Depends on the plane. Some of mine turn by rudder only(lots of dihedral) and have no ailerons. On the other hand, my Skydrill has a rudder but I rarely use it. I just fly it around with the elevator and ailerons. If I was to do it again, I would leave the rudder off that one since it doesn't have a throttle and isn't really capable of hammerheads or other such maneuvers anyway. As mentioned, the Sureshark doesn't have one and neither will the Das Splat Jr. I just started. If the plane is just for fun sport flying, it can be built lighter and simpler without a rudder IMHO. Good luck and have fun.