ECV56_Necathor Posted April 1, 2019 Posted April 1, 2019 (edited) I put this information maybe somebody can help to compare the version L, I can´t find enough info Page http://www.wwiiaircraftperformance.org/P-39/P-39.html WAR DEPARTMENT AIR CORPS, MATERIEL DIVISION Wright Field, Dayton, Ohio February 5, 1941 MEMORANDUM REPORT ON Pursuit One-Engine YP-39, A.C. No. 40-30 Subject: Acceptance Performance Test Section: Flying Branch Serial No: PHQ-M-19-1185-A Summary A. Purpose 1. Report on tests conducted at the manufacturer's plant on Bell YP-39. Airplane equipped with Allison V-1710-37 engine and 3-bladed constant speed propeller, blade design No. 614CC1.5-21, blade angle range 21° to 51° at 42" radius. Gross weight as tested 6592 lbs., c.g. location wheels down 26.1% m.a.c.; radio antenna in place; propeller not equipped with cuffs; two exhaust stacks per cylinder; venturi tube for alternate source of gyro suction retracted; wheels up, wing flaps neutral, carburetor cold, mixture control in automatic rich position, prestone and oil cooler shutters set flush with cowling during level flight, wide open in climb except where otherwise stated; guns in place. B. Test Results 1. High Speed at critical altitude for military rated power is 368 mph at 1090 bhp at 3000 rpm at 13,600 ft. The high speed is the same with or without camouflage. The camouflage consisted of one primer coat of zinc chromate and two coats of dull lacquer. 2. High speed at critical altitude for normal rated power is 348 mph at 940 bhp at 2600 rpm at 13,000 ft. 3. Speed with prestone and oil cooler shutters closed at 5000 ft. at 960 bhp at 2600 rpm is 329 mph. 4. Cruising data at 13,000 ft.: Speed MPH R.P.M. B.H.P. % Normal Rated Power 308 2280 720 75 296 2210 620 64.6 278 2120 525 54.7 246 1920 415 43.2 202 1720 310 33.5 5. Climb data: Altitude True Speed MPH R.P.M. B.H.P. Rate of climb Ft/Min Time of Climb Min. S.L. 153 3000 1090 3600 0 5,000 166 3000 1090 3600 1.4 10,000 179 3000 1090 3600 2.8 13,600 188 3000 990 3410 3.8 15,000 191 2600 835 2260 4.6 20,000 201 2600 685 1580 7.3 25,000 211 2600 550 980 11.2 30,000 220 2600 430 440 18.7 S/C 33,300 226 2600 - 100 32.4 A/C 34,400 227 2600 - 0 - For the full report see HERE See also: Memorandum Report on YP-39 A.C. No. 40-30, Tests Conducted at Manufacturer's Plant WAR DEPARTMENT AIR CORPS, MATERIEL DIVISION Wright Field, Dayton, Ohio July 17, 1941 MEMORANDUM REPORT ON Pursuit Single Engine P-39C, A.C. No. 40-2988 Subject: Flight Tests Section: Flying Branch Serial No: PHQ-M-19-1266-A Summary A. Purpose 1. Report on flight tests of Bell P-39C. Airplane equipped with Allison V-1710-35 engine and 3-bladed constant speed propeller, blade design No. 614CC1.5-21, blades not equipped with cuffs. Gross weight as tested 6689 lbs. Wheels up; wing flaps neutral; carburetor cold; one exhaust stack per cylinder; airplane camouflaged; cannon, two 30 cal. and two 50 cal. guns as well as radio antenna in place. Horsepowers were obtained from Fig 3, T.O. No. 02-5AD-1. B. Test Results 1. Military rated power speeds: Altitude Ft. Speed MPH R.P.M. B.H.P. Oil Cooler and Prestone Flap Control Position 13,050 369 3000 1150 Wide open *16,100 379 3000 1150 Flush with cowling 5,000 340.5 3000 1150 Wide open 5,000 350 3000 1150 Flush with cowling *Critical altitude for military rated power in level flight. 3. Climb data, prestone and oil cooler flaps wide open, mixture control automatic rich below 18,000 ft., automatic lean position above 18,000 ft. Oil and prestone temperatures do not meet Air Corps requirements in climb. Altitude Ft. Speed MPH R.P.M. B.H.P. Rate of climb Ft/Min Time of Climb Min. S.L. 153 3000 1150 3720 0 5,000 165 3000 1150 3720 1.35 10,000 178 3000 1150 3720 2.7 13,050 185.5 3000 1030 3040 3.6 16,750 194.5 3000 895 2360 5.0 20,000 200 2600 675 1530 6.9 25,000 211 2600 535 975 11.0 30,000 221 2600 - 440 18.4 S/C 33,200 227 2600 - 100 32.2 A/C 34,150 229 2600 - 0 - For the full report see HERE See also Bell Aircraft chart of P-39C performance WAR DEPARTMENT AIR CORPS, MATERIEL DIVISION Wright Field, Dayton, Ohio December 3, 1941 MEMORANDUM REPORT ON Pursuit Single Engine P-39D, A.C. No. 41-6722 Subject: Flight Tests Section: Flying Branch Serial No: PHQ-M-19-1325-A Summary A. Purpose 1. To report on flight tests of Bell P-39D airplane, A.C. No. 41-6722. Airplane equipped with Allison V-1710-35 engine and 3-bladed constant speed propeller, blade design No. 614-1C1.5-21, blade angle range 51.5° to 21.5° at 42 inch radius. Gross weight as tested was 7525 lbs.; c.g., wheels up, located at 25.8% m.a.c.; wheels up; wing flaps neutral; oil cooler and prestone shutters flush, and carburetor cold unless otherwise specified. Airplane camouflaged, radio antenna in place, cannon and two .50 cal. guns in nose and four .30 cal. guns in wings. Horse powers obtained from page 12 of Specification No. 123-E. Individual intake port backfire screens not installed in engine. B. Test Results 1. Speeds in level flight: Altitude Ft. Speed MPH R.P.M. B.H.P. Throttle Position Mixture Setting 5,180 336 3000 1150 Part Best power *13,100 347.5 2600 1000 Wide open Best power **13,800 368 3000 1150 Wide open Best power 13,800 365 3000 1125 Wide open Auto rich 25,300 352 3000 740 Wide open Best power 25,300 347 3000 710 Wide open Auto lean 25,300 345 3000 695 Wide open Auto rich *Critical altitude for normal rated power in level flight. **Critical altitude for military rated power in level flight. 3. Climb data: Prestone and oil cooler shutter wide open; mixture control auto rich below 20,000 ft.; auto lean above 20,000 ft. Altitude Ft. Speed MPH R.P.M. B.H.P. Rate of climb Ft/Min Time of climb Min. 0 157 3000 1150 2720 0 5,000 169 3000 1150 2720 1.84 10,000 183 3000 1150 2720 3.68 *12,400 190 3000 1150 2720 4.56 13,650 192 3000 1080 2515 5.0 15,000 194 2600 865 1880 5.7 20,000 203 2600 710 1300 8.9 25,000 213 2600 585 800 13.8 30,000 225 2600 465 300 20.8 S/C 31,100 229 2600 415 100 32.0 A/C 33,200 232 2600 390 0 - **Critical altitude for military rated power in climb. For the full report see HERE P-39D data taken from this report was used in the chart - Compartive Performance of P-39D, P-40F, and P-51 Airplanes WAR DEPARTMENT AIR CORPS, MATERIEL DIVISION Wright Field, Dayton, Ohio May 22, 1942 MEMORANDUM REPORT ON Pursuit Single Engine P-39D, A.C. No. 41-6897 Subject: Report of Flight Tests Section: Flight Section Serial No: PHQ-M-19-1385-A (Addendum No. 1) Summary A. Purpose 1. To report correction to Memorandum Report, Serial No. PHQ-M-19-1385-A. This report replaces the original which should be destroyed. 2. To report on flight tests of Bell P-39D airplane, A.C. No. 41-6897. Airplane equipped with Allison V-1710-35 engine and three-bladed constant speed propeller, blade design No. 614-1cl.5-21 blade angle range 51.5° to 21.5° at 42 inch radius. Airplane loaded to an approximate weight of 7800 pounds not including a 75 gallon belly tank installation. Wheels up; wing flaps neutral; oil cooler and prestone shutters flush and carburetor cold. Four .30 caliber wing guns, two .50 caliber synchronized guns and one cannon. Gun barrels and openings taped. Airplane as tested was fitted with winterized equipment. Horsepowers obtained from power curve dated March 25, 1941. Engine was equipped with manifold T-type screens, individual intake port screens removed. B. Test Results 1. Speeds in level flight at 13,000 feet. Belly Tank Brackets & Shackles Removed MPH Belly Tank Removed Shackles & Brackets in Place MPH Belly Tank (Full) Shackles & Brackets in Place MPH RPM Chart BHP Throttle Position Mixture setting 358 - - 3000 1170 W.O. A.R. 336.5 328 - 2600 974 W.O. A.R. - 349 - 3000 1165 W.O. A.R. - - 311.5 3000 1145 W.O. A.R. - - 294.5 2600 967 W.O. A.R. 321.5 312.5 282 2280 850 Part A.L. 301 292 264 2200 700 Part A.L. 276 267 241 2100 550 Part A.L. 257 247 221 1900 450 Part A.L. 222 212 184 1700 330 Part A.L. For the full report see HERE See also: P-39D-1 Performance Chart Memorandum Report Serial No. PHQ-M-19-1385-A WAR DEPARTMENT Army Air Forces MATERIEL DIVISION Wright Field, Dayton, Ohio December 18, 1942 MEMORANDUM REPORT ON Pursuit Single Engine P-39D-1, A.C. No. 41-28378 Subject: Critical Altitude and High Speed with two types of Intake Manifolds Section: Flight Serial No: FS-M-19-1521-A Summary A. Purpose 1. To report results of flight tests on the P-39D-1 airplane. A.C. No. 41-28378, to determine the high speed and critical altitude with the streamlined manifold consisting of "T" manifolds, Dwg. No. DRIMI-42790, pipe manifolds, Dwg. DRW-L-42791, and port manifolds, Dwg. Nos. 36086 and 36085; and also with the standard manifold with "T" screens installed consisting of "T" manifolds, Dwg. No. 40041, pipe manifolds, Dwg. No. 34167, and port manifolds, Dwg. Nos. 36086 and 36085. Airplane equipped with Allison V-1750-35 engine and with three-bladed constant speed propeller, Dwg. No. 614-1cl.5-21. Gross weight as reported by the Aircraft Laboratory was approximately 7450 pounds, at 30.9 percent m.a.c., wheels up. All tests with a 20 mm cannon in nose, two .50 caliber guns in the fuselage and four .50 caliber guns in the wings, radio antenna in place, and no sway braces installed. Power data obtained from Allison power curve for V-1710-69, 73, 35, and 39 engines dated September 29, 1942, for all tests with the streamlined manifold; power data for tests with the manifold with "T" screens was obtained from Allison curve for the V-1710-35 and 39 engines dated December 12, 1941. B. Test Results 1. High speed at 12,750 feet at 2970 RPM at wide open throttle. Intake Manifold True Speed MPH Manifold Pressure "Hg. b.h.p. from Chart Streamlined manifold 370 45.9 1162 Manifold with "T" Screens 369 45.4 1172 For the full report see HERE ARMY AIR FORCES MATERIEL CENTER Wright Field, Dayton, Ohio November 25, 1942 MEMORANDUM REPORT ON Pursuit Single Engine P-39M-3, A.C. No. 42-4706 Subject: Flight Tests Section: Flight Serial No: FS-M-19-1511-A Summary A. Purpose 1. Report on flight tests of Bell P-39M-3 airplane at the manufacturer's plant. Airplane equipped with Allison V-1710-83 engine and a three-bladed Curtiss Electric constant speed propeller, blade design No. 614-10-1-5-21, blade angle range 26° tp 56° at 42 inch radius. Gross weight at take-off was 7430 pounds with c.g. at 28.6 percent m.a.c., wheels up. Landing gear retracted; wing flaps neutral; carburetor cold; mixture auto-rich unless otherwise specified; one 37 mm cannon, four .30 caliber wing guns, and two .50 caliber nose guns in place with a corresponding ammunition load of thirty rounds of 37 ammunition, three-hundred rounds of .30 caliber ammunition per gun, and two-hundred round of .50 caliber ammunition per gun; radio, type 522, and radio mast which acts as a antenna wire in place, antenna removed; belly tank shackle and sway bracing in place; blast tube openings covered with tape. Horsepowers obtained from power curve V-1710-83 and -85 dated September 19, 1942 (2:1 propeller gear ratio; 9.6:1 blower gear). B. Test Results 1. High speeds, oil cooler shutters in flush position. Altitude Feet Speed MPH RPM b.h.p. Prestone Shutter Pos. (Turns from W.O.) Test Condition *15,900 373 3000 1125 6 Military Rated Power ** 9,500 385.5 3000 1420 6 War Emergency Power 9,500 350 3000 1125 6 Military Rated Power 2,750 345 3000 1330 6 Throttle open to 57" Hg. Man. Press. 2,750 322 3000 1125 6 Military Rated Power 30,200 337 3000 635 9 Throttle wide open at military rated RPM. *Critical altitude for military rated power in level flight. **Critical altitude for war emergency power in level flight. 5. Climb data: Prestone and oil cooler shutters wide open; mixture control in the auto-rich position. Throttle set for 50.5" Hg. at 3000 RPM or wide open when below. Altitude Feet Speed MPH RPM b.h.p. Rate of Climb Ft./Min. Time of Climb Min. S.L. 154 3000 1185 2870 0 5,000 167 3000 1210 3120 1.67 9,900 180 3000 1250 3320 3.19 15,000 188 * 1040 2640 4.91 20,000 193 * 880 2000 7.09 25,000 198 * 725 1400 10.08 30,000 203 * 595 800 14.76 35,000 208 * - 200 26.09 S/C 35,900 - * - 100 32.09 A/C 36,700 - * - - - 6. Climb data: Prestone and oil cooler shutters wide open; mixture control in the auto-rich position. Throttle set for 57" Hg. at 3000 RPM or wide open when below. Altitude Feet Speed MPH RPM b.h.p. Rate of Climb Ft./Min. Time of Climb Min. S.L. 160 3000 1355 3740 0 5,000 173.5 3000 1395 3840 1.32 6,500 177 3000 1400 3880 1.71 10,000 184 3000 1250 3310 2.69 15,000 189.5 - 1030 2640 4.38 For the full report see HERE WAR DEPARTMENT AIR CORPS, MATERIEL DIVISION Wright Field, Dayton, Ohio October 17, 1942 MEMORANDUM REPORT ON Pursuit Single Engine P-39N-1, A.C. No. 42-4400 Subject: Flight Tests Section: Flight Serial No: FS-M-19-1487-A Summary A. Purpose 1. Report on flight tests of Bell P-39N-1 airplane at the manuacturer's plant. Airplane equipped with Allison V-1710-85 engine and three-bladed constant speed aero-propeller, blade design No. A-20-156-17, blade angle range 28° to 63°, at 42 inch radius. Gross Weight at take-off was 7274 pounds with c.g. at 29.0 percent, wheels up. Wheels up; wing flaps neutral; carburetor cold; mixture auto-rich unless otherwise specified; one exhaust stack per cylinder; one 37 mm. cannon, four .30 caliber wing guns, and two .50 caliber nose guns in place with a corresponding ammunition load of thirty rounds of 37 mm. ammunition, 300 rounds of .30 caliber ammunition per gun, and 250 rounds of .50 caliber ammunition per gun. Radios and radio mast and antenna in place with belly tank shackle without sway bracing in place. Horsepowers obtained from power curve V-1710-83 and 85 dated September 19, 1942 (2.23:1 propeller gear ratio; 9.6:1 blower gear). B. Test Results 1. High Speeds, blast tubes closed. Altitude Speed MPH RPM b.h.p. Man.Pr. Hg. Oil Cooler Shutter Position Prestone Shutter Position *16,100 389.5 3000 1125 46.7 Flush 6 turns from W.O. **9,700 398.5 3000 1420 59.8 Flush 6 turns from W.O. 2,700 358.0 3000 1330 57.0 Flush 6 turns from W.O. 30,100 353.0 3000 655 26.7 Flush 6 turns from W.O. Airplane does not meet Air Corps cooling requirements at any of these powers. Test with blast tubes open showed no measurable difference in speed from test with blast tubes closed. *Critical altitude for military rated power in level flight. **High speed at critical altitude for war emergency power; critical altitude for 57" Hg. was 10,900 feet. Speed at wide open throttle at 10,900 feet was 1.5 MPH less than speed at 9700 feet. 3. Climb data, prestone and oil cooler flaps wide open; blast tubes closed; mixture control in auto-rich position. Throttle set for 50.5" Hg. at 3000 RPM of wide open when below. Altitude Ft. Speed MPH RPM b.h.p. Rate of Climb Ft/Min. Time of Climb Min. S.L. 156 3000 1170 3320 0 5,000 169 3000 1200 3600 1.45 10,000 182 3000 1230 3865 2.79 11,000 185 3000 1235 3920 3.05 15,000 194 3000 1060 3340 4.15 20,000 205 3000 885 2630 5.83 25,000 216 3000 745 1940 8.04 30,000 227 3000 630 1260 11.21 35,000 241 3000 -- 580 16.88 S/C 38,500 -- 3000 -- 100 29.2 A/C 39,400 -- 3000 -- -- -- Prestone temperature does not meet Air Corps requirements in climb. High prestone temperature observed in climb was 136°C at 11,000 feet at 1235 b.h.p. with a free air temperature of +4°C. For the full report see HERE See also: P-39N Level Speeds ARMY AIR FORCES MATERIEL CENTER Wright Field, Dayton, Ohio November 24, 1942 MEMORANDUM REPORT ON Pursuit Single Engine P-39N-1, A.C. No. 42-4400 Subject: Flight Tests Section: Flight Serial No: FS-M-19-1510-A Summary A. Purpose 1. Report on climb and take-off tests of Bell P-39N-1 airplane at the manuacturer's plant. Airplane equipped with Allison V-1710-85 engine and three-bladed constant speed propeller, blade design No. A-20-156-17, blade angle range 28° to 63°, at 42 inch radius. Gross Weight at take-off was 7301 pounds with c.g. at 28.8 percent, wheels up. Landing gear retracted; wing flaps neutral; carburetor cold; mixture auto-rich; one 37 mm. cannon, four .30 caliber wing guns, and two .50 caliber nose guns in place with a corresponding ammunition load of 30 rounds of 37 mm. ammunition, 300 rounds of .30 caliber ammunition per gun, and 200 rounds of .50 caliber ammunition per gun. Radio and radio mast and antenna in place with belly tank shackle without sway bracing in place. Horsepowers obtained from power curve V-1710-83 and -85 dated September 19, 1942 (2.23:1 propeller gear ratio; 9.6:1 blower gear). B. Test Results 1. Climb data: Prestone and oil cooler flaps wide open; blast tubes closed; mixture control in the automatic rich position. Throttle set for 57 inches Hg. at 3000 RPM or wide open when below. Altitude Ft. Speed MPH RPM b.h.p. Rate of Climb Ft/Min. Time of Climb Min. S.L. 160 3000 1355 3980 0 5,000 173 3000 1375 4240 1.22 7,500 178.5 3000 1390 4360 1.80 10,000 183 3000 1265 3900 2.41 15,000 192 3000 1060 3230 3.82 Prestone temperature does not meet Air Corps requirements in climb. Highest observed prestone temperature in climb was 126°C 1t 12,000 feet at 1225 b.h.p. with a free air temperature of -12°C. Anticipated prestone oil temperature for Air Corps "hot day" 152°C. For the full report see HERE ARMY AIR FORCES MATERIEL COMMAND Wright Field, Dayton, Ohio 4 August 1943 MEMORANDUM REPORT ON Pursuit Single Engine P-39Q-5, AAF No. 42-19615 Subject: Flight Tests Section: Flight Serial No: ENG-47-1631-A Summary A. Purpose 1. To report on flight tests of the Bell P-39Q-5 airplane, AAF No. 42-19615 at Wright Field. B. Factual Data and Test Results High Speed in Level Flight: Throttle open to 57" Hg at 3000 RPM or wide open when below. Oil shutters in flush position. Coolant shutters open to 2.9 inches of gap from flush position, corresponding to approximately 6 turns from wide open, on all tests runs. The dashed line on the speed versus altitude curve on page A-1 represents the true speed that would be obtained if the coolant shutters were closed down to give a limiting standard coolant temperature of 125° C. Altitude Ft. Speed MPH BHP from Chart Manifold Pressure "Hg. Test Coolant Shutter Position Inches open from Flush Coolant Shutter position to give 125°C STD limiting temp. In. open from flush Corresponding speed MPH 0 329 1355 57 2.9 1.8 330 5,000 352 1380 57 2.9 2.2 352 *10,000 374 1405 57 2.9 2.6 374 15,000 371 1140 46.7 2.9 1.8 372 20,000 366 940 38.6 2.9 1.2 368 25,000 358 772 31.7 2.9 0.5 361 30,000 346 620 25.4 2.9 0.0 350 * Critical altitude War Emergency Power 57" Hg at 3000 RPM Climb data: Throttle set for 57" Hg at 3000 RPM or wide open when below. Oil shutters and colland shutters wide open. Altitude Ft. Speed MPH BHP from Chart Manifold Pressure "Hg. Rate of Climb Ft/Min. Time to Climb Min. 0 172 1360 57 3690 0.0 5,000 185 1382 57 3770 1.25 *7,400 191 1400 57 3805 1.90 10,000 194 1260 51.3 3475 2.61 15,000 199 1050 42.8 2840 4.20 20,000 202 882 36.0 2200 6.20 25,000 206 740 30.2 1570 8.90 30,000 208 609 24.9 940 12.95 35,000 - - - 310 21.8 S/C 36,000 - - - 100 28.5 A/C 37,400 - - - - - * Critical altitude in War Emergency Power, Climb - 57" Hg at 3000 RPM For the full report see HERE ARMY AIR FORCES MATERIEL COMMAND Wright Field, Dayton, Ohio 9 October 1943 MEMORANDUM REPORT ON Pursuit Single Engine P-39Q-5, AAF No. 42-19615 Subject: Flight Tests Section: Flight Serial No: ENG-47-1651-A Summary High speed at 11,000 feet (critical altitude for P39N with 57 inches manifold pressure and 3000 R.P.M.) Wide open throttle and 3000 R.P.M., oil shutters in the flush position. Coolant shutters open to 2.9 inches of gap from the flush position corresponding to approximately six turns from wide open. Altitude Ft. Speed MPH BHP from Chart Manifold Pressure "Hg. Test Coolant Shutter Position Inches open from Flush 11,000 385.0 1340 54.5 2.9 Performance previously obtained, with the two external caliber .50 wing guns and the airplane at the same weight, gave the following results. Altitude Ft. Speed MPH BHP from Chart Manifold Pressure "Hg. Test Coolant Shutter Position Inches open from Flush 11,000 372.5 1340 54.5 2.9 Climb Data: Wide open throttle and 3000 R.P. M., oil shutters and coolant shutters wide open. Altitude Ft. Speed MPH BHP from Chart Manifold Pressure "Hg. Rate of Climb Ft/Min. Time to Climb Min. 0 171 1310 55.0 3470 0 5,000 185 1330 55.0 3540 1.43 * 8,100 191 1350 55.0 3580 2.29 10,000 193 1255 51.2 3307 2.85 15,000 197 1040 42.6 2640 4.54 20,000 200 870 35.5 2007 6.71 25,000 203 720 29.3 1365 9.72 30,000 206 580 24.0 725 14.66 S/C 34,900 208 450 19.2 100 29.6 A/C 35,700 -- -- -- 0 -- * Critical altitude in climb for 55 inches Hg. at 3000 R.P.M. The above results should not be directly compared with the results in previous climbs with two external guns in place. Considerable engine trouble was experienced while attempting to obtain climbs with the guns off and as can be seen from the above results, the engine was not developing full emergency power. Flight test made on the XP-63 airplane with two externally mounted wing guns on and off indicate that an increase of only approximately 110 Ft./Min. in rate of climb is obtained by removing the guns. Such a figure is close to the limites of climb determination accuracy. Since the wing gun installation on the P-39Q-5 is similar to that on the XP-63, it is probable that the removal of the wing guns on the P-39Q-5 has no greater effect than that determined for the XP-63. P-39Q-5 No. 42-19615 Climb Data P-39Q-5 No. 42-19615 Level Flight Data For the full report see HERE ARMY AIR FORCES MATERIEL COMMAND Wright Field, Dayton, Ohio 28 July 1944 MEMORANDUM REPORT ON P-39Q Airplane, AAF No. 44-3455 Subject: Report of Spin Tests Section: Flight Serial No: ENG-47-1779-A Conclusions 1. The P-39 should not be spun intentionally under any circumstances. 2. The P-39 should not be snap rolled as the roll usually ends in a spin. 3. The best spin recovery is to simultaneously apply opposite rudder and neutralize the stick. 4. Power should be cut immediately if a power on spin is entered. 5. Care must be excercised during the recovery to prevent an accelerated stall and re-enty into the spin. 6. The wing tip spin chute does not aid recovery of the P-39Q from a flat spin. For the full report see HERE AEROPLANE AND ARMAMENT EXPERIMENTAL ESTABLISHMENT BOSCOMBE DOWN Airacobras A.H.573 and A.H.701 (Allison V-1710-EA) Climb and level speed performance 25 September 1942 Summary Performance trials have been made on Airacobras A.H.573 and A.H.701 each fitted with an Allison V-1710.E.4. engine. The results were:- Maximum rate of climb 2040 ft/min at 10,300 ft. Service ceiling 29,000 ft. Time to 10,000 ft. 5.1 mins. Time to 20,000 ft. 11.7 mins. Maximum true air speed in level flight 355 m.p.h. at 13,000 ft. Airacobra AH-573 - Rate of Climb, Boost, and Time to Height Airabobra AH-701 - Level Speeds and Boost at Height For the full report see HERE (Click to enlarge) (Click to enlarge) (Click to enlarge) (Click to enlarge) (Click to enlarge) (Click to enlarge) (Click to enlarge) Supplemental Memorandum Report on XP-39B 38-326, Comparitive Speed Tests Memorandum Report on P-39C 40-2974, Flight Test for Determination of Fuel Consumption Data Memorandum Report on P-39C 40-2676, Propeller Tests Memorandum Report on P-39C 40-2990, Flight Tests - Critical Altitude and High Speed Memorandum Report on P-39D 41-6897, Report of Flight Tests Memorandum Report on P-39D 41-6897, Effect of Extended Landing Light Memorandum Report on P-39D 41-6722, Carburetor Air Heater Memorandum Report on P-39D 41-6722, Full Range Mixture Control Valve Memorandum Report on P-39D 41-6926, Intake Manifold without back-fire screens Memorandum Report on P-39F 41-7246, Flight Tests Memorandum Report on XP-39E 41-19502, Flight Tests Memorandum Report on XP-39E 41-19502, Pilot's Comments Memorandum Report on P-39N-1 42-9337, Speed Tests, smoothed camouflage finish P-39N Level Speeds P-39M Performance and Specifications Measurements of the Flying Qualities of a Bell P-39D-1 Airplane (A.A.F. No. 41-28378) Pilot's Flight Operating Instructions for Army Models P-39K-1 and P-39L-1 Airplanes Pilot's Flight Operating Instructions for Army Model P-39Q-1 Airplane The High-Speed Longitudinal Stability and Control of the P-39N-1 Airplane Airacobra A.H.573 Perliminary Handling Trails Comparative Performance of P-39D, P-40F, and P-51 Airplanes Airplane Performance Characteristics for the P-39 Planes Main © 2012 WWIIaircraftperformance.org All Rights Reserved Edited April 6, 2019 by ECV56_Necathor
1CGS LukeFF Posted April 1, 2019 1CGS Posted April 1, 2019 Going to need to be a tad bit more concise than that. 1
Ehret Posted April 1, 2019 Posted April 1, 2019 Try something: set the "unbreakable" flag in custom options; load the Kuban autumn map; remove 0.30" cals from wings; start flying over the water at about 50m. Set auto-level, set water radiator to 60%, the oil radiator to 45%, revs to 2900rpm, mix to 66% and fully advance the throttle. Then wait and check what top speed will you get. Raw performance of the P-39L is not a problem in the game. Boost timers, rampart overheats and a very sluggish pitch governor are.
CountZero Posted April 2, 2019 Posted April 2, 2019 (edited) You can do 580kmh on deck on max power, same like chart shows, i agre with Ehret speeds are ok they do great job but how usaf engine work in game is to strickt and in game problematic compared to real life. first line is combat settings, 2nd is max (1km intervals, probably if aditional test of max power is run on ~2600m it would show exact as charts) Spoiler Edited April 2, 2019 by 77.CountZero
Brano Posted April 2, 2019 Posted April 2, 2019 Airacobra in game is L model. Developers data were most probably taken from only available tests done by НИИ ВВС for P-39L-BE sr.nr. 42-4666 with Allison V-1710-63 (E-6) nr.42-26500.
-=PHX=-SuperEtendard Posted April 2, 2019 Posted April 2, 2019 (edited) 17 hours ago, Ehret said: Try something: set the "unbreakable" flag in custom options; load the Kuban autumn map; remove 0.30" cals from wings; start flying over the water at about 50m. Set auto-level, set water radiator to 60%, the oil radiator to 45%, revs to 2900rpm, mix to 66% and fully advance the throttle. Then wait and check what top speed will you get. Raw performance of the P-39L is not a problem in the game. Boost timers, rampart overheats and a very sluggish pitch governor are. With emergency power not eating combat power time and then recharging at the same rate as other planes it would be a very good upgrade for the P-39. Remember we got 60" as some sort of late setting bonus IIRC (when the P-39N/Q were using 57") , alongside the manifold pressure regulator, which we shouldn't have for the L variant, and removing the wing .30 cals wasn't really common apparently (most of the pics show them) that was mostly done with the wing .50 cal gondolas of the P-39Q. For this variant the standard emergency would be 51" (at least in the early 1943 period) and if they had access to 100 octane fuel, which aparently was rather rare at some point, with the native 92 ish octane being the more common it was a bit more limited afaik. Edited April 2, 2019 by -=PHX=-SuperEtendard
Brano Posted April 2, 2019 Posted April 2, 2019 Engine was rated for 100 octane. No "native 92" was in use. Only Land-Lease Б-100. E-4 type Allison from older Airacobra models could run on 95 octane (Domestic 4Б-78) 2
-=PHX=-SuperEtendard Posted April 2, 2019 Posted April 2, 2019 (edited) Just now, Brano said: Engine was rated for 100 octane. No "native 92" was in use. Only Land-Lease Б-100. E-4 type Allison from older Airacobra models could run on 95 octane (Domestic 4Б-78) Thanks for the clarification, so that would apply to the earlier D model which used the V-1710-35 then? (the restriction of not going too much past 50"). I recall it in an interview with a pilot but I can't find it now. I remember he (or the author) was talking about the pressure units as if they were in mmHg instead of in Hg (like 50mmHg for example). Edited April 2, 2019 by -=PHX=-SuperEtendard
Brano Posted April 2, 2019 Posted April 2, 2019 V-1710-35 was used in Airacobras Mk.I which UK found redundant and send them to USSR . 265 were loaded on ships, 212 arrived to Murmansk. First real Land-Lease model was P-39D-2. That one allready had E-6 Allison.
-=PHX=-SuperEtendard Posted April 2, 2019 Posted April 2, 2019 (edited) 21 minutes ago, Brano said: V-1710-35 was used in Airacobras Mk.I which UK found redundant and send them to USSR . 265 were loaded on ships, 212 arrived to Murmansk. First real Land-Lease model was P-39D-2. That one allready had E-6 Allison. Yes I meant the P-400/P-39D-1. I'm curious about the electric propeller governor which also affects the P-40E, are there sources that detail how fast it adjusted the RPM at high speeds to compare in game? Edited April 2, 2019 by -=PHX=-SuperEtendard
ECV56_Necathor Posted April 2, 2019 Author Posted April 2, 2019 Well thank for your replies boys. Main issue about this our L model is the one with less info that I could find, L model must be between D and N model, as you mention times on motor are really small I tried setting with D model at 15000ft and sea level but was impossible to reach the speed of the table can I even tried with settings of model N. For example climbing is far away from tables for D and N models. I will tried to do all test that I put on the info. But for example P40 have better climbing rate that P39.
E69_geramos109 Posted April 3, 2019 Posted April 3, 2019 (edited) I think the problem with P39 is that complex engine management we have to do and the time limitations for the engine setup but regarding the speed the P39 is indeed a very fast plane. What I hate about the P39 mostly is the shit visibility and the armament. 2mgs is just not enought and the main gun has a slow rate of fire so is difficult to hit anything with that. So for being a boom and zoomer the lack of armament for me is a problem. P40 at least have more punch but is slow as hell. Still need to buy it to test the P40. I think I would like the 20mm verssion of the english P400 rather the 37 mil gun [edited] 18. Claiming that FM is incorrect without the required proof and starting a flame thread based on such claim is prohibited. The form for an FM claim consists of: short but consistent description of the claim; link to a reference and to a specific part of such reference that describes correct behaviour of a disputed element/situation; game track record and the list of conditions used to recreate disputed element/situation. Exception to this rule: FM discussion Edited April 3, 2019 by SYN_Haashashin
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