The bigger the plane, the more need to use the rudder to make coordinated turns. On parkflyers, the rudder is usually only used on take-off and landing, to keep the plane lined up with the runway while keeping the wings level, and for special maneuvers. For most regular flying, there is no need to use the rudder. On my Typhoon, I use the rudder for making flat turns, flat spins, death spirals, etc.; and for controlling the tail wheel once the plane is on the ground. There are many great flying planes that don't have a rudder, like all of the ParkZone warbirds. I know of two flyers who epoxied the rudder on their miniUltraSticks.