The first XP-40 was simply a P-36A Hawk with its Pratt & Whitney Twin Wasp radial engine replaced by a supercharged Allison V-1710 engine. The liquid-cooled Allison offered no more power than the radial, but its smaller frontal area led to considerably lower drag. In April 1939 the USAAC, no doubt looking over its shoulder at the sleek new high-speed in-line engined fighters of Europe, placed the largest single fighter order it had ever made for fighters: 524 aircraft.
France ordered 140 as the Hawk 81A-1 but collapsed before they had left the factory, and the aircraft were diverted to British Commonwealth service, as the Tomahawk 1 - in some cases complete with metric instruments. Deemed unsuitable for use as a fighter in Europe, where it was thought inferior to the Spitfire, Hurricane and Bf-109, the Tomahawk was used for training and some low-level tactical reconnaissance. It proved much more valuable in the deserts of North Africa, where poor high-altitude performance mattered less and the Tomahawk's rugged airframe, relatively heavy armament, and good range was valuable. RAF No. 112 Sqn was the first to fly Tomahawks in the Western Desert, mainly for ground attack, and introduced the famous shark-tooth jaw markings under the spinner that other air forces around the world would soon adopt.
Revised versions soon followed: the P-40B or Tomahawk IIA had extra 0.30in (US) or 0.303in (UK) machine guns in the wings and self-sealing tanks; the P-40C or Tomahawk IIB added two more guns (giving it the original two 0.5in guns firing through the propeller and two smaller calibre guns in each wing) and improved the tanks again, but the extra weight did nothing to help the aircraft's lack-lustre performance. (Weight was always a major problem for the P-40.) Nevertheless, it was produced in large numbers: the British Commonwealth alone took 930 aircraft, issuing them to 16 squadrons (including two South African Air Force units and No. 3 Sqn RAAF), and sending 23 on to serve with the Soviet air force.
14,000 P-40s were produced up to 1944 and they were used by the airforces of twenty-eight nations.
Generally outperformed by the fighters it encountered, it still gained a reputation for high durability and toughness.
Span: 37' 4" (about 11 m)
Length: 31' 9" (about 10 m)
Height: 12' 4" (about 3.75 m)
Weight: 9,100 lbs. (4 tonnes) loaded
Armament: Six .50-cal. machine guns; 700 lbs. (300 kg) of bombs externally.
Engine: Allison V-1710 1150 hp. (860 kW)
Maximum speed: 362 mph. (580 km/h)
Range: 850 miles. (1350 km)
Service Ceiling: 30,000 ft. (9100 m)