Faster Action?

Springer

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I'm not familiar with "hoop strength" in tapered tubes? Hookes law is typically only applies to parallel wall cylinders-typical pressure vessel design using Hookes Law omiting the third dimension, not tapered tubes :confused:

With respect to your obvious academic qualifications, maybe you are in the wrong discussion?

Hoop strength is a major consideration within fishing rod and golf club shaft design, both of which use tapered tubes. I have personally been involved in the design changing work with regard to tapered rod sections with a view to improving hoop strength. The results were also easily measurable.

University of Life and 'Hands On' Practical Experience :eek:
 

Lohi

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Excellent!

MSc , BEng (Hons) and Pm sent.
I do not believe in PMs :p

Furthermore, this has gone way beyond the original scope, and I don't think that this thread needs more discussion about the Hooke's Law, which btw. is applicable in any general three dimensional stress state.

Springers comment about the tubular rod cross section ovalisation under overload situation is IMHO valid, and increasing the hoop strength of the rod tube decreases this unwanted feature. ;)
 

Scanny

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I do not believe in PMs :p
that's unfortunate Lohi, it was about to become interesting.

It is applicable, however try building a correlated FE model in Ansys without knowing the alignment and offsets.

I am familiar with the design intentions, just not referred to as Hoop Strength In cross sectional area work.

It has digressed, back on topic,

The Nrx and Reaction are both "fast" Rods, yet fulfil very different critera, the Reaction fulfilling yours Lohi
 

fishpond

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Hi

Scanny - please divulge on NRX vs Reaction in non-physics format - I haven't played with either?

Lohi - Hexagraph construction makes sense to me apart from the tubular spigots which means flat spot and/or ovality surely? they did consider cane style spliced ferrules at one point I believe to alleviate this

Springer - the TCR DH's in my experience aren't tip action like the trout rods just very strong - the recovery isn't as fast as some DH either; TCX appears to have quicker recovery but not the power.

Does ovality really occur during normal "optimal" loading casting or just bending into that 30lb heading off to the rapids?

Perhaps we need archetyphal examples of tip vs medium vs through action with slow/med/fast recovery rates we can all relate to for clarity?

ATB

Richard
 

Springer

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Hi

Scanny - please divulge on NRX vs Reaction in non-physics format - I haven't played with either?

Lohi - Hexagraph construction makes sense to me apart from the tubular spigots which means flat spot and/or ovality surely? they did consider cane style spliced ferrules at one point I believe to alleviate this

Springer - the TCR DH's in my experience aren't tip action like the trout rods just very strong - the recovery isn't as fast as some DH either; TCX appears to have quicker recovery but not the power.

Does ovality really occur during normal "optimal" loading casting or just bending into that 30lb heading off to the rapids?

Perhaps we need archetyphal examples of tip vs medium vs through action with slow/med/fast recovery rates we can all relate to for clarity?

ATB

Richard

The 15' TCR was without any doubt a fast actioned rod with a soft tip and a stiff butt. The 14' TCR was less so and probably the best of the bunch overall. The 12'9 TCR was fast actioned but had a better balance between tip and butt and overall a much better example than the 15' IMHO.

Ovality starts to happen the moment the tube starts to flex and increases in line with the loading placed on the blank. The more it bends the more it goes oval until eventually the blank fails.

Examples of different rod actions are many, off the top of my head good examples would be;

Fast Action - Guideline LPXe, Vision GT4 Catapult

Medium Action - Guideline Le Cie, Loop Multi

Slow Action - Scott LS2, Vision Cult, Hardy Demon

All of the above have fast/med fast recovery. Very few rods have slow recovery these days due to the advancements in carbon fiber although I can think of examples, probably best I dont mention them.
 

Orca

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Springer, thank you for your first reply to my question I have a better understanding of the terms Fast Medium and Slow action, but didn’t think this thread would get so technical, again Springer thanks.
 

Scanny

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For Anyone Interested..

A picture tells a thousand words,

A basic geometric FE model of a tip from a 14' rod. Its to show the deformation due to the deflection

Disclaimer: Its a linear model, so not representative of CFRE, its intended to show trends and load patterns. The constraints and load case are adjusted accordingly**

Ignore the areas at either end, the stress distribution shows the deformation, or Ovality of the section in bending.



 
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Long Shot

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I used to think the expression "a guid bend in the rod" referred to fish, now I know differently.
For f's sake no one mention the Hexagraph or we'll be at this forever.
Interesting stuff nonetheless.
 

Lohi

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Nice pictures Scanny, did you calculate it yourself?

Btw. Fly rod bending deviates from the linear FEM-applicability zone fairly fast, and the ovalisation of the cross section under overload is far from linear. But as you have the capabilities, I am sure we will shortly see a nonlinear FE analysis of the ovalisation. While you do it, study also increasing the stiffness in the hoop direction, and study how the ovalisation behaves. :D

Ps. My late professor in FE-course said that FEM is a great method, as in any case, no matter how wrong the results are, one always gets impressive pictures with nice colors. :cool:
 

jabster

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Intresting subject and I sure am taking notes from all this physics mumbojambo in case I decide to enroll in a university or something:)...

I think that Lohi had it right on the money when he said that all manufactures should start describing their rods in two ways = bend/action of the rod(tip, mid, full flex) and the recovery rate. It would be so much easier to read that type of rod descriptions.
 

jabster

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Examples of different rod actions are many, off the top of my head good examples would be;

Fast Action - Guideline LPXe, Vision GT4 Catapult

Medium Action - Guideline Le Cie, Loop Multi

Slow Action - Scott LS2, Vision Cult, Hardy Demon

All of the above have fast/med fast recovery. Very few rods have slow recovery these days due to the advancements in carbon fiber although I can think of examples, probably best I dont mention them.

I did quite a bit of testing with the Vision Cult's(13'2, 13'4 and 13'8) and for me they felt more like a med-fast rod then a med/full flex rod. They had a lot more tip action then I anticipated and a solid butt section. A very nice and versitale set of rods and especially the 13'4 was a real masterpiece. I did compare them with Meiser 14' #7 S rod, Echo TR 13' #7, Echo DH 13'6 #9 and DTX 14' #9 and found the action on the Cult's to be stiffer then the Echo's and more in the same ballpark with the S rod and DTX. Don't know if you guys have a different batch of them in the UK or something? Or maybe it has something to do with casting style.
 
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Scanny

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It's a single constraint and single load bending model in ProMechanica. Whilst cfre behaves differently, it's useful to show trends and load paths of the geometry- taking a few hours less to set up compared to Ansys or Star. It communicates it far more effectively, a full model would take a night to process and throw up convergence issues and be a nightmare.

It took 14 revisions in the modelling and mesh to run an Ansys study with an improvised, assumed layup-the manufacturer wasn't willing to release it. Each failed run took 4 hours before a point failed to converge, not much fun.

Something more interesting...
 
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Springer

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I did quite a bit of testing with the Vision Cult's(13'2, 13'4 and 13'8) and for me they felt more like a med-fast rod then a med/full flex rod. They had a lot more tip action then I anticipated and a solid butt section. A very nice and versitale set of rods and especially the 13'4 was a real masterpiece. I did compare them with Meiser 14' #7 S rod, Echo TR 13' #7, Echo DH 13'6 #9 and DTX 14' #9 and found the action on the Cult's to be stiffer then the Echo's and more in the same ballpark with the S rod and DTX. Don't know if you guys have a different batch of them in the UK or something? Or maybe it has something to do with casting style.

Vision themselves describe the Cult as a full flexing rod, I have found this to be the case myself. As for any similarity to a DTX I would say chalk and cheese.

One thing for sure is that people often use or test a rod with lines that were different in length and weight from what the designers originally intended. This of course can have some effect on changing how a rod feels. Manufacturers often prefer to steer clear of line weight recommendations and this can further exasperate the problem IMHO.
 
N

newfly

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What are you confused about Newfly?

Confused about how different actions affect the way a rod is cast.
For example if an average but competent castor who can cast a reasonable distance with good presentation using say a Hardy Swift changed to a different actioned rod, would he have to change the way he casts and if so in what way.
 

Springer

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Scanny,

What is the point you are trying to make with the rod tip deflection pictures? They look like nothing more than a few bent or straightened rods.

The words in the post dont mean anything top 99.9% of us :confused:
 

Springer

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Confused about how different actions affect the way a rod is cast.
For example if an average but competent castor who can cast a reasonable distance with good presentation using say a Hardy Swift changed to a different actioned rod, would he have to change the way he casts and if so in what way.

Different rod actions can respond better to different types of power/speed application during the forward cast to get the best out of them. We can cover this no problem but maybe better if you start a new thread on the subject.

Some of the techno stuff in this thread will Im sure have put a good few readers off this thread already I would imagine :)
 

jabster

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Vision themselves describe the Cult as a full flexing rod, I have found this to be the case myself. As for any similarity to a DTX I would say chalk and cheese.

One thing for sure is that people often use or test a rod with lines that were different in length and weight from what the designers originally intended. This of course can have some effect on changing how a rod feels. Manufacturers often prefer to steer clear of line weight recommendations and this can further exasperate the problem IMHO.

Well I guess I'm wrong then:) + the last post was a bit badly written. As for the comparison with the 14' DTX and Cult's I meant that the Cult's bend/action were more closer to the DTX or S rod which are med-fast then say a Echo DH which is a full flexing rod. The overall feel of the DTX and Cult's was different. All rods have been tested with lines that are recommended by the manufactures and with some that aren't. A friend of mine has some good pics taken of the different bends of the rods we tested - I'll try to get them from him and post them here.
 
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