what is the archers paradox

Archer’s Paradox

Perhaps you have heard of the archer’s paradox. It sounds kind of ominous, but it’s really not. At the core of Archery is physics. The transfer of energy from your draw to the limbs, and finally the arrow in flight. Most archers who shoot for fun aren’t that interested in the physics of it all, and I can’t blame them. It’s much easier to buy finished arrows picked from a manufacturers chart and call it a day.

As a matter of fact, in the interest of full disclosure……I only use finished arrows. Would I like to make and finish my arrows? In another life perhaps but right now I’m not even close to having the time or patience to do that.  Even if you buy finished arrows, you will still benefit from reading on to learn a little more about the arrow in flight.

Beginning of the Archer’s Paradox 

The definition of a paradox is

any person, thing, or situation exhibiting an apparently contradictory nature.

The question is what in the world does that have to do with an archer? The archer’s paradox concerns the arrow in flight. The term was coined by E.J. Rendtroff in 1913 to describe the arrow flexing around the riser when it was shot. He was able to see this because it was filmed by Clarence Hickman who is known as the father of scientific archery.

The term archer’s paradox is often mistakenly used to describe the dynamic flexing that happens when an arrow is shot. 

But there isn’t anything “paradoxical” about an arrow flexing. (Although I can watch slow motion flexing arrows all day)

But the paradoxical event can actually be seen in the feature image above. Notice the arrow pointing off center and the fact that the longbow riser is blocking the arrow from lining up straight with the target and bowstring.

So…

The simplest definition of the archer’s paradox is that arrows shot from longbows are aiming off center, and yet, still able to hit a center target. 

That my friends….is a paradox indeed.

How Is The Archer’s Paradox Possible?

The dynamic flexing is HOW it is possible. With the naked eye, arrows appear to pierce the sky with incredible straightness. Straight as an arrow….The problem is that when you look at that same arrow in slow motion, it’s anything but straight. In slow motion, your straight arrow looks more like a spinning, flopping wet noodle! It bends back and forth and oscillates around and around. It’s hard to tell, even in slow motion, but when the arrow is projected, it oscillates around two balance nodes. One is near the front, and one is near the back.

This process begins back at the bowstring. When you release the string, it remains in contact with the accelerating arrow, and the force of the string is pushing from the back of the arrow. This causes the back of the arrow to try and move faster than the front, and this makes it gyrate in flight.

The spine of the arrow is it’s calibrated stiffness. Manufactures figure this number based on many different factors. There are too many to go over in this article. But the main point is that arrows have inherent stiffness, primarily based on their length and material. That stiffness works to slow the flexing of the shaft in flight, and it moves toward stabilizing the longer it is flight. On the other side of the scale, the arrow needs some flexibility to make it around the grip and work it’s way toward the intended target.

A small amount of flexing back and forth is a good thing as it absorbs the shock of bowstring release. No flex, if it were possible, would make it more likely that the back of the arrow would not even make it past your riser. (Watch out!) The matter of the back of the arrow receiving more energy than the front because of the bowstring, and trying to get ahead of it, can’t be changed.

(Unless…..no….it’s not possible.) An arrow propelled from the front….Think about it. I’m just spitballing here, but a bow designed backward..the string on the front, holding the front end of the arrow. You pull back on the arrow…..Never going to happen.

Understanding the Archer’s Paradox

The bow type and method of release affect archer’s paradox. A compound bow and mechanical release usually cause vertical flex in arrows. Up and down.  Using your fingers to release the string on a recurve bow usually causes the arrow to flex horizontally. This is mostly because when you release with your fingers, you push the bowstring to the side which is something you can also see in slow motion. This is why the consistent release is so important. When your releases are different, you are altering the way the arrow flies from the same bow.

It also helps in understanding the paradox when you realize it doesn’t apply to compound bows or recurve bows with cutout risers. This enables the arrow to be center shot, in other words, it travels in exactly the direction it is aiming. This means that there is no paradox when shooting from a bow with a cutout. But, I thought the arrow still flexed when shot from a compound bow? It does. But that is not the paradox. The flexing is the physics of propelling something flexible from behind. Remember? And the flexing is directly affected by the stiffness of the arrow.

Of course, then there is the complex issue of arrow spine, which again, is the shafts flexibility or lack thereof. This is a large part of your accuracy, and an archer needs to pay at least some attention to the matter. If spine were irrelevant, arrow companies wouldn’t spend the money they do testing spine for different materials. They wouldn’t even make arrows with different spine, they would just make one arrow type, and everyone would shoot the same with it. Of course, this is not that case, and manufacturers understand it matters a lot.

You can check out this video which shows the arrow flexing around the riser.