The SR-71 Blackbird
The joint NASA-Air Force YF-12 research program lasted 10 years (1969-1979) and produced a wealth of data on materials, structures, loads, heating, aerodynamics, and performance for high-speed aircraft.
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.