Rod Frequency Measurement

[Wildfisher]

I am doing some work in conjunction with Magnus to try to determine a reliable method  of  electronically measuring rod frequency. It's at the early experimental stage right now, but the long term aim is to have a microprocessor controlled device that connects to a PC via the serial port that can be configured and controlled in various ways. The data will then be downloaded to the PC, saved and analysed in conjunction with the CCS data Magnus already has.

It's all bit  "nerdy"  I suppose but it's an interesting project that will help provide an objective analysis of a rod.

This is far from finished but I do have some early test results. The top 6 ? feet of  a Bloke XL50 is 21% faster than the top 6 ?  feet of a Daiwa whisker.

I had absolutely no idea what frequency ranges fly rods oscillate  in, but these tests showed:

The Whisker tip transit time  was 140 mS – which is 7.15 Hz
The Bloke    tip transit time  was 116 mS – which is 8.62 Hz

Fascinating stuff eh? 

Here are some photos of the initial experiment set up


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Test Set-Up

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Test Set-Up

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Tip transit time of the Daiwa Whisker being measured

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Infra-red beam transmitter

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Infra-red beam receiver and noise filter

[Magnus]

Looking good Fred. Those frequencies are in the right ball-park.

I had absolutely no idea what frequency ranges fly rods oscillate  in, but these tests showed:

The Whisker tip transit time  was 140 mS ? which is 7.15 Hz
The Bloke tip transit time  was 116 mS ? which is 8.62 Hz

Says exactly what it should. The Bloke tip should be physically lighter and made from a higher modulus material. So the same length should oscillate at a higher frequency.
Relevance to casting:
Think about the end of your casting stroke - when the rod is coming straight. One of those rods will let you have a little more speed than the other. Then after the loop is away the rod counterflexes and recovers straight - one will be significantly faster than the other.
The other issue is feel - the higher frequency rod damps less - so any movement at the pointy end is felt more accurately and immediately at the blunt end.

For 9ft #5 rods I'd be expecting frequencies to be significantly lower - 1 to 3 Hz. I've a contact in Norway who's already working with some of this stuff - I'll email him and ask for some typical values. He and I need to confer about how to fix rods too.

This is brillaint stuff Fred - many thanks  Incidentally if you know any golfers this will let then measure the frequency of their clubs - matched sets are meant to be preferable  :?

Magnus

[haresear]

So will this be the definitive way of determining whether one rod is "faster" than another?

Get your patent in, lads...

Alex

[Wildfisher]

Get your patent in, lads...

First I'll have to build the thing a wee bit more solidly. Right now it falls apart if I breath on it too hard.

The joys of prototypes   :lol:

Still a lot to do, hopefully I'll get onto the  firmware  for the microprocessor soon

[Wildfisher]

For 9ft #5 rods I'd be expecting frequencies to be significantly lower - 1 to 3 Hz. I've a contact in Norway who's already working with some of this stuff - I'll email him and ask for some typical values. He and I need to confer about how to fix rods too.

I would imagine that as I am using only  2 (Whisker) and 3 (Bloke) sections  of these rods  I am getting frequencies that are considerably higher than they should be. For example if I hold the Whisker steady at about 2 feet from the tip and then flex it, the frequency more than doubles. I have not tried that with the Bloke – it's my favourite rod and I don't want to risk breaking it! 

[Magnus]

Fred

Rod frequency is relative to length - like the length of a pendulum. Slowest rod frequency will come from the longest heaviest rods - DH salmon rods most likely.


Alex

Maybe just a little too late  :lol:
Have a look at http://hardyadvancedcomposites.org/carbonfribrerodtests.aspx for state-of-the-art in rod testing.
Hardy/Greys do both calculate and measure rod frequency for their rods but of course don't publish that data - no does any other rod maker. As a matter of fact rod makers offer very very little in the way of hard data.

[Wildfisher]

Hardy/Greys do both calculate and measure rod frequency for their rods but of course don't publish that data - no does any other rod maker. As a matter of fact rod makers offer very very little in the way of hard data.

why is this?

[haresear]

Maybe just a little too late  
Have a look at http://hardyadvancedcomposites.org/carbonfribrerodtests.aspx for state-of-the-art in rod testing.

Wow. I could hardly watch some of them...

Alex

[Magnus]

Mostly they won't give any hard data because they don't have it and don't understand it themselves. Most rod companies work by trial and error and a long pattern book. Come a new carbon they go through the book and try a few - if they make their own blanks. If not they describe what they want and then cast prototypes until they find what they 'want' - hard to say what they get was actually what they wanted.

Hardy is exceptional - I'd guess there are two or three companies in the world doing the type of research they are. On the one hand they have a tame rocket scientist (really!) paid for by a research grant. On the other hand they want a way to design rods in the uk and communicate with their subcontractors in the far east and then QC everything they get. One way - their way - is using FE software, image capture and a computer controlled rig. (Don't tell Fred but thats the next project )

Hardy's latest toy is a Nodding Donkey which can simulate casting. Set a rod going and leave it a few days - the rod has completed as many cycles as you or I would put it through in it's expected life. They can test the rod before and after to find out if casting changes the rod. There's a question about fatigue in carbon composites and thats the first piece of kit that can test rods that way. We know for sure cane changes with age - some top casters claim their rods soften with age - the composites industry say no! But since the wings of aeroplanes are carbon fibre they would say that! Thankfully wings are vastly thicker and stronger than the walls of rods - so the issues are not the same.

Ardbeg - yeah there are issues about reusing older blanks and about using the same blanks in different rods. Sadly, frequency can't tell me if rod A and rod B use the same blank unless all the rings are the same and all in the same place. You or I could probably cast two rods and say they feel very similar - test the frequency and chances are the figures will be similar. But, take one identical blank and have it rebuilt with three different rings sets and it feels like three different rods - Sandy Nelson and I tried it and even if the changes are relatively small they are noticeable.

As it happens Greys discontinued a successful range of rods - they stopped dealing with that sub-contractor. Shortly afterwards that company were out touting a fully developed range of rods - soon bought by a UK company and successfully marketed.
So the story goes - so please don't quote me  :? If you'd care to guess which two rod ranges we could have a little prize for the winner So - Greys and A.N.Other uk brand - name those ranges ? A cape to the winner.

Frequency may enable us to tell if there are any common denominators among, say, long casting rods or numb rods or rods with tip-bounce or rods favoured for certain attributes - feel, roll casting, loop control - all that good and mystical stuff through which I make a living. The guys spending too much time using 9ft rods to cast #5 lines at the horizon believe that if you compare rods the highest frequency is 'gooder' - some obvious stuff like its lighter and all that. However when we started measuring the stiffness of a load of the same rods we found quite a large degree of variance. In the system I use its almost one line-weight from the softest to the stiffest. Otherwise those rods are identical to all intents and purposes.

[Magnus]

When they test rods they use lines - just a weight to simulate the effect.

One of the plants they deal with in China has a very similar set-up to the one they have in Alnwick. That means rapid communication both ways. The factory has a team of composite engineers on staff. When Howard goes over to test rods, he casts a few in the morning, makes suggestions and has a revised models ready to cast after lunch. In the US or UK that would take weeks.

Once a rod has been fully developed QC is simple. They use a deflection rig similar to mine, fit a known weight (1N or somesuch) to the tip and measure the deflection. They soon know if there's a problem because the rod bends less of more than the pattern sample or the tip doesn't reach the correct position if the action is out.
Their big issue is breakage - same with all volume rod makers - which is where those destructive tests and design using FEA comes into play. This stuff is all new, the results won't show for a year or so. It takes a year or more to develop a range of rods. I know one range is being redesigned using the FEA results - instead of a combination of four carbons they reckon they can make the same using one specific material.