Recoils or not Recoils?

VGB · Post by **VGB** » Sat Jan 12, 2013 11:18 am

Thanks Bernd

I need to read that in detail. It is the 1st reference that I have seen that acknowledges the relationship of impulse force to the cast. On 1st impressions it seems it will provide the same information but does need specialist equipment. I suspect that we have both studied dynamic systems; a subject that can go into some dark places :oh:

Vince

Paul Arden · Post by **Paul Arden** » Sat Jan 12, 2013 12:52 pm

It's not just watching me cast! But watching other instructors too. There is always a similarity it bottom leg.

Paul Arden · Post by **Paul Arden** » Sat Jan 12, 2013 1:40 pm

Paul, don't you think you are trying to destabilize the rod with your test?

I don't know. What is a stabilised and destabilised rod?

Tom · Post by **Tom** » Sat Jan 12, 2013 1:47 pm

sms wrote:Bernd, one way to determine the guide placing is to try to find the direction where the blank goes in a direct line in that test.

Hi Sakke.
I have tried just that a few times,but when the guides,thread
and epoxy was finally mounted,the rod was swirling,and the
tracking was indeed not what I expected it to be.
What I think is,how important is this spineorientation?

Tom.

sms · Post by **sms** » Sat Jan 12, 2013 3:00 pm

Yeah, I just mentioned that it is one way to determine where to put the guides. I cannot remember if I've done that on any of my rods.

And since the spine isn't straight, but goes around, there is no point in that regardless.

Tom · Post by **Tom** » Sat Jan 12, 2013 3:28 pm

Agree Sakki.
The spine will change with load.
And the importance of the right,or perfect guide orientation
is a myth in my opinion.

Tom.

Merlin · Post by **Merlin** » Sat Jan 12, 2013 4:15 pm

Destabilizing: putting a bunch of vibrations to sort out instabilities (internal resonance).

Bill Hanneman · Post by **Bill Hanneman** » Mon Jan 14, 2013 4:05 am

Merlin wrote:Bill,

There is no guru here, maybe just a wizard. Your strong opinion is such that I have no intention to convince you about a more technical approach of frequency. You have your own and we can live with that, just regretting that a little bit of effort would bring us closer.

There is some "sweet spot" for every casting condition, some casters being just able to catch it as the conditions are changing (lengthening the line). In other words, there are many PPF. I won't try to convince you.

Merlin

Wizard,

What is this about a more technical approach of frequency?
I agree with all you say, except one thing, i.e., when speaking with "run of the mill" anglers, one is better off speaking in terms of cpm.

Torsten has it right, but you and Gordy will never be able to reach out to anglers using hertz. But, if you wish to talk only to engineers, I can live with that.

The only dog I have in this is fight is I believe CCS is the most useful way to talk about fly rod performance.

In other words, there are many PPF. I won't try to convince you.

You don't have to convince me. I told this to Gordy a year ago.
PPF is just a concept that can only be reconized by each individual and it depends on what he is wanting to do at the moment. This is a concept which is completely foreign to engineers and they should not even try to quantify it.

Merlin · Post by **Merlin** » Mon Jan 14, 2013 5:56 am

Bill

I can speak cpm but will compute with Hz. I cannot understand why being so close to something technically sound, you keep on creating uncertainties with approximations, having the right information at hand.

If PPF is personal, there is no reason to use it for design.

Merlin

Torsten · Post by **Torsten** » Mon Jan 14, 2013 10:36 am

Hi,

@Bill,
Please mail me your latest frequency article and I need also the article about the URRS for my archive.

About the frequency:
Yes, I've no problem at all with cpm, this is also what you're recording when using a stop watch.

However, the major drawback that I see is that the frequency depends on the stiffness and the mass distribution of the rod. Thus you have a problem when you're choosing a test weight based on the AFTM number e.g. ERN 6.9 vs 7.0 for instance. I've pointed that out already a few years ago.

In my opinion it's much simpler and faster to measure the mass directly. This means determine the mass for every section and also the balance point. This way you get a good picture of the mass distribution and you can use these raw values for other interpretations like the MOI - even it's possible to compute the natural frequency using the stiffness and the mass distribution.

An rod with recoils should have a higher performance, because of a lower mass (the durability is another aspect). Of course you should be able to measure a higher frequency as well.

Bye,
Torsten

Bernd · Post by **Bernd** » Mon Jan 14, 2013 2:23 pm

Torsten wrote:An rod with recoils should have a higher performance, because of a lower mass (the durability is another aspect). Of course you should be able to measure a higher frequency as well.

Hi Torsten,
nice post. Sounds very logical to me.
About the higher performance I (think to) understand that the highest performance will be the desired stiffness (how much the rod bends) and the desired action (where the rod bends) while having the lowest possible mass, the best mass distribution, the best balance and the lowest possible diameter for each rod.
So in regard of that to safe weight (recoils) should always be good.

The key question to me is, if we compare:

a) 2 rods having the same stiffness and the same rod action but a very slight difference in mass distribution for the blank and different (weighted) ring sets

with

b) 2 rods having the same blank but due to different ring sets slight difference in stiffness and very slight difference in rod action

where would we feel more of a difference - between the rods in a) or those in b)?

Personally I would go for b) here. That means if I compare to have titanium SIC rings with having recoils (safing a little weight) on the same blank, the little higher stiffness with the recoils is what I feel mainly.
But having a slightly different blank with titanium SIC rings on it and achieving the same stiffness and rod action I had with recoils on the other blank should make less of a difference for my feel I think.

So to me it seems as if hitting the desired stiffness and rod action with the rings one wants is more important than having the lightest possible rings in general.

This is what I have come across after having tried quite some rods with different ring set ups and comparing all of them. It's a while ago I was deeper into that though.

Paul claimed SIC rings to have killed rods for him.
I don't really agree here. I do agree that they may change stiffness and rod action into one the caster may not like anymore. But taking a little extra stiff blank and then adding SICs may already do the job!?

Sure SICs are not SICs as was pointed out here.
If we add really heavy rings that may set down the (best possible) perfomance more significally.
But as Lasse pointed out SICs do not have to mean a HUGE difference in weight.
For sure they mean a significant difference in shooting abilty and durabilty.

Lieben Gruß
Bernd

VGB · Post by **VGB** » Mon Jan 14, 2013 3:31 pm

Bernd wrote:So to me it seems as if hitting the desired stiffness and rod action with the rings one wants is more important than having the lightest possible rings in general.

Bernd

Absolutely agree with this. I build a rod to perform a task not to be the lightest, furthest, fastest possible. Sometimes that means a bit more weight on top to slow the rod down and use a lighter line for presentation.

Have you seen the report Merlin mentioned:

http://web.cecs.pdx.edu/~graig/me411/Xrod-rept.PDF

regards

Vince

Paul Arden · Post by **Paul Arden** » Mon Jan 14, 2013 4:24 pm

It's not only the mass at the tip, surely it's the taper too. A soft butt section would make the tip respond differently to a stiff one. A steep taper will result in a different tip response to a less progressive one. Of course these things are all measurable. But I don't know how you would feed them in to work out how the tip behaves. Of course when I cast I can see it :p

Cheers, Paul

Bernd · Post by **Bernd** » Mon Jan 14, 2013 4:42 pm

Paul,
what makes the HT special compared to other fly rods?

- graphite technology?

- rod action?

- stiffness profile?

- mass distribution?

- overall weight?

- diameter?

- MOI?

Any (measurable) numbers in any category pointing out a difference?

Did you get yourself another - well, something you may call to be a boat yet?

Greets
Bernd

VGB · Post by **VGB** » Mon Jan 14, 2013 5:27 pm

Paul Arden wrote:Of course when I cast I can see it :p

I can't but I'm a chump :p

Yes the other factors do combine but when I am building there is a limit to what I can effect, mass distribution being the primary factor. There is another possible way of changing performance in a built rod that is alleged to improve damping characteristics that I will play with later in the year.

regards

Vince

PS Did the pork chops arrive?

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