It looks like you don't have much control over how your seat flips though. The best thing about the Rock O Plane to me was the ring-bar that let you control how much your seat flipped. An expert rider could keep their tub upside down the entire ride!
On a side note, why have Rock O Planes disappeared from fairs/carnivals? I haven't seen one in at least 10 years. This was one of my favorite rides from childhood, and the first "upside down" ride I ever rode.