Air Force X-51A Scramjet Test Fails

WaveRider spirals out of control after tailfin problem.

X-51A WaveRider

X-51A WaveRider

The Air Force’s scramjet-powered X-51A WaveRider lost control and was destroyed seconds into a test flight on Tuesday, dashing hopes that the craft would reach its goal of speeding to Mach 6.

This third test of the Boeing X-51A was launched Tuesday off the California coast from a B-52. Plans called for the scramjet-powered craft to fly for 300 seconds, reaching a speed of 4,600 mph, but it flew for only 16 seconds before losing control, according to the Air Force.

Officials said a problem with a control fin caused the WaveRider to spiral out of control before its main engine could be ignited.

Once released over the ocean at an altitude of 50,000 feet, the X-51A was supposed to fall for several seconds before its booster rocket ignited, allowing the craft to gain its initial acceleration for about 30 seconds. The booster was then supposed to drop off, with the WaveRider accelerating to around Mach 4.5. After that, the X-51A’s jet-fuel-powered Pratt & Whitney Rocketdyne SJY61 scramjet engine was to ignite, propelling the craft to Mach 6 at a height of 70,000 feet for 300 seconds.

The WaveRider is so named because its engine allows it to ride on its own shockwave, Boeing said. The test flight picked up where another failed test left off last year. It was unclear when the Air Force planned to test the X-51A again.