Rudder? what's a rudder? all you stubby wings people only need a rudder when taxying.....
Try flying in a training glider, not to mention 18 or 25 meter wingspan, and then you will discover what a rudder is for.
There is an extremely sensitive and high tech instrument usually taped on the outside of the canopy, which will soon show if there is excess rudder one way or the other in flight... sometimes it blows off and you have to find another piece of string.....