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Douglas 2229
Douglas Aircraft Company's Model 2229 was a proposed supersonic transport (SST) originally started as a private study. The design progressed as far as making mock-ups of the cockpit area and wind-tunnel models of the overall layout. After studying the design, Douglas concluded that the SST would not work economically, and declined to enter the 2229 in the National Supersonic Transport (NST) program in 1963.
==Background==
Through the 1950s, understanding of supersonic aerodynamics had improved to the point where sustained operation at high Mach was first becoming possible. A combination of new engines, engine intakes, new planforms like the delta wing, and new materials like titanium and stainless steel had solved many of the problems of earlier designs. By the late 1950s, the United States was in the midst of building two supercruising aircraft, the Lockheed A-12 and B-70 Valkyrie, and the UK was considering the Avro 730.
The concept of a supersonic transport seemed like a natural evolution of existing designs, which had long striven for "higher, faster". However, at supersonic speeds, lift works in a very different way that subsonic, and always less efficient. Subsonic transports of the era were reaching lift-to-drag ratios of about 19, whereas even the most advanced wing designs for SSTs were around 9.〔Joseph Chambers, ("Innovation in Flight" ), NASA SP-2005-4539, 2005, pg. 9〕 This was not a concern for military aircraft, where speed was life, but an SST would require twice as much fuel to move a passenger, increasing operational costs. To offset the operational costs, proponents of the SST concept suggested the lower trip times would command higher ticket prices. This would make them attractive to a segment of the market that currently paid higher ticket prices for first class seats. In theory, the faster trip times would also allow a reduction in costs needed to fly a given number of passengers, as fewer aircraft would be needed to cover a given route.
By 1960 a number of companies had shown models or mock-ups of SST designs, but most of these were trial balloons with no serious study behind them.〔 But in an era when progress generally meant faster, there was a widespread feeling that the SST was the next natural step in aircraft design.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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