Help with FOC ...

[Bob B.]

I am looking for assistance with calculating FOC of an arrow.  I know this has been done before, but I can not find the older threads.  If you can help, I appreciate it.

Bob.

[Bjorn]

In the meantime check out Jackson's FOC calculator.

[George D. Stout]

What Bjorn said.

[drewsbow]

http://home.att.net/~sajackson/archery9.html

[Bob B.]

OK, I got two ways, the same thing but different:

A)   Distance knock throat to balance point divided by shaft length ( arrow only ) minus .5 X 100 = % FOC  {taken from an older Ashby document}

B)   Find balance point from knock throat to point of balance.  Find shaft total length. Divide shaft length by 2 and subtract from balance point.  That is your FOC length.  Divide FOC length by shaft length and multipy by 100, that is % FOC.

Anyway, it is simple to calculate and makes me feel prety good about my set up, about 480 grain arrow, from about 48 pound bow with 20 % FOC and single bevel broad heads.  If I can hit what I aim at, I will be ready Wisconsin's white-tails.    

Bob.