This week in history - April 15, 1952: B-52 first flight Published April 16, 2013 By AFNWC Historian Air Force Nuclear Weapons Center KIRTLAND AFB, N.M. -- The Air Force issued requirement for a new strategic bomber in November 1945. Boeing won the contract bid June 5, 1946. The B-52 design evolved from a straight-wing aircraft powered by six turboprop engines to the final prototype B-52s with eight turbojet engines. Two prototypes were constructed. The YB-52, the second prototype, first flew April 15, 1952. The XB-52 was damaged during a full-pressure test of its pneumatic system and did not make its first flight until Oct. 2, 1952. Built to carry nuclear weapons for Cold War deterrence, the B-52 Stratofortress replaced the Convair B-36. In total, 744 B-52s were built, with the last delivered in October 1962.