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Bow and Arrow making?
I tried making a bow the other day. I got a nice stiff but flexible stick ad shaved it down. the trouble im having is the string, I get it nice and tight so I think its ok, but I pull it back and let it go, the arrow flies lie 10 feet but my string is totally slack and unusable so I have to tighten it wich is a pain! any help?
As MRS said, your bow isn't recovering very fast at all! It's your bow, not your string.
Bow physics.....when you draw a conventional stick bow back, a non-compound bow, the most energy the bow contains is right where you get the arrow to its farthest back point. When you have it fully drawn, it's taking the most energy to hold the arrow back. When you release your arrow, again, the most energy it will contain is when the bowstring first gets released....and the energy in the bow/string quickly drops as the arrow moves forward.
If you could see a bow being shot in slow motion, you'd see the arrow accelerating quickly by the string when first released, but by the time the arrow is even halfway out of the bow, it's actually pulling the string along behind it, not being pushed by the string.
Your bow isn't releasing its energy fast enough so it's not recovering fast enough and your string goes slack.
Elasticity in wood bows is a function of their wood....that's kind of obvious given the many specific types of wood folks prefer for bowmaking. But it's also a function of the bow's shape. That's why there are only two main types of wood bow cross sections. A flat limb and a shaped limb. Flats are usually laminated with other materials to add to their strength and elasticity....shaped bows aren't. Shaped bows rely on the shape of the carving to add to the strength and elasticity.
A round cross section stick doesn't make a good bow even when dry because the forces on the front of the stick pretty much equal the forces on the back. You want the force to be greater on the front in a pulling motion, or greater on the back in a pushing motion. That's why a lot of ancient bows were fronted with animal sinew to give the front of the bow more stretch, or backed with horn or bone to strengthen its pushing motion in the back. Laminated, as previously mentioned.
Try this one next and see if it works any better for you....
Take a nice 4" diam sapling and quarter it into four triangular staves. Notice that triangle shape! Now use your pocketknife or trimplane to thin the ends (back of the bow) down to make your limbs, but try to maintain that triangular cross section as you go. That sort of bow relies on more material on the back to reinforce the pushing motion.
There's so much to say on this topic but just not enoguh time or space in this forum.
I hope that helped, though.
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