Preparations

Although most histories consider the development of the three flight vehicles the high mark of the X-15 program, in reality several ancillary areas were perhaps as important as the actual airplanes and left a more lasting legacy. Early in the program, engineers recognized the need for a carrier aircraft, although this was largely an extension of previous X-plane practice. Nevertheless, the two Boeing B-52s used by the X-15 program would go on to long careers carrying a variety of vehicles that researchers had not even dreamed of during the X-15 development. Most important, however, was the development of extensive engineering and mission simulation systems.

Although it was crude by today’s standards, the X-15 pioneered the use of simulators not just to train pilots, but also to engineer the aircraft, plan the missions, and understand the results. Not surprisingly, given the involvement of Charlie Feltz, Harrison Storms, and Walt Williams in both the X-15 and Apollo programs, the X-15 pointed the way to how America would conduct its space missions. Simulation is one of the enduring legacies of the small black airplanes.

SIMULATIONS

Immediately after World War II, the Air Force developed rudimentary simulators at Edwards AFB for the later phases of the X-1 and X-2 programs. In fact, an X-1 simulation powered by an analog computer led to an understanding of the roll-coupling phenomena, while another simulation accurately predicted the X-2 control problems at Mach 3. The importance of these discoveries led the NACA HSFS to acquire an analog computer capability in 1957, mostly because the engineering staff anticipated that simulation would play an important role in the upcoming X-15 program.-11