I remember the good ol' days, you'd yank the elevator at bit too hard and hear the thump as the wing lifts and hits back down. Get it wrong and the wing would fly off for good :-)

Great for trimming rudder/elevator gliders with warped wings, just rotate the wing a bit until the rudder trim is straight again and/or offset the wing a few mm to one side.

Hand tosses for trimming, who remembers those days?