"WaltBJ" wrote in message
om...
It's not the Mach number but the air blast, measured by indicated
airpeed in the cockpit, that hurts you. It's also known as 'Q' force,
or ram air pressure. FWIW the SR71 Q limit is low enough so serious
injury is unlikely.

That's what the SR-71 pilot said. Because of the low pressure
at altitude, it is equivalent to approx. 246 knots at sea level.
So they eject without a capsule - but with a pressure suit
inflated to 4.5 psi. That is the same pressure as in the
cockpit, so it is limp until they eject.

He passed on another interesting tidbit. They warmed
their lunch by holding it against the windshield,
which was about 300 degrees F at speed.