Unusual mechanism: The rolleron
Yes, this is a missile. Sorry about that. But it turns out the AIM-9 Sidewinder is the only well-documented example I can find, on the web, of a machine that employs these interesting little widgets called “rollerons.” See the little metal pinwheels at the trailing corners of the fins? The rolleron is basically an air-driven gyroscope, as Tom Harris explains over on How Stuff Works: