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American Journal of Physics

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Fly casting -- Mathematical models, Fly casting -- Analysis


In order to propel a fishing fly through the air toward the distant quarry, a rather massive line, to which the fly is attached, is cast. As the cast line rolls out, the fly actually accelerates horizontally and seems to defy physical law. The phenomenon is modeled simplistically to determine the magnitude of this effect. In the absence of air drag, the fly can accelerate to increase its velocity by an order of magnitude. Air friction dramatically decreases the effect, but some fly accelerationis still predicted. By tapering the flyline in various ways, the fly velocity history can be significantly modified, and some tapers are predicted to perform better than others.


Copyright 1986 American Association of Physics Teachers. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Association of Physics Teachers. The following article appeared in American Journal of Physics. September 1986, Vol. 54 Issue 9, p832-836 and may be found at:



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