NASA YF-12 Blackbird Program

Two YF-12s were flown in a joint Air Force-NASA research program at the NASA Flight Research Center (after 1976, the NASA Dryden Flight Research Center) between 1969 and 1979. A third shared plane, piloted primarily by the Air Force, was lost to an in-flight fire in 1971.

To measure the thermal loads on the YF-12 required some extraordinary ground tests. At the supersonic speeds the aircraft achieved, high temperatures produced by friction with the atmosphere made it difficult to separate the aerodynamic from the purely thermal effects upon the airplane.

Because air friction subjected the plane to extreme heat during flight, the YF-12 was also used to study high-temperature phenomena unrelated to the plane itself. Perhaps the most significant of these studies was the Cold Wall Experiment, which involved exposing a cooled cylinder to the friction and heat of a Mach 3 environment.