A sideprofile of an Easton Carbon One arrow with a spine of 900, taken with a scanning electron microscope (SEM).
The arrow is a bond of two carbon tubes, an inner and an outer tube (black wires).
The arrowhead or projectile point is the primary functional part of the arrow, and plays the largest role in determining its purpose.
Footed arrows will typically consist of a short length of hardwood near the head of the arrow, with the remainder of the shaft consisting of softwood.
By reinforcing the area most likely to break, the arrow is more likely to survive impact, while maintaining overall flexibility and lighter weight.
In order to strike consistently, a group of arrows must be similarly spined.
"Center-shot" bows, in which the arrow passes through the central vertical axis of the bow riser, may obtain consistent results from arrows with a wide range of spines.
An arrow is a fin-stabilized projectile that is shot with a bow, and usually consists of a long straight shaft with a weighty and usually pointed arrowhead attached to the front end, with fletchings and a nock at the rear end.
The use of bows and arrows by humans predates recorded history and is common to most cultures.The weight of an arrow shaft can be expressed in GPI (Grains Per Inch).The length of a shaft in inches multiplied by its GPI rating gives the weight of the shaft in grains.While the fixed-blade broadhead keeps its blades rigid and unmovable on the broadhead at all times, the mechanical broadhead deploys its blades upon contact with the target, its blades swinging out to wound the target.The mechanical head flies better because it is more streamlined, but has less penetration as it uses some of the kinetic energy in the arrow to deploy its blades.For example, a shaft that is 30 inches long and has a GPI of 9.5 weighs 285 grains, or about 18 grams.