The P-40Q was an experimental
project which attempted to produce a really modern fighter out
of the existing P-40. The modifications were in fact so drastic
that there was very little in common with earlier P-40 versions.
Two P-40Ks (serial numbers 42-9987
and 42-45722) and one P-40N (serial number 43-24571) were extensively
modified with revised cooling systems, two-stage superchargers,
and structural changes which markedly altered their appearance.
The project was assigned the designation XP-40Q.
The first XP-40Q was P-40K-10-CU
ser no 42-9987 fitted with a new cooling system, a longer nose,
and a four-bladed propeller. The radiators were moved into an
under-fuselage position, with intakes between the undercarriage
The most prominent XP-40Q feature,
used on 42-45722 and 43-24571, was the cutting down of the rear
fuselage and the addition of a bubble canopy as on the "XP-40N".
Later the wingtips were clipped. The result was an aircraft
which bore almost no resemblance whatsoever to its parent P-40
line. The V-1710-121 engine was fitted with water injection,
resulting in a power of 1425 hp. Speed increased to 422 mph
at 20,500 feet, making it the fastest of all the P-40s. An altitude
of 20,000 feet could be reached in 4.8 minutes, and service
ceiling was 39,000 feet. Four 0.5-inch machine guns were carried
by the prototypes. Wingspan was 35 feet 3 inches (after clipping),
and length was 35 feet 4 inches (2 feet longer than the P-40N).
The proposed production models
of the P-40Q were to have carried either six 0.50-inch machine
guns or four 20-mm cannon, but the XP-40Q was still inferior
to contemporary production Mustangs and Thunderbolts, and development
was therefore abandoned. Consequently, the production life of
the P-40 ended with the N version.
The second XP-40Q was briefly
used for postwar air racing. Registered NX300B, the second XP-40Q
was an unauthorized starter in the 1947 Thompson Trophy race.
It was in fourth place when it caught fire and had to drop out
of the race.
War Planes of the Second World
War, Fighters, Volume Four, William Green, Doubleday, 1964.
The American Fighter, Enzo Angelucci and Peter Bowers, Orion
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
The Curtiss P-40 Tomahawk, Ray Wagner, Aircraft in Profile,
Volume 2, Doubleday, 1965.
Hawk Dynasty: The Curtiss Hawk Monoplanes, Ken Wixey, Air Enthusiast
No 72 (1997).