The Lockheed SR-71 is an advanced, long-range, Mach 3 strategic reconnaissance aircraft developed by Lockheed Skunk Works as a Black project. The Pratt & Whitney J58-P4 engines used in the Blackbird were the only military engines ever designed to operate continuously on afterburner, and became more efficient as speed increased. Each J58 engine could produce 32,500lbs of static thrust. Conventional jet engines cannot operate continuously on afterburner. Crews flying the SR-71 at 80,000 Feet faced two main survival problems. First, with a standard pressure demand oxygen mask, human lungs cannot absorb enough of 100% oxygen above 43,000 feet to sustain consciousness and life. Second, the instant heat rise pulse on the body when exposed to a Mach 3.2 air flow during ejection would be about 450 ?F. To solve these problems, the David Clark Company was hired to produce protective full pressure suits for all of the crew members of the SR-71. These suits were later adopted for use on the Space Shuttle during ascent.
The Amazing SR-71 Blackbird