X-51A up close
The Rocketdyne SJY61 scramjet engine has virtually no moving parts, while the exterior has minimal wings. "Hypersonic combustion generates intense heat," goes part of the Air Force's explanation of the technology, "so routing of the engine's own JP-7 fuel will serve to both cool the engine and heat the fuel to optimum operating temperature for combustion."
Air enters the engine through a scoop at the front of the X-51A. "It is critical for air entering the inlet to be turbulent at hypersonic speeds, or the engine could 'unstart,' causing it to crash," according to a 2008 news release from the Purdue University School of Aeronautics and Astronautics, which has assisted in research for the X-51A program. "For this reason, air has to be converted to a turbulent flow before entering the inlet. This conversion is accomplished using a raised strip of metal placed near the inlet to 'trip' the air from smooth to turbulent."
Meanwhile, airflow over the top of the Waverider has to be smooth to minimize damaging friction and heat.
May 24, 2010 2:23 PM PDT
Photo by: U.S. Air Force photo/Chad Bellay
| Caption by: Jonathan Skillings
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