Rudder
A rudder is a device used to steer a ship or other watercraft. In its simplest form, a rudder is a flat sheet of material attached with hinges to the ship's stern. A tiller - basically, a stick or pole - is attached to the top of the rudder to allow it to be turned in different directions.
On an aircraft, the rudder is a control surface, usually attached to the fin (or vertical stabiliser) which allows the pilot to control the aircraft in the yaw axis. It is not used to effect turns - the ailerons are used for that - but the rudder is necessary to correctly balance the various acting forces in a turn. By convention, the rudder is controlled with foot pedals, usually coupled to bell cranks on the rudder via wire cables. In some (rare) aircraft, there are no rudder pedals as the rudder is controlled with springs associated with the roll control. In some designs, an all-moveable fin is used instead of a rudder. de:Ruder pl:Ster
See also