There are some other videos which should clarify the energy transfer along the fly rod shaft with other words: vimeo.com/226547073, vimeo.com/148550108, vimeo.com/114247858
-
The fly rod represents a rotating body / object which is flexible, non rigid respectively. This flexible behaviour could benefit the energy transfer as described in my work:
passion-fliegenfischen.de/experimental-investigations-on-the-fly-rod-deflection/
-
An essay especially about the impact of the angular momentum could be found here:
passion-fliegenfischen.de/_en/fly-casting/impact-of-angular-momentum/
-
Further essays are on Scribd: de.scribd.com/user/137002632
--- ---
This video refers to the “Experimental investigations on the fly rod deflection (rev. 2.0 -11/2014)” and should visualize how the angular momentum contributes to the fly cast.
-
The manner the angular momentum contributes to a non flexible and a flexible object could be significantly different. By having a closer look on the rotary motion of a fly rod, this video is going to work out some reasons for that. In the following the contribution of angular momentum is demonstrated on a backcast comparing the early and the late rotary motion (1st and 2nd phase). Let’s have a look on the initial situation of the fly cast first:
-
Dot 1 represents thicker mass elements being closer to the grip while dot 2 represents thinner mass elements being closer to the tip of the fly rod.
-
Now the caster starts with the rotary motion of the fly cast. Let’s see what happens during the 1st phase:
-
It is clearly visible, that during the 1st phase of the fly cast lower mass elements being closer to the grip (path of dot 1) are covering a larger angle than upper mass elements being closer to the tip do (path of dot 2). Hence the lower mass elements have a higher angular velocity than the upper ones. To clarify this on the following picture the angles are added.
-
Now the caster continues with the rotary motion. Let’s see what happens during the 2nd phase too:
-
During the 2nd phase it is the other way round. Now upper mass elements (path of dot 2) are covering a larger angle than lower mass elements do (path of dot 1). Hence the upper mass elements have a higher angular velocity than the lower ones. To clarify this on the following picture the angles are added.
-
In contrast to a flexible fly rod for a non flexible one the angles φ and therefore the angular velocities ω of the mass elements are not varying to each other but are identical over the duration of the fly cast. It follows φ1=φ2 and ω1=ω2. Let's see how a non flexible fly rod would behave (the non flexible axis is shown by the continuous red line)
-
Let's have a look on what we found out so far. 1st phase: for a flexible fly rod ω1 faster than ω2; for a non flexible fly rod ω1=ω2. 2nd phase: for a flexible fly rod ω1 slower than ω2; for a non flexible fly rod ω1=ω2
-
The formula L = I * ω shows how the angular momentum (L) depends on the moment of inertia (I) and the angular velocity (ω). In annex 2 of the “Experimental investigations on the fly rod deflection (rev. 2.0 - 1/2014)” the impact of the moment of inertia is worked out. The deflection modifies the moment of inertia, whereby the mass elements on the fly rod gain the different angular velocities as described before. The modification of the moment of inertia and the contribution of angular momentum are going hand in hand.
-
Let’s go back to the fly cast. In comparison to a non flexible fly rod having the same mass distribution during the 1st phase of the fly cast the thicker lower mass elements of the fly rod contribute more to the angular velocity and therefore to the angular momentum than the thinner upper ones. Than between the 1st and 2nd phase of the fly cast the contribution of angular velocity, angular momentum respectively shifts increasingly towards the upper mass elements (simply shown by the varying angles φ1,φ2).
-
The upward moving contribution of angular momentum takes up some kinetic energy increasing the velocity of the tip of the fly rod. This transmission of kinetic energy could also be clarified by a dot, which shifts towards the upper mass elements.
-
The varying contribution of angular momentum is another description for the shift of the center of the rotating mass, which is shown on figure XIII.
