B-52 Stratofortress History
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.
For more than 35 years B-52 Stratofortresses have been the primary manned strategic bomber force for the United States. The B-52 is capable of dropping or launching a significant array of weapons in the U.S. inventory. This includes gravity bombs, cluster bombs and precision guided missiles.
An appreciation for the uniqueness of the B-52 requires a survey of over 35 years of modifications, missions, and changes in national security strategy. One must examine not only roles and missions but changing profiles, tactics, and weapons improvements in order to focus on the adaptive process. Certain key characteristics have made that process possible -- without these characteristics, the B-52 would not have met the challenges of almost three decades of service.
In 1945, the Army Air Corps initiated a design competition for a new second generation strategic bomber to follow the B-36. Following further requirements definition by the Army Air Corps in 1946, Boeing was awarded a design contract for this new aircraft. The original requirements specified an aircraft that could carry a 10,000-pound bomb load, 5,000 miles, at a tactical operating altitude of 35,000 feet. This aircraft was to be capable of cruising at a minimum of 450 miles per hour (mph) at its tactical altitude.
In trying to fulfill this ambitious requirement, Boeing faced serious problems in selecting an engine that could provide both the required speed and range. The emergence of the swept- wing, pure jet B-47, coupled with the Air Force's disenchantment over very large propeller engines, caused Boeing to initiate an in-house study with its own money. This study was for an all jet bomber, able to fly the desired mission, using a new engine being designed by Pratt and Whitney. The results of this study, and further testing of the B-47, led Boeing towards the final eight engine jet design of the B-52. As the design matured, additional technology was taken from the B-36 and the B-47. Thus technology, in turn, became a primary determinant of operational requirements. Military aircraft designs matched available technology and then incorporated refinements that appeared technically or scientifically sound to achieve best performances.
By early 1949, Boeing was preparing two prototypes, the XB-52 and YB-52, both of which had been contracted for in early 1947. Although the YB was designated for service test, both models were used to refine the original design. These aircraft, weighing 390,000 pounds apiece, would be two of the largest aircraft ever built.
Even as these airships were being built, SAC requested Boeing to examine the possibility of developing a reconnaissance version. This was the first hint of interest in expanding the original nuclear strike mission specified for the B-52. The result of the SAC request was a design which could be assigned either a bombing or reconnaissance mission with no sacrifice in efficiency or performance. Although this capability was not integrated into the aircraft until introduction of the B-52B, it marked the initial swing towards mission flexibility in the B-52.
The major design emphasis was placed on superior performance with minimum airplane and system complexity. This was to be achieved by a straightforward design which provided a high standard of systems utility and functional reliability. To do this, however, required a number of innovations not anticipated in the original specifications. Some of the design features, like the on-board hydraulic system, were physically the largest yet built, while others like the pneumatic system which powered many aircraft accessories were radical departures from conventional designs. Nonetheless, the original flight test in 1952 proved successful, with performance exceeding the original specifications.
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.
The advent of the ALCM and its integration further extended the useful life of the B-52. In 1982, as the first B-52G cruise missile carrier assumed alert, the weapon system is well into its third decade of operation. The original nuclear mission has been expanded and the strike profile has come full circle as the B-52 has adapted to- changing national strategies and priorities. Its unique characteristics have allowed it to achieve different objectives, in different circumstances, against different adversaries. Through this adaptive process, the capabilities of the B-52 have been broadened to provide firepower across the spectrum of conflict. Even though technology has advanced tenfold since the advent of the B-52, it still remains the mainstay of the bomber force.
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