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Stiffness and Tip speed

Moderator: Torsten

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Lasse Karlsson
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Stiffness and Tip speed

#41

Post by Lasse Karlsson » Sat Jan 19, 2019 7:48 am

But I do Vince :D

It's the only clip of mine I have uploaded casting right to left, unless it's the release clip, but that misses the marker at the rodtip....
https://vimeo.com/26927235

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Paul Arden
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Stiffness and Tip speed

#42

Post by Paul Arden » Sat Jan 19, 2019 8:08 am

Nice video Lasse.

If we were to compare 1) with overhang that is pulled into the loop from the top to 2) overhang that is slipped into the loop from the bottom, in both cases leaving the head in the same place, I’m not sure how much difference we have. I suppose with 1 we have a little bit more haul and with 2 some line in the bottom of the loop with forward momentum.

I do use with Shooting Heads - and obviously the backcast on my Snakehead shot which is released far sooner.

I need one of those lights!!! :D

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Lasse Karlsson
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Stiffness and Tip speed

#43

Post by Lasse Karlsson » Sat Jan 19, 2019 8:22 am

The line sticks to the rod if released after RSP, that's the problem :p

When you've shot the clips we are waiting for, I'll send you the light ;)

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Merlin
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Stiffness and Tip speed

#44

Post by Merlin » Sat Jan 19, 2019 8:54 am

Hi Lasse

Yes, this is the one, and I can see that there is a rather long translation before the start of rotation, however this part is not digitalized I think.

It is thus possible that the hand paths are rather similar.

The problem with the clip is that the rotation of the rod cannot be identified, and that makes the use of this cast impossible for comparison with models. However it illustrates a pretty straight tip path.

Thanks

Merlin
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Paul Arden
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Stiffness and Tip speed

#45

Post by Paul Arden » Sat Jan 19, 2019 10:28 am

Not sure. I think the reason it shoots up is because the rod is straightening. Out of interest with Pre-RSP does it shoot up, slow and then continue again, or is it one continuos shoot?

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Lasse Karlsson
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Stiffness and Tip speed

#46

Post by Lasse Karlsson » Sat Jan 19, 2019 12:47 pm

I don't know, damn hard to figure out with a 4*4 cm cube of foam on the line stopping the shot at the first guide :D
I do know that all my longest casts, and those that feel effortless and great, come from releasing early..

And apart from it sticking, what would be the reason to release after max velocity in the intended direction? Not a fan of big spring and that kind of thing, and I've noticed even the spey guys and gals let go pretty early too ;)


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Torsten
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Stiffness and Tip speed

#47

Post by Torsten » Sat Jan 19, 2019 1:06 pm

Please, guys, try to stick to the topic. As far as I understand, Daniel used this only as example input to his model.
I'd rather like to see a discussion of the results from post number #13.

--

I think that's a nice work Daniel; I'd like to see if the results can be verified by actual measurements.
Can you describe your model a bit more detailed? How was the rod modelled?

At the first look the tip speed seems to be very high, because Grunde has measured only about 25m/s [1] - OK I'm guessing this was only for a short cast. Are there somewhere actual measurements for distance casts?

Maybe it's possible to repeat gear testing with high speed video recording and some reference markers?
Today we have access to much better video equipment, 4K cams are everywhere sold and many have high speed features.

Thanks,
Torsten

--

[1] http://www.sexyloops.com/articles/rodcast.shtml

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Merlin
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Stiffness and Tip speed

#48

Post by Merlin » Sun Jan 20, 2019 6:12 am

Hi Torsten

This is pretty technical, so I sent you a few papers on my model for information. If others are interested, they just have to let me know, I shall send the files to them.

Tip maximum speed may be optimistic, but these are competition casts, not like the one documented by Grunde. You can double maximum rotation speed so being in the 60s is possible, maybe Gordy has some data for some 170 competition cast made by Paul.

To make a comparison between an actual competition cast and a model, we need to shoot a cast with two cameras: one aiming at identifying the hand path and the rotation speed of the butt of the rod, and the other one to capture tip and line speed (with markers on the line, and on the rod butt if possible).

Any volunteer? :)

Merlin
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Graeme H
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Stiffness and Tip speed

#49

Post by Graeme H » Sun Jan 20, 2019 7:05 am

Is this what the Italians are doing with their "style" of underlining shorter rods and making high speed casts?

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Graeme
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Stiffness and Tip speed

#50

Post by guest » Sun Jan 20, 2019 8:16 am

Hi Daniel

Are the tip speeds you are quoting the loaded or unloaded speed?

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Vince
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