D-558-1 Skystreak

"The Douglas Skystreak (D-558-1) was designed in 1945 by the Douglas Aircraft Company for the US Navy Bureau of Aeronautics, in conjunction with the National Advisory Committee for Aeronautics (NACA). The Skystreak was a turbojet powered aircraft that took off from the ground under its own power and had straight wings and tails. The D-558-1 reached Mach 0.99 in level flight, but only flew supersonic in a dive. In the public mind, much of the research performed by the D-558-1 was quickly overshadowed by Chuck Yeager and the supersonic X-1 rocket plane. However, the Skystreak played an important role in aeronautical research by flying for extended periods of time at transonic speeds, which freed the X-1 to fly for limited periods at supersonic speeds. "