"the longest supersonic combustion ramjet-powered hypersonic flight"

An X-51A Waverider flight-test vehicle successfully made the longest supersonic combustion ramjet-powered hypersonic flight May 26 off the southern California Pacific coast. The more than 200 second burn by the X-51's Pratt & Whitney Rocketdyne-built air breathing scramjet engine accelerated the vehicle to Mach 6. The previous longest scramjet burn in a flight test was 12 seconds in a NASA X-43. 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.