The Bell Aircraft Corporation X-1B was similar to the Bell X-1A except for the installation of wingtips extensions for its last three flight. The NACA portion of the X-1B flight test program was for the purpose of aerodynamic heating research, accumulating data during 1956-1958. The X-1B was fitted with special instrumentation for exploratory aerodynamic heating tests. It had over 300 thermocouples installed on it.
It was the first aircraft to fly with a reaction control system, a prototype of the control system used on the X-15 and other
piloted aircraft. Midway through its flight test program, the X-1B was equipped with an Reaction Motors, Inc. XLR-11-RM-9
engine which differed, from the other XLR-11s, only in having an electric spark, low-tension interrupter type ignition in place of the older high-tension type.
On January 27, 1959 the X-1B was given to the Air Force Museum at Wright-Patterson Air Force Base, Ohio, for preservation
and public display. This aircraft completed a total of 27 glide and powered flights made by 8 USAF test pilots and 2 NACA test pilots.
Bell X-1 series aircraft description