Arrow Spine Weight Calculator:
Enter the value of total deflection weight, DW(lbs) to determine the value of Arrow weight, WA.
Arrow Spine Weight Formula:
The physics of Arrow Spine Weight (ASPW) revolves around the principles of flexibility, force, and material properties. ASPW is a measure of how much an arrow bends or deflects when a force is applied to its centre, typically using a standardized weight. This deflection is crucial in determining how the arrow will behave when shot from a bow.
When an arrow is released, the string propels it forward, but the arrow does not travel in a perfectly straight line. Instead, it bends and oscillates due to the force applied by the string, a phenomenon known as “archer’s paradox.”
The amount of deflection, or spine, must match the draw weight of the bow; if the spine is too stiff or too flexible, the arrow will not fly accurately.
A stiffer spine (lower deflection) is needed for higher draw weights, as these arrows can withstand the greater force without excessive bending.
Conversely, a more flexible spine (higher deflection) is suitable for lower draw weights, allowing the arrow to flex appropriately under lesser force.
Arrow weight, WA in grains is calculated by the product of total deflection weight, DW(lbs) in pounds and 6.75.
Arrow weight, WA = DW(lbs) * 6.75
WA = arrow weight in grains.
DW(lbs) = total deflection weight in pounds, lbs.
Arrow Spine Weight Calculation:
- An arrow has a deflection weight of 300 pounds. Calculate the Arrow Spine Weight (ASPW).
Given: DW(lbs) = 300pounds.
Arrow weight, WA = DW(lbs) * 6.75
WA = 300 * 6.75
WA = 2025grains.
- An arrow has an Arrow Spine Weight (ASPW) of 2700 grains. Calculate the deflection weight.
Given: WA = 2700grains.
Arrow weight, WA = DW(lbs) * 6.75
DW(lbs) = WA / 6.75
DW(lbs) = 2700 / 6.75
DW(lbs) = 400pounds.