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 Lockheed XB-30 proposal envisaged a bomber powered by four 2200 hp Wright R-3350-13 air-cooled radials. It was to have carried a crew of 12, and would have had a wingspan of 123 feet and a length 104 feet 8 inches. Top speed was projected to be 382 mph. Seeing that it was at a competitive disadvantage against the Boeing B-29, Lockheed withdrew its XB-30 proposal from the competition before any detailed designs could be completed. However, the work that Lockheed performed on the abortive XB-30 did not go to waste, since it was later put to use on the development of the C-69 Constellation transport.