"On This Day" In Engineering History Blog

"On This Day" In Engineering History

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June 30, 1977 – Cancelling the B-1A Bomber

Posted June 30, 2008 4:01 PM by Steve Melito
Pathfinder Tags: B-1 Bomber B-1A B-1B b-52 June 30

On this day in engineering history, U.S. President Jimmy Carter cancelled production of the B-1A bomber, a long-range aircraft that was designed to carry nuclear payloads deep within enemy territory. A former nuclear engineer and submariner, Carter cancelled the long-running B-1 program to focus development dollars on cruise missiles that could be launched from Navy ships or dropped from existing Air Force bombers such as the B-52. American cruise missiles would need carriers, however, as the Department of Defense (DoD) reminded Congress in several studies during the late 1970s. Ultimately, Carter's successor, President Ronald Reagan, would authorize the development of the B-1B – a long-range bomber with cruise-missile capabilities. As aviation historian Walter Boyne notes, however, "about 85 percent of the B-1B's airframe was common to the B-1A".

"The B-1B bomber," Boyne explains, "probably had a longer gestation period than any aircraft in aviation history." During the 1960s, the Air Force conducted several studies to develop a long-range aircraft that could replace the Boeing B-52 Stratofortress, a jet-powered subsonic bomber whose original contract dated back to 1946. These projects included the subsonic low-altitude bomber (SLAB), the low-altitude manned penetrating system (LAMPS), and the advanced manned strategic aircraft (AMSA). Although Secretary of Defense Robert McNamara favored intercontinental ballistic missiles (ICBMs) over manned bombers, AMSA mandated the development of an aircraft with supersonic capabilities at high altitudes and near-sonic capabilities at low altitudes. In 1969, AMSA was renamed the B-1A. A year later, North American Rockwell was chosen to build 244 aircraft with General Electric as the engine contractor.

Although only four B-1As were ever built, the bomber's specifications were impressive. The B-1A stood 150.2-ft. long and 33.6-ft. high, and could shoulder a maximum takeoff weight of 389,000-lbs. Approximately 115,000-lbs. of this amount was dedicated to armaments. Powered by four F-101 GE-100 turbofan engines with afterburners, the B-1A bomber boasted 30,000-lbs. of thrust per engine. The aircraft was designed to achieve a maximum speed of 750 mph at an altitude of 500 ft.; 1,320 mph (Mach 2.0) at 50,000 ft.; and reach a cruising speed of 648 mph at 50,000ft. With a range of 5,300 miles un-refueled, the B-1A could reach a ceiling of approximately 30,000 feet while carrying a crew of four: aircraft commander, pilot, offensive systems officer, and defensive systems officer. Unlike with other large aircraft, the crew used fighter-type control sticks instead of large control wheels.







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