P-40K Warhawk, Kittyhawk III

Despite the success of the Merlin engine in the Warhawk, parallel production of the Allison-powered version continued owing to the limited supplies of the license-built British engine.

The P-40K series marked the introduction of the more powerful Allison V-1710-73 (F4R) engine rated at 1325 hp for takeoff and 1150 hp at 11,800 feet. This engine had an automatic boost control.

On October 28, 1941, 600 P-40Ks were ordered for Lend-Lease supply to China. It was envisaged that this would be the last P-40 model to be built in quantity, the P-60 replacing the P-40 on the Curtiss production lines thereafter. However, delays in the P-60 program caused the order for P-40Ks to be increased to a total of 1300 aircraft on June 15, 1942.

The first P-40K model rolled off the production line in August 1942. For some odd reason, the company model number used for the P-40K is unknown.

The P-40K-1-CU and P-40K-5-CU were generally similar to late-production P-40Es except for the more powerful Allison engine. The K-5 added rotary valve cooling. The K-1 and K-5 retained the short fuselage of the P-40E, but with the extra power there was a tendency to swing during takeoff and a dorsal fin was added to correct this problem. The P-40K-10s and later production blocks had the longer fuselage that was introduced on the P-40F-5-CU. The P-40K-15-CU was winterized.

The maximum speed of the P-40K was 320 mph at 5000 feet and 362 mph at 15,000 feet. A climb to 15,000 feet took 7.5 minutes. Range was 350 miles with a 500-pound bomb attached. Ferry range was 1600 miles. Weights were 6400 pounds empty, 8400 pounds gross, and 10,000 pounds maximum. Most of the P-40Ks served with the US forces in Asia and the Pacific and under Lend-Lease with the Chinese Air Force.

192 P-40K-1-CUs were diverted to England under Lend-Lease as Kittyhawk III. RAF serials were FL875/FL905, FR111/FR115, FR210/FR361, and FL710/FL713. The first examples were delivered to the Middle East in late 1942.

Forty-two P-40Ks served with the RAAF under serials A29-164/202 (P-40K-10-CU) and A29-203/205 (P-40K-15-CU). P-40Ks servicing with the RNZAF were NZ3045/3065, NZ3090, and NZ3099. Nine P-40K-1-CUs served with the RCAF under US Army serial numbers 42-45921, 45944, 45945, 45951, 45952, 45954, 45977, 46003, and 46004.

25 P-40Ks were diverted to Brazil

The serials for the P-40Ks were as follows:

42-9730/9929 Curtiss P-40K-5-CU Warhawk
42-9930/10264 Curtiss P-40K-10-CU Warhawk
42-10265/10429 Curtiss P-40K-15-CU Warhawk
42-45722/46321 Curtiss P-40K-1-CU Warhawk

The P-40K-1 had originally been assigned serials 42-65902/66501. The P-40K-5 thru -15 were originally assigned serials 42-64502/65201. These were all cancelled and reassigned as shown above.

One P-40K-10-CU, 42-10219, was fitted with an Allison V-1710-43 and used to develop some proposed P-40 improvements under the designation XP-40K. Experiments with cowling and relocated cooling systems altered the appearance of the aircraft from time to time. One such modification produced an aircraft with radiators in a swollen wing center section and a slim, pointed nose.


War Planes of the Second World War, Fighters, Volume Four, William Green, Doubleday, 1964.

The American Fighter, Enzo Anguluci and Peter Bowers, Orion Books, 1987.

United States Military Aircraft since 1909, Gordon Swanborough and Peter M. Bowers, Smithsonian Institution Press, 1989.

Curtiss Aircraft, 1907-1947, Peter M. Bowers, Naval Institute Press, 1979.

The Curtiss P-40 Tomahawk, Ray Wagner, Aircraft in Profile, Volume 2, Doubleday, 1965.

© Joseph Baugher