Walter & Group............
More discussion on TRANSLATION and ROTATION with comments on, "pull" :-
Gordy
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Bruce...
Just thinking further about translation.
One
could also take the position that this starts the motion of
the rod in
the
direction of the cast. In doing so, it seems to me that it
would
be
valuable in counteracting the inertia of the fly line at, "rest"
(even
if a
momentary rest).
My recollecions on basic physics include the
fact that it takes
more energy
to start an object in motion than to
continue it. Having
started this,
it's likely that it would require
a bit less energy to be
applied by the
following rotational
movement.
Rod loading would also start with translational
movement.
Studies might
show that this allows for even greater rod load
with the
rotational phase
than would have been accomplished without
it.
Your thoughts on the delay of rotatory motion until max,
"pull"
is truly
enlightening. While awaiting tarpon (which didn't
show) this
afternoon, I
practiced some distance casts with this concept
foremost in
mind. My casts
were smoother and I could achieve greater
distance with
less
effort.
Gordy
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Bruce's answer:-
This is obviously a more complex issue than it first
appears.
The
effectiveness of a properly timed "pull" yields bigger
gains
than I would
expect. Certainly any forward translation that happens
near the
time of
loop straightening will impact inertia of the line that
is
closest to the
rod tip. Beyond that, inevitable slack will isolate the
line
more and more
from the motion of the tip. It is the tip
translations effect
on this
slack that I think is most
important.
If rod rotation starts with any significant amount of slack
in
the line rod
bend will be minimized as the rod is not pulling against
the
weight of the
entire length of aerialized line. The straighter the
line when
rotation
starts, the earlier the rod will bend, which will help
to
maintain a
straight line tip path. The more drift that is used at the
end
of a stroke
the more "drag" (or pull) there can be at the beginning of
the
following
cast which will pull more slack from the line prior to
rotation.
And, if
both translational and rotational drift was used,
then
translational and
rotational drag will follow, which pays even bigger
dividends.
The
exaggerated "layback" of talented distance casters before
their
delivery
casts clearly shows maximum drift of both types. In these
casts
the
analzyer will show what appears to be early, slow rotation,
but
the fact
that it was preceeded by slow rotation in the opposite
direction
at the end
of the previous cast explains why this is
possible.
I don't think that the translational movement can directly
cause
much rod
load because the motion is short in distance and fairly
slow.
However, the
effect it can have on a cast due to increased
efficiency of
rotation is
significant. Sometimes I forget to exaggerate my
drift prior to
a delivery
cast and the result is always
disappointing.....
My motto..... "throw the line as straight
as you can, then
drag out the
rest of the slack"
Bruce
Bruce Richards
Scientific Anglers/3M
4100 James Savage
Rd.
Midland, MI 48642 USA
Tel:
989-496-1113
Fax: 989-496-3374
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From
Steve Hollensed :-
Good Morning Gordy,
A quick comment and question;
I believe that the words push and pull are in the physicists lexicon -
in fact, a force is simply and commonly defined as "a push or a pull".
That is why I always relate the loading or bending of a rod to forces.
And in regards to the rotation/tranlation issue:
Doesn't the casting stroke end with the end of the rotational movement
(not including drift or follow through)? Therefore, the timing of the
rotational movement would also determine stroke length? It seems to me
that that the stroke could not continue after rotation, due to the fact
that the rotation/power snap forms the loop, and loops can't be pushed?
I ask this because of the statement about leg separation. If we want to
widen the leg separation for a longer length of line would we not want
to increase arc (wrist movement/rotation) relative to translational
movement, as opposed to just rotating earlier and reducing stroke
length?
Or perhaps a more concise way to ask the question, does rotation timing
affect stroke length?
Thanks,
Steve
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Steve:
I should have said that SOME engineers didn't like our use of the words, "push" and, "pull". Your statement tells me that isn't true across the board.
The answer to your question is YES. We can widen the loop by the placement of rotation relative to other parts of the stroke as well. I only chose one example. While we can't, "push" a loop, we can tear it open by dropping the rod tip during counterflex. Other examples:
1.) Place rotation throughout the entire stroke. This gives a VERY wide loop which isn't easy to control. It's, "doming" which is what many beginners do.
2.) We can place rotation at the very end of the cast and continue it beyond RSP. That can yield a widening of the loop such that the fly leg (upper leg) is more horizontal and the rod leg (lower leg) is much lower. This can yield good control for a purposely performed wide loop.
3.) The example I gave was the placement of the rotation way back at the start of the cast which can yield a wide loop with the fly leg way up high and the rod leg more horizontal.
This description is oversimplification. For example, in #3, I can do as described, and then continue the stroke with a straight line path of the rod tip until just before completion at which point I can then add more rotation to gain tip speed and come to RSP just below the oncoming line. This gives me the same result but with greater line speed. This additional line speed, however, won't get me much more distance because of the wide loop. It's a cast I'll occasionally use to allow the wind from behind to assist.
Your comment about wanting to have greater separation of the legs of the loop for a greater length of line is actually what distance casters are trying to avoid. Not doing it helps maintain tighter loops. At the same time, this can yield what some of us have termed the, "underslung loop" as the fly leg sags a bit below the rod leg on a very long delivery cast. The legs never collide, so we don't look at this as a tail for this reason plus the fact that this happens behind the caster on the forward cast. You will see this often with the very best distance competition casters.
Your question as to whether rotation timing can affect stroke length is one requiring some depth of thought. Technically, if we define stroke as purely the distance moved by the hand from the start of the cast to loop formation, then the very use of rotation could be seen as shortening it. Where you place it during the cast, may or may not affect its length. If you make a cast with no translational movement at all ..... just rotation to yield rod arc, you can make a fair short cast, but you don't really have any true stroke at all.
This difference between true CASTING STROKE and ROD ARC is something that we on the Glossary Committee have been debating for many months. We can have translation distinct from rotation or coincident with it. The way I look at it is that when you have both you have a more efficient CAST .. For us," the jury is still deliberating."
BRAIN FOOD !!!!
Gordy