Author Topic: Relative performance of different limb designs  (Read 4642 times)

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Offline Badger

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Re: Relative performance of different limb designs
« Reply #15 on: September 13, 2016, 10:51:25 am »
  SCP, one thing to keep in mind when building bows is that any design any draw weight should all be under the same amount of strain. This simply means if the radius of a bend gets tighter you have to make the wood thinner and wider. We often hear that a good bows is 90% broken. I feel more like a good bow is only about 70% broken, the other 20% is set we don't need to deal with. A bow with 1" of reflex, streamline design that hasn't taken much set will almost always be a fast bow.

Offline scp

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Re: Relative performance of different limb designs
« Reply #16 on: September 14, 2016, 05:20:53 pm »
A bow with 1" of reflex, streamline design that hasn't taken much set will almost always be a fast bow.

Not that long ago, I was in a binge to flip the tip of a couple of dozen bows with any string follow to make them recurved 2 to 4 inches. I broke several in the process by making the tips too thin. I should have tested the surviving bows before and after. I can do so, now that I have reassembled my "primitive" homemade shooting machine.

For the record, just in case anyone is interested and not to mislead anyone who read my earlier posts, I have to disclose that my shooting technique through the chronograph is so terrible as to lower the recorded speed as much as 15 FPS and sometime even 20 FTP. That means the commercial recurves I have, shoot around 165 FPS and often better, and many of my own unfinished bows shoot around 155 FPS. Not bad for simple sticks of hickory and oak. And of course, I do have several bows that shoot 165 FPS. I didn't expect to be that bad in shooting with bare fingers. I must have been pulling at least 2 inches less than the expected 28 inches. Live and learn!


Offline loon

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Re: Relative performance of different limb designs
« Reply #17 on: September 19, 2016, 03:56:53 am »
What I'm wondering is if there's best designs for certain GPP, ie Mollegabet better 12 gpp and up, Pyramid to 8gpp... or if that also depends on draw weight or even draw length. It's certainly true that a Turkish bow is much better than a Manchu bow at 5gpp, and a Manchu bow is much better than a Turkish bow at 14gpp... the Manchu bow stores a lot more energy, but is significantly less efficient with a light arrow

anything better than a molly curve for heavy arrows ~14gpp? i imagine it'd be better reflexed at the fade than in the middle of the lever.. or would it make any difference..
« Last Edit: September 19, 2016, 04:04:42 am by loon »

Offline scp

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Re: Relative performance of different limb designs
« Reply #18 on: September 19, 2016, 08:44:33 am »
Loon, good questions. But it would be too hard to get a generalization. We are better off trying to find a well balanced design for a specific weight bow and arrows, first. And probably for a specific wood as well.

As for me I just want to find a way to shoot 10 GPP arrows at 180 FPS. For now, I use hickory staves almost exclusively. The main question for me would be what would be the best ratio of width and thickness for hickory for my purpose. I read in "Archery, the Technical Side" that the best limb design is probably a rectangular cross section and pyramid front profile. In that book, there is a way to get that ratio. Still learning how.