Arrow Velocity Calculations
 

I decided to crunch some numbers in order to obtain a rough velocity estimate for a couple of different Bowtech bows at my draw length, and I'd definitely appreciate it if you guys would check my math and/or offer suggestions for a more accurate comparison. I am not trying to get the exact real world velocity so much as compare these bows side by side. I've also decided to be an extreme optimist and use only the highest possible velocity for each bow.

My draw length is 27.5" and all arrows would weigh the same at 386 grains. The assumptions are that 1" draw length loss results in 10fps loss, and 3 grain arrow increase results in 1fps loss.

1) 70lbs Bowtech General, IBO Speed Mod 315fps max. Velocity = 315fps - 25fps [D/L loss] - (386grs - 350grs)/3 [arrow weight loss] = 278fps

2) 60lbs 2008 Bowtech Equalizer, IBO 308fps max. Velocity = 308 - 0 [no D/L loss] - (386grs - 300grs)/3 [arrow weight loss] = 279fps

3) 60lbs Bowtech 82nd Airborne, IBO Speed Mod 350fps max. Velocity = 350fps - 25 [D/L loss] - (386grs - 300grs)/3 [arrow weight loss] = 296fps

Any additional input is greatly appreciated.

RE: Arrow Velocity Calculations
 

These are probably going to be very close. Other factors might include things you put on the string, like leaches and kisser buttons; and what sort of arrow rest you use - whisker biscuit is going to cost you a few fps over a drop away. I know on the Guardian, I chronographed a buddy's 70 lb. and, with a 28" draw and 381 grain arrows he was gettin upper 280's.

RE: Arrow Velocity Calculations
 

i have a bowtech mighty mite 80% letoff 28" draw.....only thing in my string is leaches and a loop......arrow weighs around 380.i'm shooting 290 through my shooting chrony.
i forget what ibo is on that bow.

otto

RE: Arrow Velocity Calculations
 

By my rough estimate it would appear that a 60lbs 2008 Allegiance is actually a bit faster than the Equalizer, if both are set at 27.5".

IBO 335fps max. Velocity = 335fps - 25fps [D/L loss] - (386grs - 300grs) / 3 [arrow weight loss] = 281fps

So the theoretical max is a tad higher.

RE: Arrow Velocity Calculations
 

Try the calculators on thearcheryhut.com