Originally Posted by
hotshot
From what I've read the crew could apparently bailout at maximum speed at maximum altitude because the air pressure at that height is so low that it is the equivalent of a much lower speed at lower altitude. Any of that make sense?
You are correct. Max normal operating altitude was about 85,000 feet. At that altitude, its normal cruise mach of 3.2 equates to an equivalent airspeed of about 310 knots. That dynamic pressure is very survivable in a normal flight suit. But since the SR-71 guys all wore a full pressure suit (space suit), there was really no concern about the speed. The concern was when one of the engines coughed (unstarted) at speed. That sometimes led to an inflight breakup, and the resulting lateral G forces could be more than a human could tolerate.
Carl