Hey, new to the forum and to bow building. I am going to be building a glass r/d longbow in the manner layed out here:
http://madmodder.net/index.php?topic=4424.0 I wish to do it a little differently though. I want to use a 20" riser with a length of 68". The guy in the build along did a 18" riser and total length of 66". He was also aiming to get 60-65# @28", where as I am aiming for 55# @29".
Also, from what I can tell, his bow is 2" wide, which seems really wide for a longbow, even a pretty heavy r/d one. Is this standard? I figured I'd just do it at 2" and if i needed to reduce the weight, I could side tiller from there. The problem is that I don't really want to have to take a half inch off with two layers of fiberglass to cut through. But I'm worried that if i build it any thinner that I won't get the weight I'm hoping for.
I will be using two layers of .05 fiberglass. The guy in the build along said that he was aiming for a limb thickness, apart from the fiberglass lams, of .336". Since I am aiming for a draw about 5-10# less than his, I figured I'd aim for .3" of wood. Is it accurate that about every .004" of wood is about 1# of draw?
Also, my ratio of riser length to total bow length is less than his, meaning that i will have less active limb than him which should increase my draw weight. Any idea how much of a difference in draw weight a 66" bow with 18.5" riser would have compared to a 68" bow with 20" riser, all other things being equal?
Any guess to the draw weight a 68", r/d, 2" wide, 20" riser length, .1" fiberglass, .3" wood would have at 29"? haha! Too bad there isn't a formula for this! :p
Does this sound like an ok idea? I have no idea how wide or thick the limbs generally are on a modern r/d longbow. Will I be able to side tiller enough if I end up with a draw weight that is too high? Or does this design seem like I would end up with too low of a draw weight?
Thanks! This is an awesome forum, so much good info!
Topic: Advice on project. (Read 400 times)
