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!

Swing, Spring, Whip

Moderator: Torsten

User avatar
Bernd Ziesche
Posts: 3436
Joined: Wed Jan 09, 2013 10:01 pm
Answers: 0
Location: Whereever the fish are!
Contact:

Swing, Spring, Whip

#31

Post by Bernd Ziesche »

Merlin wrote:Hi Bernd

The model considers that the whole line has the same speed up to the launch point, it does not considers the shaping of the loop,
Hi Merlin,
Your "launch point" is the end of fraction 2 in my sketch?

Image

If so, how much percentage of the whip effect has taken place here?

The answer seems quite variable to me depending on how I perform the cast and what rod-line system I have in use.

I (think I) do understand, that the tapering of the fly rod would have a benefit to the speed up of the rod tip based on the conservation of energy/momentum principle. But yet I have no clue what this means in terms of helping me to bring my fly to the fish. If I would have to make a guess, I think it doesn't contribute much here in most of my casts.

The tapering of the fly line means: We increase surface and thus increase friction in relation to line mass. How is this with the tapered fly rod? Was this also taken into account?

Thanks
Bernd
http://www.first-cast.de
The first cast is always the best cast.
User avatar
Paul Arden
Site Admin
Posts: 19528
Joined: Thu Jan 03, 2013 11:20 am
Answers: 2
Location: Belum Rainforest
Contact:

Swing, Spring, Whip

#32

Post by Paul Arden »

The reason I thought a level rod would be better because it’s the propagation of a wave (which is why I asked the question to see if I understood the basic principle). But I’m not sure now :D

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

Flycasting Definitions
User avatar
Merlin
Posts: 2101
Joined: Wed Jan 09, 2013 8:12 pm
Answers: 0
Location: France

Swing, Spring, Whip

#33

Post by Merlin »

Hi Bernd

First question: yes

Second question 75% typical in terms of speed at launch time, by comparison to absolute maximum speed. Launch time is considered as the moment when the tip begins to drop down. The gain at absolute maximum speed is higher, hence the 75%.

As stated in the article for a SH modern rod, the whip energy contribution is about 15%, but you can hardly detect it. If you want to have more chance to do so, take a tip heavy rod.

As also mentionned in the article, aerodynamics forces on the rod are not included in the energy evaluations (same for speeds).

Merlin
Fly rods are like women, they won't play if they're maltreated
Charles Ritz, A Flyfisher's Life
User avatar
Bernd Ziesche
Posts: 3436
Joined: Wed Jan 09, 2013 10:01 pm
Answers: 0
Location: Whereever the fish are!
Contact:

Swing, Spring, Whip

#34

Post by Bernd Ziesche »

Thanks Merlin!
Are there any datas/ideas how the line length outside the tip effects the level of whip effect to the line speed up?
When I add high speed to a short line, I probably put an increased whip effect to the line since I store more energy in the rod in relation to line mass outside the tip. Casting a long line in lowest possible rod bend should be opposite though. Any idea how much of a range of increasing line speed by whip effect we may have?
Using a heavy rod means I can store more energy in the rod in relation to the line mass. Would this increase the level of whip effect? Regards Bernd
http://www.first-cast.de
The first cast is always the best cast.
User avatar
Merlin
Posts: 2101
Joined: Wed Jan 09, 2013 8:12 pm
Answers: 0
Location: France

Swing, Spring, Whip

#35

Post by Merlin »

Hi Bernd

Good questions indeed

The shorter the line is, the higher the relative speed improvement (percentage) is. Although there is some interference with stored elastic energy, the whip effect is a question of rod mass (and its location along the shaft), not of spring.

A heavier rod mass brings more speed increase in terms of percentage. For example, you may have 6% speed increase due to the whip effect for a graphite rod and 20% for a cane rod in similar conditions.

To give a broaded view, if I consider a graphite rod we may have from 8% to 4% increase in speed due to the whip effect, depending on carry, and from 25% to 18% for a cane rod.

Merlin
Fly rods are like women, they won't play if they're maltreated
Charles Ritz, A Flyfisher's Life
User avatar
Bernd Ziesche
Posts: 3436
Joined: Wed Jan 09, 2013 10:01 pm
Answers: 0
Location: Whereever the fish are!
Contact:

Swing, Spring, Whip

#36

Post by Bernd Ziesche »

Hi Merlin,
some years back I tried to cast a 5wt. MED on a Tarpon rod, while having some lead on the rod tip. My idea was to increase rod bend and then have the straightening help to additionally increase line speed. My conclusion was, that there is an effect of having additionally bended the strong rod and thus get a benefit during straightening. But at the same time the lead on the tip increases swing weight of course and making for a feel, I didn't like much.
I still prefer to use rotating the lightest possible rod for the rod action and stiffness I want. It may happen though, that I prefer heavier rings over lighter ones. For example I dislike recoils.
Regards
Bernd
http://www.first-cast.de
The first cast is always the best cast.
User avatar
Paul Arden
Site Admin
Posts: 19528
Joined: Thu Jan 03, 2013 11:20 am
Answers: 2
Location: Belum Rainforest
Contact:

Swing, Spring, Whip

#37

Post by Paul Arden »

That’s very interesting Bernd. Another use for the Feel Fxxxer? :D
It's an exploration; bring a flyrod.

Flycasting Definitions
Mangrove Cuckoo
Posts: 1038
Joined: Tue Jan 29, 2013 7:51 am
Answers: 0

Swing, Spring, Whip

#38

Post by Mangrove Cuckoo »

Merlin, et al...

Is there a practical application for choosing a rod that has more "whip" percentage than say a stiff graphite rod of recent vintage?

Am I on track to think that a bamboo rod makes a short line/ long leader cast easier because of more "spring" due to the relatively heavier tip section... and that is not the same as "whip"?

I am really trying to get my head around this one!
With appreciation and apologies to Ray Charles…

“If it wasn’t for AI, we wouldn’t have no I at all.”
User avatar
Merlin
Posts: 2101
Joined: Wed Jan 09, 2013 8:12 pm
Answers: 0
Location: France

Swing, Spring, Whip

#39

Post by Merlin »

Hi Bernd

If you want to test the whip effect on a modern rod, you may use some lead wire at the level of the tip ferrule of a four piece rod, but not at the tiptop level (Feel fixer). That will have less effect on swing weight and frequency lowering, it may induce a node at this place however (tip ferrule).

If you prefer heavy rings, it may be because the rod is a bit fast. I prefer a less fast rod with recoils for speed of recovery. Heavy rings is typical of bass rods.

Merlin
Fly rods are like women, they won't play if they're maltreated
Charles Ritz, A Flyfisher's Life
User avatar
Merlin
Posts: 2101
Joined: Wed Jan 09, 2013 8:12 pm
Answers: 0
Location: France

Swing, Spring, Whip

#40

Post by Merlin »

Hi Mangrove

Whip effect is coming along with rod mass, so it is typical of cane rods. The interest for modern rods is limited although fine tuning can encourage designers to take the best of it, since it affects a little bit speed of recovery.

That extra mass in tips does not give "spring" but "whip". It lowers the rod speed generaly speaking. The forward "kick" linked to rod butt deceleration is a whip effect.

Merlin
Fly rods are like women, they won't play if they're maltreated
Charles Ritz, A Flyfisher's Life
Post Reply

Return to “Flycasting Physics”