X-15

One of the most significant aircraft in history, the X-15 was designed to explore the identifiable problems of atmospheric flight at very high speeds and altitudes. The aircraft was the first to use a throttleable rocket engine, the first to be flown to speeds of Mach 4, 5, and 6, and the first to be flown to the lower edge of space (considered by the Air Force and NASA to be an altitude of 50 miles). There were also a great number of technical achievements in materials, construction, and testing associated with the X-15. Four Air Force pilots (Maj. Robert White, Maj. Robert Rushworth, Capt. Joseph Engle, and Maj. William "Pete" Knight) and three NASA pilots (Joseph Walker, John McKay, and William Dana) earned astronaut wings for flights above 264,000 ft. On July 17, 1962, Major White set the FAI-recognized absolute altitude record for an aircraft launched from a carrier airplane when he flew the number three X-15 to 314,750 ft. However, on August 22, 1963, Joe Walker reached a height of 354,200 ft, but the record is unofficial, as the necessary FAI paperwork was not submitted. Likewise, on October 3, 1967, Major Knight reached a speed of 4,520 mph in the number two X-15 (2,327 mph faster than the recognized absolute speed record set in 1976), but the record is not recognized. After a landing mishap on November 9, 1962, the number two X-15 was extensively modified for higher performance and was redesignated X-15A-2. Air Force Maj. Michael Adams was killed on November 15, 1967, when he became disoriented after a mechanical malfunction and the number three aircraft disintegrated. The type's 199th and final flight came on October 24, 1968. The number one X-15 is on display at the National Air and Space Museum in Washington, D. C., and the number two aircraft is on display at the US Air Force Museum.

Contractors:	North American Aviation, Inc.
Locations Built:	El Segundo, Calif.
Number Built: (USAF)	Three (three)
First Flight:	June 8, 1959 (first glide flight). September 17, 1959 (first powered flight)
First Flight Model:	X-15
First Flight Location:	Edwards AFB, Calif.
First Flight Pilot:	A. Scott Crossfield
Models/Variants:	X-15. X-15A- 2
Powerplant:	One Reaction Motors XLR99 Pioneer liquid fuel throttleable rocket of between 25,000 to 50,000 lb of thrust (until the XLR99 was delivered in November 1960, the aircraft flew with two Reaction Motors XLR11-RM-5 liquid fuel rockets of 8,000 lb of thrust each)
Wingspan:	22 ft 4 in.
Length:	52 ft 5 in.
Height:	12 ft 7 in.
Weight:	56,130 lb gross
Armament:	None
Accommodation:	Pilot only
Cost:	$300 million for design, development, three aircraft, and flight testing
Max. Speed:	Mach 6.70 (4,520 mph)
Range:	More than 250 mi (flight path distance); most flights lasted 11 to 12 min.
Ceiling:	354,200 ft.