Arrow FOC and Weight Formula:
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FOC (Front of Center) is the percentage of an arrow's total weight that is located in the front half of the arrow. Total weight is the sum of all arrow components measured in grains. These measurements are crucial for arrow tuning and performance.
The calculator uses these formulas:
Where:
Explanation: The FOC percentage indicates how much of the arrow's weight is forward of the center point, affecting arrow flight characteristics.
Details: Proper FOC improves arrow stability and accuracy. Most target arrows have 10-15% FOC, while hunting arrows typically have 12-20% FOC for better penetration.
Tips: Enter all weights in grains (1 grain = 0.0648 grams). Point and shaft weights are required. Other components (fletchings, inserts, etc.) can be added for more precise calculations.
Q1: What is the ideal FOC percentage?
A: Depends on arrow use. Target archers typically prefer 10-15%, while hunters often use 12-20% for better penetration.
Q2: How does FOC affect arrow flight?
A: Higher FOC makes the arrow more stable but can reduce speed. Lower FOC increases speed but may decrease stability.
Q3: What's a typical total arrow weight?
A: Target arrows usually weigh 300-500 grains, hunting arrows 400-600 grains, but depends on bow type and purpose.
Q4: Should I include nock weight?
A: For precise FOC calculation, yes. However, nock weight is often minimal compared to point weight.
Q5: How can I adjust FOC?
A: Change point weight, use heavier inserts, or add weight tubes to increase FOC. Lighter points decrease FOC.