Douglas XB-31

XB-31
Role	Heavy bomber
Manufacturer	Douglas Aircraft
Status	Design only
Primary user	United States Army Air Forces
Number built	0

The Douglas XB-31 (Douglas Model 332) was the design submitted by Douglas after the request by the United States Army Air Forces for a very heavy bomber aircraft, the same request that led to the Boeing B-29 Superfortress, Lockheed XB-30, and Consolidated B-32 Dominator.

Design and development

Around 1938, United States Army General Henry H. "Hap" Arnold, the head of the Army Air Force, was growing alarmed at the possibility of war in Europe and in the Pacific. Hoping to be prepared for the long-term requirements of the Air Force, Arnold created a special committee chaired by Brigadier General W. G. Kilner; one of its members was Charles Lindbergh. After a tour of Luftwaffe bases, Lindbergh became convinced that Nazi Germany was far ahead of other European nations. In a report in 1939, the committee made a number of recommendations, including development of new long-range heavy bombers. When war broke out in Europe, Arnold requested design studies from several companies on a Very Long-Range bomber capable of travelling 5,000 miles (8,000 km). Approval was granted on 2 December 1939.

Despite the promising design, it never progressed past the design stage, mainly because Boeing had a huge head start with its B-29 Superfortress.

Specifications (as designed)

General characteristics

• Crew: 8
• Length: 88 ft 8.5 in (27.038 m)
• Wingspan: 140 ft 6 in (42.82 m)
• Height: 28 ft 3 in (8.61 m)
• Wing area: 1,780 ft² (165 m²)
• Empty weight: 106,994 lb (48,532 kg)
• Loaded weight: 134,200 lb (60,870 kg)
• Max. takeoff weight: 120,000 lb (54,431 kg)
• Powerplant: 4 × Wright R-3350-13 "Duplex-Cyclone" radials, 2,200 hp (1641 kW) each

Performance (estimated)

• Maximum speed: 377 mph (607 km/h)
• Range: 5,370 miles (8,640 km)
• Service ceiling: 31,600 ft (9,600 m)
• Wing loading: 41 lb/ft² (200 kg/m²)
• Power/mass: 0.066 hp/lb (108 kW/kg) originally, later upgraded to 0.089 hp/lb (147 W/kg)

Armament

• Guns:
  
  • 6× .50 in (12.7 mm) machine guns in remote ventral and dorsal turrets
  • 1× 1.46 in (37 mm) cannon in tail
  • 1× 0.79 in (20 mm) cannon in tail
• Bombs: 24,000 lb (10,886 kg) in two ventral bomb bays

See also

• B-29 Superfortress
• Lockheed XB-30
• B-32 Dominator
• Messerschmitt Me 264
• List of bomber aircraft
• List of military aircraft of the United States
• Island hopping

References

Notes

Bibliography

• Francillon, René J. McDonnell Douglas Aircraft since 1920. London: Putnam & Company Ltd., 1979. ISBN 0-370-00050-1.
• Jones, Lloyd S. U.S. Bombers: B-1 1928 to B-1 1980s. Fallbrook, California: Aero Publishers, Inc., 1974. ISBN 0-8168-9126-5.

External links

• Joe Baugher's Encyclopedia of American Aircraft
• Photo of a model at 456fis.org