Hi Gordy,
Interesting discussion of late.
I have a much more basic question for the group.
What causes the rod to load? Is
it the weight of the line (first 30 ft) or is it the resistance to movement of
the line, or is it a combination of both? How much does each factor, line weight
and rod movement, have in the making of a cast.
Lewis
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Lewis...
A very good question.
I look at it this way. The weight (mass) of
the line is only part of the equation. What really loads the rod is the
resistance to the rod's increasing movement (acceleration) to the tendency of
the line behind it to remain where it is. That is called
inertia.
The greater the mass of the line behind the rod
tip, the greater the inertia.
As the rod moves forward with linear acceleration
of its tip it bends against the resistance to the inertia of the line and
as it does so, it stores latent energy which increases as the rod bends
further. This energy is released as kinetic energy as the rod
straightens. This release of energy from the bent rod is added to that
directly imparted by the caster to propel the fly line loop once
formed.
Rod movement alone, without acceleration won't
result in true loading, for practical purposes. The greater the
acceleration against the inertia, the greater the rod bend and, therefore the
greater the load and the more latent energy can be stored in the bent
rod.
Of course, it isn't quite that simple, since there
are many forces acting upon that line including gravity and atmospheric
resistance.
(Simplistic definition of inertia: Bodies in
motion tend to remain in motion. Bodies at rest tend to remain at
rest.) This explains why it requires more energy to
start to move a stationary object than it does
to maintain that movement.
Gordy
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From Jim Laing. My brief comments in
bold red italics in his
text :-
Gordy-
I
asked about hauling after RSP the other day, mainly because
I believe haul timing has an impact on loop shape - I'm hoping
guys like Bruce, Jason and Grunde come up with some definite answers on the
detail of these complex subjects.
Bruce Richards and Noel Perkins are working with their new haul
analyzer device.
I
would like to be able to change the loop shape on command at 40, 60 and 86
feet... my goal is to do this for my next MCCI attempt (only then will I
know I'm ready). So let me take a GUESS on how to articulate two
common loop shapes...
That will be a tall order !!
1.
The semi circle - the purest of loops, but the least dynamic.
Formed when the haul finishes a fraction of a second before RSP, and an
immediate dampening of the hand as the loop forms, forcing a circular tip path
through counterflex.
Probably so, but as yet unproven..... at least as to exactly the
point of loop formation.
2. The sexyloop (copyrighted! hope Paul doesn't mind ) - more
dynamic/ complex. The lower leg forms a distinctive angle below
and behind the upper, leading edge of the loop. The loop is defined by a
ships hull angle and very geometric, suggesting the haul is pulled through RSP
into the lower edge of the loop. This keeps the tip in a
straight path to the maximum point of counterflex. I suspect there
are ways to manipulate the radii size at each of those points also.
In line with Paul's description, I think the
haul may increase the disparate, "tension" or resistance between the rod leg and
the fly leg .... therefore increasing the change in loop
shape.
3. Tackle has nothing to do with any of this - it only impacts
size of loop :---) Up to a
point.
4. I 'm pretty sure those are bad answers, but hopefully the
best of the worst! The engineers are probably ready
to break my wrist for taking an ill informed guess.
We'll leave that up to them. I have no
club.
BTW - I find nothing in the reading materials that addresses this! Not
finding anything on haul termination or rod leg tensioning either ...
That's why we're here ... trying to go way
beyond the existing fly casting literature.
Cheers,
Jim Laing