Does a “dry release” actually hurt your bow? If so, why?
In: Physics
When you release a bow you are releasing all the potential energy you have given it by drawing it back. Normally most of this force is applied to the arrow, to propel it forward. That force is still being released even without an arrow, but if there isn’t an arrow to take it then it the force goes into the bow. Do this a lot of times and the bow breaks because it can’t withstand the pounding.
Law of conservation of energy.
Think about the power that goes into an arrow when you fire it. It goes flying FAST despite having a decent amount of weight to it. You put a lot of muscle into pulling back on the string. Whether an arrow is present or not, as you’ve drawn back with the bow, you’ve put all that energy into it and your muscles are the only thing holding it steady.
When you release it, all that energy has to go somewhere. With an arrow, it goes into flinging that arrow forward at high speed. In fact the formula for kinetic energy of a moving thing is 1/2 * m * v^(2) and the fact that velocity is squared means that more speed has a much higher impact on energy.
If there’s no arrow… Where does that energy go? It has nowhere to go except the bow itself. If you imagine your muscles as punching an arrow into going flying fast, you’ve just punched the bow just as hard. Or alternatively, imagine if the arrow you shot hit the bow itself.
Yeah, it can do a lot of damage and probably ruin it in a single “shot”.
Yes, it can easily break the bow.
The reason for this comes down to the law of conservation of energy: while energy can change forms pretty easily, it cannot be created or destroyed by ordinary means. When you draw back a bow, you store a lot of energy in it, mostly through the bending of the arms. When you release the bow, all of that energy gets dumped out at once.
When you’re properly firing an arrow, the bow cheats conservation of energy just a little bit: it doesn’t destroy any energy, but it dumps almost all of it into the arrow. The arrow reacts by moving away very quickly, carrying all that energy with it until it either hits the ground or a target. The bow doesn’t have to do anything with all that energy, because it’s gone, so it is unharmed.
But this only works when there’s an arrow to dump energy into. When you dry-fire a bow with no arrow, the energy has no place to go except back into the bow. And the bow isn’t built to play fair: it would have to be much heavier and more rigid to be able to withstand that much of a sudden shock, and that would make it less effective at its job. The energy basically rips the bow apart, because it can’t take the strain.
When you pull the bow string, you’re adding a ton of potential energy.
When you release the string to make the arrow fly, most of that energy goes into the arrow to make it fly.
When there us no arrow, the energy as no where to go, so it slams into the other side of the bow and bounces back, which cause intense vibrations that can either come back and smack you in the face or make the bow shatter.
The same reason you still don’t want to point an empty gun at someone. It’s just good practice because you never know when you’ll draw the string and forget there’s an arrow loaded. Even in Hollywood there were issues back in the day when cast of Westerns would dry fire to practice and a live arrow accidentally made it’s way into the bow, other times there were miss firings when a live arrow was mixed in with the blank ones.
There is no energy being released through a projectile, so the force of the draw and fire will just be inflicted onto the weapon rather than an arrow. This can damage it.
Have you ever went to hit or kick something and missed? Like going to kick a ball REALLY hard and you just whiff it? Remember how that hurt the joint involved? Well you can heal, bows can’t.
I did this with my brother in law’s bow, I can confirm it definitely ruins the bow, or at least the cams. Oops!
For the same reason you’re more likely to injure yourself if you full-power throw a light ball versus a heavy one. If the balls is heavy all that stored kinetic energy in your arm has somewhere to go – the ball. If its light then most of the energy remains in your arm and has to dissipate through the joints and ligaments which can cause pain and injury.
Same thing with the bow.
I learned this in summer camp when I was 10 or 11. I didn’t understand the mechanics then but I understood the firm rules and always did a slow release if I didn’t have an arrow drawn.
Latest Answers