Aircraft flight control surfaces are aerodynamic devices allowing a pilot to adjust and control the aircraft's flight attitude.
KLM Fokker 70, showing position of flap and liftdumper flight controls. The liftdumpers are the lifted cream-coloured panels on the wing upper surface (in this picture there are five on the right wing). The flaps are the large drooped surfaces on the trailing edge of the wing.
Wing trailing edge flight control surfaces of a Boeing 747-8. Top left: All surfaces at neutral position; Top middle: Right aileron is lowered; Top right: spoilers raised during flight; Middle row: Fowler flaps extended (left), extended more (middle), hinged with inboard slotted part hinged even more (right); Bottom row: spoilers raised during landing
Air brakes on the rear fuselage of a Eurowings BAe 146-300
Mass balance protruding from an aileron used to suppress flutter
A rudder is a primary control surface used to steer a ship, boat, submarine, hovercraft, airship, or other vehicle that moves through a fluid medium. On an airplane, the rudder is used primarily to counter adverse yaw and p-factor and is not the primary control used to turn the airplane. A rudder operates by redirecting the fluid past the hull or fuselage, thus imparting a turning or yawing motion to the craft. In basic form, a rudder is a flat plane or sheet of material attached with hinges to the craft's stern, tail, or after end. Often rudders are shaped so as to minimize hydrodynamic or aerodynamic drag. On simple watercraft, a tiller—essentially, a stick or pole acting as a lever arm—may be attached to the top of the rudder to allow it to be turned by a helmsman. In larger vessels, cables, pushrods, or hydraulics may be used to link rudders to steering wheels. In typical aircraft, the rudder is operated by pedals via mechanical linkages or hydraulics.
Modern ship rudder (the long red rectangle behind the propeller)
RMS Olympic's rudder turned
Stern-mounted steering oar of an Egyptian riverboat depicted in the Tomb of Menna (c. 1422–1411 BC)
Steering oar of a Roman boat, 1st century AD (RG-Museum, Cologne)