12/31/2009. Remarks by Johan Visschedijk: "Stearman Aircraft Company at Wichita, Kansas designed this two-seat dual-purpose model, intended to offer one basic airframe with a choice of alternative power plants for respectively, the primary training role as the X-90 and basic training role as the X-91.

To counter the anticipated aluminum shortage the aircraft was constructed with a tube-frame fuselage and wooden flying surfaces, all covered with plastic-impregnated plywood, while the control surfaces were fabric covered.

The prototype X-90 (c/n 90000) was fitted with a 225 hp Lycoming R-680-B4D nine-cylinder radial, and flew for the first time in 1941, registered as NX21924. Subsequently it was re-engined with a 450 hp Pratt & Whitney R-985-AN-1 Wasp Junior, and designated X-91 (new c/n 91000).

This aircraft was bought by the USAAC for evaluation, designated XBT-17, and was allotted the s/n 42-8726. It was not ordered into production."

Span: Length: Height: Wing area: Weight empty: Weight loaded: Max speed: Cruise speed: Service ceiling: Range:

X-90 35 ft 9.5 in (10.91 m) 28 ft 6 in (8.69 m) 8 ft 10.3 in (2.57 m) 201 sq.ft (18.67 sq.m) 2,103 lb (954 kg) 2,813 lb (1,276 kg) 140 mph (225 kmh) 115 mph (185 kmh) 15,100 ft (4,602 m) 466 mls (750 km)

X-91 35 ft 9.5 in (10.91 m) 27 ft 9.5 in (8.47 m) 8 ft 5 in (2.57 m) 201 sq.ft (18.67 sq.m) 3,082 lb (1,398 kg) 4,150 lb (1,882 kg) 190 mph (306 kmh) 160 mph (257 kmh) 20,000 ft (6,096 m) 404 mls (650 km)