The compound bow is designed to shoot arrows through the accumulated energy transferred by the archer's muscles in the bow's arms. The distinctive feature that differentiates a compound bow from a conventional bow is the way the maximum draw force is distributed. Well, in a pulley bow, the force of maximum tension is reached at the midpoint of maximum length. After passing the point at which the maximum force is reached, there is a let-off, thanks to this phenomenon, the archer applies only 30-50% of the force needed to overcome the point at which the maximum force is required to keep the system at maximum tension. This phenomenon is caused by the use of wheels and cams in the bow, which by their shape rotate in an eccentric motion around their own axis of rotation.
To release the string in fast or short pulley bows, use the trigger (the required loop on the D-loop string), shooting with fingers risks dropping the string from the cams by which the bow can be permanently damaged. Children's, youth and longer recreational compound bows are designed for shooting with fingers and the trigger.
In archery, all technical data values are expressed in the Anglo-Saxon system of measurements:
- LENGTH: inch: in ["], 1" is 2.54 cm;
- MASS: pound: lb/lbs [#], 1 lb is 0.45 kg;
- SPEED: feet per second (feet per second): fps, 1 fps is 0.3 m/s or 1.1 km/h.
For any advanced compound bow it is necessary to mount and adjust the appropriate accessories such as:
- sight;
- arrow rest;
- a peephole (peepsight);
- string release trigger;
- D-loop, which is essential for shooting with a trigger.
Each of these components needs to be properly adjusted in order to achieve maximum effectiveness of the whole set.
The way to read the technical data.
- ATA (axle-to-axle)bow length: this is the length measured from the axis of rotation of the blocks placed on the arms on opposite sides.
- String height (brace heigt): this is the distance from the most concave point of the handle in the maypole to the string at rest, or the distance from the mount socket of the stand to the string.
- Drawlength: this is the length after the bow is drawn, measured between the point where the arrow cap meets the string and the back of the bow (on the arrowhead side).
- Tension force: this is the force that must be applied between the maypole and the string to achieve full draw. Adjustment of the tension force is most often achieved by letting go of the screws holding the arms, provided if the manufacturer has provided for this possibility.
- Maximum arrow exit velocity: the value achieved at maximum draw force.
- Weight without accessories: the weight of the bow without additional accessories.
- Let-off: is a phenomenon occurring in compound bows, which manifests itself as a percentage reduction in the force required to maintain the system after exceeding a critical point, i.e. the point at which the maximum draw force specified in the product characteristics is required. The 65% parameter means a 65% reduction in the required force compared to the maximum force.
