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Walter & Group...
[GH] From Paul Arden :
Hi Gordy,
I think it should be pretty obvious that all of the line doesn't follow the rod tip, otherwise line would simply pile into the rod tip cast after cast, and there would be no such thing as curve casts or tailing loops etc etc. The bead chain is an excellent method of working out how casts function.
The physics of the snap cast are interesting, the primary reason it functions is the large removal of mass from the traveling fly leg, which causes the acceleration. If my memory serves me right only about 15% of energy in the opposite direction is transferred through the loop.
Hope you are well. Living in an icy fog at the moment. I may have to move to the Keys.
Cheers, Paul
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[GH] From Mark Surtees :
Hi Gordy
I agree with Walter and Aitor that the sequential bead, segment, element or particle is a very good way of examining fly line dynamics. As I recall we had a lively discussion based on this very principle arising from Ally's centre of mass proposition last year. In fact if we combine this element by element analysis with changes in mass distribution and line densities then we can get a pretty reasonable picture of what happens during a cast.
As the rod proceeds forward through the stroke, the line immediately following will imitate its path. In other words, line farther back in the “chain” of line segments will tend to imitate the path of the line segment immediately preceding it.
This for example is close but it is really only part of the story. In a line with a change in mass distribution some segments may have momentum greater than those that precede them. Yes each segment will influence the next in line, but changes in mass from one segment to the next will modify the effect that the preceding segment will have on the one following. This variation in momentum plus the possible effects of changes in line density and tension explains why a small deviation in rod tip path, can result in a wave with a long wavelength but a low amplitude morphing into a wave with a short wavelength and a high amplitude and that dreaded tail as the cast rolls out…no line following the rod tip here..
So, does the line always follow the rod tip ?.. plainly not, it’s way way more complicated than that.
Do I, or should we get in a flap if someone, for the sake of encouraging control over the tip path, uses this as a means of instruction….well, no, not really.
But, is it right that CI candidates or MCI candidates reproduce such a statement as an absolute truth in an examination as an explanation of line dynamics...??
IMO it most certainly is not, by the time we get to this sort of level we should have got to grips, metaphorically speaking, with the idea that Santa Claus doesn’t actually come down the chimney at Christmas. There is a deal of effective heuristic thinking that works very well out in the field that has become “the law” with respect to casting instruction despite it being demonstrably incorrect..and this is an example of one of them.
Is it a useful teaching tool ?, well it works for Lefty and many others so…Maybe
Is it true ? No....… and should CI and MCI candidates be using it in an exam ? Well… I would be very interested to hear the opinion of experienced examiners on this one. J..
Mark
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[GH] From Alan Kato :
Hi Gordy,
One thing bothers me in the video. The fly leg of the bead chain appears to be rolling like a bunch of wheels and axles.
This rolling appears to open up the loop. The chain therefore does not follow the tip path vector.
Is it really a good analogy to a fly line? If the beads are not rolling and instead are sliding on the tiles would it not be better?
Thanks,
Alan Kato
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[GH] Alan,
Frankly, I don't know if it would make a difference. Not a bad idea to rig both up and actually try it as a simple experiment ... Perhaps that has been done.
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[GH] Gary Davison weighs in :
Gordy,
Ally hit the nail on the head on this one.
My personal long and short renditions would be the following.
Long version:
The tip top provides the momentum (Speed and Stop).
The line characteristics (Mass out the rod tip, based on it's tapered design) will dictate how the line reacts to that momentum provided.
The line's reaction is directly affected by the variables under which it has been imposed (Trajectory & Rod Variations) being applied during the casting sequence.
The uncontrolled variables though unpredictable still have to be considered in the final outlay of the line.
Shorter version:
So to keep it simple the line always follows the rod tip, based on it's physical design and the conditions under which the cast is being made.
Shorter yet version:
To simplify it even more provided by Lefty: The fly line follows the path where the rod tip speeds up and stops.
I love all levels of teaching in this sport! The key to a good instructor is knowing what level to use when communicating to your student.
Successful results are the goal.
Gary
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