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Walter & Group...
[GH] Few things evoke as much controversy during deliberations on glossary and definitions than CREEP and DRAG. Here are a few more examples. I wonder if this is the reason we see neither described in so many of our fly-casting texts (?)
We seem to be "reluctant to discuss" them, yet here we are doing just that. All this despite the fact that most of us know what these terms mean as we do this.
Seems to me that the problem is how we relate these moves to the remainder of the cast including casting arc and casting stoke.
"The devil is in the details" *
Gordy
* Dictionary of English idioms.
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[GH] From Mark Surtees:
Hi Gordy
"In my opinion, if both movements are identical not it is reasonable to define them with different words."
There is a very significant difference between…”he fell off a cliff” and “he jumped off a cliff” even though the process of plummeting to your doom is pretty much the same.
"I’ve trying to stay out of this conversation about speeds, rotations and translations."
Me too, it is a terminological dead end from an instructional perspective.
This doesn’t mean you can’t measure things though if that’s what dings your bell, but the divisions between “movements” will have to be set by convention rather than by the imposition of an arbitrarily set boundary value to differentiate between “Lift” and “Casting Stroke” for example.
Mark
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[GH] From Allan Dozier:
Gordy,
I may be oversimplifying but I have always considered what we are calling drag to just be the first part of the casting stroke when we are trying to get delayed rotation.
Any intentional forward movement of the rod (no matter how much is rotation and how much is translation) and continues to accelerate is definitely part of the casting stroke. Casting these great distances requires much rod bend which as we know requires a long stroke but the rotation also needs to be very quick.
The tremendously quick and forceful rotation shown in the Hartman video only takes a fraction of a second and thus has to take place at the very end of the stroke. I'm sure there is some advantage to the drag as to getting the line straight, etc. but it is just coincidental to this timing issue.
Allan
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[GH] Allan,
That is putting it in plain language. OK, as I see it, except for your statement: "No matter how much is rotation and how much is translation".
I like to look at DRAG whether part of the stroke (as I see it) or not as characterized by mostly translation. As you point out, it's how one delays rotation.
In the real World of casting, one cannot avoid at least a bit of rotation as this is done.
Gordy
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[GH] Ally Gowans provides some detail to our discussion :
Hi Gordy,
4. "If a rod tip speed of 100m/s is attained what line velocity is achieved?"
So long as the line isn't moving through the tip top, I'd think the speed of the tip and the line speed would be equal. In asking the question I deliberately described the rod tip’s speed and enquired of the fly line’s velocity to invite assumptions – mischievous indeed to use two quantities that are significantly different! It is impossible to ascertain the fly line velocity from the information that I gave. Rod tip speed is only relevant to discussion when the line can be related to it.
The rod tip could be drifting towards the fly line; it could be moving away and pulling the fly line in a curving path or even moving at right angles to the fly line at 100m/s. What part of the fly line is being discussed? We need to cast all of it. You rightly point out that the line (an element of the fly line) assuming no sliding movement relative to the tip would travel at the same speed as the tip but what of the rest of the fly line? If the rod tip travelled perfectly straight away from the fly line and the line remained perfectly aligned the whole of the fly line in theory would have a velocity of 100m/s as it hit the rod tip.
In practice that can’t happen because gravity reduces the height of the fly line in varying amounts so some of the line is being pulled upwards as well as forward. A long fly line cannot behave in the same manner as a short fly line because of gravity and the time required for its travel. Even if the rod tip travels in a straight line all of the fly line does not.
Even a long casting stroke is quite short compared to the length of a fly line and so at the leader end rod tip movement has very little direct influence on fly line movement. That is one of the main reasons that we find it much more difficult to perform at longer distances. At shorter distances control is much easier.
If a perfect straight line path of the rod tip is not achieved (and I doubt that any caster can really accomplish that) then I'd wonder if that rod tip speed of 100m/s cannot really be expressed in terms of velocity since it would not be a vector quantity. If the tip is moving along a portion of a curve, then wouldn't it’s would occur velocity be constantly changing? (Analogy: the rotating blade of a propeller.) The rotating blade of a propeller can have constant angular velocity. Angular acceleration would occur if the angular velocity changed.
Whatever we call it, seems to me that the line must move at the same speed as the rod tip so long as it isn't sliding through it. Correct only for the part at the tip in practice.
5. The relative hand positions on the slides don't really give us an appreciation of the likely increase in tension as everything including the caster moves in the direction of the cast. The markers do help show the beginning of his haul. On slide 3, I couldn't be sure that he didn't slide back a bit. It looks like that to me too.
Best regards,
Ally Gowans
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