Walter & Group................
Query by Jay Clark in response to discussions about the speed of the rod tip being greatest between the STOP and the RSP (Rod Straight Position). Al Crise's answer follows. My comment completes the string of messages :-
Hi Al,
The only part of that I'm a little uncertain of is the
maximum tip speed between the hand stop and RSP. I'm
sure the tip speed is actually moving the fastest in
that period but I think it is because the tip is
moving away from the SLP of line and therefore free to
accelerate without the burden of accelerating the
entire line. In other words, I'm not convinced that
that acceleration between stop and RSP translates into
an equal acceleration at the end of the fly line.
Jay
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Jay
The flexed rod, after the hand has stopped "adding" load, will try to return
to the rod straight position [RSP]. If we can move the hand through the
'stroke' we can add load/bend to the rod as we reduce this movement/force
the rod's tip is in recovery at this time the tip it is moving faster than
what the rod hand or rod butt was moving. This increased speed is what makes
the Fly Cast work not having this rod recovery would be the same as trying
to cast with the "Broom stick". The path of the recovering rod is the part
that we have to take into account as we move the hand in a Fly Cast. Were we
not to lower the hand the line would strike the rod's tip or you would cast
a doming loop.
That Jay is my old Texan answer to your thoughts. Now I have added Gordon
Hill on this thought so you might get a reply from Gordy. If I am off base
he can correct this thought.
ol Al
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My answer to both Ol Al and Jay:-
Ol Al & Jay...
I think you are both correct.
Firstly, we are talking about rod tip speed, not acceleration. For an efficient cast, it has been shown that we have smooth, constant acceleration throughout the casting stroke, and that the stroke ends with loop formation at RSP.
With an efficient tight loop cast, the tip does go fastest between the, "stop" and RSP. As it does so, this speed is almost entirely in the direction of the cast. For the tight loop, the tip varies downward a tiny bit so that at RSP it is only slightly below the oncoming line. That means that most of the momentum of the tip movement is used to pull the entire line in the direction of the cast. A tiny bit of forward motion of the tip is lost as it dips downward, but I see that as insignificant.
With the formation of a wide loop by having the rod tip reach RSP well below the oncoming line, the difference is greater, ie. more of the forward motion of the tip is lost as it dips farther down. That is one reason, as I see it, that the wide loop is less efficient for the achievement of distance.
At RSP, the rod tip begins to decelerate, but the momentum imparted to the fly line allows this line to overtake the rod tip following which the tip goes in to counterflex followed by rebound. The line overtaking the tip yields the formation of the loop.
Gordy