Belly Tapper ?

[Forwardhandle]

Hi Fellas I have been studying about making glass bows I have made self type bows for a few years now but working my way to make one with glass I usaly don't like to ask questions unless I can't find the answer my self some where but one thing that's been puzzling me is on a average self bow the belly tapper is on average about 1/16 every 5 1/2-6 in.  But on glass bows you see much flatter tapper 0.001,0.002,0.003 Ect ,could sombody explain that to me , could it be different front profile Ect ? I have googled the heck out of it but no answer ?

[JamesV]

I have measured hundreds of factory bows, and .003 taper seems to be the magic number.

James

[Crooked Stic]

I would think it has to do with the addition of the glass making things stiffer.

[kennym]

Also for narrower bows you need more thickness taper, as you have less side taper.    

[BMorv]

It has to do with the strength of the wood or composite in the case of a glass bow.  Fiberglass adds a considerable amount of bending strength to the overall limb composite.  Taking 0.003" off the thickness of a glass bow may equate to 1 lb less draw weight.  You might have to take 0.010" off of a self bow to lose 1 lb of draw weight.  It's the same reason that most self bows start out at almost twice the thickness of a fiberglass bow, they aren't as strong.  
A hypothetical example of 3 bows with similar width profiles may have the following taper rate to produce the same bend profile:
Elm Self bow- 0.010"/inch
Bamboo backed Ipe- 0.007"/inch
Glass bow- 0.003"/inch

And as mentioned, the width taper affects it too.

[Forwardhandle]

Bmorv that was a excelent exsplanation thank you and the 0.010 is where I start tapper wise with a self bows your exsplanation makes prrfect sense to me.

[mikkekeswick]

It is linked to the width profile. Parallel width limbs need more thickness taper. Pyramid width tapered limbs require less.
There is no 'magic' number for all designs.