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Air Force Getting Closer to Testing Hypersonic Weapon, Engineers Say
The Air Force program, which had a couple of failed tests, came several years after a similar NASA effort called the X-43, which in 2004 shattered speed records when it flew at nearly Mach 9.7, or about 6,600 miles per hour, for 10 seconds. But the engine couldn't withstand the temperatures involved."The engine basically melted because it got so hot," Helbach said. "They didn't actively cool it. So for our program, we actively cooled the engine, which means that along the outside of the engine, we cycled the fuel around it to suck out the heat from the engine, heat up that fuel, and then inject it into the combustor for the scramjet engine." The X-51 was designed to start its engine using ethylene and transition to a hydrocarbon fuel called JP-7 -- the same type of endothermic fuel employed by the SR-71 Blackbird spy plane. "It basically means you can dump a lot of heat into that fuel," Helbach said. "When you crack the fuel, it actually makes it more combustible. It increases the amount of combustion you can create from the fuel." For the follow-on weapons program, the Air Force has teamed with the Pentagon's research arm, the Defense Advanced Research Projects Agency, to shrink the technology into a hypersonic weapon that could fit on most of the bomber fleet, according to Kenneth Davidson, manager of the hypersonic materials development at the Air Force Research Laboratory. Posted by: Blossom Unains5562 2015-05-20 |
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