Fin
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2008-07-09T05:36:41Z
KnowledgeOfSelf
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Reverted edits by [[Special:Contributions/72.160.201.70|72.160.201.70]] ([[User talk:72.160.201.70|talk]]) to last version by ClueBot
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[[Image:Spliced feather 0002.jpg|thumb|200px|Arrow fletches are a type of fin.]]A '''fin''' is a surface used to produce [[lift (force)|lift]] and [[thrust]] or to steer while traveling in [[water]], air, or other [[fluid]] media. The first use of the word was for [[Fish anatomy#Fins|the limbs]] of [[fish]], but has been extended to include other animal limbs and man-made devices.
The foremost use of fins is to ensure the directional stability of an object moving through a fluid such as water or air and may be seen in the use of [[fletching]] on [[arrow (weapon)|arrow]]s and fins at the rear of some [[missile]]s, [[rocket]]s, self-propelled [[torpedo]]es, and [[KE-penetrator|kinetic energy penetrators]]. They are typically "planar" (shaped like small wings), although [[grid fin]]s are sometimes used in specialized cases.
Moving fins may be used to propel an object through lateral thrust (see [[mechanics]]).
Examples of fin use:
* [[Propeller]]s usually have a number of fins that work to translate torquing force to lateral thrust, thus propelling a [[ship]]. These are also called blades. In the case of high power application it is important to avoid [[cavitation]], caused by excessive negative pressure, as this can cause noise, a loss of power, and damage to the propeller.
* For [[Scuba diving|scuba]] divers' fins, see [[swimfin]].
* In [[surfing]], a [[skeg]] is a stabilizing fin located at the rear of the [[surfboard]]. A skeg has the effect of keeping the board moving forward in a controlled manner. The [[surfboard fin]] has undergone numerous phases of development.
* Constructions of the same purpose as fins (producing thrust, but working in gaseous media) instead are usually called [[wing]]s or [[Stabilizer (aircraft)|stabilizer]]s with [[aerodynamics]] as the governing science. The exception to this is the vertical surface of an aircraft to which the [[rudder]] is attached - this is still usually called a fin but is (more formally) called a [[vertical stabilizer]].
* the fin of a rocket uses pressure on both sides of the fin to create a more stable flight in a rocket
[[Category:Animal anatomy]]
[[Category:Nautical terms]]
[[Category:Aircraft components]]
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