 The XSBF-1 was a two-seat biplane, featuring an enclosed cockpit, a fuselage of all-metal construction, and wings covered largely with fabric.Power was provided by a Pratt & Whitney R-1535 Twin Wasp Junior air-cooled radial engine driving with a variable-pitch propeller.Armament was planned to be two forward-firing M1919 Browning machine guns, one of which could be replaced by a M2 Browning; the prototype carried only a single gun.