To meet a US Marine Corps requirement for a two-seat fighter with bombing and observation capability, Curtiss adapted the airframe of the USAAC's O-1 Falcon. With a Pratt & Whitney R-1340 Wasp radial engine in place of the water-cooled Conqueror six examples were delivered, two as XF8C-1s and four as F8C-1s, in January 1928. Armament comprised two fixed forwardfiring 7.62mm guns and a weapon of similar calibre on a Scarff ring in the rear cockpit, and power was provided by a 432hp R-1340B Wasp. Twenty-one additional machines (one XF8C-3 and 20 F8C-3s) were delivered later in 1928, these being essentially similar to the F8C-1s which were redesignated as OC-1s shortly after entering service, the F8C-3s becoming OC-2s.