Acceleration / Loops Conservation

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My logic is this: The word CONTINUOUS means to me that we have acceleration which continues to a given point.

The word CONSTANT, as I see it, means acceleration which not only continues, but does so at an unchanged rate to that point.

Both are correct, but I think the reason physicist Noel Perkins used the latter is that it more accurately expresses his findings.

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Mark Surtees answers a couple of my questions from yesterday's messages ( I added quotation marks for clarity) My additional comments in his text in italics G. :

"Am I really just compressing a constantly accelerated move into a shorter interval of time ?"

I don?t think so, constant acceleration would be represented by a straight line on graphs like that, whilst the second graph for the overhead shows a bit of a bumpy start, creep maybe, then an almost straight line, the first, the roll cast, plainly doesn?t, both casts are shown over the same time period.

Looks that way to me, too. Those curves in the figures were made using a Casting Analyzeer by Caroline Gotti Bono who worked with Noel Perkins at the U. of Michigan. I suspect that Bruce Richards made the casts since he worked with them on this project.

I, too, would prefer to see a straight line progression for that roll cast to use the term "constant" for the acceleration of that phase. The "almost straight line" for part of the overhead cast could be interpreted, I suppose as "almost constant acceeration", but not strictly constant. As you said, below, we also have no knowledge of the loops which resulted. The apparent imperfections in the curves may have been representative of acceleration (and other factors) which yielded other than nice tight loops. G.

The point is, neither graph would tell me anything about the loop shape or size.

"Bruce Richards has shown that most casters he's studied are more likely to form a small loop when they use translation to delay rotation."

I suspect that normally In overheads, with the possible exception of very short casts, a caster will have to use translation and rotation simultaneously in order to get the right casting stroke length and a SLP, this would be perfectly possible and still achieve near constant acceleration over the period of the casting stroke. But, in the same overhead, if you were to use a period of translational acceleration at the beginning of the casting stroke, which I believe is what we do with roll casts, and rotate late then the acceleration would be non-constant over the period of the casting stroke.

Agree ! One of our problems is that we have not yet come to consensus over the definition of CASTING STROKE. One group took the position that pure translation prior to rotation wasn't in the stroke. Another took the opposite view.

If we take the position that pure translation ("drag") isn't in the casting stroke and just look at the acceleration curve during rotation, we might come close to evidence of constant acceleration.

Some things sneak in to muddy the water along the way. One of them is what you point out: Almost all casts made by almost all casters involve the use of an admixture of changing amounts of translation and rotation as the cast is made. Add to that the likelihood that no two casts are exactly the same despite our attempt to relate them by using an exact science.

We artificially try to break these down into their component parts in order to explain what is happening ....BUT THAT ISN'T WHAT HAPPENS IN THE REAL WORLD OF FLY CASTING ! G.

If Bruce has shown that both constant and non-constant acceleration can be applied to a cast of a fixed length and we get a small loop in both cases it would lead me to believe that there is no specific link between acceleration and loop size.

Mark Surtees

Outback Rigging Ltd

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From Bob Stouffer :

Gordy
I do teach "constant acceleration" to a beginner. The constant acceleration of a fully-loaded concrete mixer in a half-block drag race. Tim Rajeff says "constant acceleration from zero to two mph". When you need a term to describe something, why not use the term? I would rather use a term that holds-up over the caster's progress and that you can read out of a dictionary. I would also bow to those of you who would say "the less said, the better".

For long, tight-loop casting, we are trained to translate smoothly with the rod held horizontally or at a shallow angle, and, at the very end of the stroke, rotate the butt through the arc as rapidly as possible. The graph of this, I thought, would yield a separate graph of acceleration for the translation and for the rod tip. In a recent email exchange with Bruce Richards, I have come to understand that the rod tip acceleration graph would also be constant because of rod bending.

I think that the same holds true to the"Lefty" style of tight-loop making - the "stab" at the end of the stroke is equivalent to the rotation. Looks different when you watch the hand and arm, but the tip of the rod does not distinguish the stylistic difference.

Let's ask our friend Liam Duffy how to make a tight-loop roll cast and see what he says.

Bob Stouffer

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Liam Duffy uses straight Irish Logic to put all this in perspective :

Hi Gordy,
Still reading (and studying) the replies in the Masterclass.

While we , as intructors should know all this one important thing to remember is that 90% of our students just want to go fishin' with a reasonable chance of success, (back to my saying "the fish don't read the books!") and " a fly in the air never caught a fish!"

Best Regards,
Liam Duffy

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Liam.... You've nailed it !

Gordy

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CONSERVATION

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On our conservation messages, by David Lambert :

Gordy, hey:

Thanks for caring enough about all this to spend decades observing it.

You're an amazing guy.

I'm with Bob (Tabbert) on passing your bonefish and conservation

observations along. These should be highly useful to those who study the

species. . .and those who fish for them. I truly believe that anecdotal

evidence is as helpful, in some cases more helpful, than the some of the

'scientific' study. That these come from a learned man of science should

count more.

I'd like to pass it along myself.

David

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David.... I deserve no credit at all. My motivation was obvious: I was witnessing the destruction of an ecosystem I loved.

Over the years I had to keep my eyes open and repeatedly ask myself, WHY ?

It was once said that an automobile engine was a device which systematically eventually destroyed itself.

Man has gotten proficient at doing the same thing to our planet.

Gordy