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 sharps4590 |
parabolic defined |
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Posts: 103 02/15/2009 08:03 |
I hope I'm posting this in the best and right place. I figured builders would have the best explanation. Exactly what is meant when the term
"parabolic" is used in reference to fly rods? I have an idea but I truly don't know.
Also, then what would be the opposite? Vic |
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canerodscom |
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Posts: 1997 02/15/2009 09:54 Bamboo preacher |
Vic,
There is no precise definition of a parabolic action. Parabolic seems to be user defined, and many users continue to use absolutely non-sensical phrases like "mildly parabolic" or "semi parabolic." Most of the time it refers to a specific rod action, or taper design. Rods described as having a parabolic action usually have two distinct flex points, one about 1/3 from the tip and another about 2/3. Another way of expressing the same action is to say the rod has a soft tip, strong middle, and soft butt. Hope this helps, Harry |
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bluejayee |
#2 | |||
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Posts: 632 02/15/2009 13:50 |
Hi Guys, I must need a typing exercise this morning. "Parabola: The curve formed by the edges of a plane when cutting through a right circular cone at
an angle parallel to one of its sides." I hardly remember that certain types of common equations describe this geometry but maybe some one can draw us a
picture. As related to rods, slow. Although Paul Young rods are named 'Parabolic' they seem to be fast but with little or no taper into the grip.
This gives the 'feel' of a 'slow' rod with the power of a fast taper. This is my own view and does not express the views of yada, yada,
yada..... Jay Edwards
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sharps4590 |
#3 | |||
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Posts: 106 02/16/2009 09:01 |
Thank ye kindly, gentlemen.
Vic |
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brooksriver |
#4 | |||
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Posts: 98 02/16/2009 09:38 |
The following definition was copied from the Paul Young
Rod Co. website when it was still active.
When putting one of these rods under the stress of casting, or playing a fish, it forms a parabolic curve, uniformly progressive. The faster action rods form a more abrupt curve, with the upper half of the rod working, and the butt section hardly showing a bend. For those of us who strive for power per weight, this indicates that the butt is loafing. It is not delivering power of flexation, which can only be achieved through recovery from stress, but merely acting as a lever, in which case the tip is doing most of the work. In making a cast with one of our Modified-Parabolic rods, the butt flexes into the grip. On the delivery of the cast, the lower half of the rod begins its recovery while the upper half of the rod is still flexed. Then as the tip straightens, a second power impulse applies, enabling its user to effortlessly shoot an abundance of line, if desired, or to precisely roll a cast with only as much line as leader. These rods are designed to effectively assume, and transmit the energy required to cast line and fly to any fishable distance, while requiring a minimum of effort by their user. Another virtue of our Modified-Parabolic rods, is their ability to protect delicate leaders, by absorbing the shock of a fighting fish, over the full length of the rod."
The following is Per Brandin's description (Comparison of Payne 201 vs Paul Young Para 15) copied from Bamboo Magazine. "The Para 15 with a heavier tip and a taper in the rest of the rod which is radically different, results in a parabolic action which bends easily all the way into and just above the handgrasp, then blends with a very powerful mid and combines with a strong quickly tapering tip. The resulting action takes some getting used to, but many seasoned cane anglers consider it the finest trout taper ever produced. In simplified terms, the Payne will bend relatively more in the tip, and the Young will bend relatively more in the butt." "The tapers of these two rods produce radically different bending profiles. This difference will cause the Young to bend a great deal more at this point above and into the grip than would the Payne whose swelled taper stops bending in this same area, keeping it very stiff. Beyond the 13" point the Para 15 has significantly more wood than does the Payne. The Para 15 will easily pick up a significant amount of line from the water with its strong tip and easily throw a very long line, but most casters wont find it as sweet in close as the Payne or as pleasant to swing all day long."
Last Edited By: brooksriver 02/16/2009 18:11.
Edited 1 time.
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ShenRods |
#5 | |||
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Posts: 182 02/16/2009 17:08 |
I did not have a Payne 201 taper handy, but I did have the Dickerson 8015 to compare to the Para-15. Both are 8' rods with a 15 ferrule. This will illustrate the basic differences in terms of dimensions and stress curves. Once miss-conception about parabolic rods is the tips - they actually will have the same tip slope as a progressive rod and may even have a finer tip as the case here. The real difference is in the butt slope - much more shallow than progressive tapers. The stress curve for the Para-15 has a characteristic dip in the middle of a parabolic taper. 
Chris |
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mattcliff |
#6 | |||
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Posts: 49 02/17/2009 13:39 |
I always found it interesting -- as a purely historical matter -- that Everett Garrison claimed in his book to have invented the term "parabolic"
rod. He says he coined it, as something of an epithet, in a conversation with Charles Ritz after the famous bicycle accident that supposedly led to the first
Ritz parabolic taper. Garrison claimed that by "parabolic," he was referring to the shape of the slope of the stress curve, i.e., what you'd get
if you hung a weight from the end of a rod with no taper at all.
I have no idea whether Garrison's claims are true, and certainly they are not consistent with other definitions of "parabolic" action. It's just what he said in his book. |
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Tim Anderson |
#7 | |||
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Posts: 15 02/17/2009 15:17 |
mattcliff wrote:I have posted this elsewhere, but the topic of who invented the term "parabolic" relative to a fly rod probably cannot be answered definitively. On p. 64 of the revised, English-language version of Charles Ritz's book, "A Fly Fisher's Life," he writes, "This is the action which I have called 'Parabolic', though the term is only a figure of speech, and the curve of the rod has absolutely nothing whatever to do with a parabola. This name used commercially dates from 1937." The story by Garrison on p. 238 in Hoagy Carmichael's Garrison book is about Ritz's broken-tip rod and the episode occurred in 1934 in Ritz's presence. The relevant part of the story is: "So, Jack Knight was so thoroughly impressed with this thing [the rod] and the feel of it he wanted to give it a name. I mentioned the fact that if you just took a plank of uniform thickness and stiffness through its entire length and anchored it into a brick wall so it couldn't move and put a weight on the end of it, its stress curve would be a true 'parabola.' He said, 'That's it. This is the 'Parabolic Rod.'" Was it Jack Knight or Garrison or Ritz or someone else who coined the name? Ritz may have been the first to use it commercially, but the origin would be hard to document now that the people involved are no longer with us. Tim |
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 quashnet |
#8 | |||
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Posts: 2447 02/17/2009 15:53 Moderatus Muscae |
Paul H. Young never claimed to have coined the term "parabolic." In his 1948 catalog, Young talked about duplicating the action of a parabolic trout
rod loaned to him by "the foremost exponent" of this action - by which I assume that he meant Ritz.
In his mid-1950's catalogs, Young showed photographs of his parabolic rods set up behind graph paper. A static pull on a fly line strung through the guides deflected the rod in order to show the curve of the rod under strain. This shape is not a smooth parabola. The rod bends strongly near the butt, then becomes much straighter in the middle, and then flexes strongly again at the tip. The taper provided what Young also called "double action." -In the circa 1955 catalog, Young said that "On delivery of the cast, the lower half of the rod gets in its power inpulse while the upper half is still flexed. Then, as the tip straightens, a seemingly second power impulse applies, which straightens a long line or shoots an abundance of line, if desired." For more about the early origins of parabolic actions (not the term "parabolic"), see this earlier discussion.
Quashnet's Paul H. Young Rod Database has photos and descriptions of over
425 PHY Co. rods, plus catalogs, accessories, etc. Thank you to all
who continue to send me PHY rod photos and info.
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fishbum |
#9 | |||
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Posts: 251 02/17/2009 16:02 |
Something about stress curves you might find interesting.
If you take most stress curves of rods that are somewhat a progressive tape like a Garrison you will find the following general equation will pretty well describe the stress curve when you apply a least squares porabola to the stress curve data. Typical r squared values will be better than 0.99xxx indicating a pretty good fit. You will need to work with at least a 2nd order polynomial and on some complicated tapers a 3rd order polynomial. For y=f(x) y=Ax^2 - Bx + C will describe the stress curve. y=-Ax^2 + Bx + C will describe the plot of the dimensions. Most stress curves are not linier since coefficent A does not go to zero. y = Bx + C is a straight line. Just some food for thought. fishbum |
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eastprong |
#10 | |||
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Posts: 429 02/17/2009 21:11 |
Fishbum:
Can you provide an example -- what are a, b, and c for any Garrison stress curve. --Rich |
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fishbum |
#11 | |||
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Posts: 253 02/17/2009 22:35 |
Garrison 212 taken from page 270 of A Masters Guide To Building A Bamboo Fly Rod.
stress data y = 5.3462x^2 - 1082.7x + 199214 R^2 = 0.9957 diameter data y = -9E-06x^2 + 0.0036x + 0.0612 R^2 = 0.9921 1 0.047 196000 5 0.081 196000 10 0.104 189000 15 0.122 184000 20 0.136 180000 25 0.150 178000 30 0.163 170000 35 0.175 167000 40 0.188 164000 45 0.199 161250 50 0.213 158000 55 0.227 156000 60 0.241 153500 65 0.254 151750 70 0.268 150000 75 0.282 148250 80 0.296 146500 As you can see by the r squared value the goodnes of fit of the data to a polynomial trend line is pretty good. If you are going to use this type of analysis you need to exclude the tip 5 or 10 inches that have been modified and the area in front of the grip where the swell starts. This still leaves the bulk of the working part of the rod. fishbum
Last Edited By: fishbum 02/17/2009 23:15.
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sharps4590 |
#12 | |||
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Posts: 107 02/19/2009 08:31 |
Wow....now I really have some food for thought!!! Thanks fellas.
Vic |
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Grayson Davis |
Parabolic? | #13 | ||
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Posts: 2 02/23/2009 17:45 |
To me, a parabolic rod is one with a faster increase in diameter for the tip than in the butt. The "hinge" is typically below the ferrule. A major
difference between the two slopes makes a rod strongly parabolic; less difference - less parabolic. Some of the P&M rods are super paras. Paul Young made
rods that I call moderate and barely detectable parabolic. This definition helps me understand certain rod actions, and gives good predictive value when
checking new taper numbers. Still, no bicycle accident that I can think of will make a straight or swelled-butt taper into my kind of para.
-Grayson |
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Salmosalar.fiberglassflyro... |
No accident for sure... | #14 | ||
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Posts: 5 02/25/2009 02:06 |
I have had the privilege of casting one of Professor Grayson's parabolics on a recent season opening day soiree. It was a nodeless version of a Paul Young
Para 15. Sublime, I enjoy casting parabolic fly rods and found this example to be exactly what I expect from a parabolic fly rod. I describe it as a two part
power action. Butt section then tip section to apply the forward motive force.
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