[/caption]On May 26, an X-51A Waverider flight-test vehicle successfully made the world's longest supersonic combustion ramjet-powered hypersonic flight. The flight was made off the southern California Pacific coast.
The X-51A Waverider's Pratt & Whitney Rocketdyne-built air breathing scramjet engine accelerated the vehicle to Mach 5. It burned for more than 200 seconds. This was more than ten times longer than the previous 12 second record by the NASA's X-43 vehicle.
Air Force officials called the test, the first of four planned, an unqualified success. The flight is considered the first use of a practical hydrocarbon fueled scramjet in flight.
X-51A Waverider Tested
"We are ecstatic to have accomplished most of our test points on the X-51A's very first hypersonic mission," said Charlie Brink, an X-51A program manager with the Air Force Research Laboratory at Wright-Patterson Air Force Base, Ohio. "We equate this leap in engine technology as equivalent to the post-World War II jump from propeller-driven aircraft to jet engines."
The X-51 launched at about 10 A.M. from Edwards Air Force Base. It was carried under the left wind of an Air Force Flight Test Center B-52 Stratofortress. When it was flying at 50,000 feet over the Point Mugu Naval Air Warfare Center Sea Range it was released. Four seconds after it was released, an Army Tactical Missile solid rocket booster accelerated the X-51 to about Mach 4.8 before the rocket booster and a connecting interstage were released.
[caption id="" align="alignleft" width="403" caption="x-51A Waverider Scramjet Under B-52, Photo Credit: US Air Force"]
[/caption]Four X-51A cruisers have been built for the Air Force and the Defense Advanced Research Projects Agency by industry partners Pratt & Whitney Rocketdyne and Boeing. Air Force officials are intending to fly the three remaining X-51As this fall.
The plan is to fly each vehicle on virtually identically flight profiles. This way, they can build knowledge form each successive flight.
How fast is Mach 5?
Hypersonic flight is normally defined as beginning at Mach 5. Mach 5 is five time the speed of sound! In more exact terms: mach 5 = 1 701.45 m / s or mach 5 = 3 806.03525 miles per hour. This is quite a unique challenge. There are many different things that can affect a flight that fast, heat, pressure and many more. These challenges make conventional turbine engines impractical.
Program officials said producing thrust with a scramjet has been compared to lighting a match in a hurricane and keeping it burning.
"This first flight was the culmination of a six-year effort by a small, but very talented AFRL, DARPA and industry development team," Mr. Brink said. "Now we will go back and really scrutinize our data. No test is perfect, and I'm sure we will find anomalies that we will need to address before the next flight. But anyone will tell you that we learn just as much, if not more, when we encounter a glitch."
While the development of the X-51A's engine and test program are complex, controlling costs has been a key objective for the Air Force. The team has incorporated or adapted existing proven technologies and elected from the outset not to build recovery systems in the flight test vehicles, in an effort to control costs and focus funding on the vehicle's fuel-cooled scramjet engine.
The X-51A Waverider flights will really provide a wide scope of knowledge of hypersonic flight and may contribute to many different technologies.
Via, Air Force
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