X-51

The Air Force Research Laboratory's X-51 Scramjet-Waverider is being built by Pratt & Whitney and Boeing. This scramjet demonstrator is to fly by 2009 at target speeds close to Mach 7. Ground tests of the X-51A will begin late 2006. The X-51A is a descendent of earlier efforts including the Advanced Rapid Response Missile Demonstrator and the liquid hydrocarbon-fuelled scramjet engine developed under the USAF’s HyTech program.

During the flight demonstrations, a B-52 will carry the vehicle to an altitude of about 35,000 feet and then release it. Initially propelled by a U.S. Army tactical missile system solid rocket booster, the scramjet will take over at approximately Mach 4.5, and the vehicle will accelerate to a flight speed near Mach 7.