Tapered vs. Parallel lams?

[pebowbender]

I posted this topic on the bowyers thread and didn't get any hits. (my bow is a R/D T/D Bingham design longbow) I met Owen Jeffry at the NCTAC yesturday and asked him for helpful tips for a hobby bowyer. He asked if I had any tapers in my limbs and I told him they were a Bingham design and they were all parrallel lams. He said (in technical terms) that the performance would be inhanced if I put .002 to .0025/in taper in the limbs. Has anyone tried this? how much limb thickness did you have to add to get equal poundage? and what performance changes did you notice? The origoinal Bingham design was two .002 reverse tapers(which makes a parallel limb) which I have already changed to all parallel lams and it dropped my brace height from 8" to 7 1/4". I'm certainly not complaning about my bows performance...just may want to try something different. Thanks for ANY input..Page

[ethan]

the tapers will basically get rid of weight at the end of the limbs, which will reduce weight and quicken your limbs up a bit.  It should also reduce hand-shock some.  I use tapers in all my bows and I would say most every bowyer does the same.  
As far as how thick they need to be, that depends on your form.  You'll probably have to experiment a little to get a formula that works.  A good rule of thumb that I've found is .005 of thickness per lam equals about 5lbs of draw weight.  That's a general rule, but that may help some.  Good luck.

Ethan

[LC]

Good question, that I don't have a answer for. The bow I build a TD recurve uses two tapers with no pararllels. I've seen some recurves that use two tapers that the tapers are reversed on as in butt to taper on each end. Go figure.

[Koko Bow]

The Great Plains SR Swift uses just parallel lams in the limbs and is smooth and quick.  The limb geometry, I would think, would play a role in how an all parallel design works compared to a parallel/taper or taper/taper design.

Matt