Do I need a new bow this year? Will that faster bow help me get my next deer or win my next 3D tournament?
Often I get a customer that comes stating that they have 1 pin on their sight because their bow shoots flat out to 40 yards. I bite my lip each time because I know Physics just never lies. Everything falls to the earth at the same rate, it does not matter if it is a bowling ball, a marble, an arrow or even a bullet shot out of a rifle. The “Acceleration of Gravity Law” states that an object will fall to the ground at a rate of (32 Feet per Second per Second) or in other words the first second an object will travel 16 feet down and it does not matter if it has forward velocity or not.
Let me break it down for you eggheads and naysayers. Go get your calculators and follow me….. Oh and by the way…. This is why the Trophy Ridge React Sight DOES work and works perfectly. The math doesn’t lie.
T=Time in Seconds
Acceleration of Gravity is D=.5GT² or Distance Traveled = .5 x 32FPS x Time in Seconds Squared
Example 1: Let’s say I want to see how far an egg will drop in 3 seconds if I were to drop it of off a bridge.
D=.5x32x3² or D=.5*32*9 or D= 144 Feet the egg drop in 3 seconds.
Now lets put this in practical terms for my archery friends who have that flat shooting bow that is so fast that their single pin hits the same mark at 10/20/30/40 yards.
We measure arrow drop in inches so we need to change 32 Feet to Inches which is 32*12=384 inches for the G value in our formula. Now we need to figure out how much time elapses after we shoot an arrow for 10,20,30,40 and 50 yards. Since we are having a little fun here let us do it for 400, 350, 325, 300, 280 and 250 Feet per second shooting bows. Keep in mind we are just doing the simple math here without figuring in deceleration of the arrow due to surface tension applied on the arrow shaft by passing air and the drag that our vanes are causing to slow down the arrow.
So let’s say you have one of the quickest bows on the market shooting 350 FPS. As you can see in the chart above the arrow shot out of that bow will have dropped a total of 22.57 inches at 40 Yards. Even if you take in to account that your Apex of arrow flight is somewhere between 10 and 20 yards you are still going to have around 18 inches of drop past 20 yards as seen in chart below. This is not what I would consider “FLAT” out to 40 yards.
I am asked the question often, “Since this bow shoots so fast I bet the deer never has a chance to jump the string?” Okay, lets put the math to this question as well. We know that sound travels at around 767 MPH or about 12.78 miles per minute or about .213 miles per second or around 1125 feet per second, the number we need. So knowing that sound travels 1125 feet per second we can figure out the time it takes sound to travel 10/20/30/40 and 50 yards. Now this time I have included data with deceleration on a 19/64”-diameter shaft and 3 Blazer Vanes set 120 degrees apart with 3 degrees helical on the arrows. Speeds in FPS are listed in each column. We also know that a deer has a reaction time of just shy of a ¼ second, I used .22 seconds of reaction time for the chart below.
All values in RED in the chart above show that the arrow will impact the deer before he hears the sound and can react or jump the string. In ALL cases the sound will get to the deer’s ears before the arrow will. In other words, the deer will always hear the shot before the arrow impacts him. This is different with a rifle as most rounds are far above 1125 feet per second. As so long as the projectile is above 1125 fps the project will hit target before the sound of the report will. Not true with a bow and arrow, nor will it ever be.
So what does all this mean to a bow hunter? First if you want to limit the chance of having a deer jump your string during a shot, keep your shots under 25 Yards. I know many of you will think, “Well I will just aim a little low at distances beyond 25 yards then.” Okay, but do you really know what that deer is going to do? Is it going to drop, turn or simply do nothing? You don’t know. So if you keep your shots under 25 yards you will eliminate that variable.
Some of the other things you can take from the data might be, “Does a faster bow really gain me much advantage in judging distance or the amount of arrow drop at longer distances?” If you are just bow hunting and you keep your shots under 25 yards, then, NO, is the answer. Save your money and maybe look at purchasing some better scent reduction clothing or tools like the Ozonics machine. Maybe a better use of that money would be better arrows or sights with smaller, easier to adjust and brighter pins.
Most people are shooting bows at around 280 FPS. If you are an occasional 3D shooter you know that most of your targets are at 40 Yards. Look at the data a bow shooting 280 FPS drops 1.33” more at 30 yards than a bow shooting 330 FPS. A bow shooting 280 FPS drops a total from 20 yards to 40 yards only 3.26” farther than a bow shooting 330 FPS. Is your money better spent on speed or forgiveness? The choice is yours. Keep in mind that the way bow manufactures get speed is making the brace height shorter, which causes a higher chance of arm or jacket slap while hunting. Another way to gain speed is a harder cam. These are harder to pull over while sitting for hours or at awkward angles in a tree stand.
I am not saying don’t go out and purchase a new bow. What I am saying, is look at the data, and decide where your HARD EARNED money is best spent. If it is a new faster hot-rod bow, that’s great. If you choose a better sight, rest, stabilizer, clothing, blind, scent elimination items, then that’s great too. We here at Bass Pro Shops can help you in whatever you choose.