Supersonic Flight

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In 1943, Theodor Von Karman, in response to a request by US Air Force headquarters, claimed that the realization of a supersonic aircraft would have been doable using the right technology and tools. The fear of breaking the "sound barrier" was finally removed in 1947, when the Captain Yaeger flew the Bell X-1 at a speed slightly above Mach 1 for few seconds, producing the famous and long-awaited sonic boom (caused by an impulsive pressure change created by the sonic waves detaching from the aircraft), music for the scientists attending that historical moment, but current nightmare for the 21st Century supersonic vehicles' designers [8]. Since the first wind tunnel investigations on high speed flow over a stationary airfoil (1918), it was clear that when the free stream velocity approached a certain value, a major increase in drag coefficient occurred at exactly what later was characterized as the drag-divergence Mach number. Thanks to the introduction of Shclieren optical system, in 1933, it was possible to state that this aerodynamic phenomenon was mainly due to the presence of regions of supersonic flow over the airfoil consequently terminating in a shock wave, which is the cause of the drag-increasing flow separation downstream the shock [1]. The presence of the wave drag represented the main technical obstacle for the design of supersonic aircraft and, to the same extent, for the improvement of their cruise efficiency. Indeed, the need of source of thrust powerful enough to overcome the increased drag force, embodies a major second technical challenge. From the 1947 four rocket engines solution of the X-1, to the 1960's state of the art B-58's GE J79 jet engines, the power issue was addressed with increasing sophistication.... ... middle of paper ... ...assessing NASA's high speed research program. 1997; . 6. Owen K. Concorde and the Americans : international politics of the supersonic transport. Washington u.a: Smithsonian Inst. Press; 1997. 7. Plencner RM, Lewis Research Center. Engine technology challenges for the high-speed civil transport plane. [Cleveland, Ohio]; Springfield, Va.: National Aeronautics and Space Administration, Lewis Research Center ; National Technical Information Service, distributor; 1998. 8. Rotundo LC. Into the unknown : the X-1 story. Washington, D.C.: Smithsonian Institution Press; 1994. 9 . Lawrence DS. The Initial Decision to Build the Supersonic Transport. AMERICAN JOURNAL OF ECONOMICS AND SOCIOLOGY 1971;30:403-412 10. Iannotta B. Son of Concorde. NEW SCIENTIST 1997 11. http://en.wikipedia.org/wiki/Boeing_2707 12. http://www.globalsecurity.org/military/systems/aircraft/qsp.htm
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