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B-1A Bomber

- question from Sarvesh

You may not know this, but the B-1 bomber program was actually the product of one of the longest aircraft development efforts in history. The project can be traced back to 1962 when the US Department of Defense began searching for a new airborne component of the nuclear triad (ground-based intercontinental ballistic missiles, submarine launched ballistic missiles, and bombers) to replace the B-52 and the soon-to-be cancelled XB-70. These studies indicated the value of maintaining a manned bomber force and convinced the US Air Force to issue a requirement for an Advanced Manned Strategic Aircraft (AMSA) in 1965. North American Rockwell won the contract in 1969 to develop, build, and test the B-1 bomber.

The aircraft Rockwell designed was an advanced swing-wing aircraft with variable engine inlets, ejectable crew capsules, and capable of a high-speed dash at over Mach 2. Four prototypes were built and flight tested between 1974 and 1979, but on 30 June 1977 Pres. Carter announced that the program would be cancelled. Pres. Carter and his Defense Department believed that the nature of the manned bombing mission had changed. Instead of building high-speed bombers to make deep penetration strikes into enemy territory, he wanted to focus development efforts on cruise missiles that could be carried aboard less expensive subsonic aircraft like the B-52. As a result, the B-1A program was halted in 1979 and development funds transferred to cruise missiles like the ALCM, SRAM, and Tomahawk.

Nonetheless, the Air Force continued research and development of the B-1 at a much reduced level during the late 1970s and early 1980s. Instead of high-speed, high-altitude missions carring bombs, the B-1 was redesigned for low-level flight at subsonic speeds carrying an armament of cruise missiles. The aircraft would hide in the ground clutter and utilize electronic countermeasures and stealth characteristics to avoid detection.

Although derivatives of the F-111 were also studied as a less expensive alternative, the Air Force and Reagan Administration concluded that the modified B-1 was far superior. Thus, development of the improved B-1B was initiated in October 1981 with the announcement that 100 aircraft would be purchased for the Strategic Air Command.

In comparison with the B-1A, the B-1B did away with the variable engine inlets and crew ejection capsules opting instead for less expensive fixed inlets optimized for transonic speeds and normal ejection seats. Although little could be done to change the stealth characteristics of a design so far advanced, minor modifications were made to the external shape and radar absorbant materials were added to give the B-1B a radar cross section less than 1% that of the B-52. Elimination of the high-speed dash requirement allowed a reduction in maximum wing sweep from 67° to 59°, and the B-1B was refitted for a much larger fuel load. The change in armament from bombs to missiles also required some changes to the weapons bay layout.
- answer by Joe Yoon, 9 September 2001

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