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Walter & Group....
[GH] We are still trying to find the detailed message from Troy Miller on fly rod design. He had put a great deal of thought and work into this a few years ago. Definitely worth revisiting.
As most of you know, I am neither an engineer or a physicist.
As a caster, I see certain definitions pertaining to fly rods in this simplistic way :-
ROD ACTION:
1. Where and how much a rod bends under a given load. (deflection curve) *
a. Tip flex
b. Mid flex
c. Full flex
2. The feel of the rod when cast.
3. Don Phillips, though an engineer, has an even simpler definition of rod action : " The behavior of a fly rod during the process of casting." **
ROD STRENGTH: Here, I can see two different ways of looking at it -
1. Power - The mass-range of line which can best be carried out of the rod tip while false casting with well controlled loops.
2. Strength of materials/construct - The maximum stress applied at a predetermined angle which the rod can withstand without breaking or undergoing permanent inelastic deformation. (Bent to the point that it cannot return to the rod straight position..... much more likely to happen with bamboo or greenheart rods.)
Don Phillips has gone into great detail on this subject. **
Al Buhr has pointed out that a fly rod can be a strong one whether of fast or slow action. Of course the reverse is true as well.
ROD WEIGHT :
1. The actual weight of the rod with no line or reel. (sometimes recorded on the rod. Common on the older bamboo rods.)
2. The rod designation (expressed as "weight" as, for example, a 5 wt. rod) based roughly on a subjective judgement of its ability to perform when cast with the first 30' of a range of wt. designated fly lines.
ROD LENGTH : The actual measured length of the rod from tip to butt.
EFFECTIVE ROD LENGTH : Here, I can't improve on the original description by Vincent Marinaro in 1976:
"The measured chord that subtends the arc of the fully bent rod becomes the true casting or effective length. Accordingly, a nline-foot rod, under full bend, may become a seven-foot rod. Another nine-foot rod, stiffer than the first nine-footer may be eight feet in length. Or to put it another way, a stiff seven-footer may be effectively longer than a limber nine-footer. " The simple diagrams in his book and in Don Phillips book make this crystal clear. ** ***
* PRESENTATION by Gary Borger, p. 191-192.
** THE TECHNOLOGY OF FLY RODS by Don Philips, 2000, pp. 45 - 50, 51 - 68.
***IN THE RING OF THE RISE by Vincent Marinaro, 1976, pp. 52-54.
Gordy
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