What was to become the first member of the PW (Pursuit, Water-cooled engine) family of US Army Air Service aircraft, the PW-1 was the work of Alfred 'Fred' V. Verville, a designer who came to the Engineering Division late in World War I. From his Verville Chasse Plane was evolved the VCP-1 fighter (only one of the two prototypes was flown). The VCP-1 formed the basis for the two VCP-2 prototypes (64349 and 64350) of which the first was used for static tests. A typical single-seat biplane of the period with a 261kW Packard 1A-1237 12-cylinder Vee engine, 64350 was first flown in early 1920 and shortly after was re-designated PW-1. Hoping to improve performance, the aircraft was tested with straight-chord wings incorporating a thicker aerofoil section and was redesignated the PW-1A at this time, but reverted to PW-1 when the original wings were refitted. A PW-1B variant with tapered wings of revised aerofoil section was planned but was cancelled.