The point of tapers in fly lines and leaders

[Will]

Excellent stuff again Lee.

Would I be right in thinking that the rates of taper on the Power Spey are slower than on the Scandi?

If so, would that mean that the differences in acceleration/drag throughout the cast will be smaller, resulting in very little difference in turnover for the two Power Speys?

Cheers

Will

[Lee Cummings]

Yes Will, the tapers on the Scandis are steep, couple that with how short they are and it’s easy to get a very pronounced effect.
With the Long Head Speys, it took the force generation of using an 18ft rod to get them both moving, the roll out race was close.

It many ways it’s cool to see them roll out side by side however I would be purposely choosing to cast each one slightly differently when on their own.
Cheers
Lee

[Will]

I'll bet!

[Merlin]

Thanks a lot Lee, that is clearer now, and if I understand well, the line with the significant sag in the rod leg at the end is the "normal" one. The other one, the reversed, shows more tension in the rod leg meaning that there is some acceleration (not so easy to capture by eyesight). I paid some interest to the sag in the rod leg in the past, when we discussed "catenaries" and it depends on both speed and acceleration of the fly leg.

So that fits well with "theory", qualitatively speaking, and the large size of the line means that its sensitivity to air drag is small. Do you know the size of the tip and of the handling section?

What type of "leader" were you using? A piece of sizeable mono? With this kind of outfit, I do not expect any exponential deceleration of the leader, this is a thing for light trout leaders and SH rods.

I guess your carry was about 75 feet or something like that.

Very interesting experiment with DH tackle, and to tease Paul, quick data delivery

Merlin

[Paul Arden]

It might be interesting to cast each one individually optimised to see how similar the loops are and the time it takes for each to unroll? I didn't get to repeat the experiment yesterday because it was Ashly's birthday. I'm building two lines at the moment that might be slightly more extreme versions.

Cheers, Paul

edit:

Very interesting experiment with DH tackle, and to tease Paul, quick data delivery

[gordonjudd]

I think this captured still image illustrates very well the difference in tension between the two lines around the point that both loops have just turned.

Lee,
The line tension on the rod leg is nominally assumed to be rho_l*v_loop.^2. That at the point when there is no loop propagation the tension in both legs should nominally be zero and they just fall to the ground since they are at the mercy of gravity.

However, I think you are correct that at the end of the cast where the leader is just entering the loop the reversed head should have more tension due to its higher rho_l value. Thus the shapes you captured after the loop rolled out show the reversed head had more tension on the rod leg at an earlier point in time.

Great video. I will look forward to getting a velocity profile of the two lines. Like Merlin I am perplexed why the velocity profiles appear to be the same.

Live and Learn.

Gordy

[Geenomad]

Had to use the 18ft Competition Rod

Great work Lee. A picture is worth a thousand words and quite a few piles of hypotheses.

Folks. If we look at the starting pic of the vid before play is clicked what are we seeing?

We aren't seeing the effects of mass distributed differently so much as the effects of the same mass being accelerated with the same force. Oh, but all that happened before the loops formed. Nothing to be seen there then.

Cheers
Mark

[Lee Cummings]

We aren't seeing the effects of mass distributed differently so much as the effects of the same mass being accelerated with the same force. Oh, but all that happened before the loops formed. Nothing to be seen there then.
Cheers
Mark

Hi Mark

That starting frame (which YouTube selected upon upload) does not give away the fact that the belly of the right way round spey was going into free fall at this point. It started out above the wrong way round line right after loop formation.

It was a fluke that they were line up in this frame.

Cheers
Lee

[Geenomad]

Hi Lee
I hear what you say but my comment was made after watching the vid frame by frame. In particular I watched from 0.13 to 0.14 several times. At about the middle of 0.14 turnover has nearly reached the leaders and I can't see either main line failing much, at least as seen against the second tree in front and to your left. Looks kosher to me mate. Not enough difference in altitude, shape or behaviour to register as meaningful to my eye. Always open to persuasion, of course.

I chose the starting frame because it seemed to demonstrate the point without requiring a full frame by frame analysis.

Cheers
Mark