The USAF's X-51A Waverider has completed the first demo flight with a B-52 Stratofortress over Edwards Air Force Base, California, in preparation to light its supersonic combustion ramjet engine.
Air Force Research Laboratory at Wright-Patterson AFB, Ohio X-51A programme manager Charlie Brink said the next B-52/X-51 flight test mission is expected in mid-January, and will be a full dress rehearsal, for its first hypersonic test flight, now planned for mid-February.
The Air Force Flight Test Center's B-52 will carry the unmanned X-51A to nearly 50,000ft over the Pacific Ocean, in February, and then release it.
Following the release, a solid rocket booster from an army tactical missile system will ignite and accelerate the X-51 to Mach 4.5.
Soon after this, the booster will be jettisoned and the X-51A's supersonic combustion ramjet propulsion system will ignite and operate for about 300 seconds, propelling the cruiser to more than six times the speed of sound.
During the test, before the cruiser plunges into the Pacific, onboard sensors will transmit data to ground systems.
The Pratt & Whitney Rocketdyne-developed X-51's scramjet engine, will burn a mix of ethylene and JP-7 fuel, in the beginning, before switching completely to JP-7.
The fuel-cooled design of X-51's engine will heat the JP-7 to an optimum combustion temperature, as well help the engine to endure extremely high operating temperatures during the long burn.
During the demo flight test on 9 December, the X-51 was in the air for 1.4 hours.
B-52 project pilot Lt. Col. Daniel Millman said after take off we climbed to 50,000ft and verified B-52 aircraft performance, handling qualities with the X-51A attached to the B-52, control room displays and software integration with the X-51A.
"The B-52 handled 'great' and the flight preceded as planned," he said.