On February 29, 1964, President Lyndon B. Johnson publicly disclosed the existence of the Top Secret Lockheed YF-12A, a Mach 3+ interceptor from the famed “Skunk Works” of Clarence L. “Kelly” Johnson. It was one of those dramatic moments in aviation history, for this single announcement introduced an airplane whose capability was so far superior to any known previous aircraft.
The YF-12A, which was initially named “A-11” by the President himself, represented five years of secret development. “Several of the craft, designated A-11, have been tested in sustained flight at speeds greater than 2,000 mph and at heights over 70,000 ft,” Johnson said. This aircraft represented all the significant frontiers of change within aircraft technology with immense military and commercial implications.
Built by Lockheed Aircraft Corp. of Burbank, Calif., the YF-12A had been tested at Edwards Air Force Base as a long-range interceptor of enemy bombers. The project was handled and financed in the usual secrecy for Air Force classified projects. Secrecy on the YF-12A was so tight that even the House Armed Services Committee was uninformed about the project until shortly before the public announcement.
The design of the YF-12A was based in large part upon its earlier relative, the A-12 reconnaissance aircraft designed and built under the Oxcart program for the Central Intelligence Agency. There were significant differences: a redesigned nose that housed the Hughes AN/ASG-18 fire-control radar; a second cockpit for the radar operator; and ventral fins to maintain stability.
The performance of the YF-12A was nothing short of phenomenal. On May 1, 1965, it established a speed record of 2,070.103 mph and climbed to an altitude of 80,259 ft. These records underlined the aircraft’s capability, Matcher A maximum speed of Mach 3.35 and a service ceiling of 90,000 ft. Powered by two Pratt & Whitney J58s each rated at 31,500 pounds of thrust with afterburning.
Yet, despite that, the YF-12A program was beset by one challenge after another. Secretary of Defense Robert McNamara would repeatedly refuse to release production funds for the F-12B, the production version of the YF-12A planned, citing budget constraints from the Vietnam War and a lower priority on continental air defense. The program, officially, was canceled in January 1968.
However, the YF-12A continued to serve invaluable research and development roles. Two of the prototypes were recalled from storage in 1969 for a joint U.S. Air Force/NASA study of supersonic cruise technology. These aircraft contributed to various NASA studies, including in-flight heating, skin-friction cooling, and tests supporting the Space Shuttle landing program.
Of the three prototypes built-YF-12As-only one survives. The first was irreparably damaged in a landing mishap, while the third was destroyed after an in-flight fire. The second prototype survived long enough to be saved for display and is at the National Museum of the United States Air Force at Wright-Patterson Air Force Base, Ohio.
The YF-12A is also a very fine testimony to the ingenuity and depth of technological prowess typical of the Skunk Works team. Unsurpassed for speed, it remains one of the fastest and most advanced interceptors developed to date. It represents a symbol from a bygone era when innovation in aviation and secrecy walked hand in glove.