<Tr> <Th> Developed into </Th> <Td> Conroy Virtus </Td> </Tr> <P> The Boeing B - 52 Stratofortress is an American long - range, subsonic, jet - powered strategic bomber . The B - 52 was designed and built by Boeing, which has continued to provide support and upgrades . It has been operated by the United States Air Force (USAF) since the 1950s . The bomber is capable of carrying up to 70,000 pounds (32,000 kg) of weapons, and has a typical combat range of more than 8,800 miles (14,080 km) without aerial refueling . </P> <P> Beginning with the successful contract bid in June 1946, the B - 52 design evolved from a straight wing aircraft powered by six turboprop engines to the final prototype YB - 52 with eight turbojet engines and swept wings . The B - 52 took its maiden flight in April 1952 . Built to carry nuclear weapons for Cold War - era deterrence missions, the B - 52 Stratofortress replaced the Convair B - 36 . A veteran of several wars, the B - 52 has dropped only conventional munitions in combat . The B - 52's official name Stratofortress is rarely used; informally, the aircraft has become commonly referred to as the BUFF (Big Ugly Fat Fucker). </P> <P> The B - 52 has been in active service with the USAF since 1955 . As of December 2015, 58 were in active service with 18 in reserve . The bombers flew under the Strategic Air Command (SAC) until it was disestablished in 1992 and its aircraft absorbed into the Air Combat Command (ACC); in 2010 all B - 52 Stratofortresses were transferred from the ACC to the newly created Air Force Global Strike Command (AFGSC). Superior performance at high subsonic speeds and relatively low operating costs have kept the B - 52 in service despite the advent of later, more advanced aircraft, including the canceled Mach 3 B - 70 Valkyrie, the variable - geometry B - 1 Lancer, and the stealth B - 2 Spirit . The B - 52 completed sixty years of continuous service with its original operator in 2015 . After being upgraded between 2013 and 2015, it is expected to serve into the 2050s . The B - 52s are expected to reach the end of their service lives by 2045, and be replaced by B - 21 Raiders . </P>

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