Thomas-Morse XP-13 Viper
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The XP-13 Viper was a prototype biplane fighter aircraft designed by the American company Thomas-Morse Aircraft Corporation. The airplane was delivered to the United States Army in 1929, but they did not adopt it.
Design and development
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This aircraft was one of several B. Douglas Thomas designs built in hopes of a production contract from the Army, following the successful Thomas-Morse MB-3 of 1919. Financed by the company, and named the "Viper", it was officially purchased by the Army in June 1929 and designated "XP-13".
The XP-13 fuselage had a corrugated aluminum skin built over a metal frame; the flying surfaces were also metal-framed, but covered with the traditional fabric. While designed to use the 600 hp Curtiss H-1640-1 Chieftain engine, (a novel 12-cylinder two-row air-cooled radial with the rear cylinders directly behind the front cylinders rather than staggered as normal in a two-row radial[1]) for which the XP-13 incorporated a complex system of baffles to direct cooling air over the engine, the engine simply would not stay cool enough, and in September 1930 it was replaced with a Pratt & Whitney SR1340C Wasp of 450 hp. Ironically, the lower-power engine actually resulted in a speed increase of 15 mph, at least partly because of the weight savings.[2]
In the end, the Army decided against production, Thomas-Morse was acquired by Consolidated Aircraft, and the prototype was lost to an inflight fire.
Variants
- XP-13
- Prototype, serial number 29-453 with 600 hp (448 kW) Curtiss H-1640-1 Chieftain hex engine[3]
- XP-13A
- The XP-13 modified with a 525 hp (391 kW) Pratt & Whitney SR-1340-C enclosed in a NACA cowling, along with a revised fin and rudder[4]
- XP-14
- This designation was used for a proposed Curtiss version of the Viper with the Curtiss H-1640-1 Chieftain hex engine
Operators
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Specifications (XP-13 (Chieftain engine))
See also
Related lists
References
- Notes
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- ↑ Gunston 1986, p.46.
- ↑ "U.S. Fighters", by Lloyd S. Jones, (Aero Publishers, Inc. Template:ISBN, 1975) pp. 46–47
- ↑ Cite error: Script error: No such module "Namespace detect".Script error: No such module "Namespace detect".
- ↑ "The American Fighter", Enzo Angellucci and Peter Bowers, (Orion Books Template:ISBN), 1987
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- Bibliography
- Dorr, Robert F. and David Donald. Fighters of the United States Air Force. London:Temple, 1990. Template:ISBN.
- Gunston, Bill, World Encyclopedia of Aero Engines. London: Guild Publishing, 1986.
External links
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