Engineering the Perfect Shot

Stance. Posture. Set. Mindset. Set-up. Coil. Load. Anchor. Transfer. Hold. Release. Follow-through. This is the shot process archers all over the world use to accurately shoot an arrow long distances. Archery has been around for thousands of years and has grown quite rapidly in the last few decades. What started out as simple bows and arrows made of wood has transformed into a high-tech sport of aluminum and carbon fiber. Archery would have never come as far as it has without the help of many different engineers.

In archery, arrows had been the same solid wood shaft for thousands of years. Solid wood shafts were always warped, couldn’t get very thin, and weren’t very durable. In the past few decades, engineers have created new advancements in arrows to make them fly faster and straighter. Shafts started being made out of hollow aluminum tubing in the 1940’s. Aluminum tubing was much lighter, straighter, and more consistent than the wooden shafts. Also, hollow tubes were significantly stiffer and lighter than solid rods. However, aluminum tubing still had some disadvantages. The shafts were easy to bend out of shape. But, in the 1980’s, arrow shafts made a revolutionary leap. Shafts made from carbon fiber were created. These shafts were lighter, stiffer, and more durable than aluminum ones. They could be made much thinner without problems concerning breakage. Since then, the preferred arrow material for pro archers has been carbon fiber.

In developing shafts, two different kinds of engineers work through the process. Both kinds of engineers usually have a background in archery or a background in carbon fiber. A design engineer will design, test and prototype the arrow. Then, manufacturing/process engineers take over to ensure the products are high-quality and consistent throughout production.

Arrows go through a very long design process in order to meet the high standards of the consumer. First, sales/marketing workers determine a set of parameters that the public is looking for in an arrow. These parameters include stiffness, straightness, shaft diameter, lightness, and appearance. Once these parameters are established, a design engineer will use them to design and build the prototype. These prototypes go through extensive testing to make sure the product is the quality and consistency that the public is looking for. Testing criteria are established by the Archery Trade Association so that consumers can get a good level of consistency between brands. In the straightness test, engineers use a laser micrometer to measure deflection by rotating the arrow on a 28” span. Deflection is how much the arrow bends and any up and down movement caused by it. The stiffness test determines the spine of an arrow. An 880 gram weight is hung from the midpoint of an arrow that has been placed across a 28” span. How much the arrow bends is measured in inches and this measurement is then used to determine the spine. For example, an arrow that bends 0.420 inches would have a spine of 420. Once the shaft has gone through all the tests in both Engineering and Quality, Pro archers on staff will shoot with the arrows and give the developers their opinions of the arrows. Once all the tests have been passed and the archers approve, the arrow moves over to the manufacturing and process engineers. They will then produce the final products, making sure that the shaft stays the same quality and consistency throughout the process.

Because it is so easy to create very stiff, light arrows out of carbon fiber, there are very few constraints. The biggest constraint is the performance of the arrow versus the cost of making the arrow. High-quality carbon fiber is very expensive, so engineers have to figure out how to keep the arrow from getting too expensive while still creating a high-performance product. The arrow has to make a profit. Another constraint is arrow length. Longer arrows aren’t as stiff as shorter arrows and have trouble being perfectly straight. In making arrows there are many trade-offs. For example, a very stiff arrow will be slightly heavier than one that is not nearly as stiff. But, a stiffer arrow will fly straighter than a bendy one. Also, arrows that have thicker walls will be more durable, but they will be heavier than thinner walled shafts. In addition, very lightweight arrows will travel very fast, but most of the energy from the shot would be released on the bow, and the bow would break in a matter of a few shots. On the other hand, a very heavy arrow would absorb all of the energy from the shot, but it’s weight would prevent it from flying very far. But, thanks to engineers, many arrows have been created with a perfect balance between light and heavy, thick and thin, and stiff and bendy.

Arrows have come a long way in the past forty years, but there are still new ideas that can make arrows even better. The most recent innovation in carbon fiber is Single Walled Carbon Nanotubes (SWCNTs). These tubes are stiffer and lighter than any other material discovered- by a lot. SWCNTs are not prime for making arrows yet. Currently, the tubes can only be grown to about one inch long. But, when the tubes can be grown to thirty inches, the world may be seeing arrows that could be as thin as one millimeter in diameter. This will definitely take many engineers and several years to achieve though.

In conclusion, without engineers, archery never would have come a far as it has. Without engineers, nobody would have developed the carbon fiber, much less SWCNTs. Nobody would have found the perfect balances that make arrows high-quality, and relatively affordable. Engineers are what make the sport of modern archery possible.

Sources:

Sielicki, John. "Archery." The New Book of Knowledge. Grolier Online, 2015. Web. 30 Jan. 2015.

Rogers, Lane. "Bow and Arrow." Grolier Multimedia Encyclopedia. Grolier Online, 2015. Web. 30 Jan. 2015.

Brock Zobell, Gold Tip Archery www.meta-synthesis.com/archery/archery.html