Curtiss P-40 Warhawk variants

In early 1937, after realizing the Hawk 75 was inferior to more modern European designs, the USAAC ordered one P-36 to be modified with an Allison V-1710 inline engine.

The prototype Hawk was fitted with a turbo-supercharged 1,150 hp (860 kW) Allison V-1710-11 engine as the XP-37 (company designation Model 75I).

The cockpit was moved back towards the tail to make room for the massive supercharger, and the engine was cooled by two radiators on either side of the nose.

The new engine conferred a 50 mph speed advantage over the already popular Hawk, and export orders from England and France came in quickly.

Testing began in 1944, revealing problems with snow and ice being packed between the wheels and track belt, stretching the latter.

This variant was not considered combat-ready, as they lacked heavy armament and armor, but as there was a shortage of decent fighter aircraft after the Battle of Britain, the RAF pressed these into service for use in North Africa anyway.

This was partly rectified with the P-40B, which had additional armor behind the cockpit, but fuel system and control line vulnerability remained a problem to some extent with all Tomahawk types.

The resulting P-40D (Model 87A) had a shorter nose with a larger radiator, four .50 Brownings in place of the .30 units, a revised windscreen, and provisions for two 20 mm cannons (one in each wing, never used).

Starting with the 24th Model 87, an additional .50 MG was added to each wing and the carburetor intake was moved forward 6 in.

Both these problems were remedied sometime late in production by enlarging the vertical stabilizer and changing how the ammunition was stored.

P-40's were more a powerful, faster-flying aircraft than the primary and advanced trainers most pre-war and early-war Allied pilots were familiar with, and transition training was often inadequate or neglected altogether in the early years of the war.

As a result, novice pilots had a hard time adjusting to the new fighter and there were many accidents on landing and takeoff in the early years of the war, with both Tomahawk and Kittyhawk types.

As a result, unless combat was taking place at low altitude, P-40 pilots often faced attack from above in the opening stages of an interception, a chronic problem which cost many lives.

[7] Another solution to the high altitude performance problem was to fit the P-40 with a supercharged Rolls-Royce Merlin engine.

Curtiss attempted to fix this by fitting a dorsal fillet to the tail of a single P-40F; however, this was not adopted into production.

Although the P-40F was superior to the Allison powered P-40s, there was a shortage of Merlin engines due to the vast number of aircraft that used them.

These were the heaviest P-40 variants, but the extra horsepower on the P-40K gave it good performance particularly at low altitude (noticeably better than the P-40E).

Many weight saving changes were made to the aircraft, including removal of armor plating and reduction of rounds per gun.

[3] In an attempt to increase performance, Curtiss lightened the P-40M by introducing a lightweight structure, lighter, smaller-diameter undercarriage wheels, removing two of the guns, and installing aluminum radiators and oil coolers.

Curtiss attempted to further improve visibility and fitted one P-40N with a bubble canopy; this feature never made it to production.

[3] A single photo exists of a P-40 with two Merlin engines mounted on top of the wings over the landing gear.

Curtiss XP-37
Curtiss YP-37 with lengthened nose.
Curtiss XP-40 in flight.
XP-40 fitted with tracked landing gear.
P-40-CU s/n 39-156, the first of almost 14,000 Warhawks to come off the production line.
A close up view of the P-40C's drop tank.
Nosed over P-40D apparently without armament or unit markings. The carburetor intake on top of the nose was positioned farther back than on subsequent Model 87 variants.
Curtiss P-40E (Kittyhawk Mk.IA) in the markings of No. 3 Squadron RAAF , which was part of the Desert Air Force .
41-36504 , a P-40E-1 with a large vertical stabilizer, similar to that of the early P-40K.
The prototype P-40F, converted from a P-40D.
An early P-40K with an enlarged vertical stabilizer.
The sole Finnish Warhawk (KH-51) was a captured Soviet P-40M-10.
P-40N at the Cavanaugh Flight Museum
A civilian P-40N. Note the revised canopy introduced on the N-5.
Curtiss XP-40Q-1
The second XP-40Q. This aircraft was sold to Joe Ziegler, who flew it in air races as "Race 82". [ 3 ] The aircraft was destroyed in the 1947 Thompson Trophy . [ 12 ]