The Boeing B-52 Stratofortress is a long-range, subsonic, jet-powered, strategic bomber operated by the United States Air Force (USAF) since 1955.
Beginning with the successful contract bid on 5 June 1946, the B-52 went through several design steps; from a straight wing aircraft powered by six turboprop engines to the final prototype YB-52, with eight turbojet engines. The aircraft made its first flight on 15 April 1952 with Tex Johnston as pilot.
Built to carry nuclear weapons for Cold War-era deterrence missions, the B-52 Stratofortress replaced the Convair B-36. Although a veteran of a number of wars, the Stratofortress has dropped only conventional munitions in actual combat. With the longest unrefueled range of any contemporary bomber, the B-52 carries up to 70,000pounds of weapons.
The USAF has had B-52s in active service since 1955, initially with the Strategic Air Command (SAC), with all operational aircraft absorbed into the Air Combat Command (ACC) in 1992. Superior performance at high subsonic speeds and relatively low operating costs have kept the B-52 in service despite proposals to replace it with the Mach3 XB-70 Valkyrie, supersonic B-1B Lancer and stealthy B-2 Spirit. In January 2005, the B-52 became the second aircraft, after the English Electric Canberra, to mark 50 years of continuous service with its original primary operator.