Rod Torque (See attachment on casting physics ... from the Loop)

Walter & Group.......

For those of you who missed the edition of the Loop containing Walter Simberski's first article on fly casting physics:  He was kind enough to send it seperately and I've included it as an attachment to this string.

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Paul Arden's answer to the question on ROD TORQUE;-

Hi Gordy, not sure why your email bounced, I'll check my filter.

 

Anyway to answer the question, no I don't intentionally use torque when overhead casting - at least not for distance, and not anymore. I do use it to throw out-of-plane loops, and especially tight ones under trees and so on.

 

However, intentional or otherwise, the technique of turning the rings in or out will also cause torque to be applied. Up until around a month ago I was turning the rings out by 45 degrees (I find the haul locks up if I don't). Last month I changed to turning the rings in by 90 degrees, which has been giving me better results, but I also managed to break three rods in less than a week (well four if you count the Helios I put my thumb through) . All the rods broke just above the first female section and the break curves up the blank. So I'm assuming that the rod has twisted through 270 degrees and is unhappy. I'm waiting to hear back from Jerry's on this.

 

I don't know if it has a damping effect but I suspect it may have a breaking effect.

Cheers,

Paul

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Paul....

 

Got it.  Now, I wonder if those rods would have broken if they had been the 9' one-piece rods with no ferrules that some of have been using for big game fly fishing.  (?)

 

I note that Loomis has deepened their ferrules on the Spey rods as an attempt to avoid breakage and, (hopefully) make it unnecessary to tape them .... at least for short term use.

 

Gordy

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From Walter Simberski ;-

 

Gordy - I believe that a slight twist at the end of a roll cast is going to do two things:

 

1. Enhance the stop. I've seen a lot of discussion lately about how much rod unloading

    contributes to the cast but I don't think anybody can dispute the fact that unloading

    the rod does contribute to the cast. In order to unload the rod we can

    apply force opposite the direction of the cast causing the rod butt to come to a stop

    and unloading the rod. We can also change the direction of the rod forcing the rod

    to unload if we control the amount of direction change.

 

2. Change the counterflex and rebound from a motion in line with the cast to one which

    is circular in motion. The rod tip will not deviate as far from the rsp as with a "straight"

    stop but it will travel in a circular path so total distance traveled in the counterflex

     state may actually be greater. Rebound will be less pronounced because of this.

 

Also note that with the roll cast the line has an anchor point so a slight deviation from

slp won't result in as pronounced of a curve as for an aerialized cast.

Walter

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Walter.....

 

Hate to be a, "doubting Thomas" but I'll need some bone fide evidence for this.  Since I really don't know, however, I won't negate the idea that torque can actually do these things.

 

When I purposely apply a bit of torque, I always get a curved layout and I have not actually been able to tell if these things are good theory or not of practical use, because I don't percieve any other difference.  The principles involved do make sense to me.

 

Gordy

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From Michael Jones:

 

Gordy:

 

Torque:  Twisting the rod torsionally along it's longitudinal plane while casting.

 

After assembling (not building) several rods, I have come to a place where I believe that the relationship of the rod's spline & the rods flex affect the cast, especially when you twist or torque the rod (see above definition).  If you try a roll cast p/u with a sink tip line, and keep the reel seat pointed generally forward, you are much more effective at lifting and positioning the line (stiffer rod), than when allowing the reel seat (and spline) to come off axis and point away from the cast.  

When we teach high stick nymph casting, the first thing I teach is "point the reel at the target"...this is a fundamental nymph casting principal as it accomplishes 2 things well:  Accuracy, by not 'torqueing' the rod, the line tends to follow the rod tips path.  Efficiency, you are using the most effective power of the rod to do the work.

Also, watch Steve R. throw a back cast, his reel points at the target, and this makes the rod and line think that there is no change in the tracking of the rod tip.

I bet Tim Rajeff would 'pipe-up' for this one?

Michael Jones
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Michael...

 

I think you are correct.

 

Incidentally, while most of us have been using the word, "spline" to mean the uni-axial stiffening of a rod, Don Phillips points out that the correct term is SPINE.  When multi-axial, he refers to the, "effective spine" ..... a term coined and used by Rod Crafters some time ago.

The term, SPLINE is more correctly applied to segments of bamboo culm cut for rod construction.( The Technology of Fly Rods, Don Phillips, pp. 19, 30, also, SPLINE, p 102.)

 

Gordy

 

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From Liam Duffy on, "overlining the rod" :-

 

Hi Gordy,
             I disagree with your discussion synopsis, all single handed lines are rated with the first thirty feet of line outside the rod tip. Now having a belly length of 30 feet the remainder if the line is "running line" which has a smaller diameter than the head, in some cases as little as 30% the diameter of the belly, consequently, one must calculate the grain weight of the running line before arriving at any conclusions with regard to "overlining" also one must factor in the effect of "hinging" Modern line have varying belly lengths so where does that leave the AFMTA rating system in relation to your discussion?
Best Regards,

Liam Duffy, M.C.I.

 

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Liam....

 

You are correct in that the formula I used is a rough approximation (that of adding the wt. of one additional line designation for each 5 or 6 feet of line out of the rod tip beyond the first 30'.)

 

Calculating the grain wt./ given length of the running line would be a more accurate way of doing it  but would go beyond the simple, "rule of thumb" way of judgement.  One would have to do it that way in the case of a line with a short 30' head.

 

Putting your concern into different words, this only works for long belly lines where you do not have thin running line involved in the calculation.  Perhaps I didn't make that sufficiently clear..... ...glad you did !

 

Gordy

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