Stearman XA-21

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.

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

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.[1] 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.[2]

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.[3] Although this change in the cockpit did not significantly affect performance, the XA-21 was not ordered into production.'[4]

The sole XA-21 had serial number 40-191.

Operators
 United States

Specifications (XA-21)
In flight
Front view

Data from Museum of the United States Air Force[4]

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 m2)
  • 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/m2)
  • Power/mass: 0.15 hp/b (250 W/kg)

Armament

  • Guns:
    • 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)

See also

Related lists

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.

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.
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