Although these aircraft were intended purely to prove the Conqueror engine, the success of this powerplant prompted a USAAC order for eighteen P-6s on October 3, 1928, these being powered by the 600 hp water-cooled V-1570-17. Although generally similar to the P-l in construction, they embodied extensively revised fuselage contours. Deliveries commenced in October 1929, but with the 11th aircraft Prestone (ethylene glycol) cooling was introduced, the designation changing to P-6A.
The V-1570-23 engine in the P-6A had a similar rating to that of the V-1570-17 that it supplanted; armament remained unchanged at two 0.3 in (7.62 mm) guns. In service, eight of the Army Air Corps P-6s were brought up to P-6A standards. Eight additional P-6s were delivered to the Netherlands East Indies and one to Japan under the export designation Hawk I.
Span: 31 ft 6 in (9.60 m)
Length: 23 ft 7 in (7.19 m)
Height: 8 ft 7 in (2.62 m)
Wing area: 252 sq.ft (23.41 sq.m)
Weight empty: 2,389 lb (1,083 kg)
Loaded weight: 3,172 lb (1,439 kg)
Max speed: 178 mph (286 kmh) at sea level
Climb: to 10,000 ft (3,050 m) 5 min 48 sec."