SR71FACT.TXT SR-71 "THE BLACKBIRD" [See BLKBIRD.GIF] Three SR-71 aircraft are being used by NASA as testbeds for high-speed, high- altitude aeronautical research. The aircraft, two SR-71As and the only SR-71B pilot trainer aircraft in operation, are based at NASA's Dryden Flight Research Center, Edwards, CA. They have been loaned to NASA by the U.S. Air Force and are the only SR-71s in service. Developed for the U.S. Air Force as reconnaissance aircraft more than 28 years ago, SR-71s are still the world's fastest and highest-flying production aircraft. The aircraft can fly more than 2200 mph (Mach 3+ or more than three times the speed of sound) and at altitudes of over 85,000 ft. This operating environment makes the aircraft excellent platforms to carry out research and experiments in a variety of areas -- aerodynamics, propulsion, structures, thermal protection materials, high-speed and high-temperature instrumentation, atmospheric studies, and sonic boom characterization. Data from the SR-71 high-speed research program will be used to aid designers of future supersonic/hypersonic aircraft and propulsion systems. Beneficiaries of this data include future hypersonic aircraft, including a high-speed civil transport. Program Management The SR-71 program at Dryden is part of NASA's overall high-speed aeronautical research program, and is expected to involve many NASA research centers, and other government agencies. Project manager at Dryden is David P. Lux. NASA SR-71 Flight Crews Each NASA crew consists of a pilot and a flight engineer. Currently assigned as SR-71 project pilots at Dryden are Stephen D. Ishmael and Rogers E. Smith. Flight engineers are Marta Bohn-Meyer and Robert E. Meyer. The Meyers are the first husband-wife team of aeronautical engineers on flight status at Dryden. Before NASA's SR-71 flights began in mid-1991, both pilot-engineer crews trained for many hours in the SR-71 flight simulator at Dryden to become thoroughly acquainted with aircraft systems and operational procedures. The flight crews continue to train on the unit before each flight and to develop flight procedures specific to upcoming research activities. The simulator at Dryden is the same unit used by the Air Force at Beale AFB, CA, before the SR-71s were retired from military use in 1990. As military aircraft, SR-71s had a crew of two -- a pilot and a reconnaissance systems officer. Research at Mach 3 One of the first major experiments to be flown in the NASA SR-71 program is a laser airdata collection system. It uses laser light instead of air pressure to produce airspeed and attitude reference data such as angle of attack and sideslip normally obtained with small tubes and vanes extending into the air stream, or from tubes with flush openings on an aircraft's outer skin. The flight tests with the SR-71 will provide information on the presence of atmospheric particles at altitudes of 80,000 ft and above where future hypersonic aircraft will be operating. The system will use six sheets of laser light projected from the bottom of one of the two "A" models. As microscopic-size atmospheric particles pass between the two beams, direction and speed will be measured and processed into standard speed and attitude references. A series of approximately 16 test flights with the laser system is expected to begin in Aug. l993 and be completed by the end of Oct. l993. An earlier laser airdata collection system was successfully tested at Dryden on an F-l04 testbed. SCIENCE CAMERA PLATFORM: The first of a series of flights using the SR-71 as a science camera platform for NASA's Jet Propulsion Laboratory was flown in Mar. 1993. From the nosebay of the aircraft, an upward-looking ultraviolet video camera studied a variety of celestial objects in wavelengths that are blocked to ground-based astronomers. Among the instruments that will be flown on the SR-71s on future missions will be ultraviolet spectrometers and infrared and ultraviolet sensors. In addition to observing celestial objects in the various wavelengths, future missions are expected to include "downward" looking instruments to study rocket engine exhaust plumes, volcano plumes, and the earth's atmosphere as part of the scientific effort to reduce pollution and protect the ozone layer. SONIC BOOM MITIGATION STUDIES: Modifications are expected to begin in 1994 to prepare one of the two SR-71A models for a significant program to study ways of reducing sonic boom overpressures that are heard on the ground much like sharp thunderclaps. A false bottom, representative of the shape that a future high-speed civil transport may have, will be installed on the aircraft and flown over a massive array of microphones on an instrumented test range. Goal of the project is to significantly reduce the "peak" of the sonic boom -- and the resulting startle affect -- as it reaches the ground. If the joint NASA-aerospace industry effort is successful, future high-speed civilian transports would be able to fly across the nation at supersonic speeds without creating sonic booms that cause adverse public reaction and even minor property damage. Dryden's Mach 3 History Dryden has a decade of past experience at sustained speeds above Mach 3. Two YF-12 aircraft were flown at the facility between Dec. 1969 and Nov. 1979 in a joint NASA/Air Force program to learn more about the capabilities and limitations of high-speed, high-altitude flight. The YF-12s were prototypes of a planned interceptor aircraft based on a design that later evolved into the SR-71 reconnaissance aircraft. Research information from the YF-12 program was used to validate analytical theories and wind tunnel test techniques to help improve the design and performance of future military and civil aircraft. The then-developing American supersonic transport project would have benefitted greatly from YF-12 research data. The aircraft were a YF-12A (serial 935) and a YF-12C (serial 937). They logged a combined total of 242 flights during the program. A third aircraft, a YF-12A (serial 936), was flown by Air Force crews early in the program. It was lost because of an inflight fire in June l971. The crew was not hurt. The YF-12s were used for a wide range of experiments and research. Among the areas investigated were aerodynamic loads, aerodynamic drag and skin friction, heat transfer, thermal stresses, airframe and propulsion system interactions, inlet control systems, high-altitude turbulence, boundary-layer flow, landing gear dynamics, measurement of engine effluents for pollution studies, noise measurements, and evaluation of a maintenance monitoring and recording system. On many YF-12 flights medical researchers obtained information on the physiological and biomedical aspects of crews flying at sustained high speeds. From Feb. 1972 until July 1973, the YF-12A was used for heat loads testing in Dryden's High-Temperature Loads Laboratory (now the Thermostructures Laboratory). The data helped improve theoretical prediction methods and computer models of that era dealing with structural loads, materials, and heat distribution at up to 800 degrees (F), the same surface temperatures reached during sustained speeds of Mach 3. SR-71 Specifications and Performance The SR-71 is a delta-wing aircraft designed and built by Lockheed. They are powered by two Pratt&Whitney J-58 axial-flow turbojets with afterburners, each producing 32,500 lb of thrust. Studies have shown that less than 20 percent of the total thrust used to fly at Mach 3 is produced by the basic engine itself. The balance of the total thrust is produced by the unique design of the engine inlet and "moveable spike" system at the front of the engine nacelles, and by the ejector nozzles at the exhaust which burn air compressed in the engine bypass system. Speed of the aircraft is announced as Mach 3.2 -- more than 2000 mph (3218.68 kph). They have an unrefueled range of more than 2000 miles (3218.68 kph) and fly at altitudes of over 85,000 ft (25908 m). As research platforms, the aircraft can cruise at Mach 3 for more than one hour. For thermal experiments, this can produce heat soak temperatures of over 600 degrees (F). The aircraft are 107.4 ft (32.73 m) long, have a wing span of 55.6 ft (16.94 m), and are l8.5 ft (5.63 m) high (ground to the top of the rudders when parked). Gross takeoff weight is about 140,000 lb (52253.83 kg), including a fuel weight of 80,000 lb (29859.33 kg). The airframes are built almost entirely of titanium and titanium alloys to withstand heat generated by sustained Mach 3 flight. Aerodynamic control surfaces consist of all-moving vertical tail surfaces above each engine nacelle, ailerons on the outer wings, and elevators on the trailing edges between the engine exhaust nozzles. The three SR-71s at Dryden have been assigned the following NASA tail numbers: NASA 831 (B model), military serial 64-17956, manufactured in Sept. 1965; NASA 832 (A model), military serial 64-17971, manufactured in Oct. 1966; NASA 844 (A model), military serial 64-17980, manufactured in July 1967. Development History The SR-71 was designed by a team of Lockheed personnel led by Clarence "Kelly" Johnson, at that time vice president of the company's Advanced Development Projects. The Advanced Development Projects is known as the "Skunk Works." The basic design of the SR-71 and YF-12 aircraft originated in secrecy in the late l950's with the aircraft designation of A-11. Its existence was publicly announced by President Lyndon Johnson on Feb. 29, 1964, when he announced that an A-11 had flown at sustained speeds of over 2000 mph during tests at Edwards, CA. Development of the SR-71s from the A-11 design, as strategic reconnaissance aircraft, began in Feb. 1963. First flight of an SR-71 was on Dec. 22, 1964. The YF-12s were experimental long-range interceptor versions of the same airframe and were first displayed publicly at Edwards on Sept. 30, 1964. _________________________________________________________________ Dave Lux, Project Manager (805) 258-3695