X-15.TXT


X-15, 1959-1968

   [See X15.gif]
   
   The X-15 was a rocket powered aircraft 50 ft long with a wingspan of
   22 ft. It was a missile-shaped vehicle with an unusual wedge-shaped
   vertical tail, thin stubby wings, and unique side fairings that
   extended along the side of the fuselage. The X-15 weighed about 14,000
   lb empty and approximately 34,000 lb at launch. The rocket engine, the
   XLR-99, was pilot controlled and was capable of developing 57,000 lb
   of thrust. It was manufactured by Thiokol Chemical Corp.
   
   The X-15 research aircraft was developed to provide in-flight
   information and data on aerodynamics, structures, flight controls, and
   the physiological aspects of high-speed, high-altitude flight. A
   follow on program used the aircraft as a testbed to carry various
   scientific experiments beyond the Earth's atmosphere on a repeated
   basis.
   
   For flight in the dense air of the usable atmosphere, the X-15 used
   conventional aerodynamic controls such as vertical stabilizers to
   control yaw and horizontal stabilizers which control pitch when moving
   in synchronization or roll when moved differentially.
   
   For flight in the thin air outside of the appreciable Earth's
   atmosphere, the X-15 used a ballistic control system. Eight hydrogen
   peroxide thrust rockets located on the nose of the aircraft provided
   pitch and yaw control.
   
   Because of the large fuel consumption, the X-15 was air launched from
   a B-52 aircraft at 45,000 ft and a speed of about 500 mph. Depending
   on the mission, the rocket engine provided thrust for the first 80 to
   120 sec of flight. The remainder of the normal 10- to 11- min. flight
   was powerless and ended with a 200-mph glide landing.
   
   Generally, one of two types of X-15 flight profiles was used; a high-
   altitude flight plan that called for the pilot to maintain a steep
   rate of climb, or a speed profile that called for the pilot to push
   over and maintain a level altitude.
   
   First flown in 1959, the three X-15 aircraft made a total of 199
   flights. Flight maximums of 354,200 ft in altitude and a speed of
   4,520 mph were obtained. Final flight was flown on Oct. 24, 1968. The
   X-15 was manufactured by North American Aviation, now known as
   Rockwell International Corporation.
   
  X-15 FLIGHT SUMMARY
  
   X-15 Pilots in chronological order with total flights:
   
     * A. Scott Crossfield, NAR, 14
     * Joseph A. Walker, NASA, 25
     * Robert M. White, USAF, 16
     * Forrest S. Petersen, NSN, 5
     * John B. McKay, NASA, 29
     * Robert A. Rushworth, USAF, 34
     * Neil A. Armstrong, NASA, 7
     * Joe H. Engle, USAF, 16
     * Milton O. Thompson, NASA, 14
     * William J. Knight, USAF, 16
     * William H. Dana, NASA, 16
     * Michael J. Adams, USAF, 7
       
   
   
   Fastest speed (basic aircraft) was 4,104 mph (Mach 6.06) on flight
   1-30-51 with pilot Joe Walker.
   
   Fastest speed with tanks was 4,520 mph (Mach 6.70) on flight 2-53-97
   with pilot William Knight.
   
   Highest altitude was 354,200 ft (67 miles) on flight 3-22-36.
   
   Total flight time was 30 hr, 13 min. and 49.2 sec.
   
   Total distance flown was 41, 763.8 miles (statute).
   
   Total flights of the X-15 was 199 between 1959 and 1968.
   
   Hours above Mach (Cumulative): Mach 1-18 hr, 23 min. and 11.6 sec;
   Mach 2-12 hr, 13 min., and 50 sec; Mach 3-8 hr, 51 min., and 12.8 sec;
   Mach 4-5 hr, 57 min., and 23.8 sec; Mach 5-1 hr, 27 min., and 15.8
   sec; Mach 6-1 min. and 16.8 sec.

  
     _________________________________________________________________
     
   
    Don Nolan
    Dryden Public Affairs Office
    (805) 258-3447
    Don_Nolan@qmgate.dfrf.nasa.gov