The gravitational constant (g) is the acceleration due to gravity, which is 32.174 feet per second per second at sea level. Archery & Crossbow Ballistics Calculator Reduce the IBO speed until the calculator shows the verified speed of 315; in this case, the correct IBO value would be 346 fps. So let's focus on that. We've created a text where you'll find some of the basics related to IBO speed and how to calculate bow speed. In other words, how much force is required to stop an arrow? A 70#/29 bow thats rated at 350 fps is has been chronographed at 315 fps with a 400 grain arrow. We operate independently and do not provide Sponsored content. That's a tough question to answer. 2022 Bear Alaskan Right-Handed 55-70 lb Model, Arrow Weight 423 grains (Easton Axis 5mm Arrows) , Additional Weight on Bowstring 20 grains. Front of Center and Kinetic Energy Calculators - Gold Tip Models at the high end of this spectrum tend to cost a lot so we should be pretty confident the top velocities bring equally impressive results before spending the cash. The greater the draw weight, the greater the speed of the arrow shot from the bow. For example, a 500 spine arrow bends .5 inches when the weight is applied. This average will get most bows within a few percent of real-world speeds. At the rated 350 fps IBO the speed should be 319 so we know that the IBO is slightly high. Calculating Compound Bow Kinetic Energy (KE) - Beginner's Guide Arrow Speed Calculator: Calculate or estimate arrow speed. Welcome to our Arrow Speed, Kinetic Energy, and Momentum Calculator, where you can easily calculate your arrows speed, kinetic energy, and momentum based on the IBO speed of your compound bow, your draw weight, draw length, and arrow weight. The factors that impact the overall speed of your arrow are: In addition, it is important to understand that sometimes even minor changes to your draw length, draw weight, and arrow weight can seriously affect the speed, kinetic energy, and momentum of your arrows when they are shot from your bow. 36 Yards - Maximum Point Blank Hunting Range. An arrows momentum is defined by how much force is required to stop an object. Your arrows kinetic energy will depend on its speed. For every inch you reduce, the draw length reduces around 10 fps of your bow speed. 1 slug equals 32.174 ft-lbs. Corrected IBO Example - A 70#/29" bow that's rated at 350 fps is has been chronographed at 315 fps with a 400 grain arrow. But let's get a bit more precise (pun unintended): Aside from your aiming skills, animals jumping the string is the most common reason for disappointing results on hunting trips with a crossbow. Arrow speed specification. Simply put, many of the best crossbows available on the market nowadays (2015) receive their speed ratings based on arrows weighing roughly 400 grain. Total string accessory weights in grains (peep, tube, silencers, etc.). However, here you'll find a bit of a contradiction because heavier arrows result in slower speeds, meaning compromising speed might be necessary to avoid losing momentum and kinetic energy so rapidly. This calculator is based on average efficiency gains as arrow weight is increased from 5 grains per pound (IBO). Now, enter the Draw length of the bow. Most professional bows use the IBO (International Bowhunting Organization) specification. Here are some interesting things to note, based on the kinetic energy chart at the top of this page: #1: Kinetic energy drops are fairly predictable. draw weight, and 350-grain arrow. To find the distance that your arrow will travel, you can use the projectile motion calculator. Now, there are a few bows rated at 350+ fps based on the International Bowhunting Organizations (IBO) standard. For every inch of draw length under 30, subtract 10 feet per second (fps) from the IBO-rated speed value. With having said that lets sight these crossbows with a maximum point blank range drop of 3 inches and a mid-range rise of 3 inches. Check out 25 similar kinematics calculators how things move , Understanding bow speed IBO specification. The arrow weight in grains (includes fletchings, wraps, inserts and also. Considering that the vital area (heart and lungs) of a whitetail deer is 6" to 8", we can see how easy it is to miss the target when using a slower bow or a crossbow. To properly calculate arrow speed, use the following formula: IBO Speed(in fps) + (Draw Length 30) x 10 Additional Weight on Bowstring (in grains) / 3 + MIN(0, (Arrow Weight(in grains) 5 x Draw Weight in Pounds) / 3 )). Now we have what we need to calculate KE: Arrow speed: 240 FPS Arrow weight: 400 grain The formula for calculating Kinetic Energy is: (Arrow weight) x (Arrow speed) x (Arrow speed) / 450,240 Privacy Policy, N1 Outdoors N-Tune Nock Tuning Reflective Arrow Wraps (various designs), N1 Outdoors Bowhunt Oh Yeah Bowhunting Tee, N1 Outdoors Just PassN Through Bowhunting Tee (Heather Royal), N1 Outdoors N-Tune Nock Tuning Reflective Arrow Tracers (24-pack), Just PassN Through Tee (featuring Magnus Black Hornet Ser-Razor Broadhead), Just PassN Through Tee (featuring Iron Will). Fast-flying arrows have flatter flight trajectories and less deviation from the wind. For every 3 grains of total arrow weight above draw weight multiplied by 5, subtract 1 ft/s from the IBO value. You can check this calculator to see how fast the arrows lose height at different flight speeds. We shot 400 grain arrows from 9 different crossbows, achieving nine different initial speeds ranging from 200 to 400 FPS in 25 FPS increments. A lighter arrow produces more arrow speed, but an increase in arrow weight (incremented by 25 grains) can increase and eventually decrease arrow kinetic energy. Thus, when a manufacturer touts its bow as having a speed of, say, 350 fps, the truth is that a hunting weight arrow of 400-450 grains from that same bow will initially leave the bow much slower especially if the draw weight and draw length are significantly reduced. The table below provides us with a general idea of how much momentum is needed for different types of wild game and it also shows us the arrows penetration capability when coupled with KE. Every inch of draw length above 30 will add 10 feet per second to the IBO value. Thats a massive difference in a hunting scenario. What is important, is understanding how this impacts the arrow you choose to buy and use when hunting, along with the broadheads you use. This is because the IBO speeds are determined under a set of particular conditions: Then, for comparing bow speeds, you'll need tomaintain these factors constant. Also, make sure to check out our best crossbow rankings for a scoop on the top equipment on the market.