Douglas XB-31

XB-31
275px
A model of the XB-31.
Type	Heavy bomber
Manufacturer	Douglas Aircraft
Status	Design only
Primary user	U.S. Army Air Force
Number built	0

The Douglas XB-31 (Douglas Model 423) was the design submitted by Douglas after the request by the United States Army Air Forces for a very heavy bomber, the same request that led to the B-29 Superfortress and B-32 Dominator.

Around 1938, 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 traveling 5,000 miles (8,000 km). Approval was granted on December 2.

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: 12
• Length: 117 ft 3 in (35.7 m)
• Wingspan: 207 ft 0 in (63.1 m)
• Height: ()
• Wing area: 3,300 ft² (310 m²)
• Empty weight: 109,200 lb (49,530 kg)
• Loaded weight: 134,200 lb (60,870 kg)
• Max takeoff weight: 198,000 lb (89,800 kg)
• Powerplant: 4× Wright R-3350-13 "Cyclone" radials, 2,200 hp (1,600 kW) each
• ** Powerplant after later redesign: 4× Pratt & Whitney R-4360 "Wasp Major" radials, 3,000 hp (2,200 kW) each

Performance

• 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:
  
  • 4× .50 in (12.7 mm) machine guns
  • 1× 1.46 in (37 mm) cannon in tail
• Bombs: 25,000 lb (11,000 kg)

References and links

• Joe Baugher's Encyclopedia of American Aircraft
• USAF Museum

Related content

Comparable aircraft

• B-29 Superfortress
• Lockheed XB-30
• B-32 Dominator
• Messerschmitt Me 264

Designation sequence

• XB-28 - B-29 - XB-30 - XB-31 - B-32 - B-33 - B-34

Related lists

• List of bomber aircraft
• List of military aircraft of the United States

See also

• Island hopping

Douglas military aircraft

Naval Fighters: XFD · F3D · F4D · F5D · XF6D - Fighters: XP-48 · P-70 · F-6 · F-10

Naval Attack: DT · T2D · XT3D · BT · TBD · SBD · XBTD · XTB2D · AD · XA2D · A3D · A4D

Bomber: YB-7 · YB-11 · B-18 · XB-19 · XB-22 · B-23 · B-26 · XB-31 · XB-42 · XB-43 · B-66

Attack: XA-2 · A-20 · A-24 · A-26 · A-1 · A-3 · A-4

Reconnaissance: O-2 · OD · O2D · O-31 · O-35 · YO-44 · YOA-5 · PD · P2D · P3D

Transports: C-1 · C-21 · C-39 · C-47 · C-53 · C-54 · C-58 · UC-67 · C-74 · C-110 · C-118 · C-124 · C-133 · C-24

Naval Transports: RD · R2D · R3D · R4D · R5D · JD · R6D - Experimental: DWC · D-558-1 · D-558-2 · X-3