Thinking back now the aux air doors top and bottom were controlled through the pitot-static system, the faster you go the more they close. If you go faster still then the air intake ramps hinged outwards at the centre point to slow the air entering the engine.
At the same time the stab feel probe was busy introducing artificial "feel" into the stabilator system. That is of course unless a bee has nested down the tube, but that's another story. Both the pitot tube and stab feel probe were located on the fin and protected from icing by a ferocious heating system, but again that's another story.
All these recollections are hazy now having long since sliced off the top of my skull, Hannibal Lechter style, on the LOX pot door hanging down in front of the SUU gun
