Split: date=September 2008

A wing's aerodynamic quality is expressed as a Lift-to-drag ratio. The lift generated by a wing at a given speed and angle of attack can be 1-2 orders of magnitude greater than the drag. This means that a significantly smaller thrust force can be applied to propel the wing through the air in order to obtain a specified lift.

Design features

Aircraft wings may feature some of the following:

• A rounded leading edge cross-section
• A sharp trailing edge cross-section
• Leading-edge devices such as slats, slots, or extensions
• Trailing-edge devices such as flaps or flaperons (combination of flaps and ailerons)
• Ailerons (usually near the wingtips) to provide roll control
• Spoilers on the upper surface to disrupt lift and additional roll control
• Vortex generators to help prevent flow separation in transonic flow
• Wing fences to keep flow attached to the wing by stopping boundary layer separation from spreading
• Winglets to keep wingtip vortices from increasing drag and decreasing lift
• Dihedral, or a positive wing angle to the horizontal. This gives inherent stability in roll. Anhedral, or a negative wing angle to the horizontal, has a destabilising effect
• Folding wings allow more aircraft to be carried in the confined space of the hangar of an aircraft carrier.
• Variable-sweep wing or 'swing wing' to allow outstretched wings for slow speed (i.e. take-off and landing) and swept back wings for high speed (usually supersonic) flight, such as the FB-111 and the F-14.

Science of wings

The science of wings is one of the principal applications of the science of aerodynamics. In order for a wing to produce lift it has to be at a positive angle to the airflow. In that case a low pressure region is generated on the upper surface of the wing which draws the air above the wing downwards towards what would otherwise be a void after the wing had passed. On the underside of the wing a high pressure region forms accelerating the air there downwards out of the path of the oncoming wing. The pressure difference between these two regions produces an upwards force on the wing, called lift.

The pressure differences, the acceleration of the air and the lift on the wing are intrinsically one mechanism. It is therefore possible to derive the value of one by calculating another. For example lift can be calculated by reference to the pressure differences or by calculating the energy used to accelerate the air. Both approaches will result in the same answer if done correctly. Debates over which mathematical approach is the more convenient can be wrongly perceived as differences of opinion about the principles of flight and often create unnecessary confusion in the mind of the layman.