X-1A Credit - NASA

The X-1A, B, and D were essentially identical rocketplanes intended to reach speeds above Mach 2. The X-1A and X-1D were destroyed in in-flight explosions; the X-1B survived, training future moon lander Neil Armstrong on its last flights in 1958.

Main Engine: XLR-11. Main Engine Propellants: Lox/Alcohol.

• 1953 February 14 - X-1A Flight 1 - Crew: Ziegler.
  Bell flight 1. Pilot familiarization. Fuel jettison test. Glide flight only.

• 1953 February 14 - X-1A Flight 2 - Crew: Ziegler.
  Bell flight 2. Planned as powered flight, but completed as glide flight following propellant-system difficulties.

• 1953 February 21 - X-1A Flight 3 - Crew: Ziegler.
  Bell flight 3. First powered flight. False fire warning.

• 1953 March 26 - X-1A Flight 4 - Crew: Ziegler.
  Bell flight 4. Plane demonstrated successful 4-cylinder engine operation.

• 1953 April 10 - X-1A Flight 5 - Crew: Ziegler.
  Bell flight 5. Pilot noted low-frequency elevator buzz at mach 0.93, did not proceed above this speed, pending buzz investigation.

• 1953 April 25 - X-1A Flight 6 - Crew: Ziegler.
  Bell flight 6. Buzz again noted at mach 0.93. Turbopump overspeeding caused pilot to terminate power and jettison remaining fuel.

• 1953 November 21 - X-1A Flight 7 - Crew: Yeager.
  AF flight 1. Reached mach 1.15. Familiarization purposes.

• 1953 December 2 - X-1A Flight 8 - Crew: Yeager.
  AF flight 2. Mach 1.5.

• 1953 December 8 - X-1A Flight 9 - Crew: Yeager.
  AF flight 3. First high-mach flight attempt by X-1A. Mach 1.9 attained at 18300 m during slight climb.

• 1953 December 12 - X-1A Flight 10 - Crew: Yeager.
  AF flight 4. Plane attained mach 2.44, but met violent instability above mach 2.3. Tumbled 15250 m, wound up in subsonic inverted spin. Yeager recovered to upright spin, then normal flight at 7625 m.

• 1954 March 21 - X-1A Flight 11 - Crew: Murray.
  AF flight 5. Date estimated.

• 1954 April 4 - X-1A Flight 12 - Crew: Murray.
  AF flight 6. Date estimated.

• 1954 April 11 - X-1A Flight 13 - Crew: Murray.
  AF flight 7. Date estimated.

• 1954 April 25 - X-1A Flight 14 - Crew: Murray.
  AF flight 8. Date estimated.

• 1954 May 14 - X-1A Flight 15 - Crew: Murray.
  AF flight 9. Date estimated.

• 1954 May 28 - X-1A Flight 16 - Crew: Murray.
  AF flight 10. X-1A attained 26564 m, un-official world altitude record for manned aircraft.

• 1954 June 4 - X-1A Flight 17 - Crew: Murray.
  AF flight 11. X-1A reached 27374 m. Encountered same instability Yeager had, but at mach 1.97. Murray recovered after tumbling 6100 m down to 20130 m.

• 1954 June 18 - X-1A Flight 18 - Crew: Murray.
  AF flight 12. Date estimated.

• 1954 July 2 - X-1A Flight 19 - Crew: Murray.
  AF flight 13. Date estimated.

• 1954 July 16 - X-1A Flight 20 - Crew: Murray.
  AF flight 14. Date estimated.

• 1954 July 30 - X-1A Flight 21 - Crew: Murray.
  AF flight 15. Date estimated.

• 1954 August 8 - X-1A Flight 22 - Crew: Murray.
  AF flight 16. Date estimated.

• 1954 August 19 - X-1A Flight 23 - Crew: Murray.
  AF flight 17. Date estimated.

• 1954 August 26 - X-1A Flight 24 - Crew: Murray.
  AF flight 18. Murray attained 27584 m. Air Force then turned X-1A over to NACA.

• 1955 July 20 - X-1A Flight 25 - Crew: Walker Joseph.
  NACA flight 1. Familiarization. Walker attained mach 1.45 at 13725 m. Noted severe aileron buzz at mach 0.90 to 0.92.

• 1955 August 8 - X-1A Flight 26 - Crew: Walker Joseph.
  Planned at NACA flight 2. Shortly before launch from B-29, X-1A suffered low-order explosion, later traced to detonation of Ulmer leather gaskets. Walker exited into B-29 bomb bay.