The Archer’s Edge: Compound Bow Basics

Archery would not be where it is today as a sport and passion without the compound bow. Slow moving arrows were not effective in our sport of hunting and something needed to change. Holless Wilbur Allen was always interested in how things worked and wanted to create a better bow. He tried numerous inventions from modifying the bows, the arrows, add parts and pieces and cut off entire recurve limbs. Allen was tradesman who made basket frames for the floral industry. He had created a machine to aid in his daily trade out of spare parts and elbow grease. The total cost to him was $20 and a new machine was valued at over $50,000. He was a master of engineering and persisted with the bow until 1966 when the compound bow with pulley system was realized. The new bow offered many advantages over the standard recurve and long bows. Allen filed for a patent in June of 1966 and it was granted in 1969. By 1977 there were over 100 different models of compound bows.  

With much of the market being comprised of compound bows it is important to understand the features and components of the bow.  

Buss Cable: A cable that synchronizes the cams, or the cam and wheel.

Cams: Cams or wheels are on each end of the limbs and rotate when the arrow is drawn and the string is pulled back.  Some bows will have a cam at each end and some will have a cam at one end and a wheel at the other.

Let-off: The ability the bow gives to hold it at full draw and not having to hold the entire draw weight.  If a 60-lb. bow has a let-off of 80% then it will only feel like a 12-lb. bow when at full draw.

Limbs: The curved ‘stiff’ parts of the bow.  There will be one at each end connected by a riser in the middle.  

Riser: The center of the bow where the grip and accessories are connected.  

String: The string that runs between the cams and has a nocking loop, a peep sight and string silencers. When the arrow is nocked and pulled back the string rotates the cams and delivers the energy through the bow to propel the arrow.

Looking at the timeline of Archery, the compound bow is a relatively new advancement. Although developments in technology have seen the components of archery changing the basic parts that make up a bow are still the same. All the parts work together to take the energy the archer exerts into pulling back the string and stores it in the limbs. The potential energy stored in the limbs becomes the kinetic energy that forces the arrows trajectory.

All mechanical systems have limitations with efficiencies in the amount of energy output versus what was exerted upon the system. Automobiles are said to use only around 30% of the potential energy stored in the combustion engine. Compound bows have been engineered so greatly that the can top out at almost 90% efficient. The string and cam system multiplies our energy input and stores the maximum potential energy in the limbs. When the string is released the cams rotate back and drive all of the energy stored through the arrow.

Another limitation to the effectiveness of a bow is the archer. Understanding the bow will help determine what kind if best for the style, size and sport of the archer.  Axle-to-axle length is important based on the type of sport or shooting you prefer to do. A longer axle-to-axle, or end of cam to end of cam, is great for longer shots and target shooting. When in a tight spot like a blind a shorter axle may be preferred. Draw weight and length are both adjustable features on most contemporary compound bows. No matter strength level it is always advised to set the bow on the lowest pound setting to train the muscles in the movement of archery.  

When you are ready to select a bow you will need to determine your eye dominance. This is which eye your brain prefers visual input from. Eye dominance isn’t always determined by your handedness. A trick to determine this is to stand with your hands together and the back of your hands facing you. Touch pointer fingers and thumb tips together to make a triangle. Slide your hands in closer to close in the triangle until it about the size for a ping pong ball to fit in. Focus on an object, say a doorknob, and line it up inside the triangle of vision. Take turns closing your eyes and see which eye the doorknob is still within the triangle. This is your dominant eye. You will notice that with the other eye the doorknob may have completely disappeared from vision.  

Archery is a sport that requires skill, practice, patience and knowledge. Being strong or having the greatest equipment will not suffice for success as an archer, whether target shooting or hunting. Learning about the components of your equipment and the mechanics of your body is important for success. Being patient with yourself during the learning phases will further your skill and once proficient in skills passing on that knowledge to others will help keep this long-lived passion of archery alive.  Shoot a man a deer and feed him for a month: teach a man to bow hunt and you steal all his weekends and upset his wife. This is just a warning to the addictiveness of the sport. It is unlike many other sports and can fascinate and frustrate you all in one day. It can drive you wild and calm you down. Whatever you gain from archery just enjoy it to the fullest.

Leave a Reply

Commenting Policy - We encourage open expression of your thoughts and ideas. But there are a few rules:

No abusive comments, threats, or personal attacks. Use clean language. No discussion of illegal activity. Racist, sexist, homophobic, and generally hateful comments are not tolerated. Keep comments on topic. Please don't spam.

While we reserve the right to remove or modify comments at our sole discretion, the Sportsman's Guide does not bear any responsibility for user comments. The views expressed within the comment section do not necessarily reflect or represent the views of The Sportsman's Guide.