Walter & Group.........
From Bruce Richards ( Part of our ongoing discussions on the start of loop formation including the fact that we had noted the rise of the fly line just behind the rod tip as it approached RSP but prior to the line actually overtaking the tip.)
I'd suggest reading this more than once and .... consider archiving it for future reference. The reason the text is rather terse is that I deleted the personal stuff between us.
Hello, Gordy:
The physics of how/when loops form is fairly straightforward. The line
is
pulled by the rod tip, all it's power and speed come from that
source
(barring hauling). As the rod tip accelerates, so does the line.
Obviously,
the line cannot overtake the rod tip until it starts to
decelerate.
Theoretically, the rod tip will accelerate all the way to RSP,
although
there is a possibility acceleration could stop slightly before that
due to
the resistance of the line. Cast without a line, the rod tip
will
accelerate all the way to RSP, although the rate of acceleration
decreases
to 0 right at RSP. With the resistance of the line there is
some
speculation that acceleration could be 0 just prior to RSP, but for
our
purposes RSP is where acceleration ends.
When acceleration of the
rod tip ends, deceleration starts due to flexing
in the opposite direction.
The fly line does not have a comparable
decelerating force working on it so
it overtakes the rod tip right at RSP
(or so close to it we can't really
tell). In most cases, the tip path isn't
perfectly straight, the tip drops
some just before and after RSP, could
that be causing the appearance of the
"rise" you note in the line? If not,
if the tip path is very straight the top
radius of the loop will be very
small and it could be the stiffness of the
line itself that causes the top
leg to rise a bit. If the line actually does
rise I would think that line
stiffness would be the reason, I can think of no
other force that would
cause it....
Happy New Year Gordy, I hope you
are able to see the Times Square ball drop
tonight, we usually have to set an
alarm to have a chance!
Bruce
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HAPPY NEW YEAR TO ALL OF YOU ..... A REALLY GREAT 2008 !
I'm a bit tired this evening after spending 6 hours non-stop teaching fly casting on the flats to 6 and 8 year old girls and boys. A really, "good tired" as I got all of them to make wide and narrow loops upon command and to shoot line.
Gordy
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(Girls outstripped the boys to an embarrassing degree !)