in search of a perfect loop

Discussion in 'Spey Clave' started by yuhina, Dec 17, 2011.

  1. James,

    Just got back... a short break...
    OK, so far I appreciated everyone's effort to maintain this thread with the spirit of good discussion... please allow me to say this one more time...

    as a side note:

    there is no need to be mad and aggressive, if you don't like the idea, go somewhere... I won't be upset... and you won't be upset by my writings either. If you agree then we have a very good platform to keep go on the discussion. In my mind, we are learning from each other here... there is no lower, no higher... and be honest with you. I am eager to learn from our discussion here... no attack, no aggressiveness... thanks..

    First, James has point out some very interesting facts that I show in the two sports video. One is hammer throw and the other one is Javelin throw.
    No doubt, javelin is liner... the arm is pushing the same direction as the javelin fly out to the same trajectory. so if you can relate this motion to spey casting, then the jevelin is the skagit head, and the fingers/palm of the athlete is the "rod tip". keep the rod tip (palm) as straight as possible and push them out. Like Chris' video. He rock the body to increase the acceleration length...(the athlete use running motion and arm stretching). Hope you got the idea of similarity of those two motions.

    Second, the hammer throw... as you can see the athlete is spining and the weight and chain is keep moving and changing directions. (this is the definition of rotation: constant changing direction, the centrifugal force is pointing to the center, the acceleration is defined as angular acceleration, the momentum is called angular momentum). So because of the spinning motion, the force is always perpendicular to the moving object. This is very different than the javelin (the force is parallel to the moving object).

    In the previous year, when I teach my college students the liner momentum concept, I always lost 30% of them when I mentioned the acceleration, then, if I get further to explain the angular momentum and the angular acceleration, I will expect to loose another 60% from the rest... at the end, about 20-30% got a grip of rotation and how it related to force. That is the reason I try to use more video and more realistic examples to explain. OK, I will stop the physics here and use more casting examples.

    If you agree the hammer is constantly changing direction and the movement is always perpendicular to the force (chain and arm). Then you will realized this is different motion than the Javelin throw. So the question lie on where is the skagit line? The hammer is the skagit line, and where is the rod tip? yse, the athlete's palms is the rod tip...so what is the chain? You tell me. this is the key. (very important) to be continued...
     
  2. Please don't tell me these whole 5 pages have been about the slight deflection caused by angular momentum in the forward cast! The chain is called overhang in speyworld BUT the analogy breaks down immediately...the hammerthrower's arm doesn't absorb, store and release energy directionally as a rod does...the direction of release of that stored energy IS the rod tip travel we have been talking about for five pages now. It is also what makes casting different from most other pursuits, and very difficult to describe. The hammerthrowing analogy is precisely 90 degrees off in my opinion. Hope that isn't too aggressive, but without an analogy for the rod storing, releasing, and directing energy the example doesn't work.
    I don't see the thrower's palm as the tip of the rod at all, because there's no rod in the hammerthrow. I think I said that once already...

    Suggestion: review Eoin Fairgraves' trick casting video, you'll see angular momentum expressed to the extreme, almost looks like he's casting one way and the line's going a different way altogether. But...the rod tip never lies.
     
  3. Mark, any comment on Ed's response to this thread on the skagitmaster forum asserting that his rod tip does indeed travel a straight path? Seems like that info would be pertinent here since you referenced his casting numerous times.
     
  4. I do have a comment on that... please check it back and I will explain them here later also ... as Ed has noted those are more complex elements in there... the different situations need to be addressed separately... It would be great to have more people join here for discussion though.. Mark
     
  5. there are more videos that show this kind of rotation of rod tip to generate tight loop. see below

    2:00 sec the rod rotation and the loop shape. we can discuss from here also...

    pay attention to his downward pressing (stroke), but the loop is slightly upward flying... this separate movements is the character of rotation in work.

     
  6. Quote from: riveraddict on Today at 12:47:59
     
  7. To anyone who still thinks a curved rod tip path in the forward stroke can create anything besides a curved line path:

    Go right ahead and cast your fly rod like a hammer thrower, and watch the belly fly out in an arc parallel to but larger than the one describe by the rod tip.

    If you "curve" a rifle barrel by putting a bend in it, the projectile (analagous to the fly line) does not continue to fly in a curve after it exits the muzzle, and only does so prior to exit because of the barrel constraining it.

    The belly of the fly line however, being both long and limber, can't help but follow the forward progress of the rod tip path in the horizontal plane ,the vertical plane, or any plane in between.

    A casting lure or plug could exhibit some of the angular properties mentioned, as the overhang at the rod tip lets the lure behave like the hammer at the end of the chain, but if you swung a fly rod like a hammer thrower, your line would respond accordingly, creating a large lateral deflection in the outbound line in the same plane as the rod. Not exactly a pretty loop...

    When analyzing line flight, I try to imagine how the fly line would behave in the absence of the caster, relying only on the movements of the rod to create its path and momentum. My experience in this reality is that any non-linear movements in the forward stroke detract from performance. Any minor anti-gravity corrections, such as the circle-up at the conclusion of the backstroke, occur before the lineal towards-the target stroke.

    This board might be better served attempting to identify and explore the factors that lead to more energy being stored in the rod prior to release in the stop, and no, I'm not qualified to lead that discussion.
     
  8. golfman,

    I agree with you about the big fly but not tight loop situation!! The loop shape is just another way we try to look into the casting mechanics.
    If you look closer about the skagit line and Scandi line, both from the same company (say Airflo). They are in different textures. The Skagit line were much stiffer than the Scandi line, even in the same diameter... I think this is because the company tend to make the skagit a bit more rigid to open up the loop a bit more. But if we do everything right, it still can produce the more desirable "wedge loop" which is more areal dynamic, cut through the wind better... if you use GPS line, those " Wedge loop" are the signature and it does cut through the wind better.

    Mark
     
  9. Great post and anologies Greg.
     
  10. Greg,

    This actually is a great suggestion!

    But remember use some overhang, because I already mentioned the hammer thrower motion involved in chain and weight. The chain being the overhang as Speyspaz pointing out...

    So how much overhang to use and to do a hammer throw motion? I suggest you can try 1, 3, 5, 7, feet and see what happen to your loop shape. If you can throw a wide open loop with 7 feet overhang, please let me know... I would be really really interested to see that in action!

    Mark
     

  11. Greg,

    Your analysis is really good, I agree those points. But we need to restrict our discussion on the forward stroke. because this is the place really hammer throw motion take place... if you want to spin the line like helicop, then there is not point to compare hammer throwing to skagit casting. I hope you agree with this, then we can go further to see how the curve rod tip can distract the line path... if this ever happen, and when it will happen.

    If you look at the BC video again at 2:00 the caster actually pressed the rod downward and the overhang and skagt line actually fly slightly upward and created the tight loop. see how he finish the rod close to the surface and rod unbend at the final point.
    Mark

    repost here, fast forward to 2:00 sec
     
  12. Mark did you know that speycasting existed before 2009?
     
  13. Oh... does it?!

    Bruce, all due respect, I post videos just for demo and for showing the points, strengthen the statement and facilitate the discussion,
    all in good will here. If you will like to show us different opinions, I will be all eared...

    Sincerely,

    Mark
     
  14. my point is that overhang and follow through with the top hand and its effect on loop shape is not anything new......now the way that you got from point A to point B.............
     
  15. Do I claim overhang is new in this entire thread? I claim use rotation motion + overhang can be another way to generate tight loop. Please keep in mind, we are focusing on how to generate a tight loop, and previous thought there is ONLY ONE way which is straight rod tip path. and I say NO,

    Got the idea?!

    Mark
     
  16. As I recall as soon as straight line path was mentioned you went elsewhere and the discussion kind of died there if you would have just asked point blank what other ways there were I am sure you would have gotten some more, as there are many more than just the three mentioned, but that is for me to know and for you to figure out on your own:cool:
     

  17. Mark I am pretty sure this is where you lost everyone because although it is not the only way to acheive a tight loop it is essential for the other ways to work
     
  18. first it was thirteen pages on tip casting,
    now we're on page six and Yuhina has just discovered overhang.
    I'm out, this is worthless.

    Newbies, beware of this guy.
     
  19. No, straight line rod tip path is not essential to create the tight loop. there are several different ways to do so...

    Is this clear enough? Bruce, give me some evidence that the videos I provide is NOT a curve path.
    remember in the early post I mention two very important position to make the rotation to work, 1) tight pivot area, 2) long forward stroke.

    Let me ask you a simple question Bruce, does the BC video make sense to you??

    Mark
     
  20. Mark,
    In the video in which you reference the downward rod movement taking place at the 2 minute mark:

    The main upward direction (slope) of the loop and line was already established by the prior direction of the caster's forward stroke, and did not occur primarily as a result any of downward force on the rod after the loop was already traveling upward and outward.

    The slight rise in the rear portion of the loop you are witnessing from the downward pressure on the rod is the inverse of the action/ reaction that occurs during the circle-up at the end of the backstroke (which momentarily drives the lower leg of the D loop down). It isn't (IMO) raising or tightening the loop as you suggest, only opening it up (actually preventing it from collapsing!) and relocating the remaining outgoing line out of the collision path. Why you would spend five pages of suspense to make such a point is a mystery to me, but I'm glad you're enjoying yourself.

    By the way, be careful criticizing my use of the hammer thrower analogy--it was your invention, and possibly a poor choice, given the myriad number of incorrect inferences that could be drawn from it!

    I leave you alone in the spotlight. Good luck.
     

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