Just out of curiosity, how much does sinew outperform rawhide as a backing? For example, there is a standard rule for determining bow length based on draw length; how is that rule modified by rawhide, and how much by sinew?
The way I understand it is that rawhide, as a backing, is little different from cloth backings, like linen, silk or denim. They help to hold the back together, but do nothing to alter the performance characteristics of the bow. Sinew is in a completely different catagory; it pulls the bow into reflex as it dries, adds draw weight, and increases the amount of bend possible for a given length bow. For a given draw weight, some of the limb thickness that had been wood, is replaced by sinew, which stretches further than any wood is capable of. The wood portion is actually thinner than it would have been in an all wood bow of the same weight, so it can bend more, without putting the belly under any more stress. In the end, you can have a very short bow, with lots of reflex, and still be able to take it to full draw without overstraining. I think your main limiting factor ends up being stacking, which can be remedied by flipping the tips. When you go as far as replacing the belly with horn, you end up with the Mongol/Turkish styles, which were often reflexed to about opposite of their full draw profiles. I seem to see quite a few sinew bows that are only about 2/3 the length that an all wood bow would need to be for a given draw length. Hope this helps, and sorry if it was long winded. Sometimes I get away from myself
