Archive for the ‘English’ Category

Manus agere

Donnerstag, Oktober 11th, 2018

The Latin term „manus agere“ is often translated as „leading the hand” and is considered as the linguistic root of the “management”. Most frequently the management is used in relation to the leadership of a company, but it plays also an important role even in the private life.

Especially the literal sense of the management, the “leading the hand” has also a meaning in terms of fly casting. The hands are connecting the body of the caster with the gear, one hand “leads” the fly rod, the other hand the fly line. Both hands transfer the input of the caster’s body into the fly rod as well as into the fly line and only if this input is taking place at the right time the fly cast can succeed or can be improved. How and when both hands of the caster transfer the input into the fly rod and fly line is the key of the quality of the fly cast.

Due to the foregoing reasons it makes sense that the instructor is watching the hands of his student in order to seek out how he “manages” the fly cast. Some instructors leave it at watching the hands and in most cases this is sufficient. In my experience the instructor is able to receive further important informations from the student by gripping his hand in order to “grip”, understand respectively the management of his student better.

This interaction between the instructor and his student is working in both directions. First the instructor “grips”, understand respectively the used input of his student when his hand follows the hand of the student passively. In the following step he can attach corrections or improvements by leading the hand of the student with his hand. The instructor is taking the leadership about the casting stroke and the student can notice directly, when and how he should apply his input into the fly rod and the fly line.

Personally I am convinced that “leading the hand” represents a very efficient way to convey the fly cast, for which reason a lot of instructors are already using this method. During my own time as a student I was able to “grip” what mattered my teacher. As an instructor I was able to attach corrections and improvements to my students, which I would not be able to fix by only watching their fly cast (especially when the student tends to apply the force, input respectively too early or suddenly).

With „leading the hand“ the instructor can not only convey the basic motions of the fly cast, but also convey the right time of the input, which is playing an important role in terms of an efficient fly cast.

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Input at the right time

Sonntag, September 2nd, 2018

Today it is established, that the fly rod not only stores energy (potential spring energy), but also includes a redistribution of the introduced energy – consisting the interrelation of the modification of the moment of inertia and the redistribution of angular momentum, called the redistribution effect – , which leads to an energy transfer from the grip towards the tip of the fly rod propelling the fly line at last[1]. This energy transfer allows the fly caster to generate the line speed needed to hit the target by minimizing his effort.

Teaching

Since the redistribution effect depends on the deflection, efficiency is hard to teach. To determine the “efficient deflection” during a casting lesson seems to be nearly impossible. But to me this difficulty is not an excuse to hang on longstanding teaching elements, but a challenge to identify those elements, which are important for efficiency !

A longstanding and accepted teaching element is “rotation at the right time”. But the problem with this element is, that nobody knows the efficiency of the cast. Since this teaching element doesn’t care a lot about the meaning of the deflection[2], it stays too much on the surface (as I already wrote in my essay “Fly rod deflection and rotation 03/2017)” and might be useful to teach effectiveness, but not necessarily efficiency. Obviously a “deeper” teaching element below the surface of “rotation at the right time” is needed to face efficiency[3].

Motion properties

There are already some motion properties known, which favour an efficient fly cast. In the video ”What matters an efficient fly cast” – http://vimeo.com/221011910 – I worked out properties, which are important in my view. They are: a

  • significant translatory motion at the beginning of the fly cast
  • rotary motion which prevails very late (delayed rotation)
  • damping of the fly rod during the later rotary motion
  • harmonious movement through the entire casting stroke

Personally I was able to adjust my casting motions to the above enumerated motion properties by practicing with an ultra soft fly rod for a certain period of time[4]. The soft fly rod represents rather a “deflection dominated” mean, for which reason a softer fly rod is basically able to trigger the redistribution effect better than a stiffer fly rod, since a stiffer fly rod represents rather a “lever arm dominated” mean. If the caster tries to cast a softer fly rod lever arm dominated by using a shorter casting arc and by applying the required effort during a shorter time span as it works well for stiffer fly rods, for a softer fly rod the cast would probably fail. That is because a softer fly rod doesn’t allow the caster to use generous deviation from the above enumerated motion properties since they highlight a deflection dominated cast.

By practicing with softer fly rods the caster is forced to think about the distribution of the effort he applies in the grip over the entire casting stroke, especially when casting a longer fly line. Finally, if a stiffer fly rod is casted similar a softer one, the lever arm property joins the redistribution effect which leads to a higher efficiency.

Grip tension

Applying effort into the fly rod requires grip tension and the amount of grip tension depends on the required effort. The caster can loosen grip tension when no effort is needed and must tense it up when effort is needed. The caster notices, that for a soft fly rod the casting stroke works best if the grip tension is smoothly increased up to a maximum around the vertical grip position for a very short moment, while grip tension could be smoothly decreased again during the further casting stroke when unloading prevails[5].

In any case in terms of efficiency it is better to focus on the grip tension instead to focus on the rotation. This seems to be a good way to ensure that the above enumerated (deflection dominated) properties are considered. The longer the carried fly line is, the more the above enumerated motion properties must be respected to ensure a proper fly cast.

In the video “Energy transfer along the fly rod shaft” – http://vimeo.com/249444926 – I explain the “grip tension at the right time” (at 0:30 min) as it is useful for a better energy transfer. The idea of “grip tension at the right time” I watched first in the video “Dynamics of Fly Casting” by Joan Wulff, in which she squeezed a sponge around the vertical grip position to visualize the moment the caster should apply the highest effort.

Input in relation to rotation

The grip tension is the requirement for the input, energy or work respectively the caster applies into the fly rod[6]. Thus to me the appellation “input at the right time” is a proper advanced teaching element, which faces an efficient fly cast much better than “rotation at the right time”. In contrast to “rotation at the right time” with “input at the right time” the caster is able to gain a better control over the deflection as it is not only important to achieve a better energy transfer, but also to minimize the waste of energy due to an improved damping[7].

The rotary motion is the most important motion property of the input. If the caster neglects the rotation during he applies his input, the fly rod will respond with a very poor output, cast respectively[8]. As a big advantage of the teaching element “input at the right time” it is focussing not only on the rotation, but pays also a higher attention to the other important motion properties enumerated above – especially to the translatory motion[9].

Even the 5th principle of fly casting[10] stated by Jay and Bill Gammel is talking about the “power” instead of the “rotation” in the right amount and place during the casting stroke. It seems they have understood that “power” as a synonym for the input is a better principle to describe the casting stroke than “rotation” could be.

Right time and phase shift

Both teaching elements are talking about the “right time” and the caster may ask, when the right time is. For rotation as well as for input the “right time” depends basically on the casters aim, the rod action, the casting length and how especially the fly rod and the fly line are balanced.  But there are tendencies showing the differences.

The “rotation at the right time” still holds true, if the caster doesn’t delay the rotation and if he still applies further “input” at the end of the casting stroke when the grip already has passed the vertical position in order to “kick” or “boost” the cast. The benefit of this further “input“ is rather less in relation to its drawback as it will produce a big waste of energy indicated by a big counterflex (bad damping).

In contrast to this the “right time” for the input is always delayed and its highest value occurs around the vertical grip position. It pays attention to a kind of phase shift between the highest input and the highest output, velocity of the tip of the fly rod respectively as the input precedes the output. This phase shift is vital in terms of efficiency since it allows the caster to reduce his input while at the same time the tip of the fly rod still gains velocity[11]. The phase shift explains, why a “kick” or “boost” at the very end of the casting stroke is detrimental in terms of efficiency.   

The “right time” for the rotation tends not to face the phase shifting as the “right time” for the input does and this is a further reason why rotation alone can’t face efficiency.

Technical point of view

Engineers and scientists usually investigate the dynamic behavior of complex bodies by stimulating them with different input functions (variation of the input) in order to determine the optimum output (input and output as a function of energy, work respectively). If the optimum output is determined, they have detected the best input function (“input at the right time”). Nothing else should hold true for the fly rod as it represents a complex and flexible slim body. The output on the one end (the tip) depends on the input on the other end (the grip). If the input is accentuated on one motion property like rotation, there is a risk to oversee the interrelation of the other important properties, which must be involved to detect the best input function possible !

Even a technical point of view clearly shows, that the teaching element “rotation at the right time” could lack some important motion properties in terms of efficiency.

Insight

The softer fly rod supports the caster to find out the advantages of the deflection. He will be able to recognize the phase shift between the highest input and the highest output and will intuitively look for the best input function (“input at the right time”) needed to generate a deflection, which leads to the best output in terms of efficiency. If he switches then to a stiffer fly rod after he has adjusted his motion properties accordingly, he might be surprised how less effort / “input” is needed to generate a proper line speed. He has learned to control the deflection better, which means that aside the spring effect the redistribution effect plays a higher and the waste of energy a minor role.

Efficiency in fly casting doesn’t mean that the caster has to decide between the deflection or the lever arm property of the fly rod. It rather means to get closer to the best interrelation of both the deflection and the lever arm. The teaching element “rotation at the right time” highlights the lever arm property of the fly rod and tends to neglect the deflection property. In comparison to this “input at the right time” combines both properties better so that they join to an efficient fly cast. Therefore “input at the right time” is a “deeper” and more complete teaching element for advanced fly casters than “rotation at the right time” could be.

In addition the teaching element “input at the right time” is already used to explain the right moment the line hand has to haul, introducing “input”, energy respectively. For which reason this teaching element should not work for the rod hand as well ?

Is it too complicate to teach ? Is it too complicate to leave it at “rotation at the right time” instead ? For advanced fly casters I don’t think so. To me it is worth to think about teaching elements which are closer to an efficient, power minimized fly cast[12]!

In my experience the teaching element “input at the right time” even works practicing with stiffer fly rods (if a softer fly rod is not available) to convey advanced fly casters what matters an efficient, power minimized fly cast.  

Many thanks to Franz- Josef, who has reviewed this essay.

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The following outline shows a simplified classification of some elements of the fly cast as I see them

read on scribd

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[1] More detailed Information about the redistribution of angular momentum and the modification of the moment of inertia (redistribution effect) can be found in my “Experimental investigations on the fly rod deflection” (Rev. 2.0 – November 2014), section F1 and annex 2.

[2] In fact the deflection is the requirement for efficiency.

[3] A good explanation about the difference of „effectiveness“ and „efficiency“ could be found here: http://en.wikipedia.org/wiki/effectiveness and http://en.wikipedia.org/wiki/efficiency

[4] In the IFFF magazine “THE LOOP” January – July 2017 there is an article published about my experience practicing with ultra soft fly rods.

[5] Especially during the unloading phase of the fly rod aside the spring effect for bigger deflections the energy of the lower mass elements contributes  to generate the velocity of the upper mass elements leading to the redistribution effect accompanied by the energy transfer and a kind of “self dynamic” (self dynamic mechanism) of the fly rod. Therefore the caster is able to decrease his grip tension during the later rotation though the tip of the fly rod still gains velocity.

[6] Some people think that rather the force the caster must appliy into the grip describes his effort. As the fly line is propeled by the energy and not by force of the tip, the same physical unit should be compared with each other  (otherwise apples would be compared to pears).

[7] In addition the figure XI of my analysis „Experimental investigations on the fly rod deflection“ has estimated how the course of the introduced input of energy and momentum transfers the kinetic energy to the tip and leads to its acceleration (green graph for the flexible fly rod). The rotation is an important aspect which goes together with the input of energy and momentum.

[8] So the caster didn’t use “input at the right time” in this case.

[9] See my essay „The meaning of the translatory motion in fly casting”.

[10] The 5th principle is: “Power must be applied in a proper amount and in a proper place during the stroke”.

[11] For a rigid fly rod there is no phase shift due to the lacking spring and redistribution effect.

[12] Fly fishers, who want to reduce their effort when fishing the whole day long e.g. at bigger rivers, lakes or at the coast, could profit a lot by casting efficiently.

 

starting the haul for the backcast at the guide ring

Dienstag, Juni 12th, 2018

When casting together with other advanced fly fishers I’m often been asked about my opinion how I think they could improve their casting. Especially seeing them going for longer casts in many cases I recommend to delay the rotation further. The astonished reactions that I get then are showing that some fly fishers think they rotate “as delayed as possible” – but in fact they don’t.

Over a decade ago I saw a hauling variant used by the danish fly fisher Nicolai Eriksen, who starts the haul for the backcast at the guide ring. I noticed that the line hand was only able to reach the guide ring if the rod hand is situated in a rear position far behind the body axis. Furthermore in this position the wrist could be relieved if the grip of the fly rod is leaned against the forearm. For the rod hand I found this to be a good initial position to delay the rotation (see video below) !



Trying this the first time was quite unfamiliar, but after a couple of time practicing this hauling variant I realized that I was able to delay my rotation further – the more the grip of the fly rod is leaned against the forearm. After adjusting my motions accordingly it works even without hauling or starting the haul lower (not at the level of the guide ring).

To me this hauling variant is a good exercise for fly fishers to check if their casting motions are adapted to a very delayed rotation. Although I normally don’t use this haul variant in fishing situations I’m convinced that this exercise can improved the casting stroke and that it is useful especially casting softer fly rods for distance.

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feelings and facts in fly casting

Mittwoch, Mai 30th, 2018

When I first stated about 10 years ago, that according to my feeling the ‘load’, deflection respectively of the fly rod could provide a significant advantage in term of minimizing the casters effort, I earned a lot of objections. A lot of people replied that the meaning of the ‘load’ is absolutely overrated. In their opinion the ‘load’ provides basically geometrical advantages – especially to carry the tip of a fly rod on a straigh path. They base their opinion basically on results of the following physical investigations:

  1. “The Rod & The Cast” by Lövoll / Borger from 2007. This great investigation pointed e.g. out, that the stored energy of the fly rod contributes about 20% to the final tip speed, what is rather less.
  2. Outcome of modelling the fly cast with a simple harmonic oscillator. This 1D model pointed out, that the deflection indeed provides an advantage in terms of efficiency (ratio of the output / input energy), but this advantage will be more or less completely eaten up by the energy loss caused by both the counterflex and the energy conversion from the stored back into the kinetic, which waste energy.

Today more recent insights are showing that the deflection (and the ‘load’ as a part of it) is the requirement for a significant better energy transfer along the fly rod shaft, which rises the efficiency. After I’ve occupied myself with the aforementioned investigations I came to the following valuation:

To 1. = The energy transfer was not in the focus of the investigations by Lövoll / Borger. Hence to claim the ‘load’ – the more as it occurs together with the deflection – can’t play an important role since it contributes rather less to the final tip speed is risky.

To 2. = A simple 1D model is basically not able to face the redistribution of energy, angular momentum respectively taking place due to the deflection. On the other hand 2D models are showing, that aside the ‘load’ an energy redistribution, redistribution of angular momentum respectively takes place enabling a better energy transfer from the grip towards the tip of the fly rod (made possible by the modification of the moment of inertia in combination with the varying angular velocities of the mass elements of the fly rod – see the following video). Further more the disadvantage of the counterflex must not be as big as assumed. I’ve read about an average counterflex by about 66% in comparison of the biggest previous deflection, but it is fair to say that an average reduction on below 20% is absolutely possible.

Physical facts are saying that the deflection provides a big potential regarding energy transfer and it is up to the caster to make the most of it. So in terms of minimizing the casters effort the meaning of the deflection is not at all overrated. To me it is good to know that my feeling I have over a decade matches physical relations. The physical background of 1. and 2. can’t be approached for explaining the entire characteristics of the fly rod. Whatever ‘feeling’ is supposed to tell.

Of course in fly fishing there are several points which are important to catch the fish – but for the most common fishing situations the fly fisher can profit by hitting the target with less effort possible – and controlling the deflection is a very important key to it (see the following video).

“The flexible elastic lever is a very smart mean to maximize energy in the line and minimize the one left in the rod.” (Merlin from sexyloops, 05/2018)

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the meaning of the translatory motion in fly casting

Freitag, März 16th, 2018

Many articles about fly casting tend to focus on the rotary motion of the fly cast, since the rotation generates the velocity of the tip most. The meaning of translatory motion is often neglected for that reason. Discussions about the translatory motion are often focused on the way how the translatory motion should overlap the rotary motion: rather uniform over the casting stroke or more at the end of the casting stroke.

With the exception of shorter accuracy cast I almost always recommend a delayed dominated rotary motion “at the very end” of the casting stroke, which leads to a dominated translatory motion at the very beginning of the casting stroke.

This translatory motion, especially as it dominates the very beginning of the casting stroke, basically causes the following:

1.)   Possible slack fly line is removed and the whole fly line pulls on the tip of the fly rod, at lastest when the rotary motion prevails.

2.)   The path of the tip is elongated.

3.)   The mass of the fly rod is set in motion, so the fly rod is not situated in a defined condition.

The translatory motion precedes, “introduces” respectively the rotary motion so to say, and the better this introduction is the better the benefit for the fly cast could be. Both findings are very important to complete the casting stroke successfully with the following dominated rotary motion.

Removing slack line is always a very good idea as well as to elongate the path of the tip for longer fly casts, but there is a further aspect. Since the translatory motion is setting the mass of the fly rod in motion, the dynamical energy transfer property of the fly rod can be improved (redistribution effect). A dominated translatory motion at the beginning of the fly cast enables a deeper deflection of the fly rod, whereby the lower mass elements of the fly rod are able to gain a higher angular velocity than the upper mass elements during the earlier fly cast. This is the moment the energy transfer along the fly rod shaft begins, which leads to an efficient fly cast[1]. This relation I worked out in my “Experimental investigations on the fly rod deflection” as well as in some videos – especially these two: http://vimeo.com/226547073http://vimeo.com/187846392

So an optimal interrelation between the translatory and the rotary motion is the key of a good fly cast. Without the translatory motion the rotary motion will miss a very important partner, who provides required properties to perform an efficient, power minimized fly cast.

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[1] In contrast to a rigid fly rod the lower mass elements of a flexible fly rod have a higher angular velocity ω than the upper ones during the early phase of the cast, rotation respectively. This leads to a „butt dominated distribution“ of angular momentum L (L = J * ω; J = moment of inertia). Since this angular momentum distributed along the lower mass elements just can’t disappear due to the energy conservation theorem, it must be transferred towards the upper mass elements during the later phase of the fly cast (energy transfer / redistribution).

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practicing with ultra soft fly rods

Montag, Juli 31st, 2017

This article was also published in The Loop Magazine, April to July edition (page 13 and 14):

practicing with ultra soft fly rods

Near the end of the year 2007 I took a private fly casting course with Uwe Rieder from Austria. After seeing my cast he stated that I could improve it by practicing with soft fly rods without double hauling. I agreed to try this of course. Uwe then provided me not with a soft fly rod but with an ultra soft one from Vision (I don‘t remember the name exactly, but I guess it was a „mirage“ – due to its softness it was not available commercially). This fly rod was so soft, that the tip of the fly rod could almost be deflected towards its grip („grip action“ – see picture with Uwe). My first casts with this fly rod were lousy, since my motions were used to much stiffer rods, but as time went by I was able to adjust my motions and I elongated my casting path. This longer casting path enabled a slow and continuous increase of the deflection of the fly rod that is vital for softer fly rods and my results steadily improved. My preferred way to cast with an almost „closed wrist“ helped me a lot during these exercises. By the way, as with other superb casters, Uwe uses very little wrist actively.

Uwe made the following comment, “Tobias, there are a lot of superb casters out there that have problems casting a longer fly line with a soft fly rod. The soft fly rod indicates who can cast really well. The soft rod separates the wheat from the chaff.“

Shortly after returning to Berlin I snapped the softest fly rod I had (which I was going to sell before I finished my course with Uwe) but exercised with this very soft rod periodically for about one year.

My practice sessions with the soft rod always started by putting the fly line stretched on the meadow. As Uwe showed me I started my casting motion from my upper body followed by the shoulder and the upper arm last. The elbow always precedes the cast, which causes a significant translatory motion. When I wasn’t able to move my elbow further, the rotary motion started to prevail.

My first time practicing this was hard. I often started the rotary motion too early, which caused vibration in my soft fly rod leading to waves in the fly line. This especially happened on my forward cast. As I understood that on the one hand my elbow didn’t precede long enough and on the other hand I forced the rotary motion too much, my casting with this soft fly rod improved more and more.

After a couple of these training sessions I felt the highest effort I needed to apply into the grip was for a very short moment around the vertical position of the grip. During the rotatory motion between the vertical position and the end position of the grip I was able to reduce my pressure on the grip since the fly rod has a kind of “self dynamic” – which means that though the upper mass elements are still gaining velocity less effort at the grip is needed.

I‘m convinced that these exercises improved my casting stroke and I found it much easier to use stiffer fly rods after making these adjustments.

Thanks to Walter Simbirski for optimizing my english.

The above descibed practicing with ultra soft fly rods is useful to trigger the redistribution properties shown with short words in the following video:

wait, wait, wait, … rotate !

Montag, Juli 10th, 2017

Being asked about the right time the caster should rotate the fly rod I don’t have to think long. My answer will be that the rotation should be strongly delayed. This holds true for longer fly casts, but I personally prefer a later rotation even for medium fly casts. I’m convinced that on the one hand a later rotation is a good medicine to avoid a lot of casting faults and on the other hand it benefits an efficient, power minimized fly cast.

To understand this context a closer look on the effects is useful. Looking on some fly casting videos of me and other caters it can be observed that the deflection of the fly rod tends to be bigger and deeper the later the fly rod is rotated. This deflection causes basically a significant

  1. shortening of the lever arm (projection of the fly rod),
  2. storing of some energy (potential ‘spring’ energy) as well as
  3. redistribution of some energy into the tip of the fly rod (the angular momentum in association with the modification of the moment of inertia).

All enumerated effects interrelate in a complex way, but here I would like to focus on the relation between the lever arm (1.) and the two further properties (2. and 3.).

For the fly rod on the one end of the lever arm the tip is located, on the other end there is the grip. The lever arm property of the fly rod is vital for generating tip speed especially as it is rotated. The longer the lever arm is, the higher the tip speed could be. Tip speed is a kinetic energy which can be transferred from the grip. The more energy should be put into the tip, the more energy at the grip is needed. This is an advantage of the fly rod as for a stiff lever arm the ratio of the output and input energy (synonymous with efficiency) remains always unchanged as it works similar a ‘plunger rod’.

For shorter lever arms the tip speed, tip energy respectively will decrease as well as the introduced energy at the grip. But in terms of the fly rod the shortening of the lever arm is accompanied by the deflection, which means that the two further properties (2. and 3.) are correlated ! As shown in my “Experimental investigations on the fly rod deflection” (rev. 2.0, 11/2014) on the one hand the shortened lever arm might cause a reduced tip speed (see section F3), but coincidently on the other hand the effort the caster has to apply decreases significantly and the tip gains additional speed upon rotation of the fly rod by efficient redistribution of energy.

Up to a limit, which is basically determined by the softness of the fly rod, the disadvantage of the initially decreasing tip speed will be significant smaller than the advantage both the storing and the redistribution of energy are providing ! So what the caster could gain is a much higher efficiency (ratio of the output and input energy) by ‘loosing’ a bit effectiveness (output energy, the tip speed is all what counts).

Caster who generate a smaller deflection are getting a longer lever arm. That might be useful especially in situations where effectiveness could be the key for success, e.g. tournament distance casting. They often prefer to rotate earlier or ‘through the casting stroke’. So in terms to their aim those casters ‘rotate at the right time’ too.

For the common fishing situations my aim is to cast as efficient as possible. Hence to me ‘Wait, wait, wait … rotate’ is a good phrasing to clarify the right time the rotation should take place.



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angular velocities of the mass elements on the fly rod shaft

Mittwoch, Juni 28th, 2017

Playing with the GIMP tool (GNU Image Manipulation Program) I superimposed some pictures taken out of a casting sequence of me. I liked the result since it visualizes how the angular velocities of the mass elements on the fly rod shaft vary over the entire casting stroke.

The angular velocity ω is determined by the angle φ divided by time t (ω = φ / t). Due to the deflection of the fly rod during the earlier phase of rotation the lower mass elements are covering a larger angle than the upper ones (shown by the violet lettering, see picture 1). According to the relationship shown above they have the highest angular velocity ω.


During the later phase of rotation it is the other way round. Now the upper mass elements are covering a larger angle (shown by the red lettering, see picture 2), for which reason they have got the highest angular velocity ω.


So what can be detected is a shift of the highest angular velocity from the lower mass elements towards the upper ones over the duration of the fly cast (see picture 3 – visualized by the black arrow), which correspond to the varying contribution of the angular velocities.

The angular velocity (ω) multiplied by the moment of inertia (I) leads to the angular momentum (L). L = I * ω. Taking the modification of the moment of inertia caused by the deflection into account, this relationship points to a contribution of angular momentum, which shifts towards the upper mass elements like the angular velocities.

Due to the energy conservation law the energy can’t just disappear, thus the energy of the lower mass elements must contribute the accelerate the upper ones, resulting in a higher angular velocity, angular momentum respectively during the later phase of rotation (energy transfer).

The towards the tip of the fly rod shifting contribution of angular momentum equals the shift of the center of the rotating mass shown in my “Experimental investigations on the fly rod deflection” (rev. 2.0, November 2014 – section F1) and indicates, that some kinetic energy could climb up along the fly rod shaft towards the tip. This behavior benefits an efficient fly cast (ratio of the output and input energy).
It is obvious that the energy transfer from the grip towards the tip of the fly rod depends on the way the fly rod is deflected. The varying contribution of the angular velocities of the mass elements is a good indicator for that.
The pictures above are taken out of a video, which I produced in order to explain what I wrote before:


download / print article

read on Scribd

To me the following picture is a good summarizing illustration about the ‘energy flow’, transfer of angular momentum respectively taking place along the fly rod shaft.

 

fly rod deflection and rotation

Sonntag, März 12th, 2017

Looking through fly fishing forums I often read a statement like this: „we rotate the fly rod and as the inevitable consequence it deflects“ (and again recently “rod bend is a consequence of our main purpose to rotate the rod”).

This statement left me unsatisfied. On the one hand I totally agree that the rotation of the fly rod is vital to generate a proper line speed to get the fly into the target. But on the other hand I was missing something. To me this statement felt uncomplete somehow, since in this view the meaning of the deflection tends to be a kind of byproduct of the rotation reduced to some geometrical advantages – basically to carry the tip of the fly rod on a straight path.

Since my „Experimental investigations on the fly rod deflection“ I can explain what I was missing: the meaning the deflection could have in terms of efficiency (ratio of output / input energy) !

As one conclusion of my investigations there is no doubt that the deflection of the fly rod enables a significant better energy transfer from the grip towards the tip. In comparison to a totally rigid fly rod – which provides basically leverage resulting from the translatory and the rotary motion – the flexible one provides two further transfer properties: 1.) the storage of energy (spring energy, the „load“) as well as 2.) the redistribution of angular momentum (associated with the modification of the moment of inertia – see section F1 and annex 2 of my investigations). Both further energy transfer properties interrelate and enable the caster to generate a proper line speed with less effort, if he deflects the fly rod in a proper manner ! Even if the rigid as well as the flexible fly rod could be massless – as investigated in my work – the flexible one has a significant better ability in energy transfer than the rigid one.

What is the insight ? The rotation in combination with the controlled deflection as well as the controlled counter deflection (reduced counterflex) is the key of an efficient fly cast ! In terms of efficiency a closer look on HOW the fly rod is deflected is important instead of THAT it just deflects as a consequence of rotation. The rotation is vital to achive this and it is always effective (“the aim is all”) somehow – but without a proper deflection the rotation alone is not efficient (1).



I produced some videos with should clarify what I’m talking about.

read on scribd
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(1) Scientists would say, that for efficiency the rotation is a necessary, but sololy not a sufficient condition ! Both conditions are only met if the optimal deflection joins the casting stroke !

velocity distribution of the mass elements on the fly rod shaft

Donnerstag, Februar 23rd, 2017

In additional contemplation to my work “Experimental investigations on the fly rod deflection” I looked at the distribution of the velocities, which mass elements of the fly rod have. Over the duration of the cast it becomes clear, that the velocities of these mass elements vary significant to each other due to the deflection. Whereas the highest velocities are located at the middle mass elements at the beginning of the cast, the highest velocities are located at the upper mass elements at the end of the cast. So the highest velocity shifts towards the tip of the fly rod. This is another clear indication for the (“complex”) redistribution processes taking place in the fly rod.

read on Scribd – print/download