Boeing 93 / XP-7

The final production PW-9D (the 16th) was retained by Boeing for the experimental installation of a 600hp water-cooled Curtiss Conqueror V-1570 engine and, as the XP-7 (Model 93), was eventually delivered to the USAAC on 4 September 1928. Distinguished from the PW-9D by a shorter, deeper nose with a larger radiator, the XP-7 enjoyed some success during trials, proving the suitability of the Conqueror for fighter installation. Proposals to build four service evaluation P-7s were abandoned when it was concluded that the basic PW-9 airframe had reached the limit of its development. The XP-7, the last Boeing fighter biplane to employ a liquid-cooled engine, was reconverted to PW-9D standards.

Engine: 600hp water-cooled Curtiss Conqueror V-1570
Take-off weight: 1479 kg / 3261 lb
Empty weight: 1 053 kg
Wingspan: 9.75 m / 31 ft 12 in
Length: 7.31 m / 23 ft 12 in
Height: 2.74 m / 8 ft 12 in
Wing area: 22.39 sq.m / 241.00 sq ft
Max. speed: 269 km/h / 167 mph