The SR-71 flight manual kind of describes it. Pyro devices fire, yanking your boots backward onto a metal plate. (so that your feet will come with you) The can

The SR-71 flight manual kind of describes it. Pyro devices fire, yanking your boots backward onto a metal plate. (so that your feet will come with you) The canopy is blasted off. A rocket launches you out. Very briefly, you experience heat like a hot oven caused by the air being compressed in front of you. It's about 500 F. The suit mostly protects you. A drouge chute gets you going feet first, head last. More pyro devices fire, cutting some straps and then pulling a seat liner tight. This tosses you out of the seat. I think more pyro devices... there were a lot. You end up with a survival kit dangling a few dozen feet below you and of course with a parachute above. You get some dye, a gun, a raft, etc.