PLEASE NOTE: In order to post on the Board you need to have registered. To register please email paul@sexyloops.com including your real name and username. Registration takes less than 24hrs, unless Paul is fishing deep in the jungle!

The point of tapers in fly lines and leaders

Moderator: Paul Arden

User avatar
Will
Posts: 279
Joined: Thu Jan 10, 2013 9:44 pm

The point of tapers in fly lines and leaders

#1

Post by Will » Sat Jun 15, 2019 10:16 am

OK, so I thought I had this sorted, but recent posts in other threads have me confused.

I’d always thought there were two main ways of looking at things taper-wise:

Roll casts/Speys: where thick line pulls lighter line off the water surface, so Spey oriented lines have back-weighted heads and long front tapers.

Presentation: where thinner line is subject to more air resistance and so slows down quicker than thick line (of the same density). This helps stop the fly line kicking, and with tapered leaders smooths the transition from fly line to fly.

But then Bruce said he’d thickened the tip of the MED to slow down turnover, citing increased mass...

And then James said that the taper in a bull-whip speeds up the tip...

Soooo...

How should I be thinking about this now?

Cheers

Will
Lineslinger
Barrio Pro-team
SGAIC
AAPGAI

"The only advice it is necessary to give the angler… is to avoid any approach to foppery, as trout have the most thorough contempt for a fop…”
WC Stewart

User avatar
Paul Arden
Site Admin
Posts: 12399
Joined: Thu Jan 03, 2013 11:20 am
Location: Belum Rainforest
Contact:

Re: The point of tapers in fly lines and leaders

#2

Post by Paul Arden » Sat Jun 15, 2019 11:00 am

Hi Will,

The thinner line has less air resistance and actually wants to speed up. At first when the loop reaches the front taper it does sometimes accelerate. However it also has less mass.

I think Gordy would tell you that less mass means less momentum change at the loop front and therefore less force pulling the line. I think others might say that the mass to surface ratio of the thinner line means that drag forces have a greater effect on slowing the line. Maybe it’s a bit of both.

I would love to hear a clear explanation. In particular I would like to understand why a whip tapers to crack and a fly line tapers to dissipate energy.

Cheers, Paul
It's an exploration; bring a flyrod.

Flycasting Definitions

User avatar
Will
Posts: 279
Joined: Thu Jan 10, 2013 9:44 pm

Re: The point of tapers in fly lines and leaders

#3

Post by Will » Sat Jun 15, 2019 12:36 pm

Yep, I was/am(?) in the mass:surface area ratio camp. But Bruce’s comments have thrown me! 😬
Lineslinger
Barrio Pro-team
SGAIC
AAPGAI

"The only advice it is necessary to give the angler… is to avoid any approach to foppery, as trout have the most thorough contempt for a fop…”
WC Stewart

User avatar
Lasse Karlsson
Posts: 3718
Joined: Wed Jan 09, 2013 9:40 pm
Location: There, and back again
Contact:

Re: The point of tapers in fly lines and leaders

#4

Post by Lasse Karlsson » Sat Jun 15, 2019 1:15 pm

Didn't Bruce sat he lengthened the front taper to delay turnover but increased the mass to ensure it would?
Can't find the reply right now...

Cheers
Lasse
Your friendly neighbourhood flyslinger

http://www.karlssonflyfishing.com

***Bring Mark back!!!!!! ***

User avatar
Paul Arden
Site Admin
Posts: 12399
Joined: Thu Jan 03, 2013 11:20 am
Location: Belum Rainforest
Contact:

Re: The point of tapers in fly lines and leaders

#5

Post by Paul Arden » Sat Jun 15, 2019 1:47 pm

I think that Bruce is comparing to a line that has a head a) not compound front and b) has heavier line behind the compound front, which it would if they both weigh the same at 30’. I think b) is rather important.

I’m in both camps, Will. I don’t think one excludes the other.

Cheers, Paul
It's an exploration; bring a flyrod.

Flycasting Definitions

User avatar
gordonjudd
Posts: 1265
Joined: Sat Jan 19, 2013 11:36 pm
Location: Southern California

Re: The point of tapers in fly lines and leaders

#6

Post by gordonjudd » Sat Jun 15, 2019 3:49 pm

I think Gordy would tell you that less mass means less momentum change at the loop front and therefore less force pulling the line
Paul,
I am not the one who came up with that explanation. Rather it is the viewpoint of researchers such as Lingard, Spolek, and Gatti-Bono who have written papers on the subject.

The effects of the tradeoff between the positive acceleration acceleration force on the line produced by the tension at the top of the loop and the negative acceleration due to drag forces on the line and fly were discussed on the old board at:http://sexyloops.co.uk/archivedboard/vi ... 24&t=12479

Thanks to you for getting that valuable resource restored.
I would love to hear a clear explanation. In particular I would like to understand why a whip tapers to crack and a fly line tapers to dissipate energy.
The slowdown of the line due to increased energy dissipation is a red herring concept.

Both the drag losses and the positive acceleration due to the momentum change of the mass going around the loop depend on the square of the velocity so an increase in the velocity is not going to favor one over the other.

It should be noted that the properties of the tear shaped loop that is propagating down a tapered whip is different than the u-shaped loop that is propagating down a fly line. Thus the effects of taper on a whip are much different than the effects of taper on a fly line.

Gordy

Geenomad
Posts: 373
Joined: Tue Aug 06, 2013 10:11 pm
Location: Melbourne

Re: The point of tapers in fly lines and leaders

#7

Post by Geenomad » Sun Jun 16, 2019 12:07 am

Maybe it's just me, though I doubt it, but I am wondering why this stuff about angular momentum has been granted asylum in this part of the Board. What has it got to do with Fly Casting, as in how to do it, better?

Cheers
Mark
"The line of beauty is the result of perfect economy." R. W. Emerson.
https://thecuriousflycaster.com

User avatar
Graeme H
Posts: 1651
Joined: Fri Jan 25, 2013 2:54 pm
Location: Perth, Western Australia

Re: The point of tapers in fly lines and leaders

#8

Post by Graeme H » Sun Jun 16, 2019 12:19 am

Other thread Mark? But yeah, I agree, the original poster should have put the angular momentum thread in TechAnal. ;)
FFi CCI

User avatar
Graeme H
Posts: 1651
Joined: Fri Jan 25, 2013 2:54 pm
Location: Perth, Western Australia

Re: The point of tapers in fly lines and leaders

#9

Post by Graeme H » Sun Jun 16, 2019 12:30 am

A taper can magnify velocity in a fly line and a whip via the same principle shown in this video. Momentum from a heavy object is transferred into a lighter one, which is then transferred into an even lighter one. To maintain momentum, the velocity increases.

For the mechanism of how the energy can be dissipated through a taper, I'll need to explain that with a tracked video tonight. I'll do that in the angular momentum thread and put a link below later.

Cheers,
Graeme


FFi CCI

Geenomad
Posts: 373
Joined: Tue Aug 06, 2013 10:11 pm
Location: Melbourne

Re: The point of tapers in fly lines and leaders

#10

Post by Geenomad » Sun Jun 16, 2019 4:56 am

Graeme H wrote:
Sun Jun 16, 2019 12:19 am
Other thread Mark? But yeah, I agree, the original poster should have put the angular momentum thread in TechAnal. ;)
Yeah I thought about that. But it's both threads really. :) Same creep into same subject matter and my objection goes well beyond forum taxonomy but will leave it at that. Rant mode cancelled. :D

Cheers
Mark
"The line of beauty is the result of perfect economy." R. W. Emerson.
https://thecuriousflycaster.com

Post Reply

Return to “Flycasting”