# Stearman Cloudboy

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

## History

The Cloudboy was designed as a commercial or military trainer. Due to economic pressure during the Great Depression, only a few aircraft were built. Three civil models were built, followed by four similar aircraft for evaluation by the United States Army Air Corps. Designated YPT-9 by the Army, it failed to gain any orders. All models 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 165 hp (123 kW) Wright J-6 Whirlwind 5 engine, three built.

### Model 6C Cloudboy

    Re-engined with a 300 hp (220 kW) Wright J-6-9 Whirlwind (R-975-1), also designated YBT-3.

### Model 6D Cloudboy

    Re-engined with a 300 hp (220 kW) Pratt & Whitney Wasp Junior, also designated YBT-5

### Model 6F Cloudboy

    Re-engined with a 165 hp (123 kW) Continental A70 engine, also designated YBT-9A.

### Model 6H Cloudboy

    Re-engined with a 170 hp (130 kW) Kinner YR-720A engine, also designated YBT-9C.

### Model 6L Cloudboy

    Re-engined with a 200 hp (150 kW) Lycoming R-680-3 engine, also designated YBT-9B

### Model 6P Cloudboy

    One 6F re-engined with 1 220 hp (160 kW) Wright J-5 engine

### YPT-9

    Military production variant of the Model 6A with a 165 hp (123 kW) 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 165 hp (123 kW) Continental A70 (YR-545-1) engine, later converted to YPT-9B.

### YPT-9B

    One YPT-9 and one YPT-9A re-engined with a 200 hp (150 kW) Lycoming R-680-3 engine.

### YPT-9C

    YBT-3 re-engined with a 170 hp (130 kW) Kinner YR-720A engine.

### YBT-3

    One YPT-9 re-engined with a 300 hp (220 kW) Wright J-6-9 Whirlwind, later converted to a YPT-9C.

### YBT-5

    One YPT-9 re-engined with a 300 hp (220 kW) Pratt & Whitney R-985-1 Wasp Junior engine.

### XPT-943

    A primary trainer derived from 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

## Surviving aircraft

* 6002 – 6L airworthy at the Candler Field Museum in Williamson, Georgia.
* 6003 – 6L airworthy at the Western Antique Aeroplane & Automobile Museum in Hood River, Oregon. It was previously owned by the Golden Wings Flying Museum.
* 6004 – YPT-9B on display at the Yanks Air Museum in Chino, California. It was previously owned by the Boeing School of Aeronautics and was acquired by the museum in 1987.
* 6010 – 6C airworthy with Robert Lock of Lakeland, Florida.

## Specifications (YPT-9B)

Data from United States Military Aircraft since 1909
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 sq ft (25.3 m$^2$)
* Gross weight: 2,814 lb (1,279 kg)
* Powerplant: 1 × Lycoming R-680-3 , 200 hp (149 kW)
Performance
* Maximum speed: 135 mph (217 km/h, 117 kn)
* Range: 490 mi (789 km, 430 nmi)
* Service ceiling: 17,000 ft (5,183 m)
* Rate of climb: 1,050 ft/min (5.3 m/s)