The US Air Force will test fly the X-51A Waverider for the first time off the coast of southern California on 25 May 2010.

During the test, the unmanned aerial vehicle (UAV) will be released from a B-52 bomber and fly autonomously for five minutes sending data to ground stations before crash landing in the Pacific.

It will be powered by a Pratt & Whitney Rocketdyne SJY61 scramjet engine accelerating the UAV to about Mach 6.

X-51A programme manager Charlie Brink said that during the 300 second test they hoped to learn more about hypersonic flight with a practical scramjet engine than on all previous flight tests combined.

Carried on the wing of a B-52H from the Edwards Air Force Base, it will be released at about 50,000ft over the Point Mugu Naval Air Warfare Center Sea Range.

A solid rocket booster will accelerate the X-51A to almost Mach 4.5 before being jettisoned.