Michael Evans replies...
Glad to offer my pennyworth. Edit as you see fit.
The front taper of my Arrowheads is not in fact designed to throw tight loops because extended front tapers tend to cause the heavier line belly to drop in the air opening the loop. What extended front tapers do do is to aid turnover with the heavy line gradually turning over ever lighter line. For this reason more energy can be put into line shoot and less is wasted in loop turnover. This makes it easier to cast further for less effort (particularly on long-belly lines) and still have good presentation. This is also why my lines are particularly good for roll and Spey casting. These casts generate less energy from the D loop than an overhead cast does from the back cast.
The reason my Arrowhead lines overhead cast so well and will throw tight loops is that I have built in an extended rear taper. Using thinner running line to turnover a heavier belly actually tightens the loop back up. The complete opposite of the front end effect. Clever eh!
Hope this helps
Yes it does! Thank you very much. As you can see I have left your answer unedited.
The 2 influences over line behaviour in the air are line speed and its ability to defeat gravity. The heavier the line (or more correctly the more dense) the faster it can travel through the friction of the air but the more gravity will pull it down given half a chance. As I said in an earlier comment front tapers are primarily for slowing the front end turnover (remember your roller-skating... the man on the end whips around very fast) and as a bonus require less energy in the toop to turn them over. Short back tapers don't do anything. But a graduated back taper can send a shock wave down the belly tightening the casting loop. "They" always say you can't cast a weight forward with the head more than a few yards from the rod tip, try doing this with one of my Arrowheads it works beautifully.
I'm not so sure that a heavier line does travel faster through the air. Line speed surely has nothing to do with the mass of the line, but has to do with the speed of the rod tip, the speed of the haul and friction of the line against the rings. Heavier lines actually have a disadvantage in terms of aerodynamics in as much as they are thicker and therefore more air-resistant. Where the heavier lines have it is with momentum. MassxVelocity. It's all question of momentum against air-resistance.
I don't find gravity to be an issue as it's always a problem of the line loosing it's momentum. However you mentioned something I had never considered and that was the opening of the loop due to gravity having a greater affect on the denser line in the lower part of the loop. This IS interesting. But what really gets me is the graduated back taper.
I don't understand why you say that this tightens the loop back up again.
I'm also interested in the 'shock wave' effect.
"They" are wrong of course. By hauling into the stop and drifting the rod tip it is quite possible to false cast overhang. Shooting heads included.
I did qualify the word heavier with the term more dense. Think of the parachutist in free fall without the shute open he travels faster because he presents less surface area. If you double the surface area of a line, you quadruple the mass behind it giving it a greater effective density with which to push through the air. The proplem is you need greater energy to get it up to limit velocity, and thats where your haul and stiffer rods in the right hands will win. Not many tournament casters use 6 weight lines!
In truth I discovered the extended back taper effect whilst cutting and splicing lines to design my current Salmon Twin lines. That it works I know, quite why is still interesting me. I think... but i'm not certain yet, that 2 factors cause the effect. 1. The thinner running line allows quicker rod tip recovery and 2, that thinner line will roll tighter kicking a shorter wave length into the overall roll of the main line.
The extended rear taper must allow a smoother transfer of energy. I can actually see why this might tighten up the loop, and it might actually slow down the unrolling of the loop allowing the loop to stay formed for longer. Which leads me to something which has been niggling me for a little while, and you might be able to answer.
I'd like to know whether a loop unrolls quicker according to it's profile. It seems to me that a thin running line is important for it allows the line to travel faster, it also
slows down the unrolling of the loop. But to what extent does the forward taper play?
Sinking lines appear to unfurl quicker than floating lines. What would be good is to slow down the unfurling effect but to increase the loop velocity.
Have you experimented with non-linear tapers?
What might be interesting is the effect of a *very* long rear taper, perhaps the same length as the forward taper.
Hi Paul, in a rush this morning so I'll be quick. Yes. The longer the taper, the slower the turnover. Because as I said yesterday the thinner the line, the less dense it is. Sinking lines turnover faster BECAUSE they are more dense. In casting you impart 2 types of energy. Forward momentum of the whole line and unrolling wave energy. The timing of the release and the drag factor of the running line can both increase or decrease the % of energy given to each... hence if you release too soon the fly and leader don't turnover properly. This is also why shooting heads and nylon backing tend to overtake themselves in the flight pattern. I claim Aerodynamics for my arrowhead not because of advertising bullshit, but because the rear running line is designed to be the right weight and profile to fly properly with the minimum of drag whilst not overtaking the belly.
No I have not experimented with non-linear tapers - sorry.
The discussion goes on...