On 23 November 1945, Air Materiel Command (AMC) issued desired performance characteristics for a new strategic bomber “capable of carrying out the strategic mission without dependence upon advanced and intermediate bases controlled by other countries”.
The aircraft was to have a crew of five or more turret gunners, and a six-man relief crew. It was required to cruise at 300 mph (260 knots, 480 km/h) at 34,000 feet (10,400 m) with a combat radius of 5,000 miles (4,300 nautical miles, 8,000 km). The armament was to consist of an unspecified number of 20 mm cannon and 10,000 pounds (4,500 kg) of bombs.
On 13 February 1946, the Air Force issued bid invitations for these specifications, with Boeing, Consolidated Aircraft, and Glenn L. Martin Company submitting proposals