Easton recommends an FOC for aluminum target arrows to be 7% - 9%, A/C/Cs 9% - 11%, and A/C/Es 11% - 16% as a starting point. They state that FOC become more important with distance. It will be far more important a 70m or 90m. It is not really significant at 18m. FOC is to do with arrow trajectory, not really as a factor to control effects of wind.

You can look at the last page of this pdf: Easton Arrow and Maintenance Guide (PDF)

 

So when people mention heavier point to combat wind, is that more about increasing total arrow weight rather than F.O.C? Or is it all just myths?

 

I think there is a lot of personal and anecdotal stuff going on. From what I have seen, most high-level target archers don't use a great deal of weight in their points. I think the discussion might be more of a bowhunter conversation--with lots of disagreements. Target archers seem to concentrate on vanes and the ability to aim off. The preference is for an arrow that will fly consistently and group well regardless of the wind conditions. However, arrow weight is a consideration where X10s are considered better than ACEs at long distances because of weight. But neither are particularly heavy.

 

You may find this interesting: Shaft selection: Picking the right arrow (Bow International)

 

F.O.C. and target archery...

Is completely overrated.

Thought I'd finish the sentence for you.

 

FOC is just a number, archers will shoot what ever works for them, generally speaking fingers, recurve, BB have a higher FOC but there certainly is a point of diminishing returns, compounds FOC is just this side of irrelevant

 

I've also had this question asked, how much FOC? I usually say... "some" start with some.. make sure you have some .. yes

😀

 

Guys -

Once you realize that FOC means Freakin' Over Complicated, you start getting it.

In most cases, head weight is A. a (spine) tuning thing and B. used to tweak overall arrow weight (trajectory).
%FOC, physics (spear ballistics) demands that the front end of the arrow be heavier than the tail end. Once that is achieved, any more is doesn't buy you much.

Viper1 out.

 

Guys -

Once you realize that FOC means Freakin' Over Complicated, you start getting it.

In most cases, head weight is A. a (spine) tuning thing and B. used to tweak overall arrow weight (trajectory).
%FOC, physics (spear ballistics) demands that the front end of the arrow be heavier than the tail end. Once that is achieved, any more is doesn't buy you much.

Viper1 out.

Agree with viper.

See guys, when you change your point weight, what's really affecting your tune is the change that induces in your dynamic arrow spine. And that's what's ultimately affecting your arrow flight, grouping and scores. Whatever is happening to the "FOC" is simply incidental, and is essentially immaterial to your tune.

Back in The Good Old Days that's what we called this "FOC" thing - dynamic spine. What happened was, we all started shooting with release aids kinda starting in the mid/late 80's. This dramatically reduced the sensitivity of our setups to dynamic spine. All we need now is sufficiently stiff and we don't need to worry about it too much beyond that.

So, once we no longer had dynamic spine to worry about, well, that anxiety had to be replaced with something..... And "FOC" was born....

lee.

 

Agree with viper and limbwalker. "FOC" is kind of like what is my riser made out of, do I need to shim my cams, should I be worried if my arrow doesn't line up with my stabilizer, etc.

This is one of those many, many worthless subjects on AT that should never be on your mind at full draw. Even on the compound bow, a 100 grain point vs a 120 grain point should never even be within 100 miles of entering your mind as you're pulling through the final stage of your shot.

This terrorism about "FOC" during your shot execution will do far more damage to your accuracy and enjoyment than whatever the CG of your shaft actually is could ever do.

Put it out your mind. Tune your bow and feel free to change your point weight 10 or 20 grains as necessary to achieve your ideal spine, and go shoot and enjoy your equipment.

"FOC" - basically just a fancy name for CG - only matters in aircraft designed for controlled flight through the air. That's probably where this terror-provoking non-problem was borrowed from, and plopped onto the shoulders of us poor archers... Who already have far more grave difficulties to worry about....

lee.

 

well, not all of us started using release aids.

In early 2004, I was moving to flex-fletch vanes from spin wings and my 400 A/C/E's were already trimmed too short, so I needed a heavier point weight to tune them. I learned about the tungsten 125 grain points that Jason McKittrick was making in Indiana, and contacted him through JimC here on AT. He sent me a couple dozen and I used them to get the tune I was after at the draw weight I was after. The fact that Vittorio was promoting the higher FOC that one could achieve using 125 grain points in A/C/E's was a very distant secondary consideration. Basically it was a matter of "I need these to tune, and if I see a tiny benefit in drift, then so be it..." But I couldn't tell you what my FOC was with those arrows and I can't tell you now. But I know a great tune when I find one and that's where my confidence comes from. Not some arbitrary number with imaginary benefits if the wind starts to blow.

 

well, not all of us started using release aids.

In early 2004, I was moving to flex-fletch vanes from spin wings and my 400 A/C/E's were already trimmed too short, so I needed a heavier point weight to tune them. I learned about the tungsten 125 grain points that Jason McKittrick was making in Indiana, and contacted him through JimC here on AT. He sent me a couple dozen and I used them to get the tune I was after at the draw weight I was after. The fact that Vittorio was promoting the higher FOC that one could achieve using 125 grain points in A/C/E's was a very distant secondary consideration. Basically it was a matter of "I need these to tune, and if I see a tiny benefit in drift, then so be it..." But I couldn't tell you what my FOC was with those arrows and I can't tell you now. But I know a great tune when I find one and that's where my confidence comes from. Not some arbitrary number with imaginary benefits if the wind starts to blow.

Sorry bout that - I cited the move to release aids on compound only as the likely source of this new terrorist threat called "FOC". As always, I meant no disrespect to finger/recurve shooters.

For folks who still shoot fingers, this is kind of a bleed over from compound/release aid, where the loss of the original worry - dynamic arrow spine - had to be supplemented with a replacement. To keep the fiddlers and cam-shimmers happy. And all those micrometers still in use at the bow press, etc.

For the guys who don't know the history of this "FOC" deal, its appearance in the minds of finger shooters looks like a real threat that they really should pay attention to. Because, as all of us are intimately aware, dynamic spine is critical with finger shooting, so when it's not right, there's an actual real problem with arrow flight.

But as you note, this threat is only an illusion. "FOC" from the compound folks has just glommed onto plain ol' garden-variety dynamic arrow spine, in the minds of the guys who need something to worry about at full draw.

For the guys who can't get it out of their heads, I just suggest do a global search-n-replace of "FOC" with "dynamic spine" everywhere in your mental game. That should restore your attention to the item that really will help your shooting...



lee.

 

Lee -

You are correct, there will always be something new to worry about.

Viper1 out.

 

Arrow FOC does affect the cross wind reaction of the arrow also. The horizontal plane fishtailing appeared to occurred at a different frequency and flight pattern. The front and back port vibration amplitude looked different also. but it really need a wind tunnel to test confirm the actual amount of drifting affected by FOC factor.

 

Again, that ultimately doesn't matter (which is why this should not be on the shooter's mind at full draw). That only refers to how and when the fletchings correct arrow flight to a coordinated condition. But you don't care terribly much about that in archery - arrows aren't powered aircraft in controlled flight, they're arrows with a fixed amount of KE making the same exact trip every time. So, for us, what matters is simply that each arrow does the same thing as all the others, and does it every time we shoot it. If they all do the same wrong thing consistently, we more or less don't care what they're actually doing wrong, if anything.

Putting it another way, it's much more important to reduce the work load of the fletchings in general, and we do this by traditional tuning. And, it so happens that the effect on dynamic arrow spine by attempting to adjust "FOC" is far, far more influential on shaft flight and where the arrow lands when shot than the negligible, tiny shift in CG/center of mass location of the shaft.

Again, when you're attempting to adjust "FOC", the change that adjustment actually induces that really matters to us is the dynamic spine. Not this "FOC"..... That's why I suggest guys just call it "dynamic spine" rather than "FOC", because that's what's actually going on under the hood here....

lee.

 

So many topics already on AT about the same subjects. For so many years.
"deterior surdus eo nullus qui renuit audire"

Worth time by time getting back to the great work Joe Tapley did many years ago ...

TOPICS ON ARCHERY MECHANICS

The basic mechanics of many aspects of Olympic recurve archery

www.tap46home.plus.com

 

<tongue-in-cheek>
Until information like this is made available in a social media / TikTok / YouTube accessible manner, it going to remain as archery lore that is only passed on from master archer to journeyman archer.
</tongue-in-cheek>

 

Just a curiosity... "they" say a higher FoC gives the fletch more effect on steering due to a longer lever arm in reference to the center of mass/pivot point; if this is true, then wouldn't a higher FoC also be more sensitive to imperfections in release? If I pluck the release a little more this time than last time, aren't I using that same, longer, lever arm to effect flight stability?

 

Just a curiosity... "they" say a higher FoC gives the fletch more effect on steering due to a longer lever arm in reference to the center of mass/pivot point; if this is true, then wouldn't a higher FoC also be more sensitive to imperfections in release? If I pluck the release a little more this time than last time, aren't I using that same, longer, lever arm to effect flight stability?

You obviously missed the point (no pun intended). The FOC combined with the new dynamic spine offsets the modulus carbon to create the archer's paradox with the additional kinetic energy dampened with balanced rods counteracting the thermal dynamics of the counterclockwise spin making the point weight equal to the calories. Besides, it works for me.

 

Good point @"TheBlindArcher" . I suspect that at release, the fulcrum point will be the plunger and rest, as opposed to the center of gravity while in flight. The fulcrum point would be the same regardless of high FOC or low FOC. But that's just me playing AT arm chair physicist.

Going along with that idea and speculating some more: having a larger mass on the tip on the other short lever arm will be better than having a smaller mass. The larger mass should be better in opposing the lever action on the nock end from the pluck. My guess is that all that really happens is that the arrow bends more due to a pluck on a higher mass tipped arrow vs a lower mass tip and that translates into more pressure against the plunger. If the plunger bottoms out, then likely a stiff acting arrow, perhaps?