Archery Calculations for Bowhunting! FOC, KE, and Momentum!

Today we're going to talk about archery calculations that matter and that you should know. Stay tuned. Okay, so the first thing we're going to talk about today is FOC, which stands for front of center. And I know, like, what's the big deal? Everybody's talking about it. Well, there's two reasons that FOC is a big deal. The first one has a lot to do with balance of your arrow and how fast that it is going to get itself on a straight trajectory out of the bow. This is especially important at longer ranges. So FOC plays a big part in that. The other thing that FOC plays a big part in is penetration. Now, we know, of course, that the more FOC we have, the more momentum we get, and the better our penetration potential becomes. So how do you figure it out? Well, actually, it's really simple. Now, you can look at calculations online and they can be intimidating. So today, we'll talk about FOC first. We'll go into some other calculations and just show you some easy calculators to use to be able to figure out everything that you need to know as an archer. So let's start with FOC. So the first thing you want to do when you're figuring FOC is just measure the length of your arrow. What's important at this stage is to know that you are measuring your hunting setup. So you have to have the broadhead on it that you intend to knock. If you have a lighted knock, you need to have that in there as well. Oftentimes, I know, like for my setup, I'll do a lot of practicing without a lighted knock and then use a lighted knock in my hunting setup. So it's important when you're configuring your FOC and really practicing that you have the complete setup every time. So in order to measure the length of your arrow, we are measuring from the tip of the broadhead down here to where the insert of the knock is right here, where the little groove is where your string sits. So if we take that measurement first, we'll see that we are at 29 inches. So the first thing we want to do after we have our 29 inches is divide that in half to get our geographic center. That would be the very center of our arrow. And so that's going to be 14 and a half, right? Is that good math? Half of 29? So the first thing I like to do is go ahead and measure that on the arrow and get to 14 and a half. This is the geographic center. 14 and a half is here. I like to use, um, it's not necessary, of course, but I like when I'm in the arrow spinner here because then I can rotate my arrow and get a really nice mark so I don't lose it. And I use a pencil. It's easy to see and it'll wipe right off. It's no big deal. So the next thing that we want to find is our center of gravity or our balance point. And you can do this in a number of ways, but this is basically where the arrow is going to perfectly balance. And it's not a fast process, this part, because things are just like a teeter-totter. So we're there for our balance point. I'm going to mark it with my thumb. I'm going to go ahead and mark it and then give it a spin so I don't lose it. So now I have this measurement here between my center of the arrow and my balance point. That is your real critical measurement. So you want to take that measurement. And I'm four and three quarters. So 4.75. So from here the calculation is very simple. All you need is that measurement between your balance point and the center point of your arrow. And you're going to divide that by the length of your arrow and then multiply by 100. Nice and easy. Doesn't take a lot of complicated looking at formulas. And my FOC on this build is 16.37, which is exactly where I wanted it to be. Now I have a little bit of weight up front to give me some extra FOC, but that's right where I want to be sitting. So figuring out FOC is quite simple. You only need to know a few things. The length of your arrow, the center of your arrow, and the balance point of your arrow. And the calculation is quite simple and it'll give you FOC exactly every time. The last equation that is really important for a hunting setup is momentum. Momentum for me is the key to everything. This is the energy required to stop your arrow, if we just put it in simple terms. This is the driving force for penetration. It is momentum. And this is something that is extremely important when it comes to your arrow build and your setup because without momentum you do not get proper penetration. So where KE favors speed, momentum favors penetration. Okay, so let's go to an online calculator and we'll go ahead and figure out the KE and momentum for our setup here. So I'm at 402 grains and that is my hunting setup. So we'll go to the calculator here. We'll put in 402 and then it wants my arrow speed. Now I know what my arrow speed is. It's 280 feet per second. That is through a chronograph and with those calculations my kinetic energy is 69.97 foot-pounds and my momentum is 0.500. So definitely suitable for a fixed blade broadhead, a hybrid, a mechanical of any sort, and also getting into some of the larger games as far as recommendations for my setup.