WaveRider Coasts in Longest Scramjet Flight

The WaveRider before its final flight, under the wing of a B-52H Stratofortress. Photo courtesy U.S. Air Force/Bobbi Zapka.

By Danielle Lucey



Boeing's unmanned hypersonic X-51A WaveRider achieved the longest ever scramjet-powered hypersonic flight last week, in a sortie out of Edwards Air Force Base in California. 



The flight lasted six minutes, with three and a half of them clocking in at a top speed of Mach 5.1, or 3,882 mph. The aircraft traveled more than 230 nautical miles in that time. 



“This demonstration of a practical hypersonic scramjet engine is a historic achievement that has been years in the making,” says Darryl Davis, president, Boeing Phantom Works. “This test proves the technology has matured to the point that it opens the door to practical applications, such as advanced defense systems and more cost-effective access to space.”



After launch, a solid rocket booster pushed the vehicle up to Mach 4.8. The aircraft then climbed to Mach 5.1 with its JP-7 jet fuel-powered scramjet engine. It was the fourth ever flight of the X-51A, exceeding its last record set in 2010. The mission was also its final flight, as the vehicle splashed down in the ocean and intentionally was destroyed. 



"It was a full mission success," says Charlie Brink, X-51A program manager for the Air Force Research Laboratory Aerospace Systems Directorate. "I believe all we have learned from the X-51A WaveRider will serve as the bedrock for future hypersonics research and ultimately the practical application of hypersonic flight."



An Air Force press release stated that there is no immediate successor planned for the X-51A program, however it is not the end of the Air Force's hypersonic research. 



The program was a collaboration between the Air Force Research Laboratory, Boeing Phantom Works and Pratt & Whitney Rocketdyne.