|Designer||Don R. Berlin|
|First flight||15 February 1941|
|Primary user||United States Army Air Corps (intended)|
|Developed from||Curtiss P-40|
|Developed into||Curtiss XP-53|
The Curtiss XP-46 was a 1940s United States prototype fighter aircraft. It was a development of the Curtiss-Wright Corporation in an effort to introduce the best features found in European fighter aircraft in 1939 into a fighter aircraft which could succeed the Curtiss P-40, then in production.
Design and development
A United States Army Air Corps (USAAC) specification based upon a Curtiss proposal was the basis for an order placed in September 1939 for the XP-46. The requirements called for a single-engine, low-wing aircraft, slightly smaller than the P-40, and with a wide-track, inward-retracting landing gear. The selected powerplant was a 1,150 hp (858 kW) Allison V-1710-39 V-12 engine. The planned armament included two .50 in (12.7 mm) synchronized machine guns in the forward fuselage and provisions for eight .30 in (7.62 mm) wing-mounted guns. The USAAC later added requirements for self-sealing fuel tanks and 65 lb (29 kg) of armor, the weights of which were to adversely affect performance.
In 1940 the British Purchasing Commission placed an order for the P-46 as a replacement for the P-40,  the name 'Kittyhawk' being allocated by the Air Ministry in anticipation of receiving the aircraft.
However, the USAAC asked Curtiss in July 1940 – while the XP-46 prototypes were under construction – to prioritize an upgraded P-40, featuring the engine intended for the XP-46. This would also avoid disruptions to the production line caused by any switch to a new airframe. The British order for the P-46 was later cancelled, and the 'Kittyhawk' name subsequently applied to the upgraded P-40.
Two prototypes, designated XP-46A, were nevertheless delivered to the USAAC; the first flight occurred on 15 February 1941. The type's performance during trials was found to be inferior to the then-contemporary P-40D. As the P-46 offered no significant improvement on the P-40, the program was cancelled.
A myth claims that work on the XP-46 was the basis of the North American NA-73X – the prototype P-51 Mustang. While North American Aviation (NAA) purchased technical aerodynamic data on the P-40 and XP-46 from Curtiss, for $56,000 and there are certain design similarities in the radiator/oil-cooler configuration of the two types, North American had already made significance on its design. NAA engineers had also made use of British research regarding the Meredith effect – the ability of an embedded ventral radiator to provide thrust.
Specifications (Curtiss XP-46A)
Data from Curtiss Aircraft 1907–1947
- Crew: one
- Length: 30 ft 2 in (9.19 m)
- Wingspan: 34 ft 3¾ in (10.45 m)
- Height: 10 ft 1 in (3.07 m)
- Wing area: 208 ft² (19.32 m²)
- Empty weight: 5,625 lb (2,551 kg)
- Max. takeoff weight: 7,665 lb (3,477 kg)
- Powerplant: 1 × Allison V-1710-39 liquid-cooled V12 engine, 1,150 hp (858 kW)
- Maximum speed: 355 mph (309 knots, 571 km/h) at 12,200 ft (3,720 m)
- Range: 325 mi (283 nmi, 523 km)
- Climb to 12,300 ft (3,750 m): 5 min
- 2 × .50 in (12.7 mm) synchronized machine guns in the forward fuselage
- Provision for 8 × .30 in (7.62 mm) wing-mounted guns
- Engel, Leonard. "Half of Everything: An American's Survey of Orders Placed in the United States." Flight, 5 December 1940, p. 472.
- Berliner 2011, p. 18.
- Baugher, Joe. "North American NA-73." USAAC/USAAF/USAF Fighter and Pursuit Aircraft: North American P-51 Mustang, 29 August 1999. Retrieved: 10 August 2010.
- Bowers 1979, p. 436.
- Berliner, Don. Surviving Fighter Aircraft of World War Two: Fighters. London: Pen & Sword Aviation, 2011. ISBN 978-1-8488-4265-6.
- Bowers, Peter M. Curtiss Aircraft, 1907-1947. London: Putnam & Company Ltd., 1979. ISBN 0-370-10029-8.
- Green, William. War Planes of the Second World War, Volume Four: Fighters. London: MacDonald & Co. (Publishers) Ltd., 1961 (Sixth impression 1969). ISBN 0-356-01448-7.
- Green, William and Gordon Swanborough. WW2 Aircraft Fact Files: US Army Air Force Fighters, Part 1. London: Macdonald and Jane's Publishers Ltd., 1977. ISBN 0-356-08218-0.
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