Overhang, Loops and Post Loop Flight - Shooting Head Physics

[robk]

I can remember last year casting in an estuary with a shooting head, probably pushing 12-15ft of overhang beyond the tip and using the 170 technique, getting clean loops, good distance and turnover at very long range..

12-15 feet of overhang using what type of shooting line?

Rob

[Ian Walker]

Rob and jmac,
I am also hoping that the theory of the shooting head can be further developed. I certainly don't have a complete understanding yet, but there are a couple of fundamental precepts that I believe any theory should be based upon. These are precepts that I believe are well known and fairly obvious. I hope by listing them that I am moving the discussion forward and help us to find a really satisfying and correct understanding of shooting head casting.

1) The fly line linear density (kg/m) is much greater than the running line.

2) Therefore the fly line can store a large amount of kinetic energy.

3) The running line stores an insignificant amount of energy.

4) The running line can transmit energy, but the only mechanism for this transmission is direct straight line tension. (i.e. You can only transfer energy from the rod to the fly line by the direct pull of the running line. There is no way to push)

5) When the rod reaches RSP (Rod Straight Position) on the final forward cast almost all the energy of the cast is now stored in the kinetic energy of the fly line.

6) This energy that is stored in the line can be expended (dissipated) in different ways depending on certain conditions. For example: If there is no tension on the back end of the fly line (e.g. Casting a shooting head with only a short length of running line that is only long enough for hauling plus overhang) then the fly line will take on the flying spaghetti configuration and the stored energy will be expended almost totally by air resistance without traveling very far. Whereas if there is a constant tension on the back of the fly line, then the fly line will form a loop and will travel through the air some distance before the loop completely unrolls. All the energy will eventually be dissipated via air resistance, but the fly line and fly will have traveled a considerable distance.

[Marc LaMouche]

Whereas if there is a constant tension on the back of the fly line, then the fly line will form a loop and will travel through the air some distance before the loop completely unrolls.

hey Ian,

could you please expand in practical terms what you mean by applying constant tension on the back end of the fly line ?

cheers,
marc

[hinkraka]

marc: If I can guess what Ian is saying, it is a shooting line with constant diameter, and the tension from that shootingline in the guides.

But I only believe that tension to be constant until the head starts to turn over, because then there is different drag on the line, creating different tension...

[Ian Walker]

"Constant Tension" was not really the correct choice of words on my part. The tension on the back end of the loop is constantly present but the value of that tension (Measured in Newtons) is not constant.

In practical terms the tension is created by frictional forces of the running line passing through guides and the air resistance of the running line . The time that the loop in the fly line takes to unroll is inversely related to the amount of tension on the back of the loop. For instance if the tension is suddenly increased by holding on to the running line during the shoot, then the loop in the fly line will unroll very quickly.

Regards,

Ian Walker

[Marc LaMouche]

thanks for clearing that up, Ian.

it was the actual resistance/friction of the shooting line i had in mind and was wondering from the previous post if letting it run through an "O" of the line hand (as in the O.K. sign, tip of index finger to tip of thumb) would be of help controlling that loop tension ?

this of course would be for fishing casts and not ultimate distance.

i'm only now getting into shooting-head casting so this thread is helping me a lot to understand the principles involved.

cheers,
marc

[crunch]

Head which has long taper has best possible energy transfer and allows longest casts. At first it flies straight, heaviest rear section in front and pulls R/L. But because R/L has friction to the guides and air the head starts to unroll.

But if we stop R/L abrubtly the stored kinetic energy transfers to the rest of the line and its speed ingreases. Mow much depends on many variables but in theory speed becomes higher than the complete head had before the R/L stop.

[robk]

For instance if the tension is suddenly increased by holding on to the running line during the shoot, then the loop in the fly line will unroll very quickly.

Agreed. The converse seems true, too. A sudden decrease in shooting line friction can cause the head to effectively stop unrolling and stall out. I found that out by splicing a very fine shooting line into the running line of a WF line. The loop went out cleanly as the standard running line was going through the guides. As soon as the thin stuff hit the guides, the cast went to hell.

[White Hunter]

I can remember last year casting in an estuary with a shooting head, probably pushing 12-15ft of overhang beyond the tip and using the 170 technique, getting clean loops, good distance and turnover at very long range..

12-15 feet of overhang using what type of shooting line?

Rob

Hi Rob K

30lb bs Amnesia, no problems.....

Cheers

Lee

[Lasse Karlsson]

For example: If there is no tension on the back end of the fly line (e.g. Casting a shooting head with only a short length of running line that is only long enough for hauling plus overhang) then the fly line will take on the flying spaghetti configuration and the stored energy will be expended almost totally by air resistance without traveling very far.

Hi Ian

I humbly beg to difer on that assumption. As I've written to Gordon I've had different observations regarding the flying spagehtti

I'm currently not able to get proper footage, but I was out last week and had no problem getting 100+ feet casts with a shootinghead attatched to an even shorter length of shootingline than you suggest. Yes I didn't haul. I only got the spaghetti configuration if I messed up my tracking. Even casting into a slight head breeze got me a loop that just stalled as it got to the front taper part, and it would fall to the ground with just a slightly collapsed front loop, and a parallel top and bottom leg.

Contrary to Gordons light line configuration, I used a 10 weight floating shootinghead of about 35 feet and thin 20 lbs flat mono shootingline. Will get some proper footage when I get home next week.

Cheers
Lasse

[Ian Walker]

Lasse,

Glad to hear your interested and have a different idea of how shooting head will behave with no running line.

I'm hoping that I get a chance to do some filming with Gordy next week. With luck we'll be able to compare results.

A couple of things that you point out are of interest to me. First whether hauling makes a difference. Second, I've primarily been concerned with "Tournament Type" casts using maximum line speed and hopefully traveling 150+ feet using a 300 grain (10.5 Wt) head and 15 lbs test Amnesia running line. Perhaps I will see different results without hauling and using a more moderate casting style.

Best regards,

Ian Walker

[crunch]

I launched just heads without R/L when I read elsewhere that Rio OutBound, which has heavy front, was good distance line. I had one few years ago and did not like it for fishing sea trout from shore where long casts and small flyes are used. It was good with large flyes though. Its loop opened soon and I came to an conclusion it was because of higher air drag of its thin and light rear section and running line, which has coiling problem as well.

As an example Vision Ace floating SH has a lot of taper. 31g head rear 1/2 weights 20g and front only 11g. When I put leader and some wool yarn to the thin front it flew almost straight rear belly in front long and landed to a pile.

But when I turned it so that I put leader to heavy rear its flight went bad. Wind causes more drag to thin section when they have same density so it got behind and head collapsed.

[savage]

Ha, missed this one. Gotta read through the posts.

But I am a user of RIO's 30ft 350 grain heads.
To get that fucker far out there, I throw a nice controlled, not too fast, back cast and let it take what it wants, then mung the lot forward. It's bloody tricky to control.

The best results I get, and mainly the reason WHY I use the heads, are with ridiculously lavishly thick bunny zonkers 20 plus centimeters. I find the large and very wind resistant fly slows the unfurling, the turn over, while the lot still keeps it's momentum, the set up seems to go farther out without flopping, as oposed to a wee bit of fluff.

It's amazing how far I can get a soaked "two treble #3/0 20cm apart hooks, joined with thick braid, with cca 35cm of 5mm wide rabbit zonker strips wrapped onto it" streamer monster. Using a not too particularly fast 8/9wt rod with 350 grain heads. Btw, don't wonder about the ethics of this fly, I use it exclusively to depike "trout" waters.

[robk]

I'm currently not able to get proper footage, but I was out last week and had no problem getting 100+ feet casts with a shootinghead attatched to an even shorter length of shootingline than you suggest.

Well that is really interesting. I have had much the same results as Ian -the flying spaghetti monster. Was the head inside the tip top at the launch? I ask because I am trying to figure out what would cause the loop to form. With really good tracking and no line wiggles,I can sort of imagine how just a small differential in top leg and lower leg velocity might allow for loop formation and travel.

Even casting into a slight head breeze got me a loop that just stalled as it got to the front taper part, and it would fall to the ground with just a slightly collapsed front loop, and a parallel top and bottom leg.

So it sounds like the change in taper caused the system to destabilize, which sort of relates to my overhang question above.

Rob

[crunch]

I think when a "shooting cast" is made a loop formation happens because of R/L drag to the guides and to the air. This can be delayed using thin and slick R/L as competition casters do.