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May11-06, 04:36 PM
Sci Advisor
FredGarvin's Avatar
P: 5,095
Quote Quote by Danger
Well, the link goes somewhere else now, but I read it pretty carefully the first time. The article very specifically stated that they're scramjets. So those must be secondary engines used only after regular jets have gotten the thing up to operational speed. (Or is there some way to accelerate incoming air to supersonic while the engine is stationary?)
I get a different article now too. Even with scramjets, the combustion process is extremely loud. To get the scramjets to an operational range, they would still need something on the range of M4+. That's faster than the SR-71. They must be counting on some sort of atmospheric effect at very high altitudes. I know there is what is refered to as an acoustic duct at about the 20 km (65,000 ft) altitude mark.