The Curtiss O-39 Falcon was a version of the O-1 Falcon two-seat observation aircraft that was powered by the Curtiss Conqueror engine. The original O-1 was powered by the Curtiss V-1150 engine, and later versions, with a 435hp engine, had a top speed of 141mph. The O-39 used the Curtiss V-1570-25 Conqueror engine, with the engine cowling and radiator taken from the Curtiss P-6E Hawk single seat fighter. The O-39 was a little heavier than the O-1G, which it was largely based on, but top speed rose to 170.5mph. While in service all the O-39s had two inches cut off the top of the rudder. All ten were built with wheel spats although there were normally removed in service.
Some of the 0-39s were given an enclosed cockpit. These aircraft had a higher top speed, of 173.3mph. The O-39 (in either configuration) was the fastest standard Army Falcon, only beaten by dedicated racers.
Engine: Curtiss V-1570-25 Conqueror
Length: 27ft 7in
Height: 10ft 3in
Empty weight: 3,328lb
Gross weight: 4,679lb
Max speed: 170.5mph (standard) or 173.3mph (enclosed cockpit)
Climb Rate: 1,620ft/ minute
Service ceiling: 22,800ft
Range: 760 miles
Armament: One fixed and one flexibly mounted .30in machine guns
Bomb load: 250lb