Douglas XB-31

The Douglas XB-31, also known as the Douglas Model 332, was Douglas's design for a very long range heavy bomber, submitted in response to the United States Army Air Forces request that also produced the Boeing B-29 Superfortress, the Lockheed XB-30 and the Consolidated B-32 Dominator. The request followed a 1939 committee report that recommended new long range heavy bombers, and the studies, for a bomber able to travel 5,000 miles, were approved on 2 December 1939. Through 1939 and 1940 Douglas studied the Model 332 with several engines, including the Wright R-2600, the Pratt and Whitney R-2800 and the Wright R-3350, which was the choice in the final Model 332F design of four Duplex-Cyclone radials of 2,200 horsepower each. The design carried a crew of eight and a wingspan of about 42.8 metres. It was rejected in favour of the B-29 and B-32 because the air corps judged the B-29 superior, so the XB-31 stayed a paper design.