Loop Dynamics

[Walter]

Mark,

You are a patient man to get this far.

How have the discussions on this forum changed anything? So far, in my opinion, they haven't for quite some time, and that’s the point. It’s a lot of misdirected brain power. If people like solving physics problems I’m happy for them but is there any value for the rest of us?

How could they potentially change casting styles specifically? They could lead to a better understanding of loop shapes and sizes, launch angles, contribution of translation, increasing line speed, and a host of other things. That sort of stuff would have value in my opinion.

I realize we are all different but things like flying fly lines are a particular pet peeve of mine. That concept affects everybody’s cast. We have an entire organization professing its validity and encouraging people to cast with wedge shaped loops to take advantage of that so called scientific principle. Wedge shaped loops may have an advantage but lift certainly isn’t one of them.

[Merlin]

Vince

I found Spolek's paper "The mechanics of flycasting, the flyline" (1986) and the loop is on board as well. Spolek used work energy equations to built his model so I do not understand your comment about both Lingard and Spolek.

Not a big issue anyway.

Merlin

[VGB]

Daniel

I lifted the review from "Comparison of numerical and analytical solutions for fly casting dynamics" - September 2003 Sports Engineering 6(3):165-175

Solutions for the fly velocity as a function of the fly displacement are available for level lines; see Lingard (1988), Robson (1990), and Spolek (1986). These solutions however omit terms in either the computation of the kinetic energy or the work done by drag. Spolek (1986) and Lingard (1988) omit the kinetic energy of the loop but they do account for the work done by drag. They both arrive at their final solution by numerical analysis. Robson (1990) omits the work done by drag on the fly and the traveling line but does include the kinetic energy of the loop.

Vince

[Stoatstail50]

We have an entire organization professing its validity and encouraging people to cast with wedge shaped loops to take advantage of that so called scientific principle.

I still have a picture of the B&N Loop and Fly Leg Lift model drawn on a napkin from 2010...it has "Bernoulli" written on it which proves that everything on it is all completely accurate.

[Walter]

For many of us their value is in how they potentially lead to a better understanding in order to improve casting styles and equipment design.

Deeply puzzled….in what way have these models improved casting styles Walter ?

Edit. Even potentially ?

Mark,

My earlier answer may have missed the tone of your question.

I think we are both aware of cases where modelling or “science” has impacted style. The hard stop is one. Translation vs rotation, my personal pet peeve, the straightish path of the rod tip and the list goes on.

What we’ve failed to do is to put things in perspective. We also tend to look at things in isolation and make broad generalizations. The straight line path of the rod tip, for example. A vector view of force tells us the best transfer of energy is to direct the line in line with the target but it’s ignoring drag and gravity. Debates around the 170 style vs the hard stop is an example of a different type. We never place bounds on rod and line weights in that discussion. I don’t know about you but for me trying the 170 with a 13 wt would be a good way to encourage shoulder injury. Beyond that, biomechanics are rarely ever discussed.

I think we can, and should, do better.

[Walter]

We have an entire organization professing its validity and encouraging people to cast with wedge shaped loops to take advantage of that so called scientific principle.

I still have a picture of the B&N Loop and Fly Leg Lift model drawn on a napkin from 2010...it has "Bernoulli" written on it which proves that everything on it is all completely accurate.

One can’t argue with science.

It’s not generally well known but Daniel Bernoulli had a somewhat strange brother who was also deeply into the physical sciences.

[Stoatstail50]

I think we are both aware of cases where modelling or “science” has impacted style. The hard stop is one. Translation vs rotation, my personal pet peeve, the straightish path of the rod tip and the list goes on.

I think that, almost without exception, none of the things you suggest have significantly impacted style either in instructorland or the wider angling community. There may be a few dedicated loopers who have bought in to the arguments but that’s it. Rot v trans, your peeve, all of these things are still totally mainstream ideas untroubled by models or debates on here…and they’re the good ones.

What we’ve failed to do is to put things in perspective

Totally….I’m sure it’s academically fascinating and I try to follow the threads as far as I am able but some discussions on these threads are promoting concepts, coam being one of them, which imply some collossal breakthrough of casting understanding totally out of proportion to the minuscule and ephemeral effect on line behaviour that such a principle may have if applied in highly constrained theoretical conditions.

It’s obvious that CoM, CoE, CoAM, are basic principles that are not going to be disturbed by discussion on sexyloops or anywhere else, but, in a cycle where my rod line system starts with no E, P or AM and ends with none too, it is hard for a layperson to accept that anything is being conserved which is relevant to performance.

[Walter]

Mark,

If that’s the case then why do you take the time to read any of it?

Walter

[Stoatstail50]

If that’s the case then why do you take the time to read any of it?

Very good question...

I like reading SL...or it's in case I might have missed something important...FOMO...not wanting to look stupid or behind the wave if there's an analytical breakthrough...curiosity at the obsessive level of granularity some people will go to in cast analysis...I quite like graphs...wondering what a fly line that goes 200mps looks like...does it get hot...the difference between semi-circles and cycloids...have I got the chips to argue about this in a pub...how long it would I argue about it in a pub...whether I may have had a different career if I'd spent more time studying maths...how many frustrated sighs and puffs and tuts does it cause vs other posts on social media...whether I can make any of it relevant for teaching purposes...whether I can make any of it relevant for fishing purposes.

When I've stoppped thinking about all that I move on to the next thread and repeat the process.

[Walter]

Mark,

So basically just idle curiosity or looking for pub appropriate discussion material? No particular area you are interested in other than the temperature of 200mps flyline?