An unmanned hypersonic flight test demonstrator flew five times the speed of sound this week, achieving the longest-ever air-breathing hypersonic flight, according to the Air Force. In the program's fourth and final test flight, the X-51A Waverider test program reached Mach 5.1 on May 1, flying more than 230 nautical miles in a little more than six minutes over the Point Mugu Naval Air Warfare Center Sea Range in the Pacific, according to a statement released today by the Air...
