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Fly Line Database

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Paul Arden
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Fly Line Database

#11

Post by Paul Arden » Thu May 02, 2019 3:59 pm

PS it was Lars’ original idea. And a great one it is too. I hope to have a database up and running in the next week or so. I’ve asked our web developers but if anyone knows of a decent secure web database application then please let me know.

Thanks, Paul
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Lasse Karlsson
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#12

Post by Lasse Karlsson » Thu May 02, 2019 4:55 pm

sms wrote:Lars, I do get very close to correct weight via repeating. With 5 times measuring, I do get within 0,1g accuracy.

I use a cheap 0,1g accuracy scale (max 1000g I think). It is quite accurate - I have couple of calibrating weight sets.
Me too, and I even have a couple of pesola spring scales to make measurements in the field...

Cheers
Lasse
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Paul Arden
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#13

Post by Paul Arden » Thu May 16, 2019 8:07 am

Just to keep you in the loop, I'm having the database option built at the moment. It should be ready in a week or so.

Cheers, Paul
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#14

Post by Paul Arden » Thu May 16, 2019 12:39 pm

Lots of interest in this project by the way. :cool:
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gordonjudd
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Re: Fly Line Database

#15

Post by gordonjudd » Thu May 30, 2019 3:15 pm

This article is worth having in mind, and maybe get allowance to use the data as a start?

https://www.tridentflyfishing.com/blog/ ... yers-guide
Lasse,
As noted in the Spolek paper the primary factor effecting how the velocity of the fly will vary as the loop propagates is its linear mass density profile. Thus from a technical standpoint it would seem a good data base would include a measurement of that profile.

The problem is getting that profile involves a lot of measurements. As noted in the article you found
Taper diagrams were created by measuring the diameter of each line every 6 inches until we were well into the running line. Yes, that’s well over 4000 data points. We used a digital micrometer, which is the only way to get an accurate reading.
To complicate matters even further in order to get the rho_l profile you would need to develop a worksheet similar to the one Grunde produced to compute the swing weight of rods to convert the measured mass and diameter values to produce the linear mass density profile. That added computation was was not done in that Trident article so the plots of there diameter measurements do not provide much information since they have no scales to see how the actual diameter varies along the length of the line.

This would be a great project, but I think it should provide more information than just a mass measurement of the first 30 feet of line to compare how they comply with the AFTMA standard. Coming up with linear mass density profiles of the lines would make for a great comparison of their expected casting characteristics, but would require a lot of work.

Gordy

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Graeme H
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Re: Fly Line Database

#16

Post by Graeme H » Fri May 31, 2019 7:22 am

This would be a great project, but I think it should provide more information than just a mass measurement of the first 30 feet of line to compare how they comply with the AFTMA standard. Coming up with linear mass density profiles of the lines would make for a great comparison of their expected casting characteristics, but would require a lot of work.

Gordy
I'd be happy enough with mass of first 30', length of the head and tapers and the comparative diameter of the running line for a start. I can normally work out how it will cast from that info and I assume others would be able too.

This project will never get off the ground if it's too hard for us to collect the data.

Cheers,
Graeme
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Paul Arden
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Re: Fly Line Database

#17

Post by Paul Arden » Fri May 31, 2019 8:55 am

Can we make a list of measurements to take? I envisage size being a potential problem, particularly with multiple entries of the same line. Maybe that's a good problem to have.

My thoughts are a minimum of two rows for each line, one being the manufacturers official target and then below this the measured line/s.The measured lines will be in a separate colour, which makes it easer to navigate.

Line Number, Make, Model, AFFTA weight, Head length, Head weight, Total length, Total weight, Diameter running line, Diameter tip

These things are all easy to measure apart perhaps from head weight which I imagine will have a larger scope for error. Density would be a wonderful measurement but might be a little bit difficult to obtain!

If we should collect more data it's easier to plan for this at the beginning.

Cheers, Paul
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gordonjudd
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Re: Fly Line Database

#18

Post by gordonjudd » Fri May 31, 2019 3:12 pm

I'd be happy enough with mass of first 30', length of the head and tapers and the comparative diameter of the running line for a start. I can normally work out how it will cast from that info and I assume others would be able too.
Graeme,
That is good news as I was mystified by the slope differences in the belly sections of the diameter profiles in the Trident article.

Can you explain how a line that has a belly taper that goes from thin at the front to thick at the back such at the Wolf Triangle taper line
Image
Would cast compared to one where the taper is in the opposite direction (thick to thin) such as the Rio In Touch Gold taper shown below?
Image

I was surprised that you would want opposite tapers for different casting situations or why a line with a nominally flat belly section (found for the majority of the lines they measured) would be the line of choice for a particular situation or casting style.
Image

Gordy

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Re: Fly Line Database

#19

Post by Paul Arden » Fri May 31, 2019 3:20 pm

I agree that the tapers are very important Gordy, and two lines of the same weight at 30ft can feel completely different, not to mention lines that are still significantly increasing in weight after 30ft. That would be tremendous information to have. But how do we measure it?

Cheers, Paul

edit: personally I've always found many of these complex tapers to be quite specialised in their application. And the more complex they are, the more specialised they become. If they have the same AFFTA weight then I think they can be compared. Be that as it may, I would start by using the same AFFTA measurement for each taper, using the same rod - and not the number written on the box.
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gordonjudd
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Re: Fly Line Database

#20

Post by gordonjudd » Fri May 31, 2019 3:57 pm

Density would be a wonderful measurement but might be a little bit difficult to obtain!
Paul,
As noted in the Trident article
Then we thought about taking density measurements, and it turns out that the differences are subtle, and not really useful, so we gave up.
I don't think you could measure the volume of a length of line very easily but with an accurate diameter profile and mass measurements for a given length of line you should be able to calculate it.

Although the float-ability of a line depends on more than just its density I do think that the density will affect the line tension around the loop directly. Thus for a given loop velocity and line diameter the line with a higher density will produce more tension that may help it to offset drag losses and thus cast further.

The MED 5 wt is a good example. As shown below the measurements taken by the Norwegian Casting Federation
Image
Show that it had a mass density of around 962 Kg/m just a shade below the 1000 Kg/m value for water. Thus it could be considered to be a floating line, but barely so.

That density gives the MED 5 this linear mass density profile that would be interesting to compare to other distance casting lines.
Image
This type of plot is the detailed information that would be great to have in a data base for the technically inclined, but it would take a lot of work to produce it as evidenced by the effort made by the Norwegians to come up with line specs for their casting games.

There must be a reason the linear mass density of that distance line goes from 1.2 g/m to .5g/m. as opposed to the other way around.
Gordy

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