How Does a Compound Bow Work?

By Archer | Compound Bow Advice

how does a compound bow work
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At first glance, it can be difficult to determine how does a compound bow work. You see the cams and the cables and wonder what purpose they serve. Luckily, you’re not alone; many first-time archers also want to know how a compound bow operates.

While compound bows have different designs. They all follow the same principle of operation. The way it works depends on its design.

Before we get into the details behind the working principle of compound bows, let us first discuss what it is and share with you a few details about its history.

What Is a Compound Bow?

A compound bow is designed for use in the practice of modern archery. It utilizes a levering system, which includes pulleys and cables to move the limbs. Compared to the traditional bow, it is the more popular choice when it comes to target practice and hunting.

Since its invention in 1966 by Holless Wilbur Allen, compound bows have become the preferred choice for both experienced and first-time archers.

In this first design, Allen cut off the end of the bow and fixed a pulley system at both ends. However, cutting the ends of the bow affected the draw distance. This limitation in the draw length proved a major challenge for Allen, who then spent the next few years trying to fix this problem. Fortunately, Allen was able to solve it by introducing a system that utilized cams and wheels.

This mechanical advantage makes the difference between a compound and a traditional bow. Over the years, this system has undergone several improvements. No matter the design or size, most manufacturers adopt the same principle of fixing a cam and wheel system onto the bow so as to improve the draw distance.

Compound Bow vs. Traditional Bow

The introduction of compound bows created the decline in traditional bows. Although, this is not to say that there aren’t old-timers who still enjoy shooting the regular bows.

The variation in the design of the compound and the traditional bow has a lot of differences in the shooting experience. For one, the compound bow enjoys a mechanical advantage that you wouldn’t usually get with a traditional bow.

Some other differences between the compound and early type of bow include:

  • Shooting Accuracy

The compound bow provides a higher level of shooting accuracy. This is one feature that makes it a popular choice for beginners. With additional equipment, such as a peep sight or a release, you can go from an amateur to a proficient archer.

While all these accessories can be included in a traditional bow, the let-off is one feature that you can only experience in a compound bow. In the hands of an experienced archer, a compound bow will give a better performance than a traditional bow.

  • Speed and Power

The mechanical advantage on the compound bow allows a higher draw weight, which results in faster arrows. When it comes to hunting, after precision, the next thing you need is speed. The ability of the arrow to travel quickly to reach its target as soon as it is fired makes all the difference.

  • Accessories

While both bows can be fitted with additional accessories, a compound bow can accommodate more accessories than the traditional bow.

Features of a Compound Bow

Before you understand how a compound bow works, you first need to know the important parts that make it up. The basic construction of a compound bow features the following:

  • Riser

The riser is the main component of a compound bow. It functions as a chassis for the attachment of other bow features, including the limbs, rest, stabilizer, and bow sight. The best compound bows feature a highly durable riser. This is to offset the high level of tension applied to the limb.

In the past, the materials used in making a riser were heavy. This made the compound bows of the past to weigh a lot, affecting one’s shooting experience. Compound bows today feature lightweight materials, such as carbon fiber and aluminum.

  • Limb

The function of the limb is to store energy. People believe that the cam and pulley system is what’s responsible for offsetting the draw weight of the bow. This is not the case. The limbs on compound bows are made of composite materials. These materials can withstand both the tension and compression forces of the fully drawn bow.

The limbs must be flexible enough to support the bow’s draw weight. Most bows made for young archers support low draw weights (up to eight pounds), while adult bows support draw weights of up to 70 pounds. Flexing the limb stores energy, while releasing it transfers that energy.

  • Cams

The cam system on a bow can either be single, double, or hybrid cam systems. This helps make it easier for the archer to achieve a perfect draw. The cam also makes it easier for you to draw the bow for an extended time. The cams are situated at the edge of the limb and generally take a lopsided shape.

The design of the cam system is an important aspect of the manufacturing process of a compound bow. While some cams are designed to be comfortable for the archer, others are designed to offer more speed when the arrow is fired.

Single-cam systems feature an idler wheel cam, which can be found at the top of the bow, and an oval power-cam located at the base. These are easy to use and quiet, but they are more difficult to tune compared to other designs.

Twin or double-cam systems feature two cams, which are either round or oval in shape. These provide more accuracy and velocity. However, the complex nature of their design makes them difficult to tune and maintain.

A hybrid cam system features a control cam at the top of the bow and a power-cam at the base. It doesn’t need much maintenance and is easy to tune.

  • Cables

The cables on a compound bow connect the limbs to the cam system. Their function is to pull the limbs and cams when the bow is drawn.

  • Cable Slide

The cable is fed through the cable slide. The plastic guide is attached to the cable and helps to keep the cables away from the line of fire of the arrow.

  • Cable Guard

More often than not, the cable guard is made from a fiberglass rod. It runs at a right angle from the riser to the bowstring. Together with the cable slide, a cable guard helps to keep the strings out of the way when the bow is fired.

  • Bowstring

The bowstring serves as an attachment point for the arrows. You will need to pull on the bowstring to rotate the cam and flex the limbs. Releasing the string will fire the arrow. The stored energy in the limbs is then channeled to the arrow, which makes it travel faster.

how does a compound bow work

How Does a Compound Bow Work?

The mechanism of a compound bow is simple. The design of the bow already features all the tools that provide the mechanical advantage to the archer. Therefore, what you will need in addition to the compound bow is an arrow.

In most cases, you will need to make adjustments to the bow to suit your shooting style. This can easily be done by following the instructions from the bow manufacturer on how to adjust the compound bow.

Here’s how you operate a compound bow:

Step 1: Place the Arrow on the Bow Rest

Some compound bow design does not feature a bow rest. Either way, you want to first get the arrow to fit into the bow. It is only after doing this that you can draw the arrow.

Putting the arrow in the bowstring is referred to as nocking. Once the arrow is perfectly rested on the bow, you will have to click the nock (rubber or metal thing at the end of the arrow) to lock the arrow into the bowstring.

When placing your arrow into the bow, you want to face the bow downwards. This is a safety precaution that prevents you from accidentally firing an arrow into the air without first taking aim. You want to also ensure that you use the right arrow that matches your type of bow. Be sure to use an arrow length that supports the bow draw length.

Step 2: Draw the Bow String so That the Cable Pulls the Cams

After successfully placing the arrow on the bow rest, you will then need to pull on the bowstring until you reach the end of the draw. Pulling the string exerts a force on the cam, which is needed to place energy into the bow.

The draw distance is not the same for every compound bow. It depends on several factors such as the length of the arrow, the draw weight of the bow, and the amount of force exerted on the bowstring.

Step 3: Draw the Arrow to Store Energy in the Limb

Drawing the arrow helps to flex the limb. Flexing the limb, in return, helps to store energy. The amount of energy stored will determine the speed of the arrow when it is released. There are different drawing styles employed by archers. The thumb, pinch, and three-finger draw are some of the most common.

The best draw for beginners is the three-finger draw, which is also known as the Mediterranean draw. This draw method involves placing the index finger at the top of the arrow and the ring and middle finger at the bottom. Placing all three fingers at the bottom of the bow is known as the Apache draw method.

Step 4: Wait for the Let-Off

You will have to keep on drawing on the arrow until you experience a let-off, which is characterized by a reduction in the holding weight when the string is drawn.

The let-off is important as it can help the archer to make a precise shot. Being able to hold the bow at full draw can make the difference in hunting and archery competitions. Compound bows used for precision archery needs a let-off of between 70% and 85%.

Step 5: Release the Arrow

The last step is to let go of the arrow. This can be done by releasing the bowstring once the let-off has been achieved. Letting go of the arrow flexes the limbs; this then transfers the stored energy from the limb to the arrows. The draw weight is what determines precision and enables the arrow to travel faster.

Quick Tips to Improve Your Accuracy With a Compound Bow

  • You will need to check that your bow is properly tuned. Tuning a compound bow involves setting the center shot alignment and timing. Timing is highly important if you want to get the cams to reach a full rotation.
  • Learn how to shoot from a different range. Practicing archery from a fixed distance makes it difficult for you to make a precise shot when the distance changes. Being able to shoot from different distances will earn you to understand the bow's performance better..
  • Use different targets for your practice. Learning to shoot only a 3D practice target might limit your accuracy when shooting a bull’s eye target. It will also be difficult for you to hunt if you aren’t experienced at precision shooting.
  • Find your shooting form. Being comfortable and relaxed is important and can improve your accuracy with a compound bow.
  • Consider using accessories. Bow accessories, such as a peep sight and stabilizers, can improve your shooting accuracy.
  • Adjust the draw weight and length. When the draw weight and length is set too high, it can alter the accuracy of the bow.

Final Thoughts

Compound bows are designed for a more precise archery experience, and they are relatively easy to use. The cams and pulleys provide mechanical advantage. This makes the difference between earlier traditional bows.

Knowing how a compound bow works is the first step to learning how to use it. Hopefully, this article has provided you with more than enough knowledge about compound bows. May you be more confident the next time you are out shooting.

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