From: email@example.com (Jean-Francois Mezei) Organization: DECUServe Date: 13 Oct 95 02:06:36 References: 1 2 3
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>> >Concord stretches at speeds past mach 1. Can anyone elucidate on this. >> >Why does it happen or does it happen? Based on an article in Science & Vie (Mars 1989), the french Aerospatiale were, at the time thinking of the next generation concorde: Concorde ATSF USA project Length 62,17m 76m Wingspan 25,60m 36,6m Takoff Weight 183t 225t 350t Max speed Mach 2 Mach 2-2,4 Mach 2,7 Passengers 128 225 300 Range 6000km 12000km At the time, the article stated that the US projects were more elaborate with a capacity of 300 passengers with take off weight of 350 tonnes. The US plane was to have been designed for Mach 2,7 (2900kmh) whereas the next generation Concorde (ATSF) was to have been limited to Mach 2,4 (2500kmh) Limiting the french "new" concorde to mach 2,4 resulted in major savings: -less high-tech materials used for the skin of plane (because of heating/expansion) -no need for special precautions with regards to fuel tanks which, at very high temperatures associated with flights above Mach 2,4 cause problems with fuel storage. The article also stated that if the existing Concorde were to be built today with todays' materials, the same 128 passenger capacity would weight only 120t instead of the currrent 183t and its range would be increased by 900km because of the lower weight and improved aerodynamics. All this is, of course,. old information (1989) but it does give some information about the heating problems on supersonic planes. The article also confirmed that the heating of the surfaces is caused by the air particles hitting the plane's surfaces and transforming their cinetic energy into heat. Is the correct interpretation correct ?: Air particle has no speed (cinetic energy = 0) Air particle is hit by moving plane. (cinetic energy = 0) Air particle is quickly accelerated (cinetic energy > 0) Air particle then de-celerates, releasing cinetic energy Air particle then returns to normal (cinetic energy =0) Or does the heat transfer not require that the air particle actually accelerate first ?