Stearman Cloudboy

Model 6 Cloudboy
	The YBT-3
Role	Training biplane
Manufacturer	Stearman Aircraft Company
First flight	1931
Primary user	United States Army Air Corps
Produced	1930-1931
Number built	7

The Stearman Model 6 Cloudboy was a 1930s American training biplane designed and built by the Stearman Aircraft Company of Wichita, Kansas.

Development[]

The Cloudboy was designed as a commercial or military trainer. It was a two-seat biplane with tandem open-cockpits and powered by nose-mounted 165 hp (123 kW) Wright J-6 Whirlwind 5 engine. It had a fixed tailwheel landing gear. The aircraft was only built in small numbers due to the American economic climate in the early 1930s. Three civil aircraft were built followed by four similar aircraft for evaluation by the United States Army Air Corps. Designated the YPT-9 by the Army it failed to gain any orders. With only a few aircraft built they all went through a number of engine changes resulting in new designations for both the military and civil aircraft.

Variants[]

Model 6A Cloudboy: Initial civil production with a 165hp (123kW) Wright J-6 Whirlwind 5 engine, three built.
Model 6C Cloudboy: Re-engined with a 300hp (224kW) Wright J-6-9 Whirlwind (R-975-1), also designated YBT-3.
Model 6D Cloudboy: Re-engined with a 300hp (224kW) Pratt & Whitney Wasp Junior, also designated YBT-5
Model 6F Cloudboy: Re-engined with a 165hp (123kW) Continental A70 engine., also designated YBT-9A.
Model 6H Cloudboy: Re-engined with a 170hp (127kW) Kinner YR-720A engine, also designated YBT-9C.
Model 6L Cloudboy: Re-engined with a 200hp (149kW) Lycoming R-680-3 engine, also designated YBT-9B
Model 6P Cloudboy: One 6F re-engined with 1 220hp Wright J-5 engine

YPT-9: Military production variant of the Model 6A with a 165hp (123kW) Wright J-6 Whirlwind 5 engine, four built (one converted to YPT-9A, one to YPT-9B, one to YBT-3 and one YBT-5).
YPT-9A: One YPT-9 re-engined with a 165hp (123kW) Continental A70 (YR-545-1) engine, later converted to YPT-9B.
YPT-9B: One YPT-9 and one YPT-9A re-engined with a 200hp (149kW) Lycoming R-680-3 engine.
YPT-9C: YBT-3 re-engined with a 170hp (127kW) Kinner YR-720A engine.
YBT-3: One YBT-9 re-engined with a 300hp (224kW) Wright J-6-9 Whirlwind, later converted to a YPT-9C.
YBT-5: One YBT-9 re-engined with a 300hp (224kW) Pratt & Whitney Wasp Junior engine.
XPT-943: A primary trainer derived fron the 6A for evaluation at Wright Field. Formed the origins of the Stearman NS and PT-13 for the US Navy and USAAC respectively.
X-70: Alternative company designation for the XPT-943.

Operators[]

United States: United States Army Air Corps

Specifications (YPT-9B)[]

Data from United States Military Aircraft since 1909^[1]

General characteristics

Crew: 2
Length: 24 ft 8 in (7.52 m)
Wingspan: 32 ft 0 in (9.76 m)
Height: 9 ft 7 in (2.92 m)
Wing area: 272 ft² (25.3 m²)
Gross weight: 2,814 lb (1,279 kg)
Powerplant: 1 × Lycoming R-680-3, 200 hp (149 kW) each

Performance

Maximum speed: 135 mph (217 km/h)
Range: 490 miles (789 km)
Service ceiling: 17,000 ft (5,183 m)
Rate of climb: 1,050 ft/min (5.3 m/s)

References[]

↑ Swanborough and Bowers 1963, p. 441.

Andrade, John (1979). U.S.Military Aircraft Designations and Serials since 1909. Midland Counties Publications. ISBN 0-904597-22-9.
Swanborough, F.G; Bowers, Peter M. (1963). United States Military Aircraft since 1909. London: Putnam.
Taylor, Michael J. H. (1989). Jane's Encyclopedia of Aviation. London: Studio Editions.
The Illustrated Encyclopedia of Aircraft (Part Work 1982-1985). Orbis Publishing. pp. 2958.

External links[]

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[Swanmil_p441-1] Swanborough and Bowers 1963, p. 441.

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