Space/Science — HabitableZone

Space/Science » in reply to Plus, a SHOCK WAVE builds up in front...

That was a problem with several WWII fighters,

particularily American ones like the P-38, P-47, and P-51. American fighters of the era tended to be heavier than those built by other countries. That meant they could hit very high speeds in a dive, sometimes into the transonic region where airflow over parts of the plane is supersonic while the rest is subsonic. The wings on those planes were relatively thick by modern standards, so in a dive the airflow on the upper surfaces would sometime exceed the speed of sound. The shock waves from that would disturb the airflow over the tail surfaces, making the controls appear to freeze. The term for this was compressibility.

It was a very dangerous situation - the plane was diving out of control at very high speed. About the best the pilot could hope for was for the plane to slow below the transsonic speed when it fell into denser air, stopping the shock waves and allowing the pilot to recover. Sometimes, the forces were so high that the plane's tail was ripped off. This first happened with the early P-38s but the P-47s and P-51s also had the problem. I'm not sure but the F4U Corsair might've also encountered compressibility. I don't recall ever reading that the F4F Hellcat ever had the problem but it wasn't as fast as the other planes.

Shock waves might well have come from the propellors, too, during a high speed dive but from what I've read, the biggest problem was from the wings.

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