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LOS ANGELES (AP) — An unmanned experimental aircraft failed during an attempt to fly at six times the speed of sound in the latest setback for hypersonic flight. The X-51A Waverider was designed to reach Mach 6, or 3,600 mph, after being dropped by a B-52 bomber off the Southern California coast on Tuesday. Engineers hoped it would sustain its top speed for five minutes, twice as long as an X-51A has gone before. But the Air Force said Wednesday that a faulty control fin prevented it from starting its exotic scramjet engine and it was lost.

Boeing's X-51 WaveRider has made aviation history by completing the longest ever supersonic* combustion ramjet-powered flight. The unmanned aerial vehicle (UAV) flew for almost three and a half minutes in the skies off the southern California coast on Wednesday, reaching an altitude of about 70,000 feet and hitting hypersonic (Mach 5) speeds. The X-51 WaveRider scramjet (supersonic combustion ramjet) is being developed for the Air Force Research Laboratory and the Defense Advanced Research Projects Agency (DARPA) by Boeing and Pratt & Whitney Rocketdyne. The goal of the program is to create a free-flying, scramjet-powered vehicle capable of operating continuously on...

In its first flight attempt, the X-51A WaveRider Wednesday completed the longest supersonic combustion ramjet-powered flight in history, flying nearly three and a half minutes at a top speed of Mach 5, although it fell short of its target duration and speed, according to Boeing. The unmanned aerial vehicle was released from a U.S. Air Force B-52H bomber off the southern California coast around 10 a.m. and flew autonomously for more than 200 seconds, powered by its Pratt & Whitney Rocketdyne supersonic combustion ramjet motor, transmitting telemetry data to ground stations, Boeing said in a news release. "Something then occurred...

Boeing's X-51A WaveRider — a jet-fueled, air-breathing hypersonic rocket — is one step closer to reality. In tests over Edwards Air Force Base in California, a B-52 bomber carried the X-51A WaveRider aloft for the first time, announced manufacturer Boeing Corp. The test was a key milestone in preparation for the X-51A to light its supersonic "ramjet" engine and propel the WaverRider at hypersonic speed for about 5 minutes, before plunging into the Pacific Ocean

PALMDALE - The next step in hypersonic flight test is under development in a hangar at The Boeing Co.'s facility at Air Force Plant 42. The unmanned X-51A "Wave­Rider" is a scramjet engine flight demonstrator, expected to provide flight test data at speeds beyond Mach 6 - about one mile per second - using its unique engine design. In a scramjet - or supersonic combustion ramjet - engine, air is scooped into the engine duct, then forced through a combustion chamber, where fuel is mixed in and ignited. This produces energy, which is forced out the rear of the engine...

Sustained hypersonic flight above speeds of Mach 5 by vehicles using air-breathing, jet-fuel-powered engines could become achievable within the next dozen years. Successful recent ground tests of jet-fueled, ramjet/scramjet demonstrator engines by Pratt & Whitney Rocketdyne and Aerojet represent important progress toward flight-testing of three separate hypersonic-vehicle programs. In September, Pratt & Whitney Rocketdyne (PWR) completed 10 months' testing of a sub-scale combustor for a hydrocarbon-powered, dual-mode ramjet engine designed to operate over a wide range of Mach-number speeds -- that is, multiples of the speed of sound. Using JP-7 jet fuel, PWR ran the combustor successfully at a variety...