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Design Techniques - Freestone sales blurb

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VGB
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Design Techniques - Freestone sales blurb

Post by VGB »

I picked this link up out of the Tackle section and it gives some insight into the design processes:

http://freestonerods.com/finite-element-analysis/

It appears that Merlin is on the right track, so well done. There are a couple of points in the narrative that might interest you.

There is also another section on Tuned Mass Damping that I'm struggling with. In my world, TMD is adding another spring and mass to the front of Grundes car:

http://www.sexyloops.co.uk/cgi-bin....ry96037

So what rod attributes are they talking about, any help would be appreciated.
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Merlin
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Post by Merlin »

Vince,

I don’t see what TMD is, it is said that: “Each finished blank is tuned using our proprietary TMD technology then hand-assembled and finished by the designer team that created them”. And “TMD allows us to design a rod that overcomes these limitations without adding or subtracting material”

Thus there seems to be some magic here: you do not add or subtract material so what are you doing then before assembling the blank? The justification is related to extra or lack of material: “Fast actions use extra material and stiffness as a choke, using brute force to control some of these unwanted vibrations. Slow actions gain smoothness by robbing the rod of material and power”.

Regarding stability, it is as you can guess a matter of stiffness and mass distribution along the rod shaft. If you want to introduce a device to kill the vibrations it will be too heavy given the spectrum of vibration to kill. There is some truth in the explanation but the situation is much more complex than what is described, IMHO.

Btw not all rods may suffer from instability, some are more involved than others (long rods, light lines).

Merlin
Fly rods are like women, they wont´play if they're maltreated.
Charles Ritz, A Flyfisher's Life
VGB
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Post by VGB »

Thank you for the response Merlin, I had thought that I was missing something obvious.

I am aware of the use of TMD on helicopters to reduced vibration caused by the main rotor but these are relatively heavy masses and I could not see it being a transferable technology to fly rods. I had also considered that there may be some matching to the line involved but that would involve detailing which lines and tapers should be used with each design of rod.

I understand your comment about instability, my 10' #3 Streamflex is quite susceptible.
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