9 -13 -5 -7 -7 -7 -2 1 -4 -13 -14 -15 -16 -16 -20 -21 -21 2 -22 -11.1 6 -21 -22 -22 -23 -23 -23 -24 -25 -26 -25 -28 -27 -27 -13 -2 -4 -5 -5 -9 —9 -13 -4 -3 -1 -1 -30 -16.0 7 6 6 6 6 6 6 6 5 5 3 2 1 -1 -2 -1 '-3 -4 -5 -5 -3 -5 -4 -6 —4 7 -7 0.6 8 -5 -6 -9 -5 -5 -6 -5 -5 -6 -6 -4 -4 -3 -4 -4 -6 -4 -5 -10 -11 -11 -1 -3 -6 -1 -13 -5.8 9 -10 -12 -12 -11 -12 -12 -9 -7 -7 -3 -4 -5 -5 0 -3 -3 -5 -7 -3 -3 -3 -2 -2 -8 2 -15 -6.2 10 -9 -10 -9 -10 -12 -12 -10 -10 -12 -12 -11 -10 -9 -9 -8 -6 -6 -4 -4 -4 -5 -5 -1 -1 -15 -8.0 11 -1 0 2 6 5 2 2 10 14 17 20 13 9 10 11 10 9 4 4 7 3 2 2 0 20 -1 6.8 12 -4 -3 -3 1 2 4 4 5 7 5 1 3 3 4 4 6 5 2 1 0 -1 -4 -5 -6 11 -6 1.3 13 -6 -7 -8 -9 -9 -10 -10 -11 -10 -11 -12 -10 -9 -6 -5 -6 -8 -9 -10 -10 -6 -6 -5 -8 -3 -14 -8.4 14 —8 -7 -9 -7 -7 -1 -1 0 1 1 2 3 4 5 5 3 3 -1 0 2 4 4 4 5 5 -11 0.2 15 5 4 3 3 0 0 0 -1 -6 -1 2 3 2 3 3 3 2 3 3 3 3 3 3 2 5 -6 1.9 16 -1 -9 -9 -15 -18 -17 -17 -20 -20 -17 -16 -15 -4 -4 -3 0 0 -3 -6 -6 -6 -6 -4 -4 2 -23 -9.2 17 -8 -12 -7 -5 -3 -3 -7 -5 -5 -6 -9 -8 -8 -2 -2 -8 -9 -10 -12 -11 -15 -16 -13 -12 -1 -19 -8.2 18 -12 -11 -12 -12 -14 -15 -14 -14 -12 -12 -9 -12 -10 -8 -6 -4 -1 1 1 8 10 6 0 0 11 -16 -6.3 19 -3 -2 -1 -2 4 4 3 -2 -4 -5 -6 -6 -6 -2 1 4 6 9 12 13 10 11 14 10 14 -8 2.6 20 13 14 16 16 19 19 20 24 21 20 19 21 20 23 22 22 20 18 18 14 14 7 4 4 26 2 17.0 21 5 5 5 10 10 18 18 11 18 17 17 17 17 22 23 24 21 22 21 20 19 21 21 19 25 4 16.7 22 19 17 15 15 9 8 8 12 17 16 16 18 19 17 17 11 10 10 10 9 7 2 1 -1 19 -1 11.8 23 -1 -4 -5 -8 -8 -6 -5 -6 -7 —8 -8 -8 -7 -6 -2 -1 -2 -2 -8 -11 -10 -12 -13 -14 1 -15 -6.8 24 -11 -11 -8 -6 -5 -2 -1 0 1 2 2 1 3 4 4 4 4 2 3 1 0 1 3 3 5 -15 -0.2 25 2 0 0 -2 -5 -7 -7 -3 -7 -7 -7 -10 -9 0 0 -1 -3 -4 -7 -8 -12 -12 -12 -13 4 -13 -5.6 26 -13 -12 -8 -6 -2 1 2 4 7 11 13 16 16 19 21 21 19 18 21 20 20 21 21 19 22 -13 10.4 27 25 21 23 18 14 16 16 26 26 30 30 33 32 34 34 40 35 34 37 35 31 30 30 32 41 13 28.4 28 32 30 29 31 33 37 35 36 36 37 34 34 36 38 40 42 36 35 35 34 33 32 32 29 43 29 34.4 29 24 24 22 18 19 19 24 30 28 28 29 29 32 33 33 29 31 31 30 29 28 21 20 19 36 17 26.2 30 18 15 15 13 12 12 12 15 12 14 14 18 24 26 26 25 27 27 23 24 25 17 20 16 32 10 18.8 31 15 10 9 9 10 9 9 4 3 2 3 7 10 12 17 14 13 11 6 6 7 3 4 2 17 0 8.1 TIME IS A. W. T TEMPERATURES ARE IN DEGREES FAHRENHEIT MEAN FOR MONTH +2.8 TABLE I SURFACE TEMPERATURE JANUARY 1945 5230 211 LADD FIELD, ALASKA Hr. Day 0100 0200 0300 0400 0500 0600 0700 0800 0900 1000 1100 1200 1300 1400 1500 1600 1700 1800 1900 2000 2100 2200 2300 2400 Max. Min. Mean 1 1 0 0 -1 -2 -2 -3 -3 -4 -5 -4 -1 8 10 13 12 12 10 9 5 4 14 13 19 19 -6 4.4 2 15 21 19 11 9 4 4 4 1 4 9 8 16 16 22 22 22 22 20 20 18 16 17 11 23 -3 13.8 3 4 3 1 2 1 0 -1 -2 -2 -6 -4 1 4 6 12 14 14 7 4 1 2 -4 -6 -8 15 -8 1.8 4 -9 -10 -10 -12 -12 -12 -12 -9 -7 -5 -5 -2 2 3 5 6 6 6 6 6 6 6 6 6 6 -14 1.7 5 5 6 5 6 6 6 6 4 4 1 2 4 4 5 6 7 8 6 7 3 0 2 0 6 8 -2 4.5 6 8 7 8 6 5 4 4 3 1 2 3 7 11 12 11 11 10 9 9 8 7 4 2 0 13 -2 6.3 7 0 0 -5 -5 -2 -7 -7 -8 -9 -12 -7 -8 -5 -1 1 3 2 0 1 1 1 2 2 2 4 -15 -2.5 8 2 2 2 2 2 0 0 0 0 0 1 1 0 0 2 2 4 0 -3 -6 -5 -6 -11 -12 5 -14 -1.0 9 -10 -11 -10 -7 -5 -5 -5 -3 -2 -2 0 1 2 2 4 5 6 6 7 7 8 8 8 8 9 -14 0.5 10 7 6 6 5 4 4 4 3 3 2 0 0 1 4 6 5 5 3 1 0 6 5 3 3 8 -3 3.6 11 3 1 -1 -2 -5 -6 -7 -7 -9 -10 -12 -14 -15 -14 -16 -15 -16 -17 -18 -18 -19 -19 -20 -20 3 -20 -11.5 12 -20 -22 -24 -26 -26 -28 -28 -33 -34 -34 -30 -29 -29 -24 -22 -21 -20 -23 -25 -31 -35 -34 -34 -35 -20 -36 -27.8 13 -36 -36 -38 -37 -38 -37 -37 -40 -43 -40 -37 -32 -28 -17 -17 -16 -16 -21 -25 -26 -27 -27 -27 -27 -16 -45 -30.2 14 -27 -27 -29 -27 -26 -27 -33 -34 -34 -33 -30 -25 -13 -8 -2 -2 -2 -1 -4 -7 -9 -10 -9 -7 -1 -36 -17.7 15 -10 -8 -5 -3 -2 0 0 0 1 1 3 4 4 7 8 7 7 8 6 5 6 6 7 7 8 -12 2.5 16 7 7 8 8 8 8 8 7 7 8 8 13 13 17 17 15 13 13 10 5 2 2 1 1 18 0 8.6 17 2 4 6 6 7 7 8 7 7 8 8 11 12 17 19 19 19 20 19 19 15 13 13 14 20 2 11.7 18 6 5 6 5 5 9 7 5 4 7 7 8 15 21 23 23 22 19 20 17 15 18 18 17 25 3 12.6 19 17 13 14 9 8 7 6 11 11 11 10 10 10 12 13 13 13 12 12 12 10 10 10 9 18 2 10.9 20 9 6 6 4 4 5 8 9 5 6 4 7 13 14 19 20 21 19 17 10 7 7 8 6 22 1 9.8 21 8 6 7 8 9 9 9 9 6 6 6 11 13 13 16 17 17 17 15 15 14 13 12 10 18 1 11.1 22 11 10 9 11 12 12 12 9 10 8 12 12 17 18 21 22 19 18 20 20 18 22 22 22 22 7 15.3 23 21 20 18 18 20 23 23 31 32 35 37 37 38 41 43 46 44 45 43 35 33 31 27 23 48 17 31.8 24 24 24 22 23 23 23 27 27 28 29 30 37 40 40 39 40 39 38 38 39 40 41 38 35 41 18 32.7 25 35 32 29 29 29 31 31 31 32 30 29 29 28 30 30 31 32 31 29 29 26 23 24 21 35 21 29.2 26 17 12 10 13 10 7 7 6 7 6 8 12 18 28 30 30 30 29 29 25 28 26 26 26 33 2 18.8 27 25 28 26 29 28 28 28 27 29 30 32 34 32 33 33 32 32 32 32 31 30 29 27 26 34 25 29.7 28 26 25 25 24 22 21 19 19 13 15 21 21 25 27 28 27 27 26 23 22 22 19 19 22 30 11 22.4 29 30 31 TIME IS A. W. T. TEMPERATURES ARE IN DEGREES FAHRENHEIT MEAN FOR MONTH +6.9 TABLE I SURFACE TEMPERATURE FEBRUARY 1945 212 5230 TABLE II ATSC DEVELOPMENTAL TEST AIRPLANES TABLE III CWTD SERVICE TEST AIRPLANES Date Model Serial Arrived Flying Time in Remarks No. Ladd Alaska, hr. A-26B 41-39182 12/2/44 93:40 B-17G 43-38221 12/7/44 183:35 B-17F 42-30981 12/10/44 62 ;00 Photographic Tests B-24J 42-51660 11/11/44 202:05 Radio and Radar Tests B-24J 44-41378 11/11/44 147:30 B-25J 44-29258 11/25/44 87:15 B-29 42-65214 1/1/45 88:20 B-29 42-24612 12/21/44 122:50 Fuel injection engines P-38L 44-24050 12/2/44 142:30 P-51D 44-14476 12/7/44 44:15 P-61 B 42-39402 12/10/44 60:45 Crashed 24 Feb. Total loss P-59A 42-22610 12/9/44 69:40 P-63 A 42-70255 12/9/44 77:10 C-46 42-60983 Under contract to TWA for fuel volatility tests. C-47A 43-48088 12/9/44 121:50 C-49K 43-2017 Under contract to Phillips Petroleum Co. for fuel volatility tests. C-54B 43-17157 11/11/44 52:35 C-69 43-10314 3/29/45 24:10 F-5E 44-23602 12/12/44 78:00 Photographic tests WINTER 1944-45 A-26B 43-22426 P-38L 44-24696 44-24697 P-47D 42-28728 ' 42-28744 P-51D 44-14484 44-14513 B-17G 43-38586 43-38516 B-24J 44-41377 44-41369 B-25J 44-29113 44-29114 B-29 42-24768 ' C-45F 48-35894 44-47157 C-46A 42-96803 44-77444 L-5B 42-99641 42-99642 TABLE IV ATSC Personnel Attending 1944-1945 Cold Weather Tests Extreme Temperature Operating Unit: Lt. Col. N. C. Thyson Chief, ETOU and C-54 Project Officer Major L. C. Smith Executive Capt. Beach Barrett Operations and C-47 Project Officer Capt. W. I. Thieme Engineering and B-25 Project Officer 1st Lt. H. G. Apostolakos Administrative and Supply Capt. H. J. Andre P-61 Project Officer Capt. J. H. Brown P-51 Project Officer Capt. J. McGuyrt P-38 Project Officer Capt. H. T. Markey P-59 Project Officer 1st Lt. F. G. Bastian B-17 Project Officer 1st Lt. J. A. Festersen B-29 Project Officer 1st Lt. D. W. Mills B-24 Project Officer 1st Lt. J. R. Payne B-29 Project Officer Capt. J. C. Reilly C-69 Project Officer 1st Lt. C. H. Tillson A-26 Project Officer 1st Lt. R. E. Wahlborg Navigator M/Sgt. W. H. Brown Inspector S/Sgt. C. E. Vincent Radio Operator S/Sgt. M. E. Parker Radio Operator Pvt. J. A. Litton B-29 Engineer E. C. Theiss Aeronautical Engineer S. J. Russell Draftsman Aircraft Laboratory: Lt. Col. F. W. Warburton Supervision Capt. A. S. Anderson Flight Control and Structures 1st Lt. W. R. Maslin Hydraulic Systems Armament Laboratory: Capt. O. E. Hopkins Guns, Turrets, Fire Control N. S. Lestz Bombing Equipment Equipment Laboratory: Major H. R. Collins Supervision Capt. C. E. Wood Electrical Equipment Capt. T. C. Warner Instrument and Navigation 1st Lt. W. H. Giedt Heating and Defrosting Sgt. W. O. King -Ground Heaters Cpl. V. A. Valey Heating and Defrosting Cpl. J. Fox Instruments Cpl. F. C. Symmes Wing and Engine Covers Materials Laboratory: Major S. C. Britton Lubrication 1st Lt. T. F. Brick Hose and Tires Photographic Laboratory: Capt. J. J. Sylvester Camera and Photo Equipment 1st Lt. C. E. Woodall Camera and Photo Equipment C/WO S. P. Balcomb Camera and Photo Equipment Sgt. R. W. LaValley Camera and Photo Equipment Sgt. L. E. Poncet Camera and Photo Equipment Cpl. R. L. Wright Camera and Photo Equipment Power Plant Laboratory: Wm. Weitzen Supervision, Oil Systems J. W. Whittle Engine Test Stand C. W. Goodman Packard Engine A. L. Watts Mechanic S/Sgt. W. E. Bourne Mechanic Pvt. R. G. Dunn Cold Starting Propeller Laboratory: Capt. J. F. Schmidt Propeller Systems 1st Lt. H. B. Graham Propeller Systems S/Sgt. H. J. Frick Propeller Systems Aircraft Radio Laboratory: Capt. P. D. Langrick Supervision 1st Lt. D. H. Stouch Radar 2nd Lt. D. S. Frankel Communication and Navigation Cpl. J. Westwick Communication and Navigation Personal Equipment Laboratory: Major R. B. Bass Emergency Equipment & Clothing Major F. T. Foster Emergency Equipment & Clothing Capt. M. P. Learned Emergency Equipment & Clothing 1st Lt. A. D. Ivlen Emergency Equipment & Clothing H. B. Washburn, Jr. Emergency Equipment & Clothing Sgt. N. Bright Emergency Equipment & Clothing Technical Data Laboratory: S/Sgt. H. K. Hotchkiss Photographic Record of Test Program Sgt. J. V. Mascelli Photographic Record of Test Program Maintenance Division: Col. P. E. Shanahan Tactical Equipment Major H. F. Helbig Engines Capt. R. C. Johnson Aircraft Capt. W. J. Renyck Associated Equipment Supply Division: Major E. H. Krause Capt. E. E. Murphy Capt. J. A. Porter 1st Lt. J. H. Ball Phillips Petroleum Co.; Fuel volatility tests R. T. Agster in charge. 17 civ- ilians on contract to AAF. Transcontinental & Western: E. V. Albert in charge. 10 civ- Fuel volatility tests ilians on contract to AAF. 5230 213 TABLE V Manufacturer’s Technical Representatives Attending 1944-1945 Cold Weather Tests Airesearch Mfg. Co. E. Freitag Allison Division of General H. S.. Hanson Motors Corp. F. G. Dougherty Dell Aircraft Corp. M. K. Woods L. A. McIntosh Bendix Aviation Corp. K. S. Jackson C. Benassi J. P. Leahy C. W. Robins J. F. Carr Chandler Evans Corp. M. C. Cartney H. H. Wallace Consolidated-Vultee Aircraft Corp. D. M. Moore W. H. Sanderson Curtiss-Wright Corp. D. D. Waters A. H. Nisita Douglas Aircraft Corp. W. W. Thayer J. F. Hill D. W. Walters Fairchild Camera & Instrument Corp. W. C. Edwards General Electric Co. C. Meloun J. Robertson Hamilton Standard Propellers R. B. Carroll Jack & Heintz, Inc. G. P. Adams Lausen Engine Co. L. R. Pierce Linde Airproducts Co. C. H. Sweatt Lockheed Aircraft Corp. L. C. Chambers C. Schmidt C. Coleman Minneapolis Honeywell Regulator Co. R. C. Ruhland A. S. Knudson W. J. Field North American Aviation, Inc. J. A. Dunham Northrop Aircraft Corp. L. L. Collings C. W. Harris Packard Motor Car Co. C. R. Jones Perfection Stove Co. E. J. Althouse Pratt & Whitney Aircraft Div. S. D. Pearson C. Blakely R. Savery Republic Aviation Corp. J. McEwan Socony-Vacuum Oil Co. D. P. Heath Sperry Gyroscope Co. R. J. Pearson E. F. Reedy Surface Combustion Div. Lee Curtain M. Maeske The Texas Co. G. V. Roark United Aircraft Products Inc. A. C. Hoffman G. G. Karlsen J. D. Olcott W. D. Sherwood Walter Kidde & Co., Inc. R. W. Bowman Western Electric Co. E. W. Brinkerhoff Union Oil Co. M. S. Reynolds 214 5230