This part of the article is going to deal with the real world numbers when a light arrow is shot vs. a heavier arrow and the speeds measured at different distances. By measuring the speed of different arrows at various distances, it is easy to calculate which arrow maintains more of its speed and thus its kinetic energy and momentum further downrange.
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Introduction and archery equipment for testing
If you care about all of the math and the theory behind how arrows decelerate after leaving the bow, please make sure to read all of the original article first. For this testing, I’ll be using two arrows that are virtually identical to each other on the outside, but one will be weighted with an extra shaft and weight layered on the inside.
These first numbers come from using two Victory VForce HV arrows, one standard that weighs in at 326 grains, the other layered with a 1516 aluminum shaft on the inside that weighs 580 grains. The heavier arrow also has additional weight on the inside near the point in order to keep the FOC of both of the arrows nearly identical. Both arrow use FOBs for the fletchings.
All arrows were shot from my Elite Envy set at 29″ and 60.2 lbs. and were chronographed with and Easton Pro Chronograph.
For this testing, I shot seven shots with each arrow at point blank range, 10 yards and 20 yards; then I threw out the highest and the lowest speed, leaving five speeds to be averaged for the results. All of the speeds in each set were within +/- 0.4 fps.
Results of arrow speed testing
|Speed (fps)||KE||Momentum||Change from 0 Yards|
|326 Grains||0 Yards||316.4||72.3||0.457||KE||Momentum|
|580 Grains||0 Yards||243.1||76.0||0.626||KE||Momentum|
The actual testing results follow what would be expected from the theory and math discussed earlier. I would like to test the speeds out to further distances and will do so in the future to get a better picture of behavior downrange.
It’s interesting to see just how much more the lighter arrow slows down and sheds its kinetic energy and momentum. The lighter arrow is losing speed at a rate 40-45% faster than the heavier arrow. At point blank range, the heavier arrow starts with 3.7 ft-lbs. of KE more than the light, and by only 20 yards it had 6.6 ft-lbs. more KE. I would say that is a significant difference!
Of course the extra KE and momentum come at a cost, trajectory. The heavier arrow is going to drop significantly more at every distance and yardage estimation becomes much more critical. A three to five yard mis-judgement in yardage with the lighter arrow could still result in a clean kill shot on an animal, while with the heavier arrow it most likely would result in a much poorer shot or even perhaps a complete miss.
That being said, having a fast arrow is no substitute for practice in yardage estimation or using a range finder when possible. Each archer needs to know their own equipment and make their own decisions on arrow weight depending on the game being hunted and where they are hunting. Know your equipment and practice with it constantly!
In the future I plan on doing testing out to forty or more yards, and also with some lighter and heavier arrows. I have some 262 grain Speed Pro Max arrows donated to the cause that should be fun to play with (yes, I will be shooting them at 60 lbs, not recommended!) I will also use some different types of fletchings (4″ feathers, 1.6″ vanes) and varying helical/offsets as well to see how much they affect the speed.
Other posts you may enjoy:
- Arrow Penetration Testing: Real Bows, Real Arrows, Real Results…Part II
- Heavy vs. Light Arrows: Downrange Speed and Power
- Penetration Testing: Why You Should NOT Use Foam for Comparing Hunting Penetration
- Helical vs. Straight Fletch: Speed and Deceleration
- Arrow Penetration Testing: Real Bows, Real Arrows, Real Results