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Pull-back

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Bernd Ziesche
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Pull-back

#1

Post by Bernd Ziesche » Sat Dec 31, 2016 4:11 pm

Geenomad wrote:To go back to my question "Why else use pull back?", if it isn't to increase tension then I am at a loss as I can't see how it might damp counter flex to keep the loop narrow. I could be wrong but I imagine it having the opposite effect on CF.
James9118 wrote: What I think happens in pull back is that it sets the loop up with more angular momentum. Rather than the line overtaking the tip as a result of the imparted velocity and forming a loop in a normal way, with pull back the loop formation is more 'aggressive for want of a better word, and as such has more angular momentum (although the linear momentum may be exactly the same).
Hi everyone.
First of all what is pull-back?
Pull-back to me is about pulling the fly line (rod-leg) almost opposite directed to the casting direction. In my understanding it (the particular tip movement) happens mainly post the start of loop formation.

James could you explain "angular momentum" here further for me, pls.?

What I am sure about:
- Pull-back significantly speeds up the unrolling of my bc.
- Depending on how strong of a pull-back I add the unrolled line has huge (clearly increased) tension.
- The unrolled line can (if I add large pb) pull very strong on my rod tip! Always feels amazing to me.
- It helps to tighten the loop.

The "trick" for me is to add huge pull-back but be ready with it before the rod-leg has too much mass. That way the much heavier (I think increased) momentum of the fly-leg can easily overtake the relatively small momentum (little mass) of the (still) short rod-leg.
If I am too late in finishing the pb it no longer works. I remember it took me a long time to get that technique really working. I have shown it to many instructors and most could not just adapt that technique either.So it seems very critical in adjusting the perfect timing.

My question is: Does pull-back speed up the (whole) fly-leg relative to the ground/target? I think yes.
But I yet haven't got an explanation matching physics here.

Free to discuss. :p
Thanks,
Bernd
http://www.first-cast.de
The first cast is always the best cast.

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James9118
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#2

Post by James9118 » Sat Dec 31, 2016 5:37 pm

I think firstly we have to agree on the definition of 'pull back' - to me this happens before RSP1, anything after that is in to 'snap' territory. If this doesn't fit with everyone else then I'm happy to be corrected.

Today a FB friend posted this video of his excellent cast - this is perfect for demonstrating pull back on the back cast:

https://www.facebook.com/ken2.ikeda/vid ... 584733036/

I hope that link works.

Bernd; Angular momentum is a measure of the mass of line travelling around a given radius over a certain timeframe. Angular momentum is very important to loop stability and propagation.

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gordonjudd
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Pull-back

#3

Post by gordonjudd » Sat Dec 31, 2016 5:42 pm

First of all what is pull-back?
Bernd,
Good question, as I think the timing of the pull back is different for different casters.

As you know we have discussed pull-back on many threads in the past. This post illustrated what you mean by pull-back where the tip of the rod is pulled forward after the loop in the backcast started rolling out. For some that decrease of the available forward rotation angle would be considered to be creep.
Image

For Paul the pull back happens before RSP1 and thus tends to increase the deceleration rate of his stop.

Can you show how the loop diameter is reduced via pull back? I would like to see how much change there is in the y direction of the tip path during counterflex in the two cases to make sure the rod angle at MCF was the same with and without pull back.

I hope we can focus on some high speed video examples this time around as previous hand waving discussions without some video examples have not been very productive.

Gordy

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James9118
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#4

Post by James9118 » Sat Dec 31, 2016 5:58 pm

Gordy - just to clarify; in your picture the movement from RSP2 to the pausing position is not pull back - that is largely irrelevant. Take a look at the drift put in by the caster in the video I posted.

Cheers, James

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guest
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#5

Post by guest » Sat Dec 31, 2016 8:23 pm

James

Is this the definition of pullback that you wanted to highlight:

http://www.sexyloops.co.uk/theboard/vie ... 906#p23906

Please can you outline the benefits?

Happy New Year casting geeks

Regards

Vince
Bright but shite

IANACI - There’s no such thing as absolutes

Free the Mark One ☝️

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Bernd Ziesche
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#6

Post by Bernd Ziesche » Sat Dec 31, 2016 8:42 pm

Hi James,
thanks for the fine explanation of angular momentum. Got it!

The video of Kenji - I think - shows exactly what I did in the picture series Gordy posted. It's just that I did it stronger (more pronounced). To me it looks similar. But to be sure I would need a frame by frame grab from Kenji's video.

You may check/compare this video (where the pictures came from):
https://vimeo.com/13699068

Now I have thought about the effect of it all evening long (while being out for dinner with my gf). :p

When I compare a "normal" cast of mine (pausing the rod in RSP1 position until starting the next cast with the unrolled line) with such a cast like in that video:

In the normal cast my rod-leg (during unrolling of the bc) increases in mass and the rod-leg can't move because the tip avoids it from moving. Near the end there is a huge "static" rod-leg and a small mass fly-leg. So I feel just little tension. No further pulling on my tip.
If instead I pull-back the tip and then follow thru - it's the follow thru allowing my (first huge momentumed) fly-leg to accelerate the (first small massed) rod-leg! The fly-leg overtakes the rod-leg and the rod-leg moves in the direction of the cast. This way the unrolled line strongly pulls on my tip and makes for a perfect tension. It's exactly this what cuts out the sack in my unrolled line.
Some casters achieve "same" (at least a very similar) effect by shooting line into the bc and then suddenly stop the shoot. Steve Rajeff does this perfectly.

Obviously we are having a very different definition for pull-back. :)

Yet I do not understand the one happening before RSP1. What exactly does the movement of a) the rod hand and b) the tip (rod) look like?

Cheers
Bernd
http://www.first-cast.de
The first cast is always the best cast.

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Bernd Ziesche
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#7

Post by Bernd Ziesche » Sat Dec 31, 2016 9:04 pm

Btw. some years ago Paul and I were heavily discussing why in all my rod hand only casts I achieve a dead straight perfect unrolled line on the grass (windless conditions). At the same time we both had the issue with the "distance phenomenon" (the line end piling up and switching side) for all our hauled casts (in windless conditions). I came up with the explanation being the line sack (and the line end just following the part of line in front of it) quite some later here:

Image

Looking at this it perefctly answeres why I have no distance phenomenon on all my none hauled casts:

I don't have any line sack in the unrolled line due to using significant "pull-back". And then I also start with less line speed (better a lower rate of accel.) in the none hauled cast. This makes the line end not increasing the the path of a slight sack (if it is in there).

What really makes for a royal distance phenomenon:
a) a huge line sack in the unrolled line and
b) starting with a high rate of accel. in the next fc sending the line end around the sack but increasing the curved path

Cheers
Bernd

P.s.: Ok, no further SL for this night otherwise my gf will put a bullet thru my head! :p :ninja:
http://www.first-cast.de
The first cast is always the best cast.

Neil Owens
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#8

Post by Neil Owens » Sat Dec 31, 2016 10:04 pm

Well that diagram shows exactly the issue I'm having with distance casts. I'm talking 60' - that's all I can do at present.

Perhaps we're not all individuals?

And no GF or SO(or guns) here, just a bottle of Bunnahabhain.

John Waters
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#9

Post by John Waters » Sat Dec 31, 2016 10:38 pm

Like the diagrams Bernd, thanks for posting.
In my view the greatest inhibitor to distance is "sag" on the backcast and therein lies the challenge of distance casting. Eliminate or minimise that and you cast a long, long way and your % of turnover will be high.
I do not use pull back on a distance backcast (if what I surmise about the impact on rod travel is correct). I try for a no sag backcast using speed. Bloody difficult with light gear and long carry. I use 85 to 90 feet of carry now (weather permitting) and gravity is always working against me but I just focus on speed and trajectory. Trajectory is also very important in generating a no sag backcast.

John

Michal Duzynski
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#10

Post by Michal Duzynski » Sat Dec 31, 2016 11:01 pm

Hi
Is Lasse using PB on his BC in this video, or is it the shooting head that kicks a bit?
I can notice a bit of bounce back of rod hand on the BC

https://youtu.be/Wl1hkpWr7iY

Mike

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