By BRENDAN MCGARRY -
The U.S. Air Force is making progress in developing a hypersonic weapon based on the success of an experimental scramjet program, engineers said.
The service in 2013 conducted its fourth and longest flight of the so-called X-51 WaveRider. After separating from a rocket launched beneath the wing of a B-52 bomber, the hypersonic vehicle built by Boeing Co. climbed to 60,000 feet, accelerated to Mach 5.1 and flew for about three and a half minutes before running out of fuel and plunging into the Pacific Ocean.
READ MORE ON DEFENSE TECH
US Air Force looking to test hypersonic weapon soon - NY to LA in 30 minutes
