ARMY AIR FORCES PROVING GROUND COMMAND
EGLIN FIELD, FLORIDA
TACTICAL SUITABILITY OF THE P-38F TYPE AIRPLANE
6 March 1943
To determine the relative tactical value of the P-38F type aircraft for combat service.
This test was initiated by a letter from the Director of Military Requirements, Headquarters Army Air Forces, Washington, D.C., dated 9 April 1942,
to the Commanding Officer, Proving Ground Command, Eglin Field, Florida, concerning the testing of aircraft to determine their operational suitability.
The test was started August 7, 1942, and was terminated January 26, 1943.
a. Description. The articles tested were the standard P-38F type airplanes, A.C. Serial Numbers 41-7536 and 41-7612.
The P-38F is a tricycle geared; single-seated, monoplane, powered with two (2) twelve (12) cylinder turbo supercharged Allison engines, models V-1710-49 (R.H.) and V-1710-53 (L.H.), which turn propellers in opposite directions.
The length is thirty-seven (37) feet, nine and five-sixteenths (9-5/16ths) inches; height nine (9) feet, nine and three-fourths (9-3/4ths) inches, and the span fifty-two (52) feet, zero (0) inches.
It is equipped with tacks to carry two (2) external droppable gas tanks of normal load of one-hundred-fifty-five (155) gallons each, or two (2) with a capacity of three-hundred (300) gallons each, if desired.
In normal flight operations with internal fuel tanks full (three-hundred (300) gallons of gas), two-thousand rounds of .50 caliber ammunition, and one-hundred-fifty (150) rounds of 20mm; the gross weight is fifteen-thousand-eight-hundred (15,800) pounds.
The armament consists of four (4) free firing .50 caliber machine guns and one (1) free firing 20mm cannon situated in the nose.
It is concluded that:
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 G’s.
It is recommended that:
a. Steps be taken to eliminate tail buffeting, and flight restrictions be retained until the correction is accomplished.
b. Suitable means of maintaining cockpit heat at altitude be installed. (Cockpit heater on P-39NO is best seen to date.)
c. Continued efforts be made to increase rate of climb and level high speed.
d. Automatic shutter control of coolant and oil temperature be installed.
e. One (1) guns switch be installed for all guns.
f. The generators and battery switch be incorporated with the master switch and the booster pump’s switch incorporated with the individual engine switches.
g. The rate of aileron roll be increased.
h. The case ejection chute control be removed from the cockpit.
i. Elevator trim be moved to rear nearer the pilot for more accessibility.
j. The offset control be replaced by a straight control column in the middle of the cockpit, if possible. If not, the control column be reduced to a minimum safe size to increase the visibility of the instrument panel and save space in the cockpit.
k. Until the automatic turbo governor is installed, a turbo tachometer be added to the instrument panel. This should be done on future types which will have intercoolers of sufficient cooling ability to allow maximum to be extracted.
l. The energizing and starter switches be placed next to the main motor switches. Also all other switches that have to be used either for starting the engines or during take-offs be grouped together.
These switches should be placed in a horizontal row, “off” when down and “on” when up. A drop bar should be placed below this so all switches could be turned on when the bar is lifted, after which the bar will drop back down.
m. Provision be made for sufficient intercooling to permit maximum horsepower to be extracted from the engines at all altitudes up to the service ceiling.
n. One (1) button on front of wheel be provided to fire 20mm cannon and machine guns, eliminating machine gun button and retaining only safety switch.
o. The toggle switch type of primer (Stromberg Electric Priming Valve-T.O. – 03-10BA-25) be installed for ease and speed of operation in interception work.
p. The starters be of such a type that both engines may be started at the same time for interception work.
q. The top glass of the canopy be redesigned so that the shell will extend four (4) inches lower, thus putting the metal strip where the new canopy joins the windows below level of pilot’s eyes, instead of level with them as is now the case.
r. Only one (1) landing light of a stationary type be installed on the leading edge of the left wing.
s. The gun sight be of the type which will accommodate a 100 mil circle, permit bulb change in flight and reflection adjustment for low level bombing.
t. As soon as the .50 caliber machine gun installations are corrected so they fire in more than a 3.5 G turn, that the gun chargers be eliminated from the cockpit.
u. The front wind screen be made of bulletproof glass.
v. Paddle blade propellers be incorporated in the P-38 design to improve climbing capabilities.
w. A gun sight be installed that will allow the 161 mil view over the nose to be used in deflection shooting.
5. RECORD OF TEST:
This test was conducted pursuant to the “Program for testing the Tactical Suitability of Service Aircraft,” this headquarters, dated 9 July 1942, a copy of which is attached as Inclosure No. 1.