User:Mr swordfish/Wing
From Wikipedia, the free encyclopedia
A wing is a surface that produces lift for flight through the atmosphereāor occasionally through another gaseous or fluid substance. An artificial wing is called an airfoil, which always have a distinctive cross-sectional shape.
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/e/e4/Seagull_wing.jpg/320px-Seagull_wing.jpg)
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/7/76/Wing.two.arp.600pix.jpg/640px-Wing.two.arp.600pix.jpg)
The word "wing" for many centuries (reportedly[by whom?]) referred mainly to the foremost limbs of birds, but in recent centuries the word's meaning has extended to include wings of insects, bats, pterosaurs, and aircraft.
"Wing" can also mean an inverted airfoil on a race car that generates a downward force to increase traction. Various species of penguins and their close relatives (such as auks) of flightless birds are avid swimmers, and use use their (rather small) wings to swim through seawater.
A wing's aerodynamic quality is expressed as its lift-to-drag ratio. The lift a wing generates at a given speed and angle of attack can be one to two orders of magnitude greater than the total drag on the wing. A high lift-to-drag ratio requires a significantly smaller thrust to propel the wings through the air at sufficient lift.