Physics of the Compound Bow :: physics weapon bow archery

A Brief History of the Bow * Arrowheads have been found in Africa that date back as far as 25,000 to 50,000 B.C. * Throughout the next few tens of thousands of years, humans had PLENTY of time to refine their techniques. Fire-hardening arrow heads, fletching arrow shafts to improve their flight characteristics, "tillering" bows so that the upper and lower limbs had the same bend radius, etc. All of these improvements helped increase the efficiency and accuracy of the bow and arrow, and helped humans to survive and advance throughout the ages. * One major advance was the creation of composite bows. Around 2,800 B.C. people began blending different materials together to create better bows. The Egyptians of these times had long composite bows capable of shooting an arrow up to 400 yards! * As you can see, the bow has been around a long while. It wasn't until recently, however, that the actual design of the bow itself was changed. In fact, this ingenious modification happened about forty years ago... The Compound Bow * On December 30th, 1969, Holless Wilbur Allen was granted the patent that would change archery forever. * The invention of the compound bow was just the beginning. As with the invention of the original bow and arrow, time and ingenuity would take the basic concept to new heights. However, the modern understanding of physics, coupled with advanced materials and construction techniques, has greatly increased the pace at which advances are made. * Using cams on one or both limbs of a bow allowed for an increased draw weight in the middle of the draw and a reduced weight at full draw. Archers firing traditional recurve bows encounter the highest resistance and draw weight at full draw. This means less time sighting in on a target before fatigue sets in, due to the strain of holding the bow at full draw. Compound bows, on the other hand, use a cam system which places the most resistance about 2/3 of the way through the drawstroke. At full draw, the compound bow reduces the tension in the bowstring by as much as 75-80%, allowing an archer to remain in position and more carefully sight in on a target.