in search of a perfect loop

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

  1. yuhina Tropical member

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    Hey Greg, How wonderful!!! I am so excited when I see your experiment!! Ah-Ha!!
    The weight distribution! The line system with sinktip and fly!! Soooo cool!! I think you are into something!! I really love your experiment and the results really can help us to solve the mystery! Maybe you will try to shift the weight along the Skagit head to see what casting stroke and loop shape will change?! I am looking forward to read your report! This is going to be great!!

    Here is my thought about the line system compare to the hammer throw action. If our assumption about the circular acceleration is correct, We should be able to superimpose the diagram I draw for hammer throw on top of the Ed’s casting diagram. It should be the same principle. However, the difficulty lies on what is “the hammer” in our Skagit casting system? And where are they located? We now know overhang is “the chain”, overhang help us to rotate “the weight” but the line system is large and soft, where is the weight? Here is my proposed “weight center” of the Skagit line system (line-sinktip-fly), the center of mass CM (see wiki link for detail http://en.wikipedia.org/wiki/Center_of_mass). When we need to predict the movement direction of a subject or dissecting the forces acting upon them. The easiest way is to locate the center of mass (CM) of the subject. For a rounded base ball, that would be in the ball center. For a donut, that would be in the imaginary center inside of the circle. The concept is also very important when dealing with soft objects… for instance, a rope, the CM should be in the middle. When you project the rope into the air, the center of mass should be follow the same trajectory of a projected base ball… although the two end of the rope might doing some crazy spin or wiggle. The center of the mass won’t move, it will follow Newton’s first law of movement (link http://en.wikipedia.org/wiki/Newton's_laws_of_motion). Going where it should be going… the wiggling two ends of the rope is inner force, it will cancel out the movement by itself if there is no outside forces action upon them. So overall, the rope will acting just like a projected baseball and the trajectory is also predictable if there is not outside force acting upon them. This concept is important, because if we can find out where is the center of the mass of our system, then we can dissect where we should put our force, and when we should release our line system into the air and let it go onto the planned trajectory (which is aimed for horizon) (to be continue)
    Mark
  2. Fred Krow Member

    Posts: 44
    Litchfield, CT
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    Mark Yuhina,

    My suggestion for this discussion is to attemp additional video of the straight line rod tip path and line loop formation.
    The problem we all have is the rod tip is moving too fast to determine much in most if not all of the internet videos.

    Let us experiment further when you visit next.

    Make up some yarn flags and attach them to the rod tip,,,, say 8 flags separated by 2" each. Bright orange or chartreuse colors about 3" long.
    We can use the bright orange Rio AFS line you have.
    Have 4 or 5 casters go through their motions with your camera running.
    High slower stops and low powerful stops of the rod will hopefully show more detail.

    Let us video mono leaders with bright lines and Skagit heads with heavy T tips.

    I have never completed signed on to the "straight line path of the rod tip" theory.
    We diagram a rod begining the forward cast under load "A" nice and bent,,,,, then we show the rod unloaded "B" at the end of the cast the rod is also bent over very similar in shape,,,,, very nice,,,,,, what happens between point "A" & "B" ? I belive the the rod tip must move above the straight line path in an arc,,,, especially with a high stop cast.


    Slack line observed in the forward cast,,,, I have seen this many times when casting with overhang,,,, the rod tip stops and over rotates downward toward the water and creats a loop. This slack loop is quickly pulled out with the line moving toward the target. When the overhang is eliminated the rod tip does not over rotate and the slack loop does not appear. We cannot see this as a caster, stand 20ft to the front and side of someone who likes overhang and watch the rod tip.

    No one discusses the concept of "speed-up-and-stop" or additional acceleration just prior to the stop. I belive this greatly influence the tight loop formation, I use the underhand cast and begin the forward cast slowly and accelerate slowly up to the final short fast acceleration to a stop with the lower hand. If you begin the forward cast with full acceleration there is little left for "s--u--a-s" at the end of the forward stroke = tailing loops.

    Tight loops tangle with the rod tip or fly line,,,,, very simple solution,,,,, at the completion of the forward stop,,,,, move the rod tip to the side about 4"-5" and you will eliminate any collision with the rod tip.

    Great discussion,,, makes one ponder the dynamics of casting.

    Regards,
    FK
  3. Greg Holt Active Member

    Posts: 154
    camano island, wa.
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    Mark--just a note. I intend to include some additional content in my previous post (#134) via editing to adddress several issues you raised. They are intended only to clarify, not to gain any advantage in advancing any theory. You'll spot them immediately.
  4. yuhina Tropical member

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    Hey Friends,

    All great points and I really appreciate all the inputs and the ideas!! really, at this moment, I feel the process of analyzing mechanics itself is more valuable than finding the final results. I do believe though, as many people pointing out, more experiments and test drives are crucial.

    Here I want to attached the original diagram again to let us focus on this issue first. If the force drive AFTER the A point is necessary?? for skagit cast + big fly... (I will like to confine the discussion in the short head + overhang casting style, just for clarity)... For some videos I viewed, it seems it is necessary to continue adding forces after A point. If stop on the A point. it seem the power would be reduced (see overhang). I see this effect in Josh Lynn's cast (also attached below ) and Tellis cast. Also noticed, the rod tip path is curving into downward direction. If this is follow though or adding force passing the A point. (In addition, I think Travis and Ed's idea of how to get to the point A is also important. should it be getting there with linear path? or it will be more relax, even use rotation path to get there like hammer throw)
    [IMG]

    1:28 sec Josh in action (thanks Wadecalvin for providing the link)

  5. yuhina Tropical member

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    Cool! Thanks Greg, (just a quick note) I think those are all crucial points and thanks for linked them to the videos! I am still working on them, i will post them tonight... Thanks again! Mark
  6. Dustin Bise Active Member

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    Hey I was bored today so I made a quick video showing my javelin cast :p

    Note of interest. Cast @ 20 seconds, I make a very non linear tip cast with direction change and actually hit the camera. Im not saying I know how to cast, in fact, i dont and am pretty much self taught with 1000 bad habits.

    Maybe my shitty casting can bring the fun back to this thread.

  7. Fred Krow Member

    Posts: 44
    Litchfield, CT
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    Straight line path of the rod tip.

    Consider the Lefty Kreh "Stab cast" the rod is extended to the rear in a horizontal direction and 180 degrees wrt the target.

    Side arm rotation to forward cast which ends in a 180 degree rotation of the rod tip facing the target.

    The loop formed is approx. 3" high.

    This cast will not work with a forward stab, the cast ends with the classic Lefty speed-up-and-stop motion.

    I have used this cast in windy conditions with a DH rod many times.

    The only video source I know of is the older "Lessons with Lefty" from about 2002.

    Regards,
    FK
  8. Greg Holt Active Member

    Posts: 154
    camano island, wa.
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    Dustin, that is some righteous entertainment, and nothing shi__y about the casting! Please PM me with the link to the tune and the lyrics!
    With only one viewing under my belt, I see your release occurring definitely above the horizontal, yet below 1 'o' clock from your view. What do you a)think, and what do you b)feel?
    We hope Mark is going to feature himself in a video with a forward movement akin to splitting firewood, with the line climbing to the heavens, sporting compact loops, no less. Hope springs eternal...
  9. SpeySpaz still an authority on nothing

    Posts: 1,826
    Roy, WA
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    Nice casting Dustin. I perceived arrow straight tip path as your rod unloaded towards the camera. You definitely have a spot in my boat whenever you can make it.
  10. Salmo_g Active Member

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    Like a bad traffic wreck I can't stop reading this thread. Here's an idea for all you physics majors and calculus addicts to chew on. It doesn't matter if the rod tip follows a straight line path or a rotational path. Huh? After 10 pages how could it come to this?

    I recall this basic concept where average velocity meets acceleration. The curved line described by say a 90* arc of the rod tip doesn't lend much to this discussion. However, the line speed is accelerating in both cases, when the rod tip is traveling in a straight line path and also when the rod tip is traveling on a rotational path. Both my physics and math teachers took that 90* arc and chopped it into little bits so that we might take a closer look at it, piece by piece. A sample 5* arc looks a lot more like a straight line path than that 90* arc does. Then, if you take the 5* arc and chop it into 5 one degree arcs, my naked eye can't really tell the difference between the 1* arc rotational path or the longer rod tip straight line path. Aha! Then at the instantaneous moment of line release, the rod tip in that instant is traveling in a straight line path even though it clearly is traveling rotationally over say one second's or two second's time.

    It seems to me then, that what is important is not whether the rod tip follows a straight line path or a rotational path, but it's important that the line is released at a point along the rotational arc (if that's the kind of casting stroke being employed), along with a stop, at a point that gives it a trajectory parallel to the intended line of travel. Isn't that how the hammer throw succeeds like the javelin even though decidedly different throwing (casting) strokes are used?

    This is so much easier when I don't know what I'm talking about.

    Sg
  11. Fred Krow Member

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    Salmo g,

    Yes, thank you,,,,,that is what the basic teachings of Lefty Kreh describe.

    The line goes in the direction the rod tip is traveling at the end of the speed-up-and-stop.

    This is how the "Stab cast" is possible and how a short stroke high stop is possible without straight line path of rod tip.

    Forget the du/dt calculus, just observe the rod and line when casting.

    Regards,
    FK
  12. yuhina Tropical member

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    just finished the Tellis casting analysis see below frame by frame... yellow line is overhang, noticed the rod tip position change and the tighten up loop after shoot out... any thought are welcome..

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    Video 0:55 sec
  13. fisshman26 Member

    Posts: 360
    Trail, B.C., Canada.
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    Look at his hands......the dip in the rod is simple rod deflection if you look at the end of the line where it joins the running line you see where the rod stop occured and thus the release of the stored energy from the rod, well above where the rod tip ends up, pretty much in line with his top hand.
  14. John Hicks Owner and operator of Sea Run Pursuits

    Posts: 2,142
    Olympia
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    Spaz, I"m pretty sure that Mark has forgotten more than you know about spey casting. I would really apreciate it if you would stop acting like you know so much about a sport that you really know little more about than what you read on the interwebs.

    Just sayin....

  15. SpeySpaz still an authority on nothing

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    Roy, WA
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    I have to agree with this post. I believe dropping the butt helps shape the loop after, after, energy transfer has occurred. I think the preceding posts illustrate this very nicely. You have more insight into the cast than you previously revealed, Mr T. Apologies for my previous slams.
  16. Dan Page Active Member

    Posts: 443
    Yelm, Wa., USA.
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    Mark,
    I've skipped most of the posts. But I think your comments on post #144 sum it all up.-----

    "" I feel the process of analyzing mechanics itself is more valuable than finding the final results.""

    Mark,
    You're a guy who like to analyze. There are no final results in sight for this thread.
    No offense here.
  17. SpeySpaz still an authority on nothing

    Posts: 1,826
    Roy, WA
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    Hi John, thanks for your insightful contribution. I have seen you cast.

    Be careful though, Dr Yuhina has issues with confrontive people. He might ban you from the thread.

    If you want to keep just sayin', we can meet on the Hinckley water next weekend and seek some proof. Game?
    Bring your longbelly, we can see if this crap holds water or whether it's just shorthead cheating. You do have the casting mechanics for longer heads, right?
    7 AM Saturday, Blue Creek boat launch. I'll buy the gas. Hell, I'll buy lunch.

    Or you could, you know, shut the fuck up.
    kindest regards.
    Bob
  18. yuhina Tropical member

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    Hi Bruce,

    I agree! even the rod tip dipped into the water, the stop should happen early on, thus caused the rod bend into the other direction. I wonder if you can point out where he stop the rod? maybe it is hard to depict, but I will love to know where is your estimation. Thanks! Mark
  19. yuhina Tropical member

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  20. John Hicks Owner and operator of Sea Run Pursuits

    Posts: 2,142
    Olympia
    Ratings: +183 / 1
    No thanks Bob, I'm actualy busy. I don't cast the long belly, only cast one a couple times. Um, I'm washing my hair, go ahead and just plug in any one of the above excuses.

    Really though, I think that Mark is a very insightful guy. Do I agree with everything he says, no probably not. I do not however bash him without ever having met him or even having any knowledge about him. I'm glad that you are feeling better about casting a long belly these days. Last year you told me that it was kicking your ass. Dan really is a good teacher I'm sure.