Faster Action?

charlieH

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Optimum load is a place which allows the blank to perform to the best of its ability without any noticeable performance drop off. So, it bends sweetly, casts a good long line and feels crisp and overall its happy days.

Thank you for that, which came in while I was writing my previous post.

You partly answer my question, but the extract I've quoted is the closest you come to defining optimum load and, as with Fruin's answer, it relies on terms that aren't exactly scientific and are pretty subjective - "sweet" and "crisp" are the two you use, which makes it sound as though we are discussing apples, not rods! And, with respect, load is surely a force (which must be measurable), not a place!

Is there also a scientific, or mechanical, answer - and a way of measuring optimal load for rods - that doesn't rely on subjective assessments like this? And if so, is it useful to know this?
 

Fruin

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I am sure that there are ways to scientifically test and record the optimal and maximum loadings for rod blanks and I assume that this is already a process in the design stages. However, I do not believe that this information in it's raw form would be of any use to a salmon angler. The optimal load is X grains, when the rod is accelerated in a fixed direction at Y m/s, giving an optimal force of Z newtons would be of little use when picking a line, unless each of us had our casting stroke scientifically analysed to make best use of the rod testing data.

What is of general use to salmon anglers is a range of line weights that the rod should, in all but extreme circumstances, cast 'comfortably' without distorting beyond it's design specification.

The caster can then determine what rod and line combination feels better for their individual casting stroke. This will be a very non-scientific, qualitative assessment where the caster is more likely to use recognised industry words like 'crisp', 'sloppy', 'fast', 'slow', 'unresponsive' than to try to apply figures to their assessment.

I do like the idea of a set figure, but like I say, to be useful it would rely as much on a costly assessment of the caster as well as the rod.
 

Blue Zulu

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The soggy or overload stage is caused by the rod blank turning too oval during compression. Every rod blank starts of round (near enough) and when it bends it goes oval, looking at its cross section. Fibers along the outside of the bend stretch, those on the inside compress and the bits on each side swell outwards. This is normal and is allowed for in the design and the choice of material used.

If you get a piece of copper pipe and bend in round your Knee you will find that it starts goes oval at the bend then usually collapses. If you put a pipe bending spring up the inside before hand, this helps prevent this. Does the technology exist to apply the same principle to rod blanks?

Sorry if that is a stupid analogy to make but my knowledge of rod construction is extremely limited :eek:
 

charlieH

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If you get a piece of copper pipe and bend in round your Knee you will find that it starts goes oval at the bend then usually collapses. If you put a pipe bending spring up the inside before hand, this helps prevent this. Does the technology exist to apply the same principle to rod blanks?

Maybe the spiral fibres on the outside of some rods are supposed to help with this? They're not so common now, but I think that, for example, the Daiwa Whisker range had them, didn't they? And I think the old Bloke XL50 does, too.

As an aside, the Hexagraphs were developed as a solution to the problem of blanks that went oval and lost power - or at least that was how they were sold. But sadly they weren't a very good solution!
 

charlieH

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I do like the idea of a set figure, but like I say, to be useful it would rely as much on a costly assessment of the caster as well as the rod.

I agree that it might not be particularly useful as a sales tool (though, of course, pseudo-scientific babble isn't altogether unknown in the marketing of tackle, and particularly rods).;)

What interests me more is really to know how large a range on the graph of loadings could be considered optimal, or acceptable. It all ties in with the recurring discussions about line weights - see this recent thread, for example - http://www.salmonfishingforum.com/forums/showthread.php?t=25665.

In order to know what range of line weights are a good match on a rod, one approach is to establish what optimal loading is and then see how far from that point is still considered acceptable.

I don't know what shape a graph of loadings would look like, but it seems to me that it might be more or less a bell chart. So depending on the exact shape of the bell, a rod might work with a wider or narrower range of weights. Different rods might have different shaped graphs, and one with a flatter top (which I suspect fuller flexing rods may have) would presumably have a wider range of tolerance than a rod that has a very narrow bell. But one can't do any of this without first being able to calculate the loadings and establishing what is optimal.

I'm hasten to add that not about to launch myself as a rod designer; it's just intellectual curiosity.
 

Springer

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If you get a piece of copper pipe and bend in round your Knee you will find that it starts goes oval at the bend then usually collapses. If you put a pipe bending spring up the inside before hand, this helps prevent this. Does the technology exist to apply the same principle to rod blanks?

Sorry if that is a stupid analogy to make but my knowledge of rod construction is extremely limited :eek:

Yes this technology exists and it is widely used in rod manufacture by companies selling the more expensive blanks. Sage use this along with Century to name a few. A simple inspection inside the female end if a section will reveal this if you know what to look for..

The term used to describe a rods blanks ability to resist going oval is 'Hoop Strength'. Hoop strength can be improved by the direction you align fibers over the 'x' and 'y' axis. Fibers aligned along the 'y' axis impact on the blanks resistance to bend and give a certain degree of hoop strength but fibers aligned around the blank or on the 'x' axis will significantly improve hoop strength. It is a fine balance that needs to be achieved and usually the circumstantially wrapped fibers are of a much lighter weight or GSM.

Another factor is where within the wrap you place these circumferential fibers, to the core, middle or outer of the blank or a combination of all three.
 

Springer

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Thank you for that, which came in while I was writing my previous post.

You partly answer my question, but the extract I've quoted is the closest you come to defining optimum load and, as with Fruin's answer, it relies on terms that aren't exactly scientific and are pretty subjective - "sweet" and "crisp" are the two you use, which makes it sound as though we are discussing apples, not rods! And, with respect, load is surely a force (which must be measurable), not a place!

Is there also a scientific, or mechanical, answer - and a way of measuring optimal load for rods - that doesn't rely on subjective assessments like this? And if so, is it useful to know this?

Yes there are ways you could study, collect and even publish this data but I think for the rod industry it is not needed and would be prohibitively expensive. Again stuff like this is kept for other composite engineering arenas with high budgets and a greater need to know factor.

Any rod manufacturer worth his salt will have someone who can do this assessment work both in the factory and on the river relying on feel and experience. They will then rely on his broad experience base and use of the subjective terms you mentioned.

I would say that this discussion has already gone way over the heads of the majority of forum members who probably feel they dont need this much information. A simple line recommendation chart would suffice.
 

Springer

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Maybe the spiral fibres on the outside of some rods are supposed to help with this? They're not so common now, but I think that, for example, the Daiwa Whisker range had them, didn't they? And I think the old Bloke XL50 does, too.

As an aside, the Hexagraphs were developed as a solution to the problem of blanks that went oval and lost power - or at least that was how they were sold. But sadly they weren't a very good solution!

These arent spiral fibers if Im thinking about the same thing, they are peaks and troughs of resin that have not been ground from the blank prior to finishing. They occur because before curing the soft blanks are wrapped very tightly using a thin plastic film which overlaps on each rotation. The resin when fluid during curing flows into these spirals as you call them and forms the shape you see.

This style of un-ground blank is seen from time to time but is not that popular from a cosmetic point of view these days. Blanks are usually passed through a grinder to remove these before they have a finish applied.
 

Fruin

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I think the problem is that we only ever have two 'knowns' in the equation - the weight of a line and the optimal loading (or force) on the rod. What a manufacturer can only presume at the design stage is the other part of the crudest equation to use F=ma (Force = mass x acceleration).
The acceleration is the part that is controlled by the caster and it would be very hard for any human to accurately deliver the required acceleration to 'optimally' load the rod to the factory design parameters.
This is why the factory can only design within parameters and the rest of the design will be done on 'feel'.
 
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Springer

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I agree that it might not be particularly useful as a sales tool (though, of course, pseudo-scientific babble isn't altogether unknown in the marketing of tackle, and particularly rods).;)

What interests me more is really to know how large a range on the graph of loadings could be considered optimal, or acceptable. It all ties in with the recurring discussions about line weights - see this recent thread, for example - http://www.salmonfishingforum.com/forums/showthread.php?t=25665.

In order to know what range of line weights are a good match on a rod, one approach is to establish what optimal loading is and then see how far from that point is still considered acceptable.

I don't know what shape a graph of loadings would look like, but it seems to me that it might be more or less a bell chart. So depending on the exact shape of the bell, a rod might work with a wider or narrower range of weights. Different rods might have different shaped graphs, and one with a flatter top (which I suspect fuller flexing rods may have) would presumably have a wider range of tolerance than a rod that has a very narrow bell. But one can't do any of this without first being able to calculate the loadings and establishing what is optimal.

I'm hasten to add that not about to launch myself as a rod designer; it's just intellectual curiosity.

I would suggest that optimal would take up quite a small place on the graph when the rod is loaded as much as it can be without performance drop off. Lots of people will never see this point on their blank with any regularity.

Now the term workable is different and will take up a far greater place on the graph and will cover a far wider range which will probably be more relevant to the majority.
 

charlieH

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These arent spiral fibers if Im thinking about the same thing, they are peaks and troughs of resin that have not been ground from the blank prior to finishing. They occur because before curing the soft blanks are wrapped very tightly using a thin plastic film which overlaps on each rotation. The resin when fluid during curing flows into these spirals as you call them and forms the shape you see.

This style of un-ground blank is seen from time to time but is not that popular from a cosmetic point of view these days. Blanks are usually passed through a grinder to remove these before they have a finish applied.

No, I'm familiar with the unground finish, and this is different. It's a thin, open spiral of some sort of thread that is applied to the outside of the blank - probably only three or four threads that usually spiral in opposite directions to give a crisscross effect. I have a feeling that Kevlar is sometimes used, but again that may be abit of pseudo-science.
 

Lohi

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...As an aside, the Hexagraphs were developed as a solution to the problem of blanks that went oval and lost power - or at least that was how they were sold. But sadly they weren't a very good solution!
In what way do you mean they failed as a good solution?

I suppose that the Hexagraphs were quite difficult and expensive to manufacture, but do you mean some other "less optimum" feature in them?

I am asking just out of curiosity, as I have actually two B&W 15' Hexagraphs in my "salmon rod collection".
 

Springer

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No, I'm familiar with the unground finish, and this is different. It's a thin, open spiral of some sort of thread that is applied to the outside of the blank - probably only three or four threads that usually spiral in opposite directions to give a crisscross effect. I have a feeling that Kevlar is sometimes used, but again that may be abit of pseudo-science.

I know what you mean Charlie, I would really think this has a greater effect on cosmetic appearance than structural integrity.

It is often the case that a top layer or veneer of a more attractive looking carbon is placed as the final wrap to enhance the cosmetic appearance. You know how we are all suckers for something that looks good!
 

Scanny

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Strange old world,I was speaking to a rod designer not more than 2 hours ago about ovality, the nuances of nano tubes and spheres, and the amorphous material solution. I got a Reaction in my hands for the first time too, the 15' feels like a bit of a rod, different to the 15' NRX
 
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newfly

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Springer,

This thread has been an interesting read even if I am still a bit confused. How would you describe the action of say a 15' Hardy Swift Mk2 and a Loop Classic rod and what difference would this mean to how they cast.
 

Springer

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Strange old world, I was speaking to a rod designer not more than 2 hours ago about ovality, the nuances of nano tubes and spheres, and the amorphous material solution.

Would you care to elaborate or are you just 'no name' dropping for effect?
 

Springer

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Springer,

This thread has been an interesting read even if I am still a bit confused. How would you describe the action of say a 15' Hardy Swift Mk2 and a Loop Classic rod and what difference would this mean to how they cast.

What are you confused about Newfly?
 

Scanny

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If I wanted effect I would have written about Hoop stress and how calculating hoop strength is nigh impossible without multi axis strain gauging in each ply, for reinforced polymers. Thankfully I didn't :)

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:

It was Mr Bell, who worked with Diawa on the Amorphous Material that superseded the Kevlar wrapping. Very interesting material and superior to the Kevlar as it became homogenous upon curing.
 
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Lohi

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If I wanted effect I would have written about Hoop stress and how calculating hoop strength is nigh impossible without multi axis strain gauging in each ply, for reinforced polymers. Thankfully I didn't :)...
I am glad about that too, as calculating hoop strength with analytical or numerical method has nothing to do with experimentally measuring something with a strain gauge... :cool:
 

Scanny

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My point that without knowing the exact orientation of each fibre in the ply, and it's orientation respective to the other fibres, then you can't use any stress calculations as you are not aware of the Normal resulting forces. Hence using Multi axis rosette strain gauges in each ply will give you an estimation over the data sample :)
 
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Lohi

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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:...
Obviously you do not have the required background to discuss about applied mechanics or strength of materials. Therefore, may I suggest, that you do not try to do so.

WBR, Lohi, M.Sc, Applied Mechanics, graduated 1987.
 
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