Compound Bow Accuracy

Question:
I am intrigued by a certain very short bow with a very large brace height. A few people who are not engineers have warned me of the evils of inaccurate “short” bows. I cannot understand what they mean. I just don’t understand how one bow can be less accurate than another. Could you please explain this to me?

Answer:
Basically a bow’s inertia affects its stability. Inertia a physics term that relates to the physical size and weight of a body. The larger an object in any direction the more stable it is when rotated around a 90 degree axis. Also, the more it weighs the more stable it is in general. This is because it is harder to accelerate the body and therefore it resists small movements better.

Here’s an example. If you take a wooden fence post and hold it at the center. It is much easier to quickly twist the post around its long axis than it is to swing it like a baseball bat. You are still rotating the same body but because the mass is farther from the center of rotation when swinging it, the post is much harder to accelerate. You also know how much harder it is to get a car rolling on a level driveway than to a child’s wagon. This is based on the pure mass.

Now the real question: how do rotational inertia and mass translate into accuracy in the field? Of course, the answer depends upon each individual’s form and how much torque they apply to the bow. If form is good, the accuracy difference between a 32 inch bow and a 42 inch bow will be small, if noticeable. However, if the form is average or poor, in theory the difference will be more noticeable because the archer isn’t holding the bow as steady through the shot. The only way to really know how well you’ll shoot a short bow is to try one at the range and see if you can get the arrows to group.

Check out all the compound bows at eders.com

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