General Henry H. (Hap) Arnold, the acting head of the Army Air Corps, had become alarmed by the growing war clouds in Europe and in the Far East. He established a special committee, chaired by Brigadier General W. G. Kilner, to make recommendations for the long term needs of the Army Air Corps. No less a personage than the famous aviator Charles Lindbergh had been a member of the committee. Lindbergh had recently toured German aircraft factories and Luftwaffe bases, and had become convinced that Germany was well ahead of its potential European adversaries. In their June 1939 report, the Kilner committee recommended that several new long-range medium and heavy bombers be developed. Hastened by a new urgency caused by the outbreak of war in Europe on September 1, on November 10, 1939, General Arnold requested authorization to contract with major aircraft companies for studies of a Very Long-Range (VLR) bomber that would be capable of carrying any future war well beyond American shores. Approval was granted on December 2, and USAAC engineering officers under Captain Donald L. Putt of the Air Material Command at Wright Field began to prepare the official specification.
In January of 1940, the Army issued requirements for a "superbomber" with a speed of 400 mph, a range of 5333 miles, and a bomb load of 2000 pounds delivered at the halfway-point at that range. The official specification was revised in April to incorporate the lessons learned in early European wartime experience, and now included more defensive armament, armor, and self-sealing tanks. This became the basis for Request for Data R-40B and Specification XC-218. On January 29, 1940, the War Department formally issued Data R-40B and circulated it to Boeing, Consolidated, Douglas, and Lockheed.
On June 27, 1940, the Army issued contracts for preliminary engineering data for the new "superbomber" to four manufacturers, which were designated in order of preference as Boeing XB-29, Lockheed XB-30, Douglas XB-31, and Consolidated XB-32.
The Douglas XB-31 (company designation of Model 423) was somewhat larger and heavier than the other three competitors. It was to have been powered by four 3000-hp Pratt & Whitney R-4360 28-cylinder air-cooled radials driving three-bladed propellers. Wingspan was to have been 207 feet with a wing area of 3300 square feet. The length of the fuselage was to have been 117 feet 3 inches. Weights were expected to be 109,200 pounds empty and 198,000 pounds maximum. The pilot and co-pilot were to be seated under separate double bubble canopies that were similar to those later fitted to the C-74 Globemaster transport and the XB-42 experimental bomber. The six other crew members were to be accommodated at separate stations throughout the fuselage. Defensive armament was to have consisted of twin 0.50-inch machine guns in remotely controlled dorsal and ventral turrets, plus a pair of 37-mm cannon in the tail. A maximum bombload of 25,000 pounds was to have been carried in two fuselage bays.
In spite of the promise of the XB-31, the B-29 had the edge in the competition since work on the Boeing design was much further along. On May 17, 1941, the Army announced that an order would be placed for 250 B-29s. This order was confirmed in September of 1941. The Douglas XB-31 project was formally cancelled in late 1941 before anything could be built.
Sources:
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McDonnell Douglas Aircraft Since 1920, Volume I, Rene J. Francillon,
Naval Institute Press, 1988.
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US Army Aircraft, 1908-1946, James C. Fahey, Ships and Aircraft,
1946.
-
Warbird History--B-29 Superfortress, Chester Marshall, Motorbooks
International, 1993.
-
The Boeing B-29 Superfortress, Mich Mayborn, Aircraft in Profile,
Doubleday, 1969.
-
B-29 Superfortress, John Pimlott, Gallery Books, 1980.
-
Famous Bombers of the Second World War, William Green, Doubleday,
1960.
-
United States Military Aircraft Since 1909, Gordon Swanborough and
Peter M. Bowers, Smithsonian Institution Press, 1989.
- American Combat Planes, Third Enlarged Edition, Ray Wagner, Doubleday, 1982.
