There are some other videos which should clarify the energy transfer along the fly rod shaft with other words: vimeo.com/187846392, vimeo.com/114247858
My work can be downloaded here:
http://www.passion-fliegenfischen.de/experimental-investigations-on-the-fly-rod-deflection/
Further essays are on Scribd and issuu:
http://de.scribd.com/user/137002632
http://issuu.com/hshl
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Eine deutsche Version dieses Videos gibt es hier: vimeo.com/150080113
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This video refers to my „Experimental investigations on the fly rod deflection" (rev. 2.0 published in November 2014) and should visualize, why the inertia and the angular momentum redistributes and why the center of the rotating mass could escape the grip of the fly rod as it is shown in figure XIII of section F1. Essays about this and other topics could be read and downloaded on issuu http://issuu.com/hshl/docs . By Tobias Hinzmann with friendly support of Dr. Franz-Josef Schmitt
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The ‘center of rotation’ is determined as the center of the gravity of all mass elements, which contribute to the angular momentum. For flexible systems this center could be different from the ‘rotation point’ which is determined as the center of the gravity of the whole system. -
In order to estimate the location of the center of rotation a closer look on the deflection and its variation during the fly cast is necessary. -
Since a significant translatory motion took already place, the fly rod is not situated in a defined condition when the caster starts to rotate. Starting from the early rotary motion of the forward cast it is visible, that the distance between the rotation point beneath the grip and the tip of the fly rod (shown by the red arrow) shortens. -
This shortening alone already modifies the inertia of the fly rod and attracts the rotating mass closer to the rotation point. Similar a figure skater, who runs a pirouette, this effect leads to an additional rotation speed. -
Around the vertical position of the grip a further effect develops. In order to visualize it, starting from this vertical position a circle is adapted to the apex of the momentary deflection of the fly rod. -
It is clearly visible that this circle moves up towards the tip of the fly rod while turning and getting smaller and smaller. This happens both the caster rotates the fly rod and over the path of retraction. So there are mass elements turning not only around the rotation point beneath the grip, but the more the longer the cast takes increasingly around a center of an upward moving circle. -
This turning and upward moving circle shifts towards the thinner parts of the fly rod, where mass elements have increasingly less weight, inertia respectively. This effect supports the development of a center, around which mass elements are turning. -
At the end of the cast the turning circle disappears and a little rest of the tip segment turns over creating the counterflex. -
Looking on all pictures of the forward cast it is visible, that during the early rotary motion the center of rotation should be the same as the rotation point, which is located somewhere beneath the grip. But then around the vertical position of the grip a center of rotation develops near the apex of the deflection of the fly rod. -
The rotation of mass elements around a circle with a decreasing radius leads to a further acceleration taking up kinetic energy, which was distributed along a larger part of the fly rod before. This decreasing radius could be also clarified by an additional shortening of the distance between the rotating mass and the center of rotation (shown by the red arrow). -
The turning and upward moving circle is another description for the movable behaviour of the center of rotation, which is the result of a redistribution of the angular momentum and the kinetic energy, starting to take place at about the vertical grip position (90 degree position). This is what figure XIII clarifies. -
