Science Gadgets Design World's First 2010-05-25 Boeing X-51 WaveRider Hypersonic Scramjet Boeing X-51 The Boeing X-51 is an unmanned scramjet demonstration aircraft for hypersonic ( Mach 7, around 8,050 km/h) flight testing. The X-51 WaveRider program is a consortium of the US Air Force, DARPA , NASA , Boeing and Pratt