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Posted 11/2/2009 Printable Fact Sheet
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Lockheed YF-12
Lockheed YF-12 (S/N 60-6936) on the taxiway. (U.S. Air Force photo)
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The YF-12 was developed as a high-altitude Mach 3 interceptor for defense against supersonic bombers. It was designed in secrecy by a team led by Clarence L. "Kelly" Johnson, director of Lockheed's Advanced Development Projects office -- better known as the "Skunk Works." The existence of the aircraft was not officially revealed until Feb. 29, 1964.

The YF-12A was the forerunner of the highly sophisticated SR-71 high-altitude strategic reconnaissance aircraft. Unlike the SR-71, the YF-12A never became operational, but during the test program, which ended in 1966, it set a speed record of 2,070.101 mph and an altitude record of 80,257.86 feet. Both records were set on May 1, 1965. To enable the YF-12A to withstand skin temperatures of more than 500 degrees Fahrenheit (generated by air friction), 93 percent of its structural weight is made up of titanium alloys. The aircraft also is coated with a special black paint that helps radiate heat from its skin. All aircraft components were developed especially for the environment of sustained Mach 3+ cruise.

The YF-12A on display at the museum (S/N 60-6935) was recalled from storage in 1969 for a joint USAF/NASA investigation of supersonic cruise technology. It was flown to the museum on Nov. 7, 1979.

Type Number built/
YF-12 3 Fighter version of SR-71

- The first YF-12A (S/N 60-6934) was converted to SR-71C S/N 64-17981.
- The second YF-12A was transferred to the National Museum of the United States Air Force.
- The third YF-12A crashed on June 24, 1971.

Armament: Three Hughes AIM-47A missiles
Engines: Two Pratt & Whitney J58s of 32,000 lbs. thrust each with afterburner
Maximum speed: Mach 3+
Range: 2,000+ miles
Service ceiling: Above 80,000 ft.
Span: 55 ft. 7 in.
Length: 101 ft.
Height: 18 ft. 6 in.
Weight: 127,000 lbs. loaded
Crew: Two

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