The Curtiss YP-20 was a development machine that went through several designation and three engines before emerging as the prototype for the P-6E.
The YP-20 began life as the third P-11 (29-374), a version of the Hawk that was to have been powered by the Curtiss R-1640 Chieftain engine. This engine proved to be a failure, and so the three P-11s were completed with other engines. Two were given the Conqueror engine and became P-6Ds. The third was given a Wright R-1820 'Cyclone' radial engine and delivered in October 1930 as the YP-20.
The original plan was to carry out some tests on the Cyclone and then install a Curtiss Conqueror in the aircraft, turning it into the XP-22. The radial engine tests took longer than expected, and another Hawk was used as the basis of the XP-22.
After the tests on the XP-22 were completed its V-1570 engine, engine cowl and landing gear were installed on the airframe of the YP-20. This combination was considered to be a success, and it was ordered into production, initially as the Y1P-22, then as the P-6C and finally as the P-6E.
The YP-20 itself was later given a turbo-supercharger and an enclosed cockpit and became the XP-6F.
Engine: Wright 'Cyclone' R-1820-9
Span: 31ft 6in
Length: 23ft 9in
Height: 9ft 2in
Empty weight: 2,477lb
Gross weight: 3,233lb
Max speed: 187mph at sea level, 184mph at 5,000ft
Climb Rate: 2,400ft/ min
Service ceiling: 27,800ft
Armament: Two .30in machine guns