in search of a perfect loop

James Mello

Inventor of the "closed eye conjecture"
Build inertia into the line, loosely like a javelin, by the combined use of linear and rotational force (distantly telated to the throwing hammer) variably applied against a linearly moving fulcrum in the form of an energy storing and releasing spring lever (rod).
Without all the components we end up with a crappy cast with misdirected energy. The line goes where the tip tells it to.
This is the physics experiment we all pursue every weekend. SHers create a curve cast by curving the tip path on the horizontal plane. Come on man.
Actually the fulcrum doesn't move linearly, but rather in a manner to keep the tip moving in a straight line cast. Watch any distance cast (which exaggerates this movement), and you'll see drift, slide loading and the hand moving towards a postions much lower than the drift..... In most cases this is actually a radial movement.

Here's an example using a single handed rod which illustrates this point....

http://www.sexyloops.com/movies/cnlpaul2.shtml
 
I remember you, Mr T!
welcome, and what are your thoughts on angular momentum as it pertains to rod deflection in the unloading phase of the forward cast?
Does the rod tip need to move in a straight line to produce a good casting loop?
regards,
Spaz

Man, I am so glad I bowed back in. It's old home week.
It is my opinion a fairly linear tip path through the forward stroke with a slight drop at the end produces a good effective casting loop. These variables will aid in the formation of an aerodynamic slightly rounded leading edge that will effectively release, turn over, and transfer energy down the line. What happens at the tip is important,, but IMO the combination of optimum loading of the bottom (where the power in the rod is stored), right amount of line stick to help store and release that energy, and d-loop direction (180 degrees) are most important. I have stood and watched Scott Mackenzie bomb out some massive casts - big release, nice rounded leading edge aerodynamic loop. Not an ultra pointed v-loop as some think to be the best type of cast.
 

James Mello

Inventor of the "closed eye conjecture"
It is my opinion a fairly linear tip path through the forward stroke with a slight drop at the end produces a good effective casting loop. These variables will aid in the formation of an aerodynamic slightly rounded leading edge that will effectively release, turn over, and transfer energy down the line. What happens at the tip is important,, but IMO the combination of optimum loading of the bottom (where the power in the rod is stored), right amount of line stick to help store and release that energy, and d-loop direction (180 degrees) are most important. I have stood and watched Scott Mackenzie bomb out some massive casts - big release, nice rounded leading edge aerodynamic loop. Not an ultra pointed v-loop as some think to be the best type of cast.
To quote Tyler Kush: "Tight loops are overrated"

This is a heck of a lot relevant with long bellies :)
 

yuhina

Tropical member
Mark,I think I might be able to offer something here that could constitute an "aha" moment for you. Not pre-scripted, not polished, but here goes:

Yesterday, as a casting excercise dealing with a different issue, I anchored the leader beyond the sinktip into the surface of the lawn. Next, I placed a weight at the junction between the sinktip and the front of the head. Then, I drew back, formed a D loop, and made a LEVEL forward stroke--no fancy stuff.
This is a basic roll cast, yes?

The forward driving loop picked up the weight and propelled it up and over and beyond the anchor, all without any tortured maneuvers of trying to drive the rod down at the end of the stroke. In fact, as expected, those types of movements detracted from the effect when added to the experiment.

So here's a thought: since most of the mass of the shooting head style D loop originates BELOW the intended flight line (and rod tip), moving it forward rapidly causes it to lift the belly, and throw it OUTWARD as it is being propelled forward without ever involving the series of events you seem intent on introducing. (Hint: think of the line as a single object, like in my tennis ball example. Gravity attempts to hold it down, until forward motion overcomes it and flings it up and over with the aid of hangdown). As a mental excercise, invert everything but the landscape, including the rod, line, & caster and run the scenario, noting that the weight would then fly downward, relative to the rod tip! Gravity seems to be a major player here...

Remembering that virtually all spey casts are modified ROLL casts, consider the possibility that the effects you are witnessing are the result of horizontal velocity acting on mass (initially positioned below the rod tip).

If you went to the casting platform, formed a backcast that stayed ABOVE the rod tip, not even letting the tail drop, then made your downsweeping forward finish, would you be in for a disappointment? Then try that again with a standard level finish, and report back in.

Cheers,
Greg

PS: I and another member have been discussing a mechanism that would secure the rod vertically, but allow it to move in a horizontal rectilinear, reciprocating fashion, simulating the (modern ordinary) casting stoke, while removing the caster from the equation. I visualize it doing to a fly line exactly what I have described above.

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
 
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
 
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.
 

yuhina

Tropical member
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)


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

yuhina

Tropical member
Mark--just a note. I intend to include some additional content in my previous post 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.
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
 
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.

 
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
 
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...
 

SpeySpaz

still an authority on nothing
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.
 

Salmo_g

Well-Known Member
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