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X-15A-2 with dummy ramjet X-15A-2 with dummy ramjet

Photo Number: EC88-0180-2
Photo Date: 1967

Formats: 539x480 JPEG Image (110 KBytes)
1150x1024 JPEG Image (618 KBytes)
3000x2670 JPEG Image (4,842 KBytes)

Photo
Description:
This photo shows the X-15A-2 (56-6671) on a research flight with a dummy ramjet engine attached to the bottom of its wedge-shaped vertical tail.

One of the experiments planned for the X-15A-2 involved tests of a functional ramjet at speeds above Mach 5. This photo was taken with a dummy ramjet. On this research flight, the X-15A-2 did not carry the two drop tanks used on its Mach 6.7 flight. It also had not yet been covered with an ablative coating. The X-15A-2 made several flights with the dummy ramjet, leading to the record Mach 6.7 flight on October 3, 1967. Delays in producing the operational ramjet, aerodynamic heating damage to the aircraft during the record flight (despite the ablative coating), and the end of the X-15 program in 1968 resulted in no flights with the actual ramjet.


Project
Description:
The X-15 was a rocket-powered aircraft. The original three aircraft were about 50 ft long with a wingspan of 22 ft. The modified #2 aircraft (X-15A-2) was longer. They were a missile-shaped vehicles with unusual wedge-shaped vertical tails, 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 rated at 57,000 lb of thrust, although there are indications that it actually achieved up to 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 testbeds 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 approximately 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. 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; ship #2; rocket powered research aircraft; ramjet engine; North American Aviation; high-speed and high-altitude flight; B-52 air launch; 4;520 mph; Mach 6.70; 354;200 ft (altitude); 67 miles (altitude); dummy ramjet


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