草稿:风筝
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风筝是一种比空气重(英语:heavier-than-air)或比空气轻(英语:lighter-than-air)的系绳飞行器,其表面与空气发生反应,以产生升力和阻力。风筝由翼、线(英语:tether)和锚组成,通常使用缰绳和尾巴来引导风筝表面,让风可以将风筝举起。[1] Some kite designs do not need a bridle; box kite(英语:box kite)s can have a single attachment point. A kite may have fixed or moving anchors that can balance the kite. The name is derived from the kite, the hovering bird of prey.[2]
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.[3] 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.[4] 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[5][6] or vehicle).[7][8]
The same principles of fluid flow apply in liquids, so kites can be used in underwater currents.[9][10] Paravanes(英语:Paravane (water kite)) and otter boards(英语:Bottom trawling) operate underwater on an analogous principle.
Man-lifting kite(英语:Man-lifting kite)s 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(英语:List of kite festivals) worldwide. Kites may be flown for recreation, art or other practical uses. Sport kites(英语:Sport kites) can be flown in aerial ballet, sometimes as part of a competition. Power kite(英语:Power kite)s are multi-line steerable kites designed to generate large forces which can be used to power activities such as kite surfing, kite landboarding(英语:kite landboarding), kite buggying(英语:kite buggying) and snow kiting(英语:snow kiting).