Curtiss P-40 Warhawk

One of the early production Curtiss P-36 aircraft was given an 864.4kW Allison V-1710-19 (G-13) engine (and designated XP-40) instead of the standard R-1830-17 engine. Apart from the essential modifications to the airframe to accommodate the Allison supercharged engine and its coolant radiator and oil cooler, it was the basic airframe of the P-36, free of development problems and ready for immediate production once the USAAC decided it was the aircraft they needed. They did; ordering an initial production batch of 524 P-40, these acquiring the name Warhawk. On 22 November 1944 the USAAF received the 15,000th Curtiss fighter built for service in World War II. It was a P-40N, the final new production version.

Despite this long production run, the P-40 Warhawk was not an outstanding fighter aircraft. It was, however, rugged and reliable and was used in all theatres of war for a variety of purposes. It was also typical of many early wartime fighters, with armament and engine changes causing the long development progression. Increased armament and equipment needed more power to maintain performance: once this had been achieved, with perhaps a margin of reserve power, more arms or increased armour or fuel tankage again eroded performance.

P-40 served with the RAF as Tomahawks; with Gen Chennault's AVG or "Flying Tiger" group in China; with the RAAF, SAAF, Soviet Union and Turkish Air Force. Improved P-40D and P-4OE served with the RAF as Kittyhawks, with the RCAF and Soviet Union; and still later versions went to the RNZAF. USAAF usage of the P-40 was mainly in the Middle East and Pacific theatres, but by far the greatest proportion of P-40 built went to Allied nations under Lend-Lease agreements.