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Q: Why does a cast “collapse” if the casting stroke is started before the previous loop has straightened?

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flyfisher666
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Q: Why does a cast “collapse” if the casting stroke is started before the previous loop has straightened?

#1

Post by flyfisher666 » Mon Aug 17, 2020 7:21 pm

A: A part of the force in the casting stroke that should have been used to generate linespeed was instead used to stop/reverse the line. Remaining force was not enough to generate sufficient linespeed for the intended cast.

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gordonjudd
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Re: Q: Why does a cast “collapse” if the casting stroke is started before the previous loop has straightened?

#2

Post by gordonjudd » Tue Aug 18, 2020 3:25 pm

A part of the force in the casting stroke that should have been used to generate linespeed was instead used to stop/reverse the line.
Joakim,
Can you post a video that shows what you are experiencing?

The simple finger/spring/marble model predicts a faster marble release speed when the initial condition of the marble has some negative velocity.

Plug distance casters also swing the plug in the opposite direction at the start of their to get longer casting distances as discussed on the old board. This was discussed on the old board but I don't know if this http://www.sexyloops.co.uk/archivedboar ... 24&t=12461 will connect to that topic so you can see some examples.

Gordy

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Lasse Karlsson
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Re: Q: Why does a cast “collapse” if the casting stroke is started before the previous loop has straightened?

#3

Post by Lasse Karlsson » Tue Aug 18, 2020 4:48 pm

Gordy, plug distance casters know that if their plug isn't directly behind the rodtip when they make their forward cast, the distance suffers, and the cast could be considered collapsed. Thats what Joakin is refering to, and it holds true.

Put the line straight behind you and make a cast that just straightens. Then put the line behind you, but make 3 meters of slack in it and make the same cast again, and watch the cast collapse.

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Lasse
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Merlin
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Re: Q: Why does a cast “collapse” if the casting stroke is started before the previous loop has straightened?

#4

Post by Merlin » Tue Aug 18, 2020 6:33 pm

What I understand is that the energy you spend to « pull back » the backward cast by an early restart is lost for the next forward one.
I am correct Joakim?

Merlin
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flyfisher666
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Re: Q: Why does a cast “collapse” if the casting stroke is started before the previous loop has straightened?

#5

Post by flyfisher666 » Wed Aug 19, 2020 11:16 am

First of all - this isn't a problem in my casting. It is instead a branch off from this thread: viewtopic.php?f=11&t=3323#p54992

I don't think my answer is the complete or best, but I do think it is a good starting point in to a discussion about it.
I already see one simplification I can do to it.
A: A part of the casting stroke that should have been used to generate linespeed was instead used to stop/reverse the line. Remaining strokelength was not enough to generate sufficient linespeed for the intended cast.

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flyfisher666
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Re: Q: Why does a cast “collapse” if the casting stroke is started before the previous loop has straightened?

#6

Post by flyfisher666 » Wed Aug 19, 2020 11:18 am

Merlin wrote:
Tue Aug 18, 2020 6:33 pm
What I understand is that the energy you spend to « pull back » the backward cast by an early restart is lost for the next forward one.
I am correct Joakim?

Merlin
I think so yes.

//Joakim

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Paul Arden
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Re: Q: Why does a cast “collapse” if the casting stroke is started before the previous loop has straightened?

#7

Post by Paul Arden » Wed Aug 19, 2020 5:09 pm

Hi Gordy,

at the extreme situation you have a whip-crack which is mostly followed by loop failure on the cast. I have never seen a whip crack followed by an outstanding cast. But even trying to hit “loop straight” (or the boing) leads to similar failure by me.

“Inertia” I thought should be part of this explanation.

I can certainly make a video of this by the way! I’ve trained myself to arrive on the field like a ball of fireworks. :D

Cheers, Paul
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gordonjudd
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Re: Q: Why does a cast “collapse” if the casting stroke is started before the previous loop has straightened?

#8

Post by gordonjudd » Wed Aug 19, 2020 6:14 pm

Gordy, plug distance casters know that if their plug isn't directly behind the rodtip when they make their forward cast, the distance suffers, and the cast could be considered collapsed.
Lasse,
I think we must be talking about different things.

Here is an example of what I am talking about where a plug distance casters swings the plug in the opposite direction to give it some negative velocity at the point they start making their forward cast.

https://vimeo.com/449374881

Merlin's finger/spring/marble model says that "kinetic capture" of the plug's initial K.E. will result in a higher launch speed of the marble.

Gordy

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Re: Q: Why does a cast “collapse” if the casting stroke is started before the previous loop has straightened?

#9

Post by Paul Arden » Wed Aug 19, 2020 6:54 pm

Hi Gordy,

I’ve thrown 6oz leads off piers when I was in my late teens. Never a full pendulum - it was actually banned for safety reasons! - but a layback. I fully understand the concept! But when I apply to fly casting the loop fails.

That’s easy to test. Why is an interesting question. I assume it’s because the line is the weight and along its length each part is subject to inertial problems.

Cheers, Paul
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gordonjudd
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Re: Q: Why does a cast “collapse” if the casting stroke is started before the previous loop has straightened?

#10

Post by gordonjudd » Thu Aug 20, 2020 1:42 am

That’s easy to test.
Paul,
That would be great to get some video examples.

I have cracked off many a fly in my time by starting the forward cast too early, but did not notice that it had the effect of collapsing the loop on the forward cast.
Gordy

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