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XA-21
Stearman XA-21 with streamlined cockpit
General information
Type	Ground attack
National origin	United States
Manufacturer	Stearman Aircraft
Status	Prototype
Primary user	United States Army Air Corps
Number built	1
History
First flight	1938

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.

Design and development

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.

Operational history

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.

Operators

 United States

• United States Army Air Corps

Specifications (XA-21)

Data from Museum of the United States Air Force

General characteristics

• Crew: 3
• Capacity: 5,560 lb (2,520 kg)
• 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 sq ft (56.39 m)
• Empty weight: 12,760 lb (5,789 kg)
• Gross 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

Performance

• Maximum speed: 223 kn (257 mph, 414 km/h)
• Cruise speed: 174 kn (200 mph, 322 km/h)
• Wing loading: 30.0 lb/sq ft (147 kg/m)
• Power/mass: 0.15 hp/b (250 W/kg)

Armament

• Guns: ** 4 × wing-mounted 0.30 in (7.6 mm) M1919 Browning machine guns
  • 1 × nose-mounted 0.30 in (7.6 mm) in machine gun
  • 4 × aft-firing 0.30 in (7.6 mm) in machine guns
• Bombs: 2,700 lb (1,200 kg)

See also

Related lists

• List of military aircraft of the United States

References

Notes

1. "Stearman XA-21 (Stepped Cockpit)." Museum of the United States Air Force. Retrieved: 17 July 2017.
2. Bowers 1989, p. 273.
3. "Swift Attack Bombers Race For Jobs In Army Air Corps." Popular Mechanics, June 1939.
4. ^ "Stearman XA-21 (Streamlined Cockpit)." Museum of the United States Air Force. Retrieved: 17 July 2017.
5. Phillips, Edward (2006). Stearman Aircraft: A Detailed History. North Branch, MN: specialtypress. pp. 135–138, 202. ISBN 9781580070874.

Bibliography

• Bowers, Peter M. Boeing Aircraft since 1916. London: Putnam, Second edition, 1989. ISBN 0-85177-804-6.
• Wagner, Ray. American Combat Planes of the 20th Century, Third Enlarged Edition. New York: Doubleday, 1982. ISBN 978-0-930083-17-5.

External links

• "Stearman XA-21"

• 1930s United States attack aircraft
• Stearman aircraft
• Shoulder-wing aircraft
• Aircraft first flown in 1938
• Twin piston-engined tractor aircraft