Douglas D558-3 Skyflash

In early 1950's, a several high-speed flight researches were being proceeded by different agencies, the NACA's hypersonic research, the Air Force's Project 1226 and the Navy's D-558 program. In 1954, Langley team of NACA gathered those similar researches from military services and aerospace industries, combined with the Air Force and Navy to launch the new "Project 1226" competition. As Navy liked to keep in the 'space race' and Douglas liked to run for future manned spaceplanes, the D-558-3 Skyflash (Model 684) design was sponsored by Navy to enter the competition. The D-558-3 was planned to install with the rocket engine which selected by NACA, and air-launch from Boeing B-50. In 1955, while Navy decided to save the development cost and not to be put in the dissenting vote position, NACA and the Air Force agreed with the North American's proposal as the winner of the competition which became the X-15 program.