Douglas XB-31: Difference between revisions

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{{short description|American bomber project}}
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==Design and development==
==Design and development==
Around 1938, United States Army General [[Henry H. Arnold|Henry H. "Hap" Arnold]], the head of the [[US Army Air Corps]] (USAAC), 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]]. The Douglas firm at the time was working on an even larger, 212 foot (64.6 meter) wingspan four-engined strategic bomber prototype airframe, the [[Douglas XB-19]], that would make her maiden flight in late June 1941.
Around 1938, United States Army General [[Henry H. Arnold|Henry H. "Hap" Arnold]], the head of the [[US Army Air Corps]] (USAAC), 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]]. The Douglas firm at the time was working on an even larger, 212 foot (64.6 meter) wingspan four-engined strategic bomber prototype airframe, the [[Douglas XB-19]], that made her maiden flight in late June 1941.


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&nbsp;km). Approval was granted on 2 December 1939.
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&nbsp;km). Approval was granted on 2 December 1939.
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Throughout 1939 and 1940 Douglas investigated designs of the Model 332 with different powerplants ([[Wright R-2600]], [[Pratt & Whitney R-2800 Double Wasp|Pratt and Whitney R-2800]], [[Wright R-2160 Tornado|Wright R-2160]], [[Wright R-3350 Duplex-Cyclone|Wright R-3350]]). All were designed to have roughly same operating range, with variations in the projected service ceiling.<ref>Buttler, Tony, and Griffith, Alan, 2015. ''American Secret Projects: Fighters, Bombers, and Attack Aircraft, 1937-1945.'' Manchester: Crecy Publishing. {{ISBN|978-1906537487}}.</ref>
Throughout 1939 and 1940 Douglas investigated designs of the Model 332 with different powerplants ([[Wright R-2600]], [[Pratt & Whitney R-2800 Double Wasp|Pratt and Whitney R-2800]], [[Wright R-2160 Tornado|Wright R-2160]], [[Wright R-3350 Duplex-Cyclone|Wright R-3350]]). All were designed to have roughly same operating range, with variations in the projected service ceiling.<ref>Buttler, Tony, and Griffith, Alan, 2015. ''American Secret Projects: Fighters, Bombers, and Attack Aircraft, 1937-1945.'' Manchester: Crecy Publishing. {{ISBN|978-1906537487}}.</ref>


The XB-31 design was rejected in favor of the B-29 and B-32 (along with the XB-30) because the USAAC found the B-29 superior to the Douglas and Lockheed designs.<ref>http://www.joebaugher.com/usaf_bombers/b31.html</ref>
The XB-31 design was rejected in favor of the B-29 and B-32 (along with the XB-30) because the USAAC found the B-29 superior to the Douglas and Lockheed designs.<ref>{{cite web |url=http://www.joebaugher.com/usaf_bombers/b31.html |title = Douglas XB-31}}</ref>


==Specifications (Model 332F as designed)==
==Specifications (Model 332F as designed)==
{{Aircraft specifications
{{Aircraft specs
|ref={{citation needed|date=May 2019}}
|plane or copter?=plane
|prime units?=imp
|jet or prop?=prop
<!--
General characteristics
-->
|crew=8
|crew=8
|length main=88 ft 8.5 in
|length ft=88
|length alt=27.04 m
|length in=8.5
|length note=
|span main=140 ft 6 in
|span alt=42.82 m
|span ft=140
|span in=6
|height main=28 ft 3 in
|span note=
|height alt=8.6 m
|height ft=28
|area main=1,780 ft²
|height in=3
|area alt=165.54 m²
|height note=
|empty weight=
|wing area sqft=1780
|empty weight alt=
|wing area note=
|loaded weight main=106,994 lb
|aspect ratio=<!-- sailplanes -->
|loaded weight alt=48,532 kg
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|max takeoff weight main=120,000 lb
|max takeoff weight alt=48,532 kg
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|gross weight lb=106994
|engine (prop)=[[Wright R-3350]]-13 "Duplex-Cyclone"
|gross weight note=
|type of prop=[[radial engine|radials]]
|max takeoff weight lb=120000
|power main=2,200 hp
|max takeoff weight note=
|power alt=1641 kW
|fuel capacity=
|performance header=Performance (estimated)
|more general=
|max speed main=377 mph
<!--
|max speed alt=607 km/h
Powerplant
|range main=5,370 miles
-->
|range alt=8,640 km
|eng1 number=4
|ceiling main=31,600 ft
|eng1 name=[[Wright R-3350-13 Duplex-Cyclone]]
|ceiling alt=9,632 m
|eng1 type=18-cylinder air-cooled radial piston engines
|climb rate main=
|eng1 hp=2200
|climb rate alt=

|loading main=41 lb/ft²
|prop blade number=<!-- propeller aircraft -->
|loading alt=200 kg/m²
|prop name=
|power/mass main=0.066 hp/lb
|prop dia ft=<!-- propeller aircraft -->
|power/mass alt=108 kW/kg) originally, later upgraded to 0.089 hp/lb (147 W/kg
|prop dia in=<!-- propeller aircraft -->
|prop dia note=
<!--
Performance
-->
|max speed mph=377
|max speed note=
|cruise speed mph=
|cruise speed note=
|stall speed mph=
|stall speed note=
|never exceed speed mph=
|never exceed speed note=
|minimum control speed mph=
|minimum control speed note=
|range miles=5370
|range note=
|combat range miles=
|combat range note=
|ferry range miles=
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|ceiling ft=31600
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|g limits=<!-- aerobatic -->
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|climb rate ftmin=
|climb rate note=
|time to altitude=
|wing loading lb/sqft=41
|wing loading note=
|fuel consumption lb/mi=
|power/mass={{cvt|0.066|hp/lb|kW/kg}}, later {{cvt|0.089|hp/lb|kW/kg}}
|more performance=
<!--
Armament
-->
|guns=<br/>
|guns=<br/>
**6× .50 in (12.7 mm) [[M2 Browning|machine gun]]s in remote ventral and dorsal turrets
**6× .50 in (12.7 mm) [[M2 Browning|machine gun]]s in remote ventral and dorsal turrets
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**8x 1,000 lb (454 kg) bombs
**8x 1,000 lb (454 kg) bombs
**16x 500 lb (227 kg) bombs
**16x 500 lb (227 kg) bombs
|rockets=
|missiles=
|hardpoints=
|hardpoint capacity=
|hardpoint rockets=
|hardpoint missiles=
|hardpoint bombs=
|hardpoint other=

|avionics=
}}
}}


Latest revision as of 13:03, 19 March 2022

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[edit]

Around 1938, United States Army General Henry H. "Hap" Arnold, the head of the US Army Air Corps (USAAC), 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. The Douglas firm at the time was working on an even larger, 212 foot (64.6 meter) wingspan four-engined strategic bomber prototype airframe, the Douglas XB-19, that made her maiden flight in late June 1941.

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.

Throughout 1939 and 1940 Douglas investigated designs of the Model 332 with different powerplants (Wright R-2600, Pratt and Whitney R-2800, Wright R-2160, Wright R-3350). All were designed to have roughly same operating range, with variations in the projected service ceiling.[1]

The XB-31 design was rejected in favor of the B-29 and B-32 (along with the XB-30) because the USAAC found the B-29 superior to the Douglas and Lockheed designs.[2]

Specifications (Model 332F as designed)[edit]

Data from [citation needed]

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 sq ft (165 m2)
  • Gross weight: 106,994 lb (48,532 kg)
  • Max takeoff weight: 120,000 lb (54,431 kg)
  • Powerplant: 4 × Wright R-3350-13 Duplex-Cyclone 18-cylinder air-cooled radial piston engines, 2,200 hp (1,600 kW) each

Performance

  • Maximum speed: 377 mph (607 km/h, 328 kn)
  • Range: 5,370 mi (8,640 km, 4,670 nmi)
  • Service ceiling: 31,600 ft (9,600 m)
  • Wing loading: 41 lb/sq ft (200 kg/m2)
  • Power/mass: 0.066 hp/lb (0.109 kW/kg), later 0.089 hp/lb (0.146 kW/kg)

Armament

  • Guns:
    • 6× .50 in (12.7 mm) machine guns in remote ventral and dorsal turrets
    • 1x machine gun in tail
    • 1× 0.79 in (20 mm) cannon in tail
  • Bombs:
    • 4x 2,000 lb (907 kg) bombs
    • 8x 1,000 lb (454 kg) bombs
    • 16x 500 lb (227 kg) bombs

See also[edit]

Aircraft of comparable role, configuration, and era

Related lists

References[edit]

Citations[edit]

  1. ^ Buttler, Tony, and Griffith, Alan, 2015. American Secret Projects: Fighters, Bombers, and Attack Aircraft, 1937-1945. Manchester: Crecy Publishing. ISBN 978-1906537487.
  2. ^ "Douglas XB-31".

Bibliography[edit]

  • 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[edit]

Retrieved from "https://en.wikipedia.org/w/index.php?title=Douglas_XB-31&oldid=1078025091"