Kittyhawk 1A [Curtiss P-40E]  [@ RAF Duxford]

The P-40 originated as a development of the radial-engined Curtiss P-36A Hawk. In July 1937 the USAAC ordered the prototype of a possible variant, designated XP-40 and powered by the new liquid-cooled Allison V-17l0 12-cylinder Vee-type engine. The tenth production P-36A was fitted with the new power plant on the assembly line, and this aircraft (P-40) flew for the first time in October 1938.

France’s Armée de 1’Air, which during the phoney war’ period of 1939/40 was already operating the nimble Curtiss Hawk 75A (P-36A), placed an order for 140 P-40s, these being given the export designation Hawk 81 A-1. Before the first Hawk 81 A-1 could be delivered France fell and the full order was taken over by the British Purchasing Commission on behalf of the RAF. Although considered unsuitable for operational use by Fighter Command, the P-40s were fitted with four wing-mounted Browning 7.7mm (0.303in) machine guns and allocated to Army Co-operation Command as the Tomahawk I, for use in the tactical reconnaissance role. They served until 1942, when they were replaced by another American type, the North American Mustang I.

Kittyhawk III [Curtiss P-40M]  [@ RAF Duxford]

With the inclusion of an armoured windscreen and armour plating for the pilot, designated P-40B, 110 of these aircraft went to the RAF as the Tomahawk IIA. The next variant was the P-40C, which was fitted with larger, self-sealing fuel tanks and two more wing guns, with 930 going to the RAF as the Tomahawk IIB. The RAF’s Tomahawk IIBs was different to the American version in that it had the fuselage-mounted armament deleted and was fitted with four wing guns instead of six.

The P-40D was substantially redesigned, its four wing guns being upgraded to 12.7mm (0.50in) calibre and the nose armament removed. Provision was also made for the carriage of bombs under the wings or fuselage. Only 22 P-4ODs went to the USAAF as the Hawk 87A Warhawk, but 560 were allocated to the RAF, which gave them the new name Kittyhawk I. The USAAF preferred the P-40E, with six wing guns; it ordered 820 of this model and another 1500 became Kittyhawk 1As.

Installation of the much superior Packard-Merlin engine produced the P-40F. The RAF received 21 Kittyhawk IIs (P-4OK) and 600 Kittyhawk IIIs (P-4OM) and 586 Kittyhawk IVs (P-4ON). Production finally ended in December 1944 after 13,738 aircraft had been built.