Known by the company designation Model X-85,[1] the Stearman XOSS-1 was designed during 1937 in response to a U.S. Navy specification calling for an observation-scout type aircraft, capable of operating from either water or land, and stressed for catapult launching from battleships and cruisers.[2] The new aircraft was intended to replace the Curtiss SOC as the standard observation and gunnery spotting aircraft in service aboard the Navy's battleships.[3]
In response to the request for proposals, the Navy received designs from Stearman Aircraft, Chance Vought, and the Naval Aircraft Factory. The Stearman Model 85, given the designation XOSS-1, was a conventional two-seat biplane, with the pilot and observer seated in tandem in a fully enclosed cockpit. The aircraft could be operated with either float or wheeled landing gear, with the former being of the single center-float type, and the latter being a conventional taildraggerundercarriage. The XOSS-1 had the unusual feature of being fitted with full-span flaps on the upper wing to reduce stalling speed.[2] It was powered by a Pratt & Whitney R-1340 Wasp radial engine.[1]
Operational history
Flying for the first time in September 1938, the XOSS-1 proved to have benign flying characteristics, and over the next several months was evaluated against the Naval Aircraft Factory XOSN, another conventional biplane, and the Vought XOS2U, a mid-wing monoplane.[2]
The evaluation proved that the XOSS-1 was conventional in all respects; the full-span upper-wing flap reduced the aircraft's landing speed to 57 miles per hour (92 km/h), while the top speed achievable was 162 miles per hour (261 km/h). Both the XOSS-1 and the XOSN-1, despite not possessing any significant faults, were considered to be insufficiently advanced, being inferior in performance and potential to the Vought machine.[2] The XOS2U-1 was declared the winner of the competition in May 1939,[4] and the XOSS-1's development came to an end. The aircraft was used for liaison purposes by the Navy, being scrapped at NAS Jacksonville in 1941.[5]
