This week in flight test history Published July 29, 2016 412th Test Wing Public Affairs EDWARDS AIR FORCE BASE, Calif. -- July 24, 1951 - The Bell X-1D made the first, and the only successful, flight of its career when it was air-dropped from an EB-50A mother ship to make an unpowered glide to the Rogers Dry Lake Bed. Jean “Skip” Ziegler was the pilot. The X-1D was the first of the “second generation” X-1 rocket research planes to be completed; it was intended for heat transfer research.