Aileron in the context of "Fly-by-wire"

Steering is the control of the direction of motion or the components that enable its control. Steering is achieved through various arrangements, among them ailerons for airplanes, rudders for boats, cylic tilting of rotors for helicopters, and many more.

A centre stick (spelled center stick in American English), or simply control stick, is an aircraft cockpit arrangement where the control column (or joystick) is located in the center of the cockpit either between the pilot's legs or between the pilots' positions. Since the throttle controls are typically located to the left of the pilot, the right hand is used for the stick, although left-hand or both-hands operation is possible if required.

The centre stick is a part of an aircraft's flight control system and is typically linked to its ailerons and elevators, or alternatively to its elevons, by control rods or control cables on basic aircraft. On heavier, faster, more advanced aircraft the centre stick may also control power-assist modules. Modern aircraft centre sticks are also usually equipped with a number of electrical control switches within easy finger reach, in order to reduce the pilot's workload.

A vortex generator (VG) is an aerodynamic device, consisting of a small vane usually attached to a lifting surface (or airfoil, such as an aircraft wing) or a rotor blade of a wind turbine. VGs may also be attached to some part of an aerodynamic vehicle such as an aircraft fuselage or a car. When the airfoil or the body is in motion relative to the air, the VG creates a vortex, which, by removing some part of the slow-moving boundary layer in contact with the airfoil surface, delays local flow separation and aerodynamic stalling, thereby improving the effectiveness of wings and control surfaces, such as flaps, elevators, ailerons, and rudders.

A flap is a high-lift device used to reduce the stalling speed of an aircraft wing at a given weight. Flaps are usually mounted on the wing trailing edges of a fixed-wing aircraft. Flaps are used to reduce the take-off distance and the landing distance. Flaps also cause an increase in drag so they are retracted when not needed.

The flaps installed on most aircraft are partial-span flaps; spanwise from near the wing root to the inboard end of the ailerons. When partial-span flaps are extended they alter the spanwise lift distribution on the wing by causing the inboard half of the wing to supply an increased proportion of the lift, and the outboard half to supply a reduced proportion of the lift. Reducing the proportion of the lift supplied by the outboard half of the wing is accompanied by a reduction in the angle of attack on the outboard half. This is beneficial because it increases the margin above the stall of the outboard half, maintaining aileron effectiveness and reducing the likelihood of asymmetric stall, and spinning. The ideal lift distribution across a wing is elliptical, and extending partial-span flaps causes a significant departure from the elliptical. This increases lift-induced drag which can be beneficial during approach and landing because it allows the aircraft to descend at a steeper angle.

An aircraft in flight is free to rotate in three dimensions: yaw, nose left or right about an axis running up and down; pitch, nose up or down about an axis running from wing to wing; and roll, rotation about an axis running from nose to tail. The axes are alternatively designated as vertical, lateral (or transverse), and longitudinal respectively. These axes move with the vehicle and rotate relative to the Earth along with the craft. These definitions were analogously applied to spacecraft when the first crewed spacecraft were designed in the late 1950s.

These rotations are produced by torques (or moments) about the principal axes. On an aircraft, these are intentionally produced by means of moving control surfaces, which vary the distribution of the net aerodynamic force about the vehicle's center of gravity. Elevators (moving flaps on the horizontal tail) produce pitch, a rudder on the vertical tail produces yaw, and ailerons (flaps on the wings that move in opposing directions) produce roll. On a spacecraft, the movements are usually produced by a reaction control system consisting of small rocket thrusters used to apply asymmetrical thrust on the vehicle.

Flight control surfaces are aerodynamic devices allowing a pilot to adjust and control the aircraft's flight attitude. The primary function of these is to control the aircraft's movement along the three axes of rotation. Flight control surfaces are generally operated by dedicated aircraft flight control systems.

Development of an effective set of flight control surfaces was a critical advance in the history of development of aircraft. Early efforts at fixed-wing aircraft design succeeded in generating sufficient lift to get the aircraft off the ground, however with limited control. The development of effective flight controls allowed stable flight.