Stearman XOSS

The Stearman XOSS was an American biplane observation floatplane developed for the United States Navy during the late 1930s.

Known by the company designation Model X-85, 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.

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.

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 centre float type, and the latter being a conventional tail dragger undercarriage.

The XOSS-1 had the unusual feature of being fitted with full-span flaps on the upper wing to reduce stalling speed.

It was powered by a Pratt & Whitney R-1340 Wasp radial engine.





34 ft 6 in (10.52 m) on floats


36 ft (11 m)


13 ft (4.0 m)


NACA 23012

Gross weight

4,791 lb (2,173 kg)


1 × Pratt & Whitney R-1340 radial engine, 600 hp (450 kW)


Maximum speed

162 mph (261 km/h, 141 kn) at 6,000 feet (1,800 m)


832 mi (1,339 km, 723 nmi)

Service ceiling

18,500 ft (5,600 m)

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