The Stearman XA-21 (Model X-100) was a competitor in a United States Army Air Corps competition for a twin-engined attack aircraft which (after redesigns) led to the Douglas A-20 Havoc, Martin A-22 Maryland and North American B-25 Mitchell.
|Stearman XA-21 with streamlined cockpit|
|National origin||United States|
|Primary user||United States Army Air Corps|
Design and developmentEdit
The X-100, designated XA-21 following purchase by the Army Air Corps, was a twin-engined high-winged monoplane of all-metal construction. Its initial design featured an unusual "stepless cockpit" arrangement, much like those on most German World War II bombers designed during the war years from the He 111P onwards, with a streamlined, well-framed greenhouse canopy enclosing both the pilot and bombardier stations.
The XA-21 was first tested with the streamlined cockpit but this configuration was found to restrict the pilot's forward vision, and the aircraft was rebuilt with a conventional (stepped) nose and cockpit structure. Although this change in the cockpit did not significantly affect performance, the XA-21 was not ordered into production.'
The sole XA-21 had serial number 40-191.
Data from Museum of the United States Air Force
- Crew: 3
- Length: 53 ft 1 in (16.18 m)
- Wingspan: 65 ft 0 in (19.81 m)
- Height: 14 ft 2 in (4.32 m)
- Wing area: 607 ft2 (56.39 m2)
- Empty weight: 12,760 lb (5,789 kg)
- Useful load: 5,560 lb (2,520 kg)
- Loaded weight: 18,230 lb (8,269 kg)
- Powerplant: 2 × Pratt & Whitney R-2180-7 Twin Hornet radial engines, 1,400 hp (1,030 kW) each
- Maximum speed: 223 knots (257 mph, 414 km/h)
- Cruise speed: 174 knots (200 mph, 322 km/h)
- Wing loading: 30.0 lb/ft2 (147 kg/m2)
- Power/mass: 0.15 hp/b (250 W/kg)
- 4× wing-mounted 0.30 in (7.62 mm) M1919 Browning machine guns
- 1× nose-mounted 0.30 in machine gun
- 4× aft-firing 0.30 in machine guns
- Bombs: 2,700 lb (1,200 kg)
- "Stearman XA-21 (Stepped Cockpit)." Museum of the United States Air Force. Retrieved: 17 July 2017.
- Bowers 1989, p. 273.
- "Swift Attack Bombers Race For Jobs In Army Air Corps." Popular Mechanics, June 1939.
- "Stearman XA-21 (Streamlined Cockpit)." Museum of the United States Air Force. Retrieved: 17 July 2017.
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