Garrison stress graphs

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Fcs
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Re: Garrison stress graphs

#21

Post by Fcs »

GeoF wrote:
03/09/22 09:36
In conclusion, is anyone up for generating a Hexrod graph with Hoagy's original calculated taper dimensions, assuming level line, tip impact 2.5, 14/64 ferrule, etc., etc.?? I'd love to see that. And especially I would love to see if that graph regenerated the stresses on the table p258, rather than the stresses in the accepted Hexrod graph that uses the 212 taper on p280.
Well George it sounds like you are the one most motivated to burrow into this at the moment. Just enter the taper into Hexrod and see what comes out. Will only take a few minutes to do this. Use 50ft of DT6 off the tip and you will have the same 272 grains that Garrison/Carmichael used. A tip impact factor of 2.5, and use a 13/64 standard ferrule in Hexrod which weighs nearly the same as Garrison's 14/64 ferrule. Line in guides weight will probably be the biggest difference between Garrison & Hexrod, and whatever is caused by calculating at 5 vs. 1 inch segments.
"Wherever the fish are, that's where we go."
Richard Wagner

GeoF
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Re: Garrison stress graphs

#22

Post by GeoF »

Harry, good point about line length. On p243 Hoagy assumes 50ft of DT-6-F line, yet in spite of the line being DT he uses a constant 5.44 gr/ft, which would imply a level line of that constant weight per foot. I agree that apples to apples is best, so if someone can do a Hexrod graph (with Hoagy's original calculated taper dimensions, assuming level line, tip impact 2.5, 14/64 ferrule, etc., etc.) they should use that same 50ft of DT-6-F line.

trland
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Location: Northern Illinois

Re: Garrison stress graphs

#23

Post by trland »

As Frank has mentioned, it would not take you very long to input the parameters you want in Hexrod. The knowledge you will gain by playing around with different variables will be invaluable and will answer some of your questions immediately.

Mike

GeoF
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Re: Garrison stress graphs

#24

Post by GeoF »

As Frank and Mike suggesteded, I spent some time on Hexrod this morning. I had asssumed Hexrod was proprietary, but instead I am amazed this impressive software is free to everyone.
As some among you might have suspected, the published version of model 212 used a different impact factor and line length compared to Hoagy's values in The Book. 2.044 vs Hoagy's 2.50 and 40ft vs Hoagy's 50ft. Once apples were lining up with apples, the low stress values of the published version rose to come within a percent or two of Hoagy's figures. For example, the published stress values of 152651, 159987, 154657, and 151156 at 5", 10", 20", and 30" respectively became 198722, 186603, 178889, and 172658 with impact factor and line length adjustment. Those later figures are in decent agreement with the graph of goal stresses on p257 of The Book, namely 196000, 189000, 180000, and 172000 respectively. The stresses with adjusted impact factor and line length are within a percent or two of Hoagy's goals.

GeoF
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Re: Garrison stress graphs

#25

Post by GeoF »

In conclusion, I can't thank all of you enough for clearing up my confusion. When I started this thread I wondered why the graph on p257 of The Book didn't match the published graph of model 212 data on Hexrod. I now see they are in fact the same graph when adjusted for scaling on the y axis and when adjusted for parameters like impact factor, line length, etc..
This has been a very cool experience for me. I so appreciate all your time spent and all your thoughtful replies.
Take care all, and I can't wait to become part of the community of bamboo rod owners now that the math/science nerd in me can appreciate them so much more.
Cheers,
George

trland
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Posts: 477
Joined: 10/29/17 16:17
Location: Northern Illinois

Re: Garrison stress graphs

#26

Post by trland »

Nice job George! I was in the same place as you about 4 years ago so I knew it would eventually click. And, yes, Frank has done an amazing job with HexRod. For me, it’s a resource that would be difficult to be without when it comes to making rods. Designing, planning, modifying, access to tapers, Handmill settings, comparing, understanding, experimenting, record keeping…it’s all there and easily accessible from any web browser. Now go make some rods!
Mike

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