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The Human Spaceflight Archive
There were five versions of the Bell X-1 rocket-powered research aircraft that flew at the NACA High-Speed Flight Research Station, Edwards, California. The bullet-shaped X-1 aircraft were built by Bell Aircraft Corporation, Buffalo, N.Y. for the U.S. Army Air Forces (after 1947, U.S. Air Force) and the National Advisory Committee for Aeronautics (NACA).

The X-1 Program was originally designated the XS-1 for EXperimental Sonic. The X-1’s mission was to investigate the transonic speed range (speeds from just below to just above the speed of sound) and, if possible, to break the "sound barrier." Three different X-1s were built and designated: X-1-1, X-1-2 (later modified to become the X-1E), and X-1-3. The basic X-1 aircraft were flown by a large number of different pilots from 1946 to 1951.

The X-1 Program not only proved that humans could go beyond the speed of sound, it reinforced the understanding that technological barriers could be overcome. The X-1s pioneered many structural and aerodynamic advances including extremely thin, yet extremely strong wing sections; supersonic fuselage configurations; control system requirements; powerplant compatibility; and cockpit environments. The X-1 aircraft were the first transonic-capable aircraft to use an all-moving stabilizer. The flights of the X-1s opened up a new era in aviation.

The first X-1 was air-launched unpowered from a Boeing B-29 Superfortress on Jan. 25, 1946. Powered flights began in December 1946. On Oct. 14, 1947, the X-1-1, piloted by Air Force Captain Charles "Chuck" Yeager, became the first aircraft to exceed the speed of sound, reaching about 700 miles per hour (Mach 1.06) and an altitude of 43,000 feet.

The number 2 X-1 was modified and redesignated the X-1E. The modifications included adding a conventional canopy, an ejection seat, a low-pressure fuel system of increased capacity, and a thinner high-speed wing.

The X-1E was used to obtain in-flight data at twice the speed of sound, with particular emphasis placed on investigating the improvements achieved with the high-speed wing. These wings, made by Stanley Aircraft, were only 3 3/8-inches thick at the root and had 343 gauges installed in them to measure structural loads and aerodynamic heating.

The X-1E used its rocket engine to power it up to a speed of 1,471 miles per hour (Mach 2.24) and to an altitude of 73,000 feet. Like the X-1 it was air-launched.

The X-1 aircraft were almost 31 feet long and had a wingspan of 28 feet. The X-1 was built of conventional aluminum stressed-skin construction to extremely high structural standards. The X-1E was also 31 feet long but had a wingspan of only 22 feet, 10 inches. It was powered by a Reaction Motors, Inc., XLR-8-RM-5, four-chamber rocket engine. As did all X-1 rocket engines, the LR-8-RM-5 engine did not have throttle capability, but instead, depended on ignition of any one chamber or group of chambers to vary speed.

There were also X-1A, X-1B, and and a short-lived X-1D models of the X-1.

X-1A
X-1A

The Bell X-1A was similar to the Bell X-1, except for having turbo-driven fuel pumps (instead of a system using nitrogen under pressure), a new cockpit canopy, longer fuselage and increased fuel capacity. The X-1A arrived at Edwards Air Force Base, California on January 7, 1953, with the first glide flight being successfully completed by Bell pilot, Jean "Skip" Ziegler. The airplane also made five powered flights with Ziegler at the controls. The USAF was attempting a Mach 2 flight and USAF test pilot Charles "Chuck" Yeager was eager. He reached speed of Mach 2.435, at a altitude of 75,000 feet on December 12, 1953, a speed record at the time. But all was not well, the aircraft encountered an inertial coupling phenomenon and went out of control. Once the X-1A had entered the denser atmosphere (35,000 feet) it slowly stabilized and Yeager was able to return to Edwards. The aircraft had experienced high-speed roll-coupling, something aerodynamicists had predicted, but this was the first actual encounter.

On August 26, 1954, Major Arthur Murray, USAF test pilot flew the X-1A to an altitude record of 90,440 feet. NACA High-Speed Flight Station received the aircraft in September 1954 and returned it to Bell for the installation of an ejection seat.

NACA test pilot Joseph Walker made a familiarization flight on July 20, 1955 followed by another scheduled flight on August 8, 1955. Shortly before launch the X-1A suffered an explosion. The extent of the damage prohibited landing the crippled aircraft. The X-1A was jettisoned into the desert, exploding and burning on impact. Walker and the B-29 crew returned to base in satisfactory condition. Four pilots had completed 29 flights (including aborts).

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X-1B
X-1B
The Bell X-1B was a second-generation X-1 used by the U.S. Air Force for pilot familiarization before being turned over to NACA in December 1954. The X-1B had a modified fuselage with greater capacity for fuel tanks, an improved cockpit, and a turbopump fuel system as compared with the X-1. The NACA used the X-1B primarily for aerodynamic heating and reaction-control research from 1956 to 1958.

The aircraft was fitted with special instrumentation for exploratory aerodynamic heating tests. It had over 300 thermocouples installed on it. The X-1B was the first aircraft to fly with a reaction-control system; a prototype of the reaction-control system used on the X-15 and other piloted test aircraft.

The X-1B was given to the Air Force Museum at Wright-Patterson Air Force Base Dayton, Ohio, on January 27, 1959, for preservation and display. This aircraft completed a total of 27 glide and powered flights by eight U.S. Air Force and two NACA test pilots. Second-generation X-1 aircraft were 35.8 feet long and had a wingspan of approximately 28 feet.

10 photos
X-1E
X-1E
The X-1E, the last of the X-1 aircraft series, was used to obtain in-flight data at twice the speed of sound, with particular emphasis placed on investigating the improvements achieved with the high-speed wing. The airplane was the first aircraft to fly supersonically with a 4% wing, and thus the first to prove the high-mach capability and adequate stability using a thin airfoil section. The X-1E made 26 flights and a captive flight with two NACA High-Speed Flight Station test pilots. It flew to a Mach of 2.24 and an altitude of 73,458 feet. Like its predecessors is was air launched from a Boeing B-29.
11 photos
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