Here is the disconnect regarding the effects of tapering a fly line that was buried in the pre-load thread:
The propagation of the loop formed in a fly cast (what I will call the “fly wave”) is often equated to what goes on in a whip. For example the Virtual Flycasting site says:
In his book Modern Fly Lines Bruce Richards states that,” The relationship between the whip and the fly line is obvious."
However, Lingard's graph shows the effect of tapering the end of a fly line will slow down the fly velocity as compared to the velocity at the end of the loop roll out with a level line. This implies the impact of the taper is to slow down the velocity of the fly so you get a more controlled turn over of the loop at the end of the cast.
In contrast, for the wave that Goriely analyzed in his whip wave paper. he shows the end of the whip is tapered to speed up the turn over of the whip and make it easier to crack.
How could the same effect (tapering the line) have the opposite effect in the fly wave as compared to the whip wave? Is Lingard wrong when he calculates that tapering the line will slow down the turn over of the fly?
If someone has a copy of Bruce Richards Modern Fly Line book maybe they can share what he has to say on the subject.
I think this discussion on line taper came from Bruce's Book but aside from this reference
The primary purpose of the front taper of the fly line is to allow proper delivery of the fly and leader. The taper from the belly of the line to the tip acts to reduce the mass of the line. As the loop of any fly line travels through the air, the mass of the moving part of the line decreases because that part becomes shorter. In tapered lines it decreases even more because the line becomes smaller towards the tip. This increases acceleration, resulting in greater wind resistance and greater energy dissipation, and therefore a more delicate delivery.
I could not find anything specific however about the impact of the taper on the turn over velocity of the fly.
To me this quote is a bit contradictory in that it says the purpose of the taper is to get a proper delivery of the fly but then it says "the taper will increase the acceleration of the fly" which would cause it to speed up not slow down.
I was hoping for more enlightenment on the subject and found some excellent observations and answers to questions on the effect of line taper by Bruce Richards here.
He says:
Now, about the taper. As the top leg gets shorter it gets lighter which causes the acceleration. If the line is tapered also it gets lighter even faster as it gets shorter.
.....
I know this may seem a little hard to believe, but check with a physicist, I have, it is correct.
I do not know who he talked to when he says a tapered line will get faster as the line density that goes around the loop decreases. However, it must not have been Lingard because that is just the opposite effect on the fly velocity that Lingard predicts.
Maybe even the experts are confused about what is going on with taper. I know I am.
Lingard says it will slow down the fly, Goriely says it will speed up the tip speed of a whip, and the above link on taper seems to be saying both.
What is going on here?
Gordy