Ball Joints

I realize SimpleRockets is focused on rockets but I believe there are some interesting things that could be done with ball joints. I wanted to make a swashplate similar to one on an rc helicopter and attempted to use pistons, but was unsuccessful. The connection on both sides of the piston is rigid, so it could not pivot. If one side was mounted rigidly and the other free to rotate, I believe it would enable someone to make a functioning helicopter.