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Monday, July 14, 2008

What is a Compound bow?

Holles Wilbur Allen invented the compound bow in 1967 in his home state of Missouri. This bow uses pulleys and cables that form a leverage system to bend the limbs or ends of the bow. The long bow, also known as the recurve bow, has limbs that are much more flexible than the compound bow. The compound bow stores more energy than most other bows but that results in very stiff limbs. It is virtually impossible to pull the bow back with the single string. This problem is solved with the pulleys and cables. A string is attached to a pulley with a cable attached to the opposite limb. The pulley will turn when the string is pulled back. The pulley, in turn, pulls the cable which bends the limbs and voila! ...stored energy ready to send an arrow flying.


Compound bow Advantages

One of the advantages of a compound bow is its resistance to severe temperature changes and atmospheric moisture. As a result the accuracy and speed of the arrow as well as how far the arrow will travel makes this bow much more effective than your standard long bow.


Compound bow Strength

What gives these bows added strength is not only the pulleys and cables but also the make up of the shaft and limbs. The main shaft of the compound bow, also known as the riser, is composed of either magnesium or aluminum; both strong but lightweight materials. As a matter of fact, the top performing compound bows are made of and aircraft quality 6061 aluminum. The reason for using this material is to keep the rise as unbending as possible. You want the riser to be very stiff so you can add other pieces of equipment to bow such as quivers, sights, or stabilizers.

The limbs are made of a mixture of alloys and are built for strength. They have to be able to withstand the high tensile forces from the drawing of the string. They store all the energy the bow generates.


The Cams and Strings

Usually at the end of the bow is a wheel also called the cam. There are many different ways to use the cam to store energy depending on the bow design. There are also different types of cams that store the energy in the limbs. These different cam types are knows as bow eccentrics. The Binary Cam, Hybrid Cam, Dual Cam and Single Cam are the 4 most often used but some prefer the Hinged Cam and Quad Cam.

The strings and cables are made of polyethylene and should be strong yet flexible as they need to stretch when the bow is drawn. This moves the energy from the bow to the arrow when the string is release resulting in maximum distance. The cables, on the other hand, are made of steel surround by a clear plastic.


Arrows for the Compound bow

The arrows used with the compound bow do not vary very much from the arrows used by a standard long bow. The arrow shafts are composed of either carbon or aluminum. However, because of the force a compound bow produces the user is ill advised to try launching an arrow with a wooden shaft, as it will probably break due to the strength of this bow. The manufacturers of arrow do produce arrows of different lengths and rigidity to work with the different styles of compound bows. Matching the stiffness of an arrow to the correction style of compound bow will greatly increase accuracy.

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