Welcome Dr William McGlinn

[Paul Arden]

Hi guys,

following some recent discussions on the Board here http://www.sexyloops.co.uk/theboard/vie ... =11&t=2056 regarding Physics of Fly Fishing: Fly Casting Mechanics and Fly Fishing Optics to be found here https://www.amazon.de/dp/B01AOMP9JU/ref ... 31_TE_M1DP, Gordy suggested I invite Dr McGlinn to the Board for some technical discussions, which he has kindly agree to!

So William, you will find here some very technical people, and some not so technical people (such as myself!). I look forward to your discussions here.

Many thanks!
Paul

[Merlin]

Hello Dr McGlinn, it is really nice to have you on the board, welcome.

Since some of us have read your book and will likely ask specific question about it (I pointed some tiny bugs/typos, but I think it is better to send a short mail to you instead of raising an issue for a detail here on the forum, if you find that acceptable), did you find the time to look at the technical forum threads and the various publications that members posted? If so what is you perception?

Second question: would you be interested in helping us to understand some unresolved issue like loop morphing (dolphin nose)?

Many thanks in advance for your answers.

Merlin

[gordonjudd]

Dr. McGlinn,
Welcome to the board, and congratulations on writing a book dealing with the dynamics of fly casting that has some in-depth technical analysis on this complicated subject.

I appreciate your willingness to join in our technical discussions and look forward to learning more about your approach to quantifying what goes on in casting. I think that you will find there is a wealth of measured data on different aspects of casting on the technical forum that will be of interest to you.

I hope that you will have the time to look over some of the long standing questions that have eluded us over the years (loop morph is a prime example), and will find it worthwhile to working on the myriad technical questions that will come up about casting in the future.

I look forward to learning more about the physics of casting from you, and hope that our friendly back and forth on the technical forum will be mutually beneficial.

Gordy

[VGB]

Hi Dr McGlinn

Welcome to the board and thank you for coming along. Unfortunately, I'm traveling, so lacking a keyboard but I have 2 queries:


Please can you expand on the part just before equation 8.5, where you talk about haul timing and the relative movement of the rod tip to the line leading to the haul ideally being about half the unloaded frequency. I can't picture the sequence, I think you are saying that rod tip is uncoupled from the line early in the stroke?

Secondly, have you any idea why the sloped and thrust do not work together as described at the end of Chapter 7?

Regards

Vince

[Bernd Ziesche]

Hi Dr McGlinn,
great to have you here for a week! Thanks for joining us!

What do you think how much percentage of the fly cast in detail do we (you) understand today?

Regards
Bernd

[grunde]

Cool!

Welcome to the circus :-)

I've bought the book and look forward to dive into it.

Cheers,
Grunde

[Eagle Crest]

Hi Dr. McGlinn,
I was trying to buy your book, and all I can find is the ‘Kindle’ digital format. Is there a hard copy version? I would prefer something I can scribble notes on, underline whatever, and hold in my hands.

Following up on a topic that Gordon mentioned, was the loop morph topic in the ‘Dolphin Nose’ thread. I happened to begin to read this technical thread about the time I was involved with Global Fiber Optic Sensing System group, and it struck me that the loop behaved like a soliton. Particularly the way a sufficiently large impulse that forms a soliton can split (evolve) into two or more solitons. As I was trying to understand wave equations and find the non-linearity part and the dispersion part of a cast/loop, and see if it fit into either the KdV equation or perhaps the non-linear Schrodinger or even a sine-Gordon model, I realized that the fly leg and the loop were moving mass and perhaps a transport equation was more rigorous. I used a simplification that a loop was a cycloid (half of a cycloid) and using the parametric equations, I found that the motion (momentum and energy) in the x-direction patterned a sigmoidal plot profile like the sine-Gordon and the energy profile in the y-direction is similar to the sech pulse envelop of the KdV or NLS.
Do you have an opinion on whether a loop is a wave, or a transport, or is it possibly, a dual nature phenomenon?

Thanks,

Steve

[William McGinn]

Steve,

Until yesterday I didn't know about the `Dolphin Nose'. I used to know about Solitons Sine-Gordon and KDV but that is in the somewhat distant past. But I don't see any particular topologiical character to the `Dolphin Nose Effect. My uneducated guess it is related (or is) the two dimensional flapping flag instability.

Bill Mcglinn

[Eagle Crest]

Okay, the flapping flag instability is a new concept. Does that mean it's a wave or a transport, or dual nature? Have you heard of the bead chain fountain? https://www.youtube.com/watch?v=DDSRsMGbNV8 This dolphin-nose phenomenon seems to be quite common if once you recognize it and are looking for it. Such as belt driven equipment, chain drives (chain saws, bicycle chains,...) and so forth.

Then, about your book - is it in hard copy?

And finally for this post, when I did the cycloid (i.e., the loop) parametric equations as a function of angular velocity, took the first derivative in time to get the velocity, then used a finite point mass of the fly line, I get a plot of energy in the x and y directions. By using the Hamiltonian mechanics, I see that the kinetic energy of the point mass as it translates from the fly leg through the loop to the rod leg changes into potential energy. By Hooke's Law, that ought to become the tension in the rod leg (and the motive by which we 'shoot' line). Gordy has shown that if the rod leg is stationary, the loop and the fly leg accelerate. This must mean that the tension is being transferred back through the loop to the fly leg. Do you concur?

I realize I need to get your book, as you may have addressed this in some fashion, but we only get this 'week' with you and I want to ask while you are available.

Thanks, again,

Steve

[William McGinn]

Steve,

I did know about the bed chain fountain and had read a bit about it a couple of years ago, but don't remember what I understood. (This is a continuing problem with me)

The kinetic energy of a element of the fly line as it passes from the fly leg to rod leg doesn't change into potential energy but rather into the kinetic energy of fly leg thus (hopefully) increasing the velocity of the fly leg.

There is no hard copy edition. I couldn't find a publisher that wanted to take a chance. I have pdf and htllm copies and would have been willing to send copies to anyone but I didn't know how to make contact with a audience. I had a hard time getting in `KIndle' form - and it is not satisfactory, doesn't handle equations very well at all.

Bill