FOC

[String Cutter]

What is the best % for FOC. I'm trying to work out an arrow for my longbow and it comes out to 22%.. Is this good?? What happens if I go higher???

[Night Wing]

When I tune an aluminum arrow to my two recurves, I try to maintain a good balance between speed and a heavy arrow with regards to trajectory since I shoot low poundage bows. I'm not too concerned with the FOC percentage. I'm more concerned with GPP (grains per pound). My complete setup for both of my Blacktail TD recurves is below and both bows are around 17.0% FOC.

Blacktail TD Recurve: 66", 42# @ 30". BS: 14StrDyna97. BrcHt: 7 1/4". NP: 5/8". Split Finger/Tab. Arrow: 32", 2212 Aluminum. PW: 185 Grains. BH: STOS 145 Grain. AW: 528 Grains. GPP: (12.57). FOC: 17.3%

Blacktail TD Recurve: 66", 37# @ 30". BS: 13StrDyna97. BrcHt: 7 5/8". NP: 5/8". Split Finger/Tab. Arrow: 32", 2212 Aluminum. PW: 180 Grains. BH: STOS 145 Grain. AW: 523 Grains. GPP: (14.13). FOC: 17.0%

[Rob DiStefano]

imo, there is no 'best' foc.  

some folks have been killin' critters for many decades without a clue as to what 'foc' even stands for!  

personally, i like a big bunch of front end weight, and the more holding weight you have the easier it is to attain higher foc values.  lots depends on arrow design, materials and yer desired target gpp and foc.  lower holding weights will be harder to achieve a good gpp and foc, heavier draw weights make that task really easy.

what does added foc do?  it adds steerage and stability to the arrow.  for me, it makes tuning the arrow to the bow lots easier, as well.  some say it aids penetration, but i dunno about that for sure.  some say added front end weight decreases arrow spine, but i don't see that at all with carbons, even if weak spined carbons are what ya got.

[Stiks-n-Strings]

I posted this discussion some time back and the general consensus was around 13% to 17% was best.
 
 I'm like Rob though I really don't think there is a best.

 My set up out of my striker is about 12.5 gpp and I think right around 15.5% foc and it thumps when it hits. My arrows fly like darts with broadheads. My filed tips fly pretty good but a noticable bit better with hunting heads and that's all that matters to me.

[COMPOUNDLESS IN CONCRETE]

When I first got my recurve in May, I was shooting around 8 gpp with I think around 15% foc.  I added 105 more grain in tip weight and weight tubes and am now at 11.3 gpp with 21.5% foc and the difference in arrow flight is pretty significant.  And the group sizes are a lot better now.

[Terry Green]

Achieving good arrow flight should be paramount....whether 15 or 30% FOC.  FOC is NOT as important as arrow flight.  

You can get good arrow flight from either FOC percentage I mentioned above, and you don't NEED one over the other to get 'better arrow flight'.  What you need is proper spine, properly flecthed, dialed into your properly tuned bow.  If you do that, FOC will take care of itself.

That said.....22% is fine....and it would be if it was 18 or 26% ...as long as you are getting good flight.

[Ragnarok Forge]

Terry and Rob already have this covered.  

Put the arrow in the right spot and meat on the table ensues.  The further forward I have gotten my FOC the easier, as in far easier, it has become to get my arrows to tune.

[eric-thor]

like terry and rob said ...

in addition to them Dr.Ashby 's  testing show'd that significant improvement at 19% and up . so 22% is definately significant. but flight is paramount in anycase.

[Bowmania]

Rob, is this a misprint?  "some say added front end weight decreases arrow spine, but i don't see that at all with carbons, even if weak spined carbons are what ya got."  I thought adding weight tunes the arrow to the bow.  I don't see how it can do anything else.

Bowmania

[Raging Water]

Perhaps a definition of FOC would help.

[Terry Green]

Originally posted by Bowmania:
I thought adding weight tunes the arrow to the bow.  I don't see how it can do anything else.

Bowmania

Lots of things go into tuning bows and arrows.....and 'taking away weight' also can tune an arrow to the bow....but its just one of many tuning variables.

[Rob DiStefano]

Originally posted by Bowmania:
Rob, is this a misprint?  "some say added front end weight decreases arrow spine, but i don't see that at all with carbons, even if weak spined carbons are what ya got."  I thought adding weight tunes the arrow to the bow.  I don't see how it can do anything else.

Bowmania

yup, that's what i said - not at all a misprint.

29.25" beman 500's with 350gr up front, total arrow weight of 580gr, pushed out of a 55# longbow.  add to that i use a 4" 4-fletch with offset only, no helical ever.  the arrows fly straight and true from 5 to 35 yards.

though there are guidelines for arrow spine and balance, not all is written in stone and for some folks a different path works very well.  ALSO, your form and how you aim and shoot a bow is part of the 'spine equation', too.

[Rob DiStefano]

Originally posted by Raging Water:
Perhaps a definition of FOC would help.

Front Of Center - the percentage of arrow balance with regards to the center of total arrow length.  

online spreadsheet for foc and gpp  HERE

lemme echo what terry has already said - FOC IS NOT AS IMPORTANT AS GETTING GOOD ARROW FLIGHT.  

i'll add to that that GPP IS MORE IMPORTANT THAN FOC - YOU DON'T EVER WANNA SHOOT TOO LIGHT AN ARROW!!!

[MSwickard]

If you achieve prime arrow flight you will be amazed at what you can do with point weight when using a carbon arrow.  Example:  I have CX Terminator Selects cut so they are 29-7/16" BOP, w/ 100 brass inserts and 160 gr points w/ 125 gr steel adapters.  Total arrow weight is 678 gr. w/ 28% EFoC.  I can drop the point weight down to 188 gr and still have excellent arrow flight.  So basically, I can change point weight and have many combos to use.

[Greg Skinner]

Fortunately with the vast array of available arrow materials and point weights it is possible to obtain just about any finish weight and FOC balance you want if you are willing to do a little experimenting, especially if you are shooting a bow that is somewhere in the 52-60 lb draw weight.  For my bows in the 57-60 range I just decide what final grain weight I want and then try different shaft spines and point weights to get that weight while maximizing FOC.  For me that comes out to be 650-680 grains and 25%-28% FOC.  They fly great with (3) 3" feathers using field points.  Broadheads need (3) 4" feathers, good out to about 35 yards, which is about as far as my eyesight can focus well enough to shoot anyway.

[Ryan Rothhaar]

The rule of thumb I always heard in the "PAD"- that is "Pre-Ashby Days"    - was that the arrow should balance around 1/3 of the way between the middle of the shaft and the tip of the point - something like 17% FOC if my math is right.

I don't think there is a "Best" FOC - but, frankly, I don't worry about it at all as a single unit variable.  If you get reasonable weight/spined arrows flying well out of your bow the FOC will be reasonable by default.

I don't like putting the cart before the horse....

Ryan

(PS - Rob, you need a "cart-before-the-horse" gremlin!)

[chopx2]

Originally posted by Rob DiStefano:
but i don't see that at all with carbons, even if weak spined carbons are what ya got.

My PERSONAL (let stress PERSONAL) experience is that carbon arrow spine with ultra high FOC (like in the 25-35% range) is more affected by LENGTH of the arrow than point weight.

[amicus]

Good Arrow flight is good.

Good Arrow flight with Hfoc is better.

Gilbert