page_title: Boeing B-52 Stratofortress
section_title: Overview
hierarchical_section_title: Boeing B-52 Stratofortress / Design / Overview
caption_attribution_description: A Boeing B-52H Stratofortress (61-023) flying with its vertical stablizer sheared off. The aircraft was being used as a testbed to identify structural weaknesses in the airframe when the event occurred. The crew, with the assistance of Boeing engineers on the ground, was able to land the aircraft safely.
context_page_description: 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 since the 1950s. The bomber is capable of carrying up to 70,000 pounds of weapons, and has a typical combat range of more than 8,800 miles without aerial refueling.
  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.
  The B-52 has been in service with the USAF since 1955. As of June 2019, 58 are in active service, 18 in reserve, and approximately 12 more aircraft in long-term storage.
context_section_description: The B-52 shared many technological similarities with the preceding B-47 Stratojet strategic bomber. The two aircraft used the same basic design, such as swept wings and podded jet engines, and the cabin included the crew ejection systems. On the B-52D, the pilots and electronic countermeasures (ECM) operator ejected upwards, while the lower deck crew ejected downwards; until the B-52G, the gunner had to jettison the tail gun to bail out. The tail gunner in early model B-52s was located in the traditional location in the tail of the plane, with both visual and radar gun laying systems; in later models the gunner was moved to the front of the fuselage, with gun laying carried out by radar alone, much like the B-58 Hustler's tail gun system.
  Structural fatigue was accelerated by at least a factor of eight in a low-altitude flight profile over that of high-altitude flying, requiring costly repairs to extend service life. In the early 1960s, the three-phase High Stress program was launched to counter structural fatigue, enrolling aircraft at 2,000 flying hours. Follow-up programs were conducted, such as a 2,000-hour service life extension to select airframes in 1966–1968, and the extensive Pacer Plank reskinning, completed in 1977. The wet wing introduced on G and H models was even more susceptible to fatigue, experiencing 60% more stress during flight than the old wing. The wings were modified by 1964 under ECP 1050. This was followed by a fuselage skin and longeron replacement (ECP 1185) in 1966, and the B-52 Stability Augmentation and Flight Control program (ECP 1195) in 1967. Fuel leaks due to deteriorating Marman clamps continued to plague all variants of the B-52. To this end, the aircraft were subjected to Blue Band (1957), Hard Shell (1958), and finally QuickClip (1958) programs. The latter fitted safety straps that prevented catastrophic loss of fuel in case of clamp failure. The B-52's service ceiling is officially listed as 50,000 feet, but operational experience shows this is difficult to reach when fully laden with bombs. According to one source: "The optimal altitude for a combat mission was around 43,000 feet, because to exceed that height would rapidly degrade the plane's range."
  In September 2006, the B-52 became one of the first US military aircraft to fly using alternative fuel. It took off from Edwards Air Force Base with a 50/50 blend of Fischer–Tropsch process (FT) synthetic fuel and conventional JP-8 jet fuel, which burned in two of the eight engines. On 15 December 2006, a B-52 took off from Edwards with the synthetic fuel powering all eight engines, the first time an air force aircraft was entirely powered by the blend. The seven-hour flight was considered a success. This program is part of the Department of Defense Assured Fuel Initiative, which aimed to reduce crude oil usage and obtain half of its aviation fuel from alternative sources by 2016. On 8 August 2007, Air Force Secretary Michael Wynne certified the B-52H as fully approved to use the FT blend.
caption: B-52H (AF Ser. No. 61-0023), configured at the time as a testbed to investigate structural failures, still flying after its vertical stabilizer sheared off in severe turbulence on 10 January 1964. The aircraft landed safely.[93]
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