|Manufacturer||Curtiss Aeroplane and Motor Company|
|Primary user||United States Army Air Service|
Design and development
In 1929, three Curtiss P-11 Hawks were ordered with 600 hp (447 kW) Curtiss H-1640 Chieftain engines. These proved a failure, and before completion, the third was converted to use a 9-cylinder 575 hp (429 kW) Wright Cyclone, being completed as the YP-20. Testing with the R1820 was prolonged, so the Army's intention to promptly switch to a Curtiss V-1570 Conqueror engine and redesignate the aircraft XP-22 was dropped; another P-11 was chosen for that instead.
Except for the engine change and its Townend ring cowling, the YP-20 was not drastically different from the P-6 from which both it and the P-11 derived, though the YP-20 had more fin and less rudder area, and featured a steerable tailwheel, rather than the original skid. Later, a crankcase cover, gear strut fairings, and wheel pants were added.
In June 1931, the AAC held a competition to evaluate the P-6, P-12, XP-22, and YP-20. The XP-22 came out the winner, but the YP-20 was given a nose and landing gear graft from the XP-22, becoming the XP-6E (P-6E prototype). With the addition of a supercharger and an enclosed cockpit, it was tested as the XP-6F.
Specifications (original YP-20)
Data from Curtiss Aircraft 1907–1947
- Crew: 1
- Length: 23 ft 0 in (7.01 m)
- Wingspan: 31 ft 6 in (9.60 m)
- Height: 9 ft 3 in (2.82 m)
- Wing area: 252 sq ft (23.4 m2)
- Airfoil: 'Clark Y
- Empty weight: 2,523 lb (1,144 kg)
- Gross weight: 3,231 lb (1,466 kg)
- Powerplant: 1 × Wright R-1820-9 Cyclone 9-cylinder air-cooled radial piston engine, 650 hp (480 kW)
- Propellers: 2-bladed fixed-pitch propeller
- Maximum speed: 188.6 mph (304 km/h; 164 kn)
- Cruise speed: 150 mph (241 km/h; 130 kn)
- Range: 237 mi (206 nmi; 381 km)
- Service ceiling: 27,800 ft (8,500 m)
- Rate of climb: 2,600 ft/min (13 m/s)
- Guns: 2 × fixed forward-firing 0.300 in (7.62 mm) M1919 Browning machine guns
- Fitzsimons, Bernard, ed. Illustrated Encyclopedia of Weapons and Warfare (London: Phoebus, 1978), Volume 12, p.1255.
- Fitzsimons, p.1255.
- Bowers, Peter M. (1979). Curtiss aircraft, 1907-1947. London: Putnam. pp. 256–266. ISBN 0370100298.
- Lednicer, David. "The Incomplete Guide to Airfoil Usage". m-selig.ae.illinois.edu. Retrieved 16 April 2019.
- Fitzsimons, Bernard, ed. Illustrated Encyclopedia of Weapons and Warfare. Volume 12, pp. 1255–6, "Hawk, Curtiss Models 34 and 35 (P-1 to P-6 and F6C". London: Phoebus Publishing, 1978.
- Donald, David, ed. Encyclopedia of World Aircraft. Etobicoke, ON: Prospero Books, 1997.
- Jones, Lloyd S. U.S. Fighters. Fallbrook, CA: Aero Publishers, 1975.