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Offline Kegan

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Theoretical bow
« on: October 05, 2009, 05:55:59 pm »
How good a bow do you think this would be?

Pyramid bow, length corresponding to draw (starting with about 66-68" for 28"). Limbs wide enough for the wood, tapering to 5/16"-3/8" tips. Now, this same bow, slightly deflexed through the handle, and reflexed in the outer limbs for a final net reflex of about 2". Tempered to increase compression strength, with a light low-stretch string like FF or Dyneema.

The pyramid design would put mass in the inner limbs, and reduce the outter limbs. The R/D profile would "isolate" the bend towards the inner limbs,without severley overstressing the inner limbs and  keeping the outter stiff and prevent the mid limb from wanting to keep going forward- both of which should help with bow efficiency. The string would also, but more so just help keep the limbs from wanting to vibrate when they slam home. The tips would be just heavy enough to resist wanting to twist off, but still be light enough to help speed. Mostly they'd be just stiff levers.

It seems that all those "efficiency" increasers would also help shooting qualities alot- almost no movement on release and a really smooth draw. The cast should be good, but more than that- the bow itself doesn't seem that difficult to make.

Thoughts?
« Last Edit: October 05, 2009, 05:59:37 pm by Kegan »
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Offline sailordad

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Re: Theoretical bow
« Reply #1 on: October 05, 2009, 06:05:46 pm »
well my first thought is
 
you should make it to see if your hypothosis is correct or not nad let us all know whats what with it
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Offline Stoker

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Re: Theoretical bow
« Reply #2 on: October 05, 2009, 06:07:55 pm »
Every thing works on paper  ;D sounds good giver a try
Thanks Leroy
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Offline Kegan

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Re: Theoretical bow
« Reply #3 on: October 05, 2009, 06:16:33 pm »
Okay, if you guys say I should build it I guess I should. Oh who am I kidding, like I needed convincing   ;D

I'm just curious if there's any big flaws I'm not seeing here. Like "that would shear the tips off!" and what not. Seems simple, and in my experience anything that seems like a good idea but isn't being used alot usualy has a big flaw SOMEWHERE.
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Offline MaceG

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Re: Theoretical bow
« Reply #4 on: October 05, 2009, 10:27:07 pm »
So basically, your talking about a reflex/deflex pyramid bow?
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Offline TBod

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Re: Theoretical bow
« Reply #5 on: October 06, 2009, 06:16:35 am »
I like it!

Sounds close to a Andaman-Holmegaard. I made one similar to TBB4 p124.

The with tapers  2,5"-2" from the fades to about 40% of the total limb.
Then "Eiffel tower shape" and increasing thickness.
I reflexed it when tempering the belly to 1,5" of total reflex.
Haven't shoot it yet but I like the design.
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Offline avcase

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Re: Theoretical bow
« Reply #6 on: October 06, 2009, 11:47:09 am »
Kegan,
Regardless of whether the design is new or not, your reasoning behind why the design works so well is right on the mark. Because of this, I'd bet that you have an excellent chance to build a winner.
Alan
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Offline Kegan

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Re: Theoretical bow
« Reply #7 on: October 06, 2009, 01:16:06 pm »
Mace- Pretty much :)

Thanks Tbod and Avcase! I'm sorta inclined to try it first with a pece of lumber, but that might limit when I can attempt this. Unless I build a hot box... >:D
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Offline bootboy

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Re: Theoretical bow
« Reply #8 on: October 07, 2009, 11:41:14 am »
kegan i want to see it BUILD IT BUILD IT!!!!
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Offline Del the cat

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    • Derek Hutchison Native Wood Self Bows
Re: Theoretical bow
« Reply #9 on: October 07, 2009, 04:16:36 pm »
Sounds good...I'd been musing on a pyramid with reflexed Holmie type levers on the end...
I've got a whole string of ideas and timber which is calling to me.
Stuff gets in the way of the bowmaking though :(
Del
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Offline Kegan

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Re: Theoretical bow
« Reply #10 on: October 07, 2009, 04:47:26 pm »
Thanks guys :). I have a new heat gun on the way, one cranking 300 watts more than our old one (and I do mean OLD). Hopefully that should help >:D.

Just need to find a stave and get chopping, or pick up a board.

Another question. R/D bows seem to have alot of tension forces going on. Would a piece of relativley straight grained hickory lumber be able to survive this kind of abuse?
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