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Shooted cast

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Lasse Karlsson
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Re: Shooted cast

#11

Post by Lasse Karlsson » Wed Sep 02, 2020 5:46 am

So now less than 180 degrees seperation causes a tail? 🤣

Where do you measure from to get 15 degrees on that cast? Your feet?
Do you have a link to that app?

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Re: Shooted cast

#12

Post by Lasse Karlsson » Wed Sep 02, 2020 5:51 am

Paul Arden wrote:
Wed Sep 02, 2020 3:47 am
You think the bottom part of the rod leg is pulling the fly leg? Anyway I agree it’s not 30. Let me see if my phone has a protractor...
The day I think that the rod leg which is fed by the flyleg pulls the flyleg, is the day I've gone insane :D

How come yiu think theres a difference in release timing depending on how thick the line you're about to shoot is? And why does it matter less if it's fatter? You usually think thinner moves faster, so fat needs all the help it can get, not less?

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Re: Shooted cast

#13

Post by Merlin » Wed Sep 02, 2020 9:40 am

do you have parameters for haul length and haul speed???
Gary

I looked at the 2D casting model using three hauling scenarios in « optimum conditions » for a competition cast, that means late, but not too much, at the limit of the tailing zone for the tip path. The best haul is a compromise, not necessarily the longest in time, but on the long side. A short haul (170 ms duration, 1 m distance) is not so effective in speed by comparison. Max haul speed is the same of course (11.8 m/s).

Since the loop is generally shaped before MCF (I could see that on some of Lasse’s videos), I measured the time between RSP and MCF, and in the conditions of the model (rod, cast, max haul speed, etc.), this time is in between 60 ms to 80 ms. The shortest haul ended close to RSP (slightly before), and the longest one (340 ms, 2 m) finished after MCF (40 ms after). The haul in between (260 ms, 1.5 m) finishes at MCF approximately (15 ms before). The intermediate haul is just a little bit slower (0.5 %).

Does that answers you question?

Merlin
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Re: Shooted cast

#14

Post by Merlin » Wed Sep 02, 2020 9:41 am

Are you modelling counterflex and RSP2?
Incidentally why is the cast supposed to be horizontal?
Paul

I do not have a model including rod cast and line flight at the same time, they are distinct. I do not envisage writing an intermediate model to link both, that is too complicate for a human like me.

The cast is supposed to be horizontal in order to find the mathematical solution of the mechanics of the flight in simplified conditions. That is why most models use that assumption. But since the aim is to identify important parameters and not to match perfectly a cast, that is OK for me.

Merlin
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Re: Shooted cast

#15

Post by Merlin » Wed Sep 02, 2020 9:44 am

Have a look, there is slow mo of the delivery and release, let me know what you think.
Could you use my video, or something similar and mark where the release position should be for the best result?
Mike,

They seem to me to be pretty good at first sight, the opening of the hand being very close to the stop, there may be one image difference in the first video but I’m not sure. What is the number of frames per second? That will give us an order of magnitude of the number of ms at stake. Ideally (strange thing in real life), the release should take place somewhere around the end of the haul, just as the loop is shaped. The haul may sometimes finish after loop is shaped (see comments above for Gary). Without seeing the loop it is not possible to comment further unfortunately. And I guess that defining what is a “shaped loop” on a video might be a difficult point to establish exactly. Have a look at this nice video from Lasse illustrating timing release for a shoot.

https://vimeo.com/26927235

If I do not fool myself the loop is shaped between 20 ms and 30 ms after RSP. The first release time is about 50 ms to 60 ms after RSP, 30 ms after loop shaping. For the second part of the video it takes place as loop shaping ends (approximately). There is a lag time for the shoot in the first part of the video. Interesting and for the time being I think the model is not able to catch it. The shaping of the loop is not included, and that may well be the point. There is some dynamic in the loop tangential speed which may constrain the beginning of the shoot in that case.

Merlin
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Re: Shooted cast

#16

Post by Mangrove Cuckoo » Wed Sep 02, 2020 12:27 pm

Merlin wrote:
Wed Sep 02, 2020 9:40 am
do you have parameters for haul length and haul speed???
Gary

I looked at the 2D casting model using three hauling scenarios... The intermediate haul is just a little bit slower (0.5 %).

Does that answers you question?

Merlin
Um... uh... probably? :upside:

Just for kicks, last evening during my daily "fun with flyrods" session, I tried to deliberately release the haul before RSP. This was not on max distance casts, but long enough to bend the rod a bit... maybe 75 - 90 feet.. And just with a simple flyline, not a shooting head.

The results impressed me.

I can't say for sure that my release was actually prior to RSP, or by how many ms, but it surely improved the cast. I concentrated on releasing much earlier than my usual full extension, and I tried to release clean(?).

FWIW... it suggested to me that hauling longer, in this distance, was not better but worse. It somehow felt as if I neede to speed up to be working within the parameters of the rod, compared to the long haul that made the rod wait for me. If that makes any sense?
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Paul Arden
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Re: Shooted cast

#17

Post by Paul Arden » Wed Sep 02, 2020 1:00 pm

Hi Lasse,

15 degrees came from picking a target that I would normally use to sight. And then using the iPhone measure app (level), eye to target, with two bits of tape aligned either side of the phone for sighting.

Why do I think it matters less with running line as opposed to shooting line? Well firstly I’ve experimented with different release timings in practise. And I find that to be the case. So then I would ask why is this? And I would think in the case of a Head it’s because if we delay the release then the Head quickly turns over. In terms of actually shooting running line I don’t see much shoot until after the bottom leg of the loop has formed.

But over the years I’ve realised that you are carrying less line, so I have a bit of running line at the top of the loop. If you haven’t then I can see how you would get a different result.

Cheers, Paul
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Re: Shooted cast

#18

Post by Paul Arden » Wed Sep 02, 2020 1:12 pm

Interesting stuff here Merlin,
Since the loop is generally shaped before MCF (I could see that on some of Lasse’s videos), I measured the time between RSP and MCF, and in the conditions of the model (rod, cast, max haul speed, etc.), this time is in between 60 ms to 80 ms. The shortest haul ended close to RSP (slightly before), and the longest one (340 ms, 2 m) finished after MCF (40 ms after). The haul in between (260 ms, 1.5 m) finishes at MCF approximately (15 ms before). The intermediate haul is just a little bit slower (0.5 %).
I would have thought with Heads optimum release point is RSP or slightly before. And with a full line something around RSP (possibly as late as MCF but I think that would be late). I’m surprised that the Haul is continuing to MCF. Lasse often talks about releasing pre RSP and I’m certain I’ve seen that with the light bulb release.

I don’t think that release timing in relation to the haul is as important as release timing in relation to loop formation. With a shooting head I actually often release the line before the haul has completed its full arm movement. I sometimes play with that and the MED but I had always envisaged poking around RSP and not MCF.

Cheers, Paul
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Re: Shooted cast

#19

Post by Lasse Karlsson » Wed Sep 02, 2020 1:50 pm

Paul Arden wrote:
Wed Sep 02, 2020 1:00 pm
Hi Lasse,

15 degrees came from picking a target that I would normally use to sight. And then using the iPhone measure app (level), eye to target, with two bits of tape aligned either side of the phone for sighting.

Why do I think it matters less with running line as opposed to shooting line? Well firstly I’ve experimented with different release timings in practise. And I find that to be the case. So then I would ask why is this? And I would think in the case of a Head it’s because if we delay the release then the Head quickly turns over. In terms of actually shooting running line I don’t see much shoot until after the bottom leg of the loop has formed.

But over the years I’ve realised that you are carrying less line, so I have a bit of running line at the top of the loop. If you haven’t then I can see how you would get a different result.

Cheers, Paul
Hi Paul

Ixnay on the head turns over faster vs belly of a full line, both are equal length.

And I think its interesting that you would rather change between pieces of string, rather than keep things the same.
You carrying slightly more just so you can release later seems to be counterproductive, but I won't argue here, keep doing it, leaves more room for me to mess up and still beat you as usual 😉

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Re: Shooted cast

#20

Post by Paul Arden » Wed Sep 02, 2020 2:34 pm

Of course! Some day I’ll learn to cast :D But it won’t be any time soon. :cool:

Cheers, Paul
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