P-40

1. To report on comparative speed tests on the XP-40 airplane, A.C. No. 38-10, with three sets of exhaust stacks. Airplane equipped with Allison V-1710-19 engine and with three-bladed constant speed propeller, blade design No. 614cc1.5-12, blade angle range 25 to 49.5 degrees at 42 inch radius. All tests with wheels up, flaps neutral, cabin closed, carburetor cold, cowl flaps closed and with mixture auto-rich. Three sets of exhaust were used:- (1) Standard XP-40 exhaust stacks (one 2-1/4 inch diamter opening per cylinder); (2) Materiel Division exhaust stacks, Dwg. No. X-40D3857; (3) Materiel Division exhaust stacks, Dwg. No. X-40G1720 (not interconnected).

1. Speeds for all three sets of exhaust stacks at 11,600 ft.:

1. To report on speeds on the XP-40 with standard exhaust stacks. Airplane equipped with V-1710-33 engine and three-bladed, constant speed propeller, blade design No. 614cc1.5-12. All tests with wheels up, flaps neutral, cabin closed, carburetor cold, cowl flaps closed and mixture auto-rich.

1. Critical altitude for rated horse power is 13,800 ft. for 960 bhp at 2600 rpm.

2. Speeds at 11,600 ft. for comparison with test exhaust stacks (Ref. Mem. Report No. PHQ-M-19-1206-A):

a To report on speed tests pm Pursuit 1-engine (P-40) airplane, A.C. No. 39-165, with and without leading edge blisters in place. Airplane equipped with Allison V-1710-33 engine and 3-bladed constant speed propeller, blade design No. 614CC1.5-12, blade angle range 24° to 49° at 42 inch radius. Airplane camouflaged and flown with normal military load, landing gear retracted, wing flaps neutral, cabin and ventilators closed, carburetor cold, radiator shutters in neutral position. Cabin ventilator intake hole in leading edge of right wing open in test without blisters in place but covered in test with blisters.

a Tests at 15,000 ft. and 2770 r.p.m.:

1. Flight test at the manufacturer's plant of the Curtiss P-40B airplane equipped with Allison V-1710-33 engine and 3-bladed, constant speed propeller, blade design No. 89301-3. Gross weight 6835 lbs. Landing gear retracted, cabin and ventilators closed, carburetor cold, wing guns in place, blast tubes for synchronized guns in place, radio antenna in place. Airplane camouflaged.

1. High speed at 15,000 ft. at wide open throttle was 352 mph at 1090 bhp at 3000 rpm, radiator shutters neutral.

2. High speed at 5000 ft. was 319 mph at 1085 bhp at 3000 rpm, radiator shutters neutral.

3. High speed at 2600 rpm at 15,000 ft. at wide open throttle, was 331.5 mph at 920 bhp, radiator shutters neutral.

4. Speed at rated power at 5000 ft. was 307 mph at 950 bhp at 2600 rpm, radiator shutters closed one notch from neutral position.

5. Crusing data at 15,000 ft., radiator shutters closed two notches from neutral position.

1. Report on flight tests conducted at the manufacturer's plant on Curtiss P-40D. Airplane equipped with Allison V-1710-39 engine and 3-bladed constant speed propeller, blade design No. 89301-3, blade angle range 24.5° to 54.5° at 42" radius. Gross weight as tested 7740 lbs., c.g. location, wheels up, 27.9% m.a.c.; whee;s up; wing flaps neutral; radio antenna installed; prestone and oil cooler flaps flush with cowling in level flight, wide open in climb; four 50 cal. wing guns and uncovered blast tubes in plane, except where otherwise stated.

1. Level flight speed tests:

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

1. Report on performance of Curtiss P-40E. Airplane equipped with Allison V-1710-39 engine (backfire screens in intake ports) and 3-bladed constant speed propellers, blade design No. 89301-3. Gross weight as tested approximately 8011 lbs. with belly tank removed; c.g. location wheels up 28.5% m.a.c.; landing gear retracted; wing flaps neutral; radio antenna installed; prestone and oil cooler shutters flush with cowling in level flight, wide open in climb; six 50 cal. wing guns with uncovered openings in wings in place. Weight of belly tank and fuel 366 lbs. (capacity 52 gals.).

1. High speed tests:

2. Climb data; propeller set for 3000 rpm for first 5 min. with throttle open tp 43.9" Hg. manifold pressure or wide when below.

1.Report on performance of P-40E airplane, A.C. No. 40-633, equipped with four different propellers, each test being run with a propeller of particular blade design number, hub number, and spinner type as indicated. Airplane equipped with V-1710-39 engine and flown with wing flaps neutral, wheels up, carburetor cold, mixture "auto-rich" except where specified, cowl flaps neutral for level flaps and wide open for climbs. Airplane flown at a gross weight of approximately 8035 pounds with full gas and oil load, belly tank shackles in place, six .50 caliber guns without ammunition (no ballast), provision for spin chute but no spin chute in place. Horsepower figures obtained from power curve V-1710-39 dated December 12, 1941.

1. High Speeds in level flight.

3. Maximum rate of climb at wide open throttle and 2600 RPM.

1. Report on performance tests of P-40F airplane equipped with Packard-Merlin V-1650-1 engine and three-bladed constant speed propeller, design No. 89301-3, blade angle range 26.5° to 56.5° at 42 inch radius. Gross weight as tested 8450 pounds. Except where otherwise stated, landing gear retracted; wing flaps neutral; carburetor cold; cabin closed; cooling shutters in flush position in level flight, wide open in climb; six .50 caliber guns in place with openings taped; wing bomb shackles with sway braces installed. b.h.p. figures obtained from preliminary power charts furnished by Power Plant Laboratory.

1. High Speeds, mixture control auto-rich

4. Climb results: Throttle open to 48" Hg. manifold pressure or wide open when below 48" Hg. in both high and low blower ratios; high blower used above 13,000.

1. Report on performance of P-40F airplane, AAF No. 41-13635 equipped with five different propellers, each test being run with a propeller of particular blade design number, hub number, and spinner as indicated. Airplane equipped with V-1650-1 engine and flown with wing flaps neutral, wheels up, carburetor cold, mixture "auto-rich", auto boost "off", radiator flaps neutral for level flight and wide open for climbs. Configuration for all tests as follows: Six .50 caliber wing guns with ball type vent tubes in place, belly tank shackles and sway braces, but no tank installed; no ammunition in place, and full gas and oil load at take-off.

1. High Speed at 18,100 feet altitude.

3. Maximum rate of climb at wide open throttle and high blower, 2850 RPM.

1. Report on performance of P-40-F airplane equipped with three-bladed constant speed propeller, Dwg. No. 101344-24 and standard spinner. Memorandum Report No. FS-M-1549-A lists comparative performance with five other propellers. Airplane equipped with V-1650-1 engine and flown with wing flaps neutral, wheels up, carburetor cold, mixture "auto-rich", auto boost "off", high blower ratio, radiator flap neutral for level flight and wide open for climb, full gas and oil load at take-off, six .50 caliber wing guns with ball type blast tubes in place, no ammunition, and belly tank shackles in place. Horsepower figures obtained from power charts.

1. Level flight speeds at 18,100 feet.

2. Maximum rate of climb at wide open throttle and high blower, 2850 RPM. Belly tank sway braces installed (without tank).

1. Report on flight tests of Curtiss P-40N (P-40K loaded to 7413 pounds with the same drag comditions as P-40N) airplane at the manufacturer's plant. Airplane equipped with Allison V-1710-81 engine and a three-bladed 11 feet 0 inches constant speed electric propeller, balde design No. 89303-24, blade angle range 54.5° to 24.4° at 42 inch radius. Gross weight at take-off was 7413 pounds with c.g. location at 30.15 percent m.a.c., wheels up. Wheels up, wing flaps neutral, carburetor cold, mixture auto-rich, unless otherwise specified, one flame dampening stack per cylinder, four .50 caliber wing guns with blast tubes taped and 235 rounds of .50 caliber ammunution per gun. Radio and radio mast and single strand antenna in place with belly tank shackle in place. Equipped with experimental aluminum alloy radiators, Dwg. No. B22959, Serial No. 9-R, and Dwg. No. B22959, Serial No. 10-L. No rear view mirror, no external gun peep sight. Horsepowers obtained from power curve V-1710-81, 83, and 85, dated October 28, 29, 1942 (2:1 propeller gear ratio; 9.6:1 blower gear).

1. High speeds, cowl flaps in the neutral position.

3. Climb data, cowl flaps open, mixture control in the autorich position. Throttle set for 57 inches Hg. at 3000 RPM or wide open when below.

4. Climb data, cowl flaps open, mixture control in the auto-rich position, throttle set for 50.5 inches Hg. at 3000 RPM or wide open when below.

It is concluded that:

1. To report results of performance tsts on the P-40N-5, AAF No. 42-105241, with additional data to calculate range and endurance under combat configurations.

The maximum rate of climb: 1640 ft/min at 11,400 ft.

Time to 10,000 feet.: 6.2 minutes

Time to 20,000 feet.: 14.2 minutes.

Service ceiling: 28,700 feet.

Estimated absolute ceiling: 29,900 feet.

The position of the pressure head, the position error correction, and the correction to the altimeter when connected to the static of the airspeed system are included in the report.

Maximum rate of climb: 1530 ft/min at 12,000 ft.

Time to 20,000 ft.: 15.0 mins.

Service ceiling: 27,600 ft.

Maximum level speed with tank fitted = 322 m.p.h. at 14,200 ft.

Maximum level speed with tank removed = 332 m.p.h. at 14,400 ft.

Maximum rate of climb: 1350 ft/min. at 12,000 feet.

Time to reach 10,000 ft.: 7.9 mins.

Time to reach 20,000 ft.: 17.25

Service ceiling: 28,600 feet.

Maximum true airspeed: 331 m.p.h. at 14,000 feet.

The handling characteristics have deteriorated with change of propeller. There is now a marked change of directional trim with change of speed. On the climb at low airspeeds, full starboard rudder bias is necessary to fly feet off, but in the dive the aircraft has to be re-trimmed in the opposite direction. The aircraft has also to be re-trimmed in level flight for varying throttle positions. The change of trim with speed would be a serious handicap to the pilot during combat and considerably reduces the usefulness of the aircraft as a fighter. Apart from this, the general handling characteristics are similar to a normal Kittyhawk I.

Max. rate of climb at full throttle height M.S. gear: 2020 ft/min @ 10,200 ft.

Max. rate of climb at full throttle height F.S. gear: 1620 ft/min @ 17,000 ft.

Time to reach 10,000 ft.: 5.0 mins.

Time to reach 20,000 ft.: 10.9 mins.

Time to reach 30,000 ft.: 21.8 mins.

Service ceiling: 34,300 feet.

Estimated absolute ceiling: 35,400 feet.

Max. level true air speed in M. S. supercharger gear: 347 m.p.h. @ 14,700 ft.

Max. level true air speed in F. S. supercharger gear: 354 m.p.h. @ 20,400 ft.

An 83 (Imperial) gallon externally carried belly fuel tank of moulded plywood has been treated as an overload item on a Kittyhawk at normal maximum load, and its effect on performance in speed and climb determined.

On rated power the initial climb is decreased from 2000 ft. per minute to 1580 feet per minute by the addition of the tank. The time to 20,000' is increased from 11.7 minutes to 15.8 minutes, while the estimated service ceiling is decreased from 32,300' to 26,800'.

The top speed on military power at full throttle height is decreased from 348 m.p.h. at 12,300' to 314 m.p.h. at 12,000'and the top speed on rated power at full throttle height is reduced from 330 m.p.h. at 11,800' to 300 m.p.h. at 11,300' by the addition of the tank.

The top speed figures have been analysed and making some broad assumptions and with the consumption figures available, a curve is given showing the probable increase in range, at constant indicated airspeed, due to the addition of the tank.

The effect of polishing the aircraft in stages has been investigated -