KR concept vs new concept questions, and perhaps an interesting test

Started by JasonGotaProblem, March 25, 2021, 07:47:44 PM

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jurelometer

since you are a physics nerd, I would suggest a bit f light reading.  There are tons of papers on the physics of fishing rod casts, especially fly rods, but much of it is relevant to spinners.  It is a favorite subject for grad students who can't come up with something useful :)

Most of these papers are accessible (free) and easy to find if you still have a .edu email address.    You will find more structured arguments, and some basic descriptions of what is going on in a cast from a physics standpoint.

The problem here is that we are starting with a premise (different guide styles are more effective for some combination of cast weight a distance desired) without either any observations of this phenomenon, or any articulated  theory about why this might be true. 

Jeri and Boon make good points. 

I think the following would help frame a potential debate:

Fishing rod guides have two independent effects  during the cast.

A)  First in the during loading/unloading (casting stroke) phase.  The dimensions and locations of the guides can effect how energy is stored and released in the blank  by changing where the load is concentrated.  In addition to distance potential, this can to a lesser extent potentially  affect ease of use and accuracy.

B)  Next is the post release phase.  The cast is released, and the initial trajectory and velocity of the projectile has been established.  The  blank has mostly finished any oscillating  generated by the casting stroke.  At this point,  no guides are probably the best option.  The guides are fundamentally an impediment to distance.  Mostly this is due to the effect of impact ( the line smacking the guide frames and a bit on the blank).    The dimensions and locations  of the guides will affect the amount of energy robbed from the coils and waves in the line whacking the guides and to a lesser extent the blank.

The problem is that optimizing for loading/unloading negatively impacts optimizing for post release guide impacts and vice versa.   So the guide designers and rod builders are executing a compromise to acheive the best outcome for a certain use case,  which involves a bit of experience/trial and error.

From at least a marketing standpoint, the newer guide systems are focused on optimizing the post release phase, although placement and size are still factored in for loading.  But my guess is that these folks are betting that the biggest gain comes from paying more attention to the post release phase.


My take on your premise:

1. I would argue that  combinations of slower rod action (c-curve)  lighter  line,  lighter weight, shorter desired  distance, makes all of this less critical.  A slight bit more effort on a short easy cast with an easily loaded road may not even be noticed.  In other words the lower the demand for distance and payload, the less all this matters.

2.  The shorter the desired distance, the more likely accuracy is important.  The best way to get an accurate rod is to keep the blank length as short as possible, and have most of the loading occurring toward the tip. Blank  selection to accurately match the payload is very important.  I suspect that there has to be a reasonable number of properly located guides for the tip to load and track straight, but the  new guide systems should be compatible with this.

3.  Projectile mass and speed will effect the coil size coming off a spinning reel (and more importantly impact force on the guides), and a  slower speed  /lighter projectile cast may actually result in larger coils (more time for the coils to expand, less forward force pullingthe coils tighter.    So the benefit of rapid reduction guide systems may or may not scale evenly based on usage model, but I don't see how a benefit  suddenly becomes a disadvantage.

All of this is a long winded way of saying that for casting, the more you care about distance, the more you have to pay attention to both blank selection and guide style and placement, including  focusing on the post release phase.  The more you care about accuracy or ease of use, the more you can focus on just blank selection, and not worry so much about guide systems.


A quick side note on friction: sliding friction from the line rubbing on the guides is much less of an issue, as the compressive force of the line against the ring is neglible -another reason not  to shell out for high dollar inserts :) .  I think that  line being pulled through the air  is subject to a different set of friction equations.  Since air is a fluid, the surface area of the line is now a factor.  The farther the cast, the more line is out, the more friction slowing down the cast - thinner/limper line is your friend here.

-J

Jeri

Quote from: JasonGotaPenn on June 17, 2021, 01:52:32 PM
Quote from: Jeri on June 17, 2021, 07:51:23 AM
Isn't this the very problem of trying to create rules and generalisations, they just don't apply or can be wrong or faulty in certain situations.

As Boon has suggested, to increase kinetic energy through an ultra light situation, either more mass or more speed is necessary - so. would a much longer rod generate more speed in the lure and line, so challenging your generalisation?

Agreed that other than the laws of physics, most generalizations, like some casts, fall short. I'll be the first to agree with that. However if you lengthen the rod on one it's not an apples to apples comparison, but if you lengthen both, the original question reappears.

Though based on everything I've learned thus far, K series guides do seem to favor longer rods. But based on your own description you build from the top down, you're not lining the spool shaft up with the edge of a table and going from the bottom up like Fuji is suggesting, or you'd end up with your bottom guide a lot closer to the reel seat. So that begs the question of are you technically building a KR concept, or are you building a different concept using K series guides? Not saying that negatively btw, clearly it's working. I'm just seeking clarity.

So I guess a better way to phrase the question is: for a low weight lure, which layout has a greater effect on (or is a greater detriment to) initial momentum?

I'll be the first to admit, I'm not using all the aspects of the conventional 'rules' of the KR Concept, and if you had to put a name on it, I would say 'KR Hybrid'.

I use the idea that rapid reduction of the guide eye sizes and ignoring numerical progression to achieve the reduction. And apart from using small single leg KT guides, I ignore traditional KW type guides, and occasionally use KL guides. Though having found issues with the rigidity of KL guides in getting optimum performance, have reverted to using LC guides for the reduction section of my designs - more rigid and can use smaller guides than an equivalent KL in the same position. The concern with these guide designs is not the sloping guide face, but the height of the overall guide eye.

However that said, on very light applications I will revert to KL guides to achieve the rapid reduction, but again will ignore various 'rules' for positioning the first guide, as the 'rules' don't work should you use say a Shimano reel with a zero offset shaft - for then the first guide would be placed at infinity - as the shaft in those reels is parallel to the blank. I'll ignore the architecture of the reel, and concentrate on the effects of the line coming off the reel, and the energy therein when it approaches the first guide, to accommodate that to achieve better line flow and line speed. I find that the conventional schemes induce an element of 'choking' of the line flow, and hence by pushing the first guide distance out, I can reduce or eliminate that aspect.