Sorry if this is the wrong place to ask this, but it seemed more historical than scientific! For as long as I can remember, my dad (in the way of dads everywhere) has claimed that before we'd broken the sound barrier, we thought that the controls would invert when a plane went supersonic. I've always been skeptical of this! If any one could confirm this it would be great and a laymans explanation of why would also be amazing!
The ailerons on an aircraft wing create low pressure on the top part of the wing. Now we have lower pressure at the top and high pressure at the bottom so the wing moves upwards. Now when you fly at supersonic speeds, this effect is obviously very more pronounced. So much so that if you do not reduce the size of the ailerons, the low pressure at the top will actually bend the wing upwards changing it's shape completely. With a bent wing the aircraft would roll in an opposite direction to the one the pilot intended. The engineers obviously knew that this would happen and compensated by making the ailerons smaller and/or making the angle that they deflect from the chord line of the wing less.
(Note: The theory of lift i spoke about is known as bernoulli's theorem. I read that NASA now claims this is not the primary cause of lift. They say it's Newtons 3rd. Every action equal and opposite reaction. Air gets deflected downwards by the wings and the opposite reaction "lift")
I think that idea might have originated in experiments because airflow going through a nozzle gets faster and going through a diffusor it gets slower, except when the flow is super sonic, this effect gets reversed. So maybe they thought that would be the same with control surfaces but this obviously only a guess.
The origin of this myth is a film called The Sound Barrier from 1952 which fictionally depicted reversing controls as the solution (and British doing it). The real solution was an "all-moving tail" to reduce shock-wave interference, which was kept classified at least five years (including the production period of the film), possibly longer.
If you read this transcript from Chuck Yeager you see he specifically describes using conventional controls:
When I got above 94% of the speed of sound, the nose begins to come up on the airplane. I just cranked the leading edge up on the horizontal stabilizer to keep the nose down. When we went a little faster, the mach meter went off the scale and when it did, all the buffeting smoothed out, because the supersonic flow went over the whole airplane. And even I knew we had gotten above the speed of sound.