P-38 Performance Tests

WAR DEPARTMENT
AIR CORPS, MATERIEL DIVISION
Wright Field, Dayton, Ohio
February 12, 1941

MEMORANDUM REPORT ON
Lockheed YP-38 Airplane, A.C No. 39-689

Subject:      Flight Test
Section:      Flying Branch
Serial No:   PHQ-M-19-1191-A

Summary

A.Purpose
 
  1.Flight test of the Lockheed YP-38 airplane equipped with Allison V-1710-27 and 29 engines and constant speed propellers, blade design No. 615CC1.5-6. Airplane flown at full military load of 13,500 lbs., c.g. at 29.44% m.a.c. Radio antenna in place, gun openings covered, wheels up, wing flaps neutral.
 
B.Factual Data
 
  1.Speeds with original cooling air scoops on turbos, prestone and oil cooler shutters in the flush position:


 Altitude Ft.True Speed MPHB.H.P. per EngineR.P.M.Mixture Control

   5,00034511503000Auto rich
   5,00033410002600Auto rich
   5,000301  7502280Auto lean
   5,000262  5002000Auto lean
 20,00039011503000Auto rich
 20,00038110002600Auto rich
 20,000349  7502280Auto lean
 20,000308  5002000Auto lean

  2.With new smaller type of cooling air scoops on turbos, mixture automatic rich, prestone and oil shutters in the flush position:

 20,00039311503000         
 20,00038410002600 

    Note:All level flight runs made with prestone and oil cooler shutters in the flush position. Airplane will not meet Air Corps cooling requirements with shutters in this position.

  3.Climb data - prestone and oil cooler shutters wide open:


 Altitude Ft.Rate of Climb
Ft/Min
BHP/EngineR.P.M.True Airspeed
MPH
Time
Min.

          03200113530001610   
   5,000320011353000171  1.56
 10,000313011303000182  3.13
 15,0002830112530001934.8
 20,0002300  96526002066.8

    Altitude obtained in 6 mins is 18,100 ft. using military power for 5 mins.

For the full report see HERE


WAR DEPARTMENT
AIR CORPS, MATERIEL DIVISION
Wright Field, Dayton, Ohio
December 24, 1941

MEMORANDUM REPORT ON
Pursuit Twin-Engine P-38D, A.C No. 40-774

Subject:      Performance Tests
Section:      Flying Branch
Serial No:   PHQ-M-19-1328-A

Summary

A.Purpose
 
  1.To report on performance tests of P-38D airplane, A.C. No. 40-774. Airplane equipped with Allison V-1710-27 and V-1710-29 engines and three-bladed constant speed propellers, blade design No. 615CC1.5-6 and 614CC1.5-6, normal blade angle range 21.5° to 56.5° at 42" radius. Airplane not weighed at Wright Field but loaded with 2485 lbs. useful load. Landing gear retracted; wing flaps neutral. Cockpit cabin closed; prestone and oil cooler shutters in faired position, radio antenna in place, guns installed and not covered. Engine equipped with individual port backfire screens.
 
B.Test Results: Based on horse power figures furnished by Power Plant Laboratory. Data obtained from dynamometer tests of V-1710-27 engine, A.C. No. 40-3012. However, horse power data still appears doubtful in the light of results obtained in flight tests (i.e. Note: that 300 h.p. are required to change from 319.5 mph at 2600 at 2000 bhp to 322 mph at 3000 rpm at 2300 bhp at 5000 ft.). Practically all flight tests on airplanes equipped with torque meters show that the power chart method for determination of B.H.P. is not reliable.
 
  1.Level flights speeds:


 Altitude Ft.True Speed MPHR.P.M.B.H.P. per Engine

 *20,100   375   30001150
 20,100340   2280  750
 20,100328.52200  675
 20,100313.02100  575
 20,100293.01900  450
 20,100271.01700  330
   5,000322   30001150
   5,000319.526001000
   5,000295.52280  750
   5,000277.52200  625
   5,000266.02100  550
   5,000249.01900  450
   5,000224.01700  325

*Carburetor air intercooling is insufficient to meet Air Corps requirements but is better than on the P-38E.

For the full report see HERE


WAR DEPARTMENT
AIR CORPS, MATERIEL DIVISION
Wright Field, Dayton, Ohio
October 31, 1941

MEMORANDUM REPORT ON
Pursuit Twin-Engine P-38E, A.C No. 41-1983

Subject:      Acceptance Performance Tests
Section:      Flying Branch
Serial No:   PHQ-M-19-1313-A

Summary

A.Purpose
 
  1.Report on flight tests of P-38E conducted at the manufacturer's plant. Airplane equipped with Allison V-1710-27 and V-1710-29 engines and three-bladed constant speed propellers, blade design No. 615CC1.5-6 and 614CC1.5-6, normal blade angle range 21.5° to 56.5° at 42" radius. Gross weight as tested 14,458 lbs., c.g. 30.85% m.a.c. with wheels up. Landing gear retracted; wing flaps neutral; cockpit cabin and ventilator closed; prestone and oil cooler shutters in faired position in level flight, wide open in climb; radio antenna in place; flush cover plates over gun openings.
 
B.Test Results
 
  1.Level flights at 5000 ft. density altitude, corresponding pressure altitude 5225 ft., free air temperature plus 3° C., mixture automatic rich.:


 True Speed, MPHAve.
RPM
Ave.
Intake
Man. Pressure
"Hg.
Ave.
Ex.
Man. Pressure
"Hg.
Ave.
Carb.
Air Temp
°C.
Ave.
Oil
"In" °C.
Ave.
Prestone
"Out" °C.

 Corrected
for
Compressibility
Not Corrected
for
Compressibility

 337.5338.830004031   30   80105
 332.5338.830003830   27.582105
 327.2328   30003628.924.582104
 321.5322.130003428.221.582103
 313.9315   30003227.319.581101

  2.Level flights at 20,000 ft. density altitude, corresponding pressure altitude 18,400 ft., free air temperature -7° C., mixture automatic rich for military and normal rated r.p.m. tests, in automatic lean position for cruising r.p.m. flights.


 True Speed, MPHAve.
RPM
Ave.
Intake
Man. Pressure
"Hg.
Ave.
Ex.
Man. Pressure
"Hg.
Ave.
Carb.
Air Temp
°C.
Ave.
Oil
"In" °C.
Ave.
Prestone
"Out" °C.

 Corrected
for
Compressibility
Not Corrected
for
Compressibility

 377   382.1300037   27   53   89124
 369.8375.3300035   25.747.588122
 363.5368   300033   24.243   88121
 355.2380   300031   23.438   88120
 348.5353   300029   22.333   88118
 381   386.1260037.527.757.576116
 373   378   260035   26.251   76116
 366   371.2260033   25.145.576115
 359   363.8260031   23.440   76114
 352   356.2260029   22.634.276112
 354.2359.2228032   24.243   80115
 333.5337.2215029   22.534   80110
 318.3321.7200027   21.428.579108
 288   290   180023.419.419   78110

  3.Advantage was taken of a day when for all practical purposes air conditions were standard and the following level flight was obtained; density altitude 20,000 ft., pressure altitude 19,920 ft., free air temperature -24° C., mixture control in automatic rich position

387394300040.528.55089115

The test had to be discontinued after 4 mins. when the left engine cut out. Inspection of the Cuno strainer showed metal particles. A report has not yet been received as to the nature of the failure.

  4.Climb data, mixture control in automatic rich position:


 Std.
Alt.
Ft.
Elapsed
Time in
Climb
Min.
True
Speed
MPH
Ave.
R.P.M.
Ave.
Intake
Man.
"Hg.
Ave.
Exhaust
Man.
"Hg.
Ave.
Carb.
Air
°C.
Free
Air
Temp
°C.

          00      162300040.634.929+17
   5,0001.57172300040.632.430   +  4.5
 10,0003.30183300040.630.433-  5
 14,6005.00194300040.629.040-13
 15,0005.15195260037.628.632-14
 20,0007.21209260037.627.044-24
 25,0009.75223260037.627.057-34
 26,00010.28227260037.626.960-35

Test discontinued at 26,000 ft. due to high carburetor air temperature.

For the full report see HERE


WAR DEPARTMENT
AIR CORPS, MATERIEL DIVISION
Wright Field, Dayton, Ohio
December 23, 1941

MEMORANDUM REPORT ON
Pursuit Twin-Engine P-38E Airplane, A.C No. 41-1983

Subject:      Performance Tests
Section:      Flying Branch
Serial No:   PHQ-M-19-1327-A

Summary

A.Purpose
 
  1.Report on acceptance performance tests of P-38E conducted at the manufacturer's plant. Airplane equipped with Allison V-1710-27 and V-1710-29 engines and three-bladed constant speed propellers, blade design No. 615CC1.5-6 and 614CC1.5-6, normal blade angle range 21.5° to 56.5° at 42" radius. Gross weight as tested 14,458 lbs., c.g. 30.85% m.a.c. with wheels up; landing gear retracted; wing flaps neutral; cockpit cabin and ventilator closed; prestone and oil cooler shutters in faired position in level flight, wide open in climb; radio antenna in place; flush cover plates over gun openings.
 
B.Test Results:     Based on horse power figures furnished by Power Plant Laboratory. Data obtained from dynamometer tests of V-1710-27 engine, A.C. No. 40-3012.
 
  1.Level flight speeds.


 Altitude Ft.True Speed MPHR.P.M.B.H.P. per Engine

   5,000340.530001150
 *20,000   393   30001150
 *20,000  386.526001000
 *20,000  352.52280  750
 20,000336   2150  650
 20,000319   2000  550
 20,000287.51800  375

*Carburetor air intercooling is insufficient to meet Air Corps cooling requirements.

  2.Climb data, mixture control in automatic rich position:


 Altitude
Ft.
Elapsed Time in
Climb Min.
True Speed
MPH
R.P.M.B.H.P. per Engine

           00     16230001125
   5,000  1.5717230001128
 10,000  3.3018330001127
 14,600  5.0019430001116
 15,000  5.151952600  999
 20,000  7.212092600  977
 25,000  9.752232600  955
 26,00010.282272600  950

Test discontinued at 26,000 ft. due to high carburetor air temperature (60° C.)

For the full report see HERE



LOCKHEED AIRCRAFT CORPORATION
Burbank, California

Report No. 2338
August 5, 1942

Contract Model Specification
For Lockheed Lightning II
Two Engine Interceptor Fighter Airplane

Model P-38F-13-LO, P-38F-15-LO, P-38G-15-LO, Lightning II,
Lockheed 322-60-19, 322-68-19

Summary

The following are the performance characteristics at a Gross Weight of 14,673 pounds:
GUARANTEED
 
  *High Speed at 27,000 Ft. with 1150 BHP per engine404 MPH
  *High Speed at   5,000 Ft. with 1150 BHP per engine340 MPH
Endurance at Normal Power (1000 BHP per engine) at 20,000 Ft.1.1 Hr.
**Time to climb to 20,000 Ft.7.6 Min.
Distance required to take-off or land over a 50 ft. obstacle, within2100 FT.
 
The performances stated in this paragraph are guaranteed to +/- 1.5%.
Engine power ratings for both the V-1710-F5 and the V-1710-F10 engine installations shall be the same.
 
*   Based upon sea level compressibility correction.
** 5 minutes at 1150 BHP per engine, 2.9 minutes at 1000 BHP per engine.

Performance Summary


ARMY AIR FORCES PROVING GROUND COMMAND
EGLIN FIELD, FLORIDA

TACTICAL SUITABILITY OF THE P-38F TYPE AIRPLANE
6 March 1943

Conclusions

                 a.    For a general combination of climb, range, endurance, speed, altitude and fire power, the P-38F is the best production line fighter tested to date at this station. Types tested include the P-47, P-51, P-40F and P-39D-1.

                 b.    The allowable maximum diving speed is not as great as desired for combat operations.

                 c.    At speeds above allowable diving speeds especially over twenty-thousand (20,000) feet, violent vibrations from tail buffeting are experienced.

                 d.    The maintenance difficulties experienced were greater than with any other standard type of American fighter.

                 e.    The subject aircraft is easy to fly. However, a longer period of time will be required for a pilot to become familiar with the operations and maximum performances of the aircraft than is required for a normal single engine fighter.

                 f.    The cockpit installations are crowded and not arranged in a specific orderly fashion.

                 g.    While the rate of climb is superior to all other types tested to date, this is not as great as required, especially below twenty-thousand (20,000) feet, and all excess weight in the structure and installations not vital to combat operations should be reduced or eliminated whenever possible.

                 h.    Cooling capacity of the intercooler is not sufficient to allow maximum horsepower to be extracted from the engine at altitude.

                 i.    The guns will not feed properly during maneuvers which create a pull of greater than 3-1/2 Gs.

For more of this report see HERE


ARMY AIR FORCES
MATERIEL CENTER
Wright Field, Dayton, Ohio
February 10, 1943

MEMORANDUM REPORT ON
P-38G-1 Airplane, A.C No. 42-12687

Subject:      Performance Tests
Section:      Flight
Serial No:   FS-M-19-1538-A

Summary

A.Purpose
 
  1.Report on performance of P-38G-1 equipped with V-1710-51 and -55 engines and three bladed constant speed propellers, design Nos. 88996-18 and 89303-18, blade angle range 22.7 to 57.7 at 42 inch radius. Take-off gross weight 13,900 pounds, c.g. location wheels up, 30.9 percent m.a.c. Tested with one 20 mm. cannon (50 rounds of ammunition) and two .50 caliber guns (400 rounds), radio antenna (three wire) in place, and with 180 gallons of fuel. Wheels up, wing flaps neutral, prestone and oil cooler shutters in the faired position for level flight and wide open in climb. Mixture control auto-rich for high speeds and climb. Brake horsepower figures in this report were obtained from power curves.
 
B.Test Results
 
  1.Level flight speeds at 3000 RPM.


 AltitudeTrue
Speed
MPH
b.h.p.
per
Engine
Estimated
Gr. Wt.
pounds
Manifold
Pressure
"Hg.
Remarks

   5,000346.5122013,55044.7 
   5,000355.5132013,55048.0 
 *14,700  378.0122013,52544.7 
 **22,600    404.0122513,50044.7 
 24,400403.0117513,45043.2Carb Air Temperature
Limiting Factor.
 30,000396.0  98013,40036.0Turbo RPM
Limiting Factor.

*1320 b.h.p. can not be used at this level due to carburetor air temperature limitation (57°C)
**Critical altitude of turbo installation for 44.7 inches HG manifold pressure. Carburetor air temperature is the limititing factor.

  4.Climb data at 3000 RPM


 AltitudeTrue
Speed
MPH
Avg. b.h.p.
per
Engine
Rate of
Climb
Ft/Min.
Time of
Climb
Min.
Intake
Man . Pr.
"Hg.
Limiting
Factor

 S.L.15612003300      044.7-
   6,00017112103660  1.7144.7-
 10,00018112103630  2.8144.7-
 15,00019612103500  4.2144.7-
 20,00021911953280  5.6844.7Carb. Temp.
 25,00023010902680  7.3640.6Carb. Temp.
 30,000246  9852100  9.4636.0Carb. Temp. and
Turbo RPM
 35,000264  690120012.4827.2Turbo RPM
 S/C 35,000    280-  10022.04-Turbo RPM
 A/C 39,700    --      0---

For the full report see HERE

See also:Memorandum Report on P-38G-1, No. 42-13687, FS-M-19-1538-A (Addendum #1)


ARMY AIR FORCES PROVING GROUND COMMAND
EGLIN FIELD, FLORIDA

SUPPLEMENTARY REPORT
ON
TACTICAL SUITABILITY OF THE P-38G TYPE AIRPLANE
AS COMPARED TO THE P-38F
3 May 1943

Conclusions

                 a.    All conclusions and recommendations applying to the P-38F, apply to the P-38G.

                 b.    Inasmuch as the general maneuverability of this aircraft is probably the lowest of any type of current fighter aircraft, and in view of the competition facing the P-38G in the European Theatre, all possible effort should be made to improve its rate of climb and high speed.

                 c.    The P-38G turns much better than the P-38F (will close 180° in 360° circle) due to maneuver flaps.

                 d.    Buffeting was noticeable but at higher speeds and accelerations than in the P-38F.

                 e.    The P-38G will outzoom the P-38F.

                 f.    The P-38G will hold its altitude in turns at thirty-five-thousand (35,000) feet, whereas the P-38F loses altitude.

                 g.    The P-38G holds its advantages over the P-38F at all altitudes.

                 h.    The lack of sufficient intercooling holds down the performance of the P-38G as well as the P-38F.

For more of this report see HERE


ARMY AIR FORCES
MATERIEL COMMAND
Flight Section
Wright Field, Dayton, Ohio

Memorandum Report On
P-38J Airplane, AAF No. 43-13563
27 October 1943

Subject:      Flight Tests
Section:      Flight
Serial No:   FS-M-19-1656-A

Summary

Level flight results of the P-38J, AAF No. 43-13563 were obtained with wheels up, wing flaps neutral, intercooler flaps flush, coolant flaps automatic and carburetor auto-rich.


Altitude
Feet
b.h.p.Man.
Pr.
"Hg.
Carb.
Air
°C
Engine
RPM
Turbo
RPM
Exhaust
Back pr.
"Hg.
True
Speed
MPH

10,000152060  32  300018,30039.2375  
15,000151060  35  300021,90040.5391.5
  20,300*150060  42.5300026,40045  408  
25,000130050.233.5300026,40037.5403.5
30,000109041  26  300026,40030.7391  
35,000  88032.618  300026,40024.2362  

Conclusion
 
Results of flight test on two P-38J airplanes at Wright Field indicated that these airplanes are unsatisfactory for tactial use above 20,000 ft. Considerable induction system leakage was encountered in both airplanes resulting in a loss of critical altitude of approximately 7500 ft. Additional trouble was encountered while testing the first of these airplanes at war emergency power in that one engine had to be changed and several revisions were required in the exhaust system before tests could be continued. It is believed that the P-38J airplanes at Wright Field are representative production airplanes and it is recommended that immediate action be taken to correct the leakage in the induction system, either through redesign or better production control of the manifold leading from the turbo to the engine.

For the full report see HERE

See also:Memorandum Report on P-38J Airplane, No. 43-13563, FS-M-19-1656-A (Addendum #1)


ENGINEERING DIVISION MEMORANDUM
REPORT SERIAL No. Eng-47-1706-A
4 FEBRUARY 1944

Flight Tests on the Lockheed
P-38J Airplane, AAF No. 42-67869

Summary

       The P-38J is designed as a high altitude fighter interceptor. This airplane has a fast rate of climb and performs well at high altitude, however, caution must be used in acrobatics and diving maneuvers at all altitudes to keep below limiting airspeeds. These airspeed limitations are low due to tail buffeting which may eventually cause structural failure and are definitely objectionable and hazardous from a combat viewpoint. The stability about all axis is good, the radius of turn is fairly large for a fighter and the rate of roll is fair at medium speeds, but slow at high speeds because of heavy aileron forces. The single engine operations, visibility on the ground and in the air and cockpit layout is good.

       High speed and climb performance have been completed on this airplane at a take-off weight of 16,597 lb. This loading corresponds to athe average P-38 combat weight with full oil, 300 gallons of fuel and specified armament and ammunition.

       The principal results are as follows:

Max speed at critical altitude, 25,800'
(60.0" Hg. Man. Pr. & 3000 rpm) = 421.5 mph
 
Max speed at sea level
(60.0" Hg. Man. Pr. & 3000 rpm) = 345.0 mph
 
Rate of climb at sea level
(60.0" Hg. Man. Pr. & 3000 rpm) = 4000'/min.
 
Rate of climb at critical altitude, 23,400 ft.
(60.0" Hg. Man. Pr. & 3000 rpm) = 2900'/min.
 
Time to climb to critical altitude, 23,400 ft.
(60.0" Hg. Man. Pr. & 3000 rpm) = 6.49 min.
 
Service Ceiling = 40,000'

For more of this report see HERE


ENGINEERING DIVISION MEMORANDUM
REPORT SERIAL No. Eng-47-1749-A
5 JULY 1944

Flight Tests on the Lockheed
P-38J Airplane, AAF NO. 43-28392
Using 44-1 Fuel

Summary

       The P-38J-15 is a twin-engine, high altitude interceptor-fighter. The airplane performs well at high altitude, having a good maneuverability and radius of turn when using maneuvering flaps. The rate of roll is fair at medium speeds and slow at high speeds because of high aileron forces. This is improved in later models by the use of aileron boost.

       The principal results are summarized in the following paragraphs.

       In level flight at 19800 ft., the critical altitude for 70" hg. manifold pressure, 3000 RPM, and 26,300 limiting turbo RPM, a maximum speed of 419 MPH was attained. At this altitude a high speed of 402.5 MPH was attained at 60" Hg. manifold pressure. At 24000 ft., the critical altitude for 60" Hg. manifold pressure, 3000 RPM, and 26,300 limiting turbo RPM, a high speed of 413 MPH was attained.

       At sea level a maximum rate of climb of 4040 ft/min was attained at 70" Hg. manifold pressure and a rate of climb of 3570 ft/min at 60" Hg. manifold pressure and 3000 RPM. The service ceiling of the airplane was 39,000 ft., and the absolute ceiling was 39,700 ft.

For more of this report see HERE


ARMY AIR FORCES
AIR TECHNICAL SERVICE COMMAND
Wright Field, Dayton, Ohio

Memorandum Report On
P-38L Airplane, AAF No. 44-25092
11 Decemeber 1945

       Flight tests were conducted on the P-38L airplane, AAF No. 44-25092, at Wright Field, Dayton Ohio and Miami Depot, Miami, Florida in order to obtain a performance and range check of the data given as tentative figures in Pilot's Flight Operating Instructions, AN 01-75-1.

       Level Flight Performance

       The following speed data was obtained with the airplane in the clean configuration. Data is corrected to weight at altitude as given in Figure 4, Appendix A and NACA standard day conditions.

       a.    True speed at sea level at war emergency power, 1530 BHP and 3000 RPM, was 342 MPH.

       b.    True speed at critical altitude, 26,000 feet, at war emergency power, 1495 BHP and 3000 RPM, was 416 MPH.

       c.    True speed at sea level at military power, 1395 BHP and 3000 RPM, was 331 MPH.

       d.    True speed at critical altitude, 26,200 feet, at military power, 1385 BHP and 3000 RPM, was 408 MPH.

       e.    True speed at sea level at normal rated power, 1110 BHP and 2600 RPM, was 302 MPH.

       f.    True speed at critical altitude, 32,200 feet, at normal rated power, 1138 BHP, was 400 MPH.

Speed at Altitude   Rate of Climb   Time to Climb

Unfortunately, portions of the original report are missing.


(Click to enlarge)
 
(Click to enlarge)
 
(Click to enlarge)

Supplemental
 
Memorandum Report on P-38G, A.C. No. 42-12690: Stall Tests
Estimated Performance of the P-38F and P-38G, February 19, 1943
Comparison of Rolling Velocities
P-38J Time to Bank 90°
Additional Performance of P-38J Airplanes, 11 March 1944
Allison V-1710-91 Engine Operated on Grade 104/150 Fuel.
Fighter Comparison Chart
P-38 Tactical Planning Characteristics & Performance Chart

WWII Aircraft Performance