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XB-38 Flying Fortress
Role Strategic bomber
Manufacturer Boeing
First flight 19 May 1943
Retired 16 June 1943
Status Cancelled
Primary user United States Army Air Forces
Number built 1
Developed from B-17 Flying Fortress

The XB-38 Flying Fortress was a single example conversion of a production B-17E Flying Fortress, testing whether the Allison V-1710 V type engine could be substituted for the standard Wright R-1820 radial engine during early World War II.

Design and development

The XB-38 was the result of a modification project undertaken by Boeing and Vega (a subsidiary of Lockheed) on a B-17 Flying Fortress to fit it with liquid-cooled Allison V-1710-89 V-type engines. It was meant as an improved version of the B-17, and a variant that could be used if air-cooled Wright R-1820 radial engines became scarce. Completing the modifications took less than a year, and the XB-38 made its first flight on May 19, 1943. Only one prototype was built, and it was developed from an existing B-17 bomber.

While the XB-38 delivered a slightly higher top speed, after a few flights it had to be grounded due to a problem with engine manifold joints leaking exhaust gases. Following the fixing of this problem, testing continued until the ninth flight on June 16, 1943. During this flight, the third (right inboard) engine caught fire, and the crew was forced to bail out. The XB-38 was destroyed and the project was canceled, in part because the V-1710 engines were needed for other projects such as the P-38 Lightning, P-39 Airacobra, P-40 Warhawk, P-51A Mustang, and P-63 Kingcobra fighter aircraft.


 United States

Specifications (XB-38)

Data from Lockheed Aircraft since 1913.[1]

General characteristics

  • Crew: 10
  • Length: 74 ft 0 in (22.56 m)
  • Wingspan: 103 ft 11 in (31.67 m)
  • Height: 19 ft 2 in (5.84 m)
  • Wing area: 1,420 ft² (131.9 m²)
  • Empty weight: 34,750 lb (15,762 kg)
  • Loaded weight: 56,000 lb (25,401 kg)
  • Max. takeoff weight: 64,000 lb (29,030 kg)
  • Powerplant: 4 × Allison V-1710-97 turbosupercharged liquid-cooled V12 engines, 1,425 hp (1,063 kW) each


  • Maximum speed: 327 mph (284 knots, 526 km/h)
  • Cruise speed: 226 mph (197 knots, 364 km/h)
  • Range: 3,300 mi (2,870 nmi, 5,310 km)
  • Service ceiling: 29,600 ft (9,020 m)


See also


  1. Francillon 1982, p.215.
  • Francillon, René J. Lockheed Aircraft since 1913. London:Putnam, 1982. ISBN 0-370-30329-6.
  • Hess, William N. and Jim Winchester. ""Boeing B-17 Flying Fortress:Queen of the Skies". Wings Of Fame. Volume 6. London:Aerospace Publishing, 1997. ISBN 1-874023-93-X. ISSN 1361-2034. pp. 38–103.
  • Jones, Lloyd S. U.S. Bombers, B-1 1928 to B-1 1980s. Fallbrook, CA: Aero Publishers, 1962, second edition 1974. ISBN 0-8168-9126-5.

External links

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