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Maximum Rod Bend

Moderators: Paul Arden, Bernd Ziesche, Lasse Karlsson

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Merlin
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Re: Maximum Rod Bend

#91

Post by Merlin »

Gordy
How are you calculating the elastic energy in the rod? Is it based on the perpendicular tip deflection and the spring constant of the rod (i.e. k1*x.^2/2 + k3*x.^4/4) or on the curved shape of the rod along with its variable stiffness characteristics?
For the 2D casting model I map rod characteristics, so rod stiffness (non linear) measured for normal deflection is calculated along the pull angle of the line and is used to derive the elastic energy within the rod with the normal deflection of the rod as a parameter.
Does the maximum elastic energy correspond with the maximum perpendicular tip deflection and thus it is a bit less at MCL?
None of them, maximum elastic energy occurs about 20 ms before MCL and 25 before MRD (which is 33 ms after MAV in the run I use). This is why I chose the elastic energy in the rod as a characteristic of its loading state.
His curve shows that the max haul velocity (based on the separation speed of the hands) was around 75 ms after MAV when false casting and a shorter 60 ms difference on the delivery cast.
And the 2D model says it should be above 50 ms or something like that after MAV, IMHO it is consistent with Ulrik’s observations.

Merlin
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Bernd Ziesche
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Re: Maximum Rod Bend

#92

Post by Bernd Ziesche »

Paul Arden wrote: Sun Jan 17, 2021 6:12 am If my arm was as long as the line
Then you wouldn't need the rod and could gently drop the fly off your hand.... :blush: :pirate:
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Lou Bruno
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Re: Maximum Rod Bend

#93

Post by Lou Bruno »

Bernd Ziesche wrote: Wed Jan 13, 2021 9:09 pm Hi Lou,
You started this thread from here:
Lou Bruno wrote: Thu Dec 31, 2020 1:03 pm When teaching hauling we usually mention the two major benefits of hauling...increase bend and increase line speed.
...
These are some of the secondary thoughts, don't expect answers, merely thought provocing.
Lou
After nearly 60 posts, what are the benefits auf hauling as you understand them by now?

Oh, and let me add, I did expect answers when I started reading all 6 pages!
Cheers
Bernd
[/quote]

Bernd,

Sorry for the delay in responding.

Years ago, when I was taught how to haul, I noticed how energized my line became. At that time I didn't understand why.
Most of my reading literature would mention the two benefits of hauling are greater line speed and helps in bending the rod.

So, now, I don't subscribe to the belief that hauling aids as much to bending the rod. Came to this conclusion not only in reading the threads for this post but by actually trying to replicate what was said.

I've been trying to coordinate my haul much later, as close to the "stop" RSP, as possible. Also, I was practicing, trying to maintain as narrow a casting arc as possible while hauling. For me this is a major change, especially when casting longer line lengths > 60ft.

My main take away, was that hauling increases line speed. Due to speed of the bent rod recovering as well as trying to time the haul with that.

Lou
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Re: Maximum Rod Bend

#94

Post by Lou Bruno »

gordonjudd wrote: Fri Jan 15, 2021 6:25 pm

Thus since the length of line from the first stripping guide to the tip follows the rod the assumption is that the distance from the hauling hand to the first guide+the line length from the first guide to the tip + the length of line from the tip to the fly is constant. That means a plus distance change from the hauling hand to the first stripping guide will produce the same distance change (it will get shorter) in the length of line from the tip top to the fly.
Gordy
Any chance in further clarifing this...."it will get shorter" we're slipping line during the BC correct...what and how "gets shorter?"
After clarification, is this something I could demonstrate?
Lou
Lou Bruno
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Re: Maximum Rod Bend

#95

Post by Lou Bruno »

When I can get back to casting...winds have been howling.
I will time my haul close to RSP1 and try to tune my haul at MCL.
Tried this before, but wasn't convinced, that, I developed more tails trying to haul as close as possible to RSP1.
Also, not slipping as much line out during my bc seems to be beneficial on my fc... I'll be further testing this.
Lou
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Lasse Karlsson
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Re: Maximum Rod Bend

#96

Post by Lasse Karlsson »

Lou Bruno wrote: Sun Feb 07, 2021 1:58 pm
gordonjudd wrote: Fri Jan 15, 2021 6:25 pm

Thus since the length of line from the first stripping guide to the tip follows the rod the assumption is that the distance from the hauling hand to the first guide+the line length from the first guide to the tip + the length of line from the tip to the fly is constant. That means a plus distance change from the hauling hand to the first stripping guide will produce the same distance change (it will get shorter) in the length of line from the tip top to the fly.
Gordy
Any chance in further clarifing this...."it will get shorter" we're slipping line during the BC correct...what and how "gets shorter?"
After clarification, is this something I could demonstrate?
Lou
Hi Lou

It's the line outside the rodtip that gets shorter, by the amount of line the linehand pulls in through the rings 😊

Cheers
Lasse
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Lou Bruno
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Re: Maximum Rod Bend

#97

Post by Lou Bruno »

Lasse
Ah..thanks
Lou Bruno
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Re: Maximum Rod Bend

#98

Post by Lou Bruno »

Did some casting today. When I try to haul around RSP1, my loops were narrow. Also, my line seemed to be more energized... faster perhaps. When I try and haul around MCL my loops did become wider. Also, my line speed seemed slower.
Lou
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Paul Arden
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Re: Maximum Rod Bend

#99

Post by Paul Arden »

I’m not sure I could make those adjustments in my casing Lou with any degree of certainly and would need slow motion footage of my cast. The other issue we have is actually measuring the haul, I thought I was acceleration right up to haul stop, but it seems from slow motion video analysis that the acceleration peaks earlier.

All I can really time is when I start to think about rapidly accelerating the haul.

Cheers, Paul
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