Author Topic: another osage war bow attempt  (Read 7493 times)

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Offline Badger

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Re: another osage war bow attempt
« Reply #15 on: March 31, 2016, 12:24:12 pm »
   I have found that the full rounded shape is fine as long as the mass of the bow is in line with the draw weight. Heavy bows tend to shoot well with full rounded shapes where lighter bows are usually better off going with elyptical tillers depending on the wood used. ELBs are somewhat unique because we have very specific demensions we need to adhere to. The 5/8 ratio of depth to width being the determining factor. If a bow is too narrow it is not pleaseant to shoot but if it is made a reasonable width it will carry too much mass on a lighter bow. The elyptical tiller shape allows for a higher mass in the bow. Bows over 100# seldon need to take this into consideration unless they are made from something very heavy like ipe. I just finished a 110# ipe long bow that I needed to go slightly elytical on because it would have been too narrow if I didn't or would have carried too much mass. A 50# bow made with eastern red cedar about 1 1/8 wide will usually do nicely with a full rounded tiller. While an osage bow is usually better off more elyptical.

Offline willie

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Re: another osage war bow attempt
« Reply #16 on: April 01, 2016, 12:55:28 am »
Badger

nice explanation. hope you can clarify a little.

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If a bow is too narrow it is not pleaseant to shoot

Because of hand shock?  Not pleasant in what way?


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but if it is made a reasonable width it will carry too much mass on a lighter bow.

Too much mass for good efficiency? 

Just trying to figure out what qualities you are trying to balance with a good design

thanks
willie

Offline Badger

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Re: another osage war bow attempt
« Reply #17 on: April 01, 2016, 10:15:52 am »
   If a bow is too narrow besides being not comfortable to hold it will tend to twist in the mid outer limbs. If you build a 74" long 80# elb with a full arc circle it only calls for about 21 oz. With yew it might work out perfect but with a heavy dense wood the bow would have much higher mass. An elliptical tiller changes the projected mass of the bow.