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X-15A-2 launch from B-52 with ablative coating and external tanks X-15A-2 launch from B-52 with ablative coating and external tanks

Photo Number: EC68-1889
Photo Date: 1967

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Photo
Description:
After receiving a full scale ablative coating to protect the craft from the high temperatures associated with high-Mach-number supersonic flight, the X-15A-2 (56-6671) rocket powered research aircraft was then covered with a white sealant coat and mounted with additional external fuel tanks. This ablative coating and sealant would help the #2 aircraft reach the record speed of 4,520 mph (Mach 6.7). Under the lower fin is a dummy ramjet engine. It was intended to use the X-15A-2 for tests of an actual engine but this never happened.

Project
Description:
The basic 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 XLR-99 rocket engine, manufactured by Thiokol Chemical Corp., was pilot controlled and was capable of developing 57,000 lb of rated thrust. (Actual thrust reportedly reached 60,000 lb.) North American Aviation built three X-15 aircraft for the program.

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 rudder surfaces on the vertical stabilizers to control yaw and movable horizontal stabilizers to 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 reaction control system. Hydrogen peroxide thrust rockets located on the nose of the aircraft provided pitch and yaw control. Those on the wings provided roll 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.

The X-15 was flown over a period of nearly 10 years -- June 1959 to Oct. 1968 -- and set the world's unofficial speed and altitude records of 4,520 mph (Mach 6.7) and 354,200 ft in a program to investigate all aspects of manned hypersonic flight. Information gained from the highly successful X-15 program contributed to the development of the Mercury, Gemini, and Apollo manned spaceflight programs, and also the Space Shuttle program.

The X-15s made a total of 199 flights, and were manufactured by North American Aviation.

X-15-1, serial number 56-6670, is now located at the National Air and Space Museum, Washington DC.

North American X-15A-2, serial number 56-6671, is at the United States Air Force Museum, Wright-Patterson AFB, Ohio. The X-15-3, serial number 56-6672, crashed on 15 November 1967, resulting in the death of Maj. Michael J. Adams.


NASA Photo by: NASA photo

Keywords: X-15; rocket powered research aircraft; full scale ablation; seal coat; North American Aviation; high-speed & high-altitude flight; B-52 air launch; 4520 mph; Mach 6.70; 354;200 ft (altitude); 67 miles (altitude); dummy ramjet; XLR-99; Maj. Michael J. Adams


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