ORIGINAL: mike31
WRONG! Rudder is used to co-ordinate turns. Banking causes the nose to yaw in the opposite direction. The rudder is used to bring the nose back to the desired direction of the turn. When flying full scale the term used is step on the ball. That is the turn co-ordinator for those that don't fly full size aircraft. Using top rudder will lead to a stall, eventually.
Actually i've flown a few (horribly built) RC airplanes that required Opposite rudder to keep it co-orridnated in a turn. So i wouldn't just say he's flat out "wrong" just maybe one of his planes has some weird quirks to them.