The Boeing X-51 WAverider will be undergoing testflights at the end of 2009 and into 2010 The tests are to try and fly hypersonic for 5 minutes instead of previous tests that lasted for a few seconds of hypersonic flight.
The WaveRider stays airborne, in part, with lift generated by the shock waves of its own flight. The design stems from the goal of the program — to demonstrate an air-breathing, hypersonic, combustion ramjet engine, known as a scramjet.
“We built a vehicle around an engine,” said Joseph Vogel, the X-51 project manager with Boeing, which is building a series of four test planes under a $246.5-million program managed by the Air Force Research Laboratory in Dayton, Ohio.
NASA tested the concept in 2004, breaking the record for a jet-powered aircraft with a speed of Mach 9.6, or nearly 7,000 mph. But the vehicle, known as X-43, only flew for a few seconds and its copper-based engine was not designed to survive the flight.
The X-51 engine, made by Pratt & Whitney, is made from a standard nickel alloy and is cooled during flight by its own fuel. The program’s goal is to fly for about five minutes. The military has its eye on high-speed cruise missiles as well as space vehicles that wouldn’t need carry-on oxidizers. The space shuttle, for example, carries both liquid oxygen and liquid hydrogen, to power its main engines.
The WaveRider’s first flight is scheduled for October over the Pacific Ocean. It will be carried into the air by a B-52 bomber, then released at an altitude of about 50,000 feet. A solid-rocket booster will ignite and speed it up to about Mach 4.8 and if all goes well, the aircraft’s engine will take over from there, boosting the speed to more than Mach 6.
There were ground tests of hypersonic flow up to mach 3 and future tests will go up to mach 4. This is to show that a combined ramjet and scramjet combination can work with ramjet power up to a speed where the scramjet can take over.