1. What is FOC in Archery?

FOC (Front of Center) is a measurement that describes the balance point of an arrow, expressed as a percentage of the arrow's total length. It's crucial for arrow flight stability and accuracy.

2. How Does the Calculator Work?

The calculator uses the FOC equation:

Where:

• \( a \) — Balance point from nock end (inches)
• \( l \) — Total arrow length (inches)

Explanation: The equation calculates what percentage of the arrow's total length is in front of the exact center point of the arrow.

3. Importance of FOC Calculation

Details: Proper FOC affects arrow stability, accuracy, and penetration. Most target arrows have 10-15% FOC, while hunting arrows typically have 12-20% FOC for better penetration.

4. Using the Calculator

Tips: Measure arrow length from bottom of nock groove to end of shaft (not including point). Measure balance point from nock end to where arrow balances perfectly.

5. Frequently Asked Questions (FAQ)

Q1: What's the ideal FOC percentage?
A: Depends on arrow use: 10-15% for target shooting, 12-20% for hunting. Higher FOC increases stability but reduces speed.

Q2: How do I adjust FOC?
A: Add weight to front (heavier points, insert weights) to increase FOC, or add weight to rear (weight tubes, heavier nocks) to decrease FOC.

Q3: Does FOC affect arrow spine?
A: Yes, changing FOC by adding weight affects dynamic spine. Higher FOC makes arrow act stiffer, lower FOC makes it act weaker.

Q4: Should I include broadhead weight when calculating FOC?
A: Yes, broadheads significantly affect FOC. Always calculate with your hunting setup installed.

Q5: Does arrow material affect ideal FOC?
A: Carbon arrows typically perform best with higher FOC than aluminum arrows of similar spine and length.