Stearman XBT-17

The X-90 was a low-wing cantilever monoplane with two-seats in tandem under an enclosed canopy.

It had a fixed conventional landing gear and was powered by a 225 hp (168 kW) Lycoming R-680 engine and first flew in 1940.

It had wooden wings and a steel tube forward fuselage in order minimize use of aluminium.

In 1942 the aircraft was re-engined with a 450 hp (336 kW) Pratt & Whitney R-985 engine and redesignated the Model X-91.

The X-91 was evaluated by the United States Army Air Force as the XBT-17 but no more were built.

Variants

Stearman X-90

Prototype basic trainer with a 225 hp (168 kW) Lycoming R-680 engine.

Stearman X-91

The X-90 re-engined with a 450 hp (336 kW) Pratt & Whitney R-985 engine for USAAF evaluation.

Stearman XBT-17

United States Army Air Force designation for the X-91.

Specifications

Crew

two

Length

27 ft 9 in (8.46 m)

Wingspan

35 ft 9 in (10.90 m)

Wing area

200 sq ft (19 m2)

Empty weight

3,080 lb (1,397 kg)

Gross weight

4,150 lb (1,882 kg)

Powerplant

1 × Pratt & Whitney R-985-AN-1, 450 hp (340 kW)

Performance

Maximum speed

190 mph (310 km/h, 170 kn)

Cruise speed

160 mph (260 km/h, 140 kn)

Service ceiling

20,000 ft (6,100 m)

Rate of climb

1,300 ft/min (6.6 m/s)

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