For glass bow. What your thoughts on riser length? lets say a 15" over a 16" or 17" .Do you think the bow performs better one way or the other .Pro/cons
What bow length do you have in mind? something short like a 60" might be ok with a 15", but if its longer, personally I would go with 16 to 17. I find most really short risers a bit too cramped for my liking.
Just depends on your overall bow design.
Generally, longer risers will give you less shock and a shorter working limb, which increases stability reduces the mass of the limbs. That being said, 16" seems to be a good length, as many amazing bows are made with it. I personally wouldn't go shorter than that, as there is really no benefit (that I can see anyways). I use 22" in my design (though my bows are 68", on the long side).
Have only completed 2 bows, so someone with more experience may have a better answer/correct a misconception of mine.
As a side note, Binghams uses 18 inch risers in their 68" RD Longbow designs, for all of those who have used them as a starting point in bow building. That length produces a good shooting stable bow.
I have built them from 16" to 22" in the same RD longbow design. In general the longer the riser the better the performance will be. But as you lengthen the riser you will need more taper in the stack or you will end up with too much bend off the fades. My best overall LB build uses a a 21" riser, .04 taper and 7" tip wedges to maintain low full draw tip angle (eliminates stacking). Also remember if you are interested in performance build it with deep cores and narrow width profile. Glass or carbon is the heaviest part of the lam stack, deep narrow limb profiles optimize the ratio of glass or carbon to wood producing a rigid, lightweight limb. Hope this helps.
Bonner
Wish I had read that post before Dan! Will be using much more taper on my next bow haha.