After two unsuccessful test flights, the X-51 completed a flight of 300 seconds and reached speeds of over Mach 5 on May 1, 2013 for the longest duration hypersonic flight. The X-51 is named "WaveRider" because it uses its shockwaves to add lift. Continue reading for videos and more information.
The program is managed by the Aerospace Systems Directorate within the United States Air Force Research Laboratory (AFRL). On May 1st 2013, the X-51 completed its first fully successful flight test on its fourth test flight. The X-51 and booster detached from a B-52 and was powered to Mach 4.8 (3,200 mph; 5,100 km/h) by a booster rocket. It then separated cleanly from the booster and ignited its own engine. The test aircraft then accelerated to Mach 5.1 (3,400 mph; 5,400 km/h) and flew for 240 seconds until running out of fuel; this test was the longest air-breathing hypersonic flight.