YF-12 "Blackbird"
The YF-12 "Blackbird" was an experimental fighter-interceptor version of the Lockheed A-12 aircraft. In 1964 President Lyndon Johnson publicly acknowledged the existence of the Lockheed A-12 Mach 3+ spy plane program and shows a picture that is actually an YF-12A. In Air Force flight tests on May 1, 1965, the YF-12 set a speed record of 2,070.101 miles per hour and an altitude record of 80,258 feet. First publicly displayed at Edwards Air Force Base, California, in 1964, the YF-12 was never adopted by the military as an operational aircraft. It was, however, a precursor to the SR-71 Blackbird reconnaissance plane.
The Lockheed A-12 family, known as the Blackbirds, were designed by Clarence "Kelly" Johnson. They were constructed mostly of titanium to withstand aerodynamic heating. Fueled by JP-7, the Blackbirds were capable of cruising at Mach 3.2 and attaining altitudes in excess of 80,000 feet. The first version, a CIA reconnaissance aircraft that first flew in April 1962 was called the A-12. An interceptor version was developed in 1963 under the designation YF-12A. A USAF reconnaissance variant, called the SR-71, was first flown in 1964. The A-12 and SR-71 designs included leading and trailing edges made of high-temperature fiberglass-asbestos laminates.
The Johnson Administration considered improvement in defense against manned bomber attack in order to preclude the Soviets from undercutting the Nike-X defense. The investment cost (including R&D) was estimated at about $1.5 to $2.4 billion and would provide for a small force of F-111 or F-12 type interceptors (e.g., 48 F-111s or 32 F-12s) and about 42 aircraft warning and control aircraft (AWACS). With the introduction of these new types of aircraft, the US might have been able to phase out most of the present interceptor aircraft and a large part of the ground-based aircraft warning and control network, thus producing an actual saving in operating costs over the longer term.
The F-12 and F-111 interceptors, equipped with the improved ASG-18/AIM-47 fire control and missile systems, and used with an effective Airborne Warning and Control System (AWACS), would be better than the existing force in operating from degraded bases, countering concentrated bomber attacks, operating independently of a vulnerable fixed ground environment, and dealing with bombers attacking at low-altitude or carrying air-to-surface missiles. With strategic warning it was estimated that 32 UE F-12s or 48 UE stretched F-111As could achieve the same number kills before weapons release as the current force which had a 10 year cost of $3.0 billion. The 10 year systems cost for the 32 UE F-12 force had increased by 1966 from the previously estimated $1.9 billion to $2.9 billion. Estimates for the F-111 force remained at $1.5 billion. The F-111 force therefore appeared substantially more efficient than the F-12s against the currently projected threat. Supplementary calculations indicated that it was comparable in efficiency to the F-12 force against possible future threats.
Secretary of Defense Robert McNamara chose in 1966 to upgrade the F-106 instead of developing the F-12, and deferred deployment of SAM-D, a continental air defense system. The F-12 development program was reoriented in FY 67 and FY 68 to include further design studies for the F-111 interceptor, cost studies, and adaptation of the Navy AWG-9 fire control system for ADC use, using the YF-12 as a test bed.
During mid-1967, Defense Affairs assisted Mr. Charles W. Harper, Deputy Associate Administrator for Advanced Research and Technology (Aeronautics), in lengthy negotiations to obtain release from the Air Force of certain technical data on the F-12/SR-71 aircraft series needed by NASA to fulfill effectively its research role in aeronautics and its supporting role in the development, under government programs, of both military and civilian supersonic aircraft. DOD and the Air Force concurred in the desirability of making the cats available to NASA, but difficulty was encountered in persuading the manufacturer to release the data, which were being held closely as proprietary information. NASA had formulated plans for studies of the F-12/SR-71 aircraft with the objectives of (1) helping to establish correlation between flight and propulsion system performance and predictions based upon ground facility tests and analog simulation, (2) assessing the technology advances as represented by these aircraft. and (3) identifying problem areas that had not been anticipated in early studies of other supersonic aircraft development programs.
Two YF-12 aircraft were flown in a joint Air Force-NASA research program at the NASA Flight Research Center (now the NASA Dryden Flight Research Center) between 1969 and 1979, although the second plane, piloted primarily by the Air Force, was lost to an inflight fire in 1971. The two YF-12 aircraft bore the serial numbers 60-6935 and 60-6936.
The NASA Dryden Flight Research Center (NASA-DFRC) involvement with the YF-12A, an interceptor version of the Lockheed A-12, began in 1967. Ames Research Center was interested in using wind tunnel data that had been generated at Ames under extreme secrecy. Also, the Office of Advanced Research and Technology (OART) saw the YF-12A as a means to advance high-speed technology, which would help in designing the Supersonic Transport (SST). The Air Force needed technical assistance to get the latest reconnaissance version of the A-12 family, the SR-71A, fully operational.
Eventually, the Air Force offered NASA the use of two YF-12A aircraft, 60-6935 and 60-6936. A joint NASA-USAF program was mapped out in June 1969. NASA and Air Force technicians spent three months readying 935 for flight. On 11 December 1969, the flight program got underway with a successful maiden flight piloted by Col. Joe Rogers and Maj. Gary Heidelbaugh of the SR-71/F-12 Test Force. During the program, the Air Force concentrated on military applications, and NASA pursued a loads research program. NASA studies included inflight heating, skin-friction cooling, "coldwall" research (a heat transfer experiment), flowfield studies, shaker vane research, and tests in support of the Space Shuttle landing program. Ultimately, 935 became the workhorse of the program, with 146 flights between 11 December 1969 and 7 November 1979.
The second YF-12A, 936, made 62 flights. It was lost in a non-fatal crash on 24 June 1971. It was replaced by the YF-12C. The YF-12C was delivered to NASA on 16 July 1971. From then until 22 December 1978, it made 90 flights. Following the loss of a YF-12A in a non-fatal accident in June 1971, NASA acquired the second production SR-71A (61-7951) from the Air Force. Because the SR-71 program was shrouded in the highest secrecy, the Air Force restricted NASA to using the aircraft solely for propulsion testing with YF-12A inlets and engines. It was designated the YF-12C, and given a bogus tail number (06937).
The NASA YF-12 research program was ambitious; the aircraft flew an average of once a week unless down for extended maintenance or modification. Program expenses averaged $3.1 million per year just to run the flight tests. NASA crews for the YF-12 included pilots Fitzhugh Fulton and Donald Mallick, anf flight test engineers Victor Horton and Ray Young. Other NASA test pilots checked out in the YF-12A included John Manke, William Dana, Gary Krier, Einar Enevoldson, Tom McMurtry, Steve Ishmael, and Michael Swann. The YF-12C was flown only by Fulton, Mallick, Horton and Young during its NASA research missions.
