Editing Curtiss P-40 Warhawk (section)

==Variants and development stages==
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[[File:Curtiss P-40, with shark mouth paint (00910460 060).jpg|thumb|A USAAF Curtiss P-40K-10-CU, serial number 42-9985, {{circa|1943}}]]
{{See also|Curtiss P-40 Warhawk variants}}
;XP-40
:The original Curtiss XP-40, ordered July 1937, was converted from the 10th P-36A by replacing the radial engine with a new Allison V-1710-19 engine. It flew for the first time in October 1938.
This new liquid-cooled engine fighter had a radiator mounted under the rear fuselage
but the prototype XP-40 was later modified and the radiator was moved forward under the engine.
;P-40
:The P-40 (Curtiss Model 81A-1) was the first production variant, 199 built.
;P-40A
:One P-40 was modified with a camera installation in the rear fuselage and re-designated P-40A.
*Revised versions of the P-40 soon followed: the '''P-40B''' or '''Tomahawk IIA''' had extra .30&nbsp;in (7.62&nbsp;mm) US, or [[.303 British|.303 in]] (7.7&nbsp;mm) machine guns in the wings and a partially protected fuel system; the '''P-40C''' or '''Tomahawk IIB''' added underbelly drop tank and bomb shackles, self-sealing fuel tanks and other minor revisions, but the extra weight did have a negative impact on aircraft performance. (All versions of the P-40 had a relatively low [[power-to-weight ratio]] compared to contemporary fighters.)
*Only a small number of '''P-40D''' or '''Kittyhawk Mk I'''s were made, fewer than 50. With a new, larger Allison engine, slightly narrower fuselage, redesigned canopy, and improved cockpit, the P-40D eliminated the nose-mounted .50&nbsp;in (12.7&nbsp;mm) guns and instead had a pair of .50&nbsp;in (12.7&nbsp;mm) guns in each wing. The distinctive chin airscoop grew larger so it could adequately cool the large Allison engine.
*Retrospective designation for a single prototype. The '''P-40A''' was a single camera-carrying aircraft.
*The '''P-40E''' or '''P-40E-1''' was similar in most respects to the P-40D, except for a slightly more powerful engine and an extra .50&nbsp;in (12.7&nbsp;mm) gun in each wing, bringing the total to six. Some aircraft also had small underwing bomb shackles. Supplied to the Commonwealth air forces as the '''Kittyhawk Mk IA'''. The P-40E was the variant that bore the brunt of air-to-air combat by the type in the key period of early to mid 1942, for example with the first US squadrons to replace the AVG in China (the AVG was already transitioning to this type from the P-40B/C), the type used by the Australians at Milne Bay, by the New Zealand squadrons during most of their air-to-air combat, and by the RAF/Commonwealth in North Africa as the Kittyhawk IA.

[[File:P40F Merlin.JPG|thumb|The Fighter Collection's P-40F G-CGZP, showing Merlin 500 engine]]
[[File:Curtiss P-40Fs near Moore AAF 1943.jpg|thumb|In the vicinity of [[Moore Field]], Texas. The lead ship in a formation of P-40s is peeling off for the "attack" in a practice flight at the US Army Air Forces advanced flying school. Selected aviation cadets were given transition training in these fighters before receiving their pilot's wings, 1943.]]

*'''P-40F''' and '''P-40L''', which both featured [[Packard V-1650|Packard V-1650 Merlin]] engine in place of the normal Allison, and thus did not have the [[carburetor]] scoop on top of the nose. Performance for these models at higher altitudes was better than their Allison-engined cousins. The L in some cases also featured a fillet in front of the [[vertical stabilizer]], or a stretched fuselage to compensate for the higher torque. The P-40L was sometimes nicknamed "[[Gypsy Rose Lee]]", after a famous stripper of the era, due to its stripped-down condition. Supplied to the Commonwealth air forces under the designation '''Kittyhawk Mk II''', a total of 330 Mk IIs were supplied to the RAF under Lend-Lease. The first 230 aircraft are sometimes known as the '''Kittyhawk Mk IIA'''. The P-40F/L was extensively used by US fighter groups operating in the Mediterranean Theater.
*'''P-40G''': 43 P-40 aircraft fitted with the wings of the Tomahawk Mk IIA. A total of 16 aircraft were supplied to the Soviet Union, and the rest to the US Army Air Forces. It was later redesignated '''RP-40G'''.
*'''P-40K''', an Allison-engined P-40L, with the nose-top scoop retained and the Allison-configured nose radiators scoop, cowl flaps and vertical-stabilizer-to-fuselage fillet. Supplied to the Commonwealth air forces as the '''Kittyhawk Mk III''', it was widely used by US units in the CBI.
*'''P-40M''', version generally similar to the P-40K, with a stretched fuselage like the P-40L and powered by an Allison V-1710-81 engine giving better performance at altitude (compared to previous Allison versions). It had some detail improvements and it was characterized by two small air scoops just before the exhaust pipes. Most of them were supplied to Allied countries (mainly UK and USSR), while some others remained in the US for advanced training. It was also supplied to the Commonwealth air forces as the '''Kittyhawk Mk. III'''.
*'''P-40N''' (manufactured 1943–44), the final production model. The P-40N featured a stretched rear fuselage to counter the torque of the more powerful, late-war Allison engine, and the rear deck of the cockpit behind the pilot was cut down at a moderate slant to improve rearward visibility. A great deal of work was also done to try and eliminate excess weight to improve the Warhawk's climb rate. Early N production blocks dropped a .50&nbsp;in (12.7&nbsp;mm) gun from each wing, bringing the total back to four; later production blocks reintroduced it after complaints from units in the field. Supplied to Commonwealth air forces as the '''Kittyhawk Mk IV'''. A total of 553 P-40Ns were acquired by the Royal Australian Air Force, making it the variant most commonly used by the RAAF. Subvariants of the P-40N ranged widely in specialization from stripped down four-gun "hot rods" that could reach the highest top speeds of any production variant of the P-40 (up to 380&nbsp;mph), to overweight types with all the extras intended for fighter-bombing or even training missions. The 15,000th P-40 was an N model decorated with the markings of 28 nations that had employed any of Curtiss-Wright's various aircraft products, not just P-40s. "These spectacular markings gave rise to the erroneous belief that the P-40 series had been used by all 28 countries."<ref>McDowell 1968, p. 68.</ref> Since the P-40N was by 1944 used mainly as a ground attack aircraft in Europe, it was nicknamed '''B-40''' by pilots.<ref>Vader 1970, p. 137.</ref> Survivors redesignated as ZF-40N in June 1948.
[[File:Curtiss P-40N.jpg|thumb|Curtiss P-40N Warhawk "Little Jeanne" in flight]]
*'''P-40P''': The designation of 1,500 aircraft ordered with V-1650-1 engines, but actually built as the P-40N with V-1710-81 engines.
*'''XP-40Q:''' Three P-40N modified with a 4-bladed prop, cut-down rear fuselage and [[bubble canopy]], four guns, squared-off wingtips and tail surfaces, and improved engine with two-speed supercharger. Even with these changes, its performance was not enough of an improvement to merit production when compared to the contemporary late model '''P-47D'''s and '''P-51D'''s pouring off production lines. The XP-40Q was, however, the fastest of the P-40 series with a top speed of {{convert|422|mph|km/h|abbr=on}} as a result of the introduction of a high-altitude supercharger gear. (No P-40 model with a single-speed supercharger could even approach {{convert|400|mph|km/h|abbr=on}})
*'''P-40R''': The designation of P-40F and P-40L aircraft that had Allison engines retrofitted in the field for standardization and logistics.
*'''RP-40''': Some American P-40s were converted into reconnaissance aircraft.
*'''TP-40''': Some P-40s were converted into two-seat trainers.
*'''Twin P-40''': A single photo exists of a P-40 mocked up with two Merlin engines, mounted atop the wings, over the main landing gear.<ref>Donald 1997, p. 291.</ref>