X-2 Credit - NASA

X-2 was an AAF/ Bell project that flew three supersonic flight research aircraft, powered by liquid rockets. Originally designated XS-2. The X-2 was the first swept-wing X rocketplane. It exceeded Mach 3, but in the course of doing so uncovered the supersonic aircraft problem of inertial coupling. On its last flight the aircraft crashed and the pilot was killed.

Main Engine: XLR-25-CW-1. Main Engine Propellants: Lox/Alcohol.

• 1945 July 1 - Goddard's rocket team ends its work. -
  Goddard's rocket team ends its work at the Naval Engineering Experiment Station at Annapolis, Maryland. During the previous three years the team had developed a variable-thrust rocket motors. This required hundreds of proving-stand tests, but eventually producing a successful motor, later used on the Bell X-2 rocket plane.

• 1945 December 14 - X-2 rocket airplane development starts. -
  AAF contracted with Bell for development of three supersonic flight research aircraft, powered by liquid rockets. Designated XS-2, and later X-2.

• 1953 May 12 - X-2 explodes in air - Crew: Ziegler.
  During a Bell captive-carry flight test over Lake Ontario, X-2 number 46-675 suddenly exploded, killing Bell test pilot Jean Ziegler and observer Frank Wolko. The EB-50A mothership managed to land, although damaged. Only after several other mysterious X-plane losses was the cause found to be a rocket engine gasket made of Ulmer leather, which decomposed and became explosively unstable after sustained exposure to liquid oxygen.

• 1954 August 5 - X-2 Flight 1 - Crew: Everest.
  First glide flight of the second X-2, number 46-674, after delivery to Edwards AFB a month earlier. Damaged on landing.

• 1955 March 8 - X-2 Flight 2 - Crew: Everest.
  Second glide flight. Propellant system check. Minor damage on landing.

• 1955 April 6 - X-2 Flight 3 - Crew: Everest.
  Third glide flight. Damaged on landing. Following flight, plane returned to Bell plant for extensive modifications to landing gear system to prevent further landing accidents and for installation of its rocket engine.

• 1955 October 25 - X-2 Flight 4 - Crew: Everest.
  Aborted powered flight attempt; became 4th glide flight.

• 1955 November 18 - X-2 Flight 5 - Crew: Everest.
  First powered flight. Mach 0.992 at 10,675 m. Slight fire damage from engine bay fire.

• 1956 March 24 - X-2 Flight 6 - Crew: Everest.
  Second powered flight, mach 0.91.

• 1956 April 25 - X-2 Flight 7 - Crew: Everest.
  3d powered flight, mach 1.4 at 15250 m.

• 1956 May 1 - X-2 Flight 8 - Crew: Everest.
  Fourth powered flight, mach 1.683 at 16,378 m.

• 1956 May 11 - X-2 Flight 9 - Crew: Everest.
  Fifth powered flight, mach 1.8 at 18,300 m.

• 1956 May 22 - X-2 Flight 10 - Crew: Everest.
  Sixth powered flight, mach 2.53 at 17.803 m.

• 1956 May 25 - X-2 Flight 11 - Crew: Kincheloe.
  Seventh powered flight; pilot checkout, mach 1+.

• 1956 July 12 - X-2 Flight 12 - Crew: Everest.
  Eighth powered flight, premature engine shutdown.

• 1956 July 23 - X-2 Flight 13 - Crew: Everest.
  Ninth powered flight, Lt. Col. Frank K. Everest (USAF) flew the Bell X-2 rocket-powered research plane at a record speed of Mach 2.87, ust over 1,900 mph, at 20,802 m.

• 1956 August 3 - X-2 Flight 14 - Crew: Kincheloe.
  10th powered flight, mach 2.5+, 26764 m.

• 1956 August 8 - X-2 Flight 15 - Crew: Kincheloe.
  11th powered flight, premature engine shutdown.

• 1956 September 7 - X-2 Flight 16 - Crew: Kincheloe.
  12th powered flight. Capt. Iven C. Kincheloe (USAF) set new unofficial altitude record for manned flight at Edwards AFB, Calif., piloting a Bell X-2 rocket-powered aircraft to a height of 38,491 m, top speed Mach 1.7.

• 1956 September 27 - X-2 Flight 17 - Crew: Apt Milburn.
  After having been launched from a B-50 bomber over the Mojave Desert in California, Capt. Milburn G. Apt (USAF), flying an X-2 rocket-powered plane on its 13th powered flight, set a record speed of 3,377 kph, or Mach 3.196 at 19,977 m. Subsequent loss of control from inertial coupling led to the destruction of the aircraft and the death of the pilot.

• 1956 September 27 - X-2 reaches Mach 3. -
  After having been launched from a B-50 bomber over the Mojave Desert in California, Capt. Milburn G. Apt (USAF), flying an X-2 rocket-powered plane on its 13th powered flight, set a record speed of 2,094 mph, or Mach 3.196. In the course of the flight the aircraft crashed and the pilot was killed.