A kite is a tethered heavier-than-air craft with wing surfaces that react against the air to create lift and drag. A kite consists of wings, tethers and anchors. Kites often have a bridle to guide the face of the kite at the correct angle so the wind can lift it.[2] Some kite designs don’t need a bridle; box kites can have a single attachment point. A kite may have fixed or moving anchors. One technical definition is that a kite is “a collection of tether-coupled wing sets“.[3]
The lift that sustains the kite in flight is generated when air moves around the kite's surface, producing low pressure above and high pressure below the wings.[4] The interaction with the wind also generates horizontal drag along the direction of the wind. The resultant force vector from the lift and drag force components is opposed by the tension of one or more of the lines or tethers to which the kite is attached.[5] The anchor point of the kite line may be static or moving (e.g., the towing of a kite by a running person, boat, free-falling anchors as in paragliders and fugitive parakites[6][7] or vehicle).[8][9]
The same principles of fluid flow apply in liquids, so kites can be used in underwater currents, but there are no everyday uses as yet.[10][11]
Man-lifting kites were made for reconnaissance, entertainment and during development of the first practical aircraft, the biplane.
Kites have a long and varied history and many different types are flown individually and at festivals worldwide. Kites may be flown for recreation, art or other practical uses. Sport kites can be flown in aerial ballet, sometimes as part of a competition. Power kites are multi-line steerable kites designed to generate large forces which can be used to power activities such as kite surfing, kite landboarding, kite fishing, kite buggying and snow kiting.