Col. John Paul Stapp was an Air Force Surgeon who underwent trials to see how much a human pilot could take. He volunteered for a series of tests at Edwards Air Force Base on rocket sleds. Stapp broke speed record after speed record.
His last run on the sled was on December 10, 1954. Increasing the rocket power behind him, he accelerated to 1,017 kph (632 mph) in five seconds, then came to a complete stop in less than two seconds. That meant more than 40 Gs, and that he momentarily weighed 3,084 kg (6,800 lbs). Emergency workers were standing by to rush him to hospital; all the blood vessels in his eyes had burst, leaving him blind – he would recover his sight later, but he’d also have two black eyes due to the forward motion of his eyes inside his head. He’d cracked a few ribs and broken both wrists, but he survived.
Incidentally, Stapp’s ride also gave us what we now know as Murphy’s Law.
His story is just one of a dozen in the post Past Lives: Remembering 12 of History’s Greatest Test Pilots & Early Aviation Pioneers at Urban Ghosts. Read about people who set aviation records and those who tested flying machines from before the Wright Brothers up to NASA experiments.
http://www.improb.com/airchives/paperair/volume9/v9i5/murphy/murphy2.html