Experimental Air Force aircraft goes hypersonic

An experimental unmanned aircraft developed for the U.S. Air Force has flown at more than five times the speed of sound in a test off California.

The Air Force said in a statement Friday the X-51A WaveRider flew for more than three minutes under power from its exotic scramjet engine and hit a speed of Mach 5.1

The WaveRider was released Wednesday from a B-52 bomber 50,000 feet above the Pacific and was initially accelerated by a rocket before the scramjet kicked in. The flight ended with a planned plunge into the ocean.

It was the fourth and final flight of an X-51A by the Air Force, which is studying ways to deliver strikes around the globe within minutes. Previous flights ended in failure or didn't reach the intended speed.