it is known as the conventional layout. Sometimes there may be two or more fins, spaced out along the tailplane. Some types have a horizontal "canard" foreplane ahead of the main wing, instead of behind it. This foreplane may contribute to the trim, stability or control of the aircraft, or to several of these. Aircraft controls Kite control Kites are controlled by wires running down to the ground. Typically each wire acts as a tether to the part of the kite it is attached to. Free-flying aircraft controls Gliders and airplanes have more complex control systems, especially if they are piloted. The main controls allow the pilot to direct the aircraft in the air. Typically these are: The yoke or joystick controls rotation of the plane about the pitch and roll axes. A yoke resembles a steering wheel, and a control stick is a joystick. The pilot can pitch the plane down by pushing on the yoke or stick, and pitch the plane up by pulling on it. Rolling the plane is accomplished by turning the yoke in the direction of the desired roll, or by tilting the control stick in that direction. Rudder pedals control rotation of the plane about the yaw axis. There are two pedals that pivot so that when one is pressed forward the other moves backward, and vice versa. The pilot presses on the right rudder pedal to make the plane yaw to the right, and pushes on the left pedal to make it yaw to the left. The rudder is used mainly to balance the plane in turns, or to compensate for winds or other effects that tend to turn the plane about the yaw axis. On powered types, an engine stop control ("fuel cutoff", for example) and, usually, a Throttle or thrust lever and other controls, such as a fuel-mixture control (to compensate for air density changes with altitude change). Other common controls include: Flap levers, which are used to control the deflection position of flaps on the wings. Spoiler levers, which are used to control the position of spoilers on the wings, and to arm their automatic deployment in planes designed to deploy them upon landing. The spoilers reduce lift for landing. Trim controls, which usually take the form of knobs or wheels and are used to adjust pitch, roll, or yaw trim. These are often connected to small airfoils on the