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Aviation History
1964
1964 - 1913.PDF
1056 B-70. . . high-Mach flight; but there is no substitute for flight experience with a wide range of test vehicles. There is still a lot to be gained in flying the huge XB-70 in sustained Mach 3 flight. Even with the flight programme held to its miserable current allotment of 180 flying hours, an American supersonic transport or large high-speed bomber of the future will benefit beyond measure from the experi- ence to be gained. The fact remains that an aircraft is more than an aerodynamic shape in a wind tunnel. Advanced bombers (or "manned delivery systems") are on the drawing boards, and Ameri- can SSTs are in the brochures and the wind tunnels. Ironically, North American Aviation has lately been eliminated from the FAA's SST airframe competition. Ups and Downs A bare discussion of the technicalities of the B-70 would deprive the reader of an insight into the agonies of the US defence establish- ment over the years that the aircraft was evolving. Awareness of current developments in missiles and satellites tends to make us lose perspective, and forget the place of aircraft in the planning of the early fifties. The first 4,200 n.m.-range B-47 entered Strategic Air Command's inventory at the end of 1951 at about the time that the B-52 follow- on was planned. The early B-52, at twice the weight of a B-47, could carry a 20-megaton bomb over a combat radius of approximately 3,000 n.m. SAC was never over-enthusiastic about the later, supersonic-dash B-58, primarily because of its low unrefuelled range and relatively restricted bomb load. In late 1954 SAC's commanding general—none other than Curtis LeMay—requested that the Department of Defense consider a B-52 follow-on for the 1965-75 period that could use existing runways and maintenance facilities. The new type would have a minimum unrefuelled range of 6,000 n.m., with "as high a speed as possible." Air Research and Development Command issued System Requirement WS-110A requesting an industry study of a bomber for SAC that would have a cruising speed of Mach 0.9 and maxi- mum possible speed during a 1,000-mile penetration of enemy territory, coupled with an over-riding requirement for peak penetra- tion altitude and range. The first SAC wing was to be delivered by 1963. Concurrently the competitive WS-125 nuclear-powered bom- FUGHT International, 25 June 1964 ber requirement was also issued. While Gen LeMay was worrying about bombers for SAC—and he has never stopped doing so the Strategic Missiles Evaluation Committee had been studying the feasibility of an ICBM carrying a thermonuclear warhead. This celebrated group made its prediction in March 1954 that such a weapon could become operational in the period 1960-62. The strategic missile versus bomber controversy was born. The group studying the major effort to be undertaken in produc- ing the first ICBM recommended that the technical and scientific management of that project was too much for one company. On the other hand, the long-range bomber team came to the opposite conclusion, and recommended that a single prime contractor could manage the development of the entire weapon system and not just the air vehicle. On July 13, 1955, six major airframe manufacturers looked at WS-110A; of the six, Lockheed and Convair were already working on WS-125. Two competitive Phase 1 design contracts were issued on November 11,1955, one to Boeing and the other to North American. Their bids were returned to the USAF in October 1956. These submissions serve to remind us that at that time sustained long-range supersonic flight was restrained by the apparently huge fuel requirements compounding other problems. Both WS-110A entries were of immense size and weight. North American's design was a 750,0001b delta, with two huge "floating" outer wings capped by 190,0001b tanks each the size of a B-47 and containing sufficient fuel to give intercontinental high-subsonic range. Near the target the wing panels, with their bulky containers, were jettisoned while the rest of the aircraft accelerated to Mach 2.3 for the final dash and escape. On seeing this monstrosity Gen LeMay made the oft- quoted crack "This isn't an airplane, it's a three-plane formation." It was evident that the requirement that the new machines should use existing facilities could not be met. Breguet's equation and the state-of-the-art aerodynamics and propulsion efficiency stood in the way of progress. Both bids were flatly rejected. Shortly thereafter WS-110A was reduced to a six-month feasibility study of other approaches. Boeing and North American turned to area-ruled profiles and, at the end of the feasibility study in July 1957, were both using boron high-energy fuels in their new designs. North American had another trick up its sleeve. In March 1956 A. J. Eggers and C. A. Syvertson of the National Advisory Committee for Aeronautics (later became part of NASA) research laboratory at Langley Field, Virginia, published a secret research paper Aircraft Configurations Developing "This isn't an airplane, it's a three-plane for- mation" was the comment of General Curtis LeMay on North American's original proposal
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