I have been digging deeper into FOC and have absorbed the Ashby reports and youtube vids from this year's Michigan discussion with Dr. Ashby and Troy Breeding. I have delved recently into wood arrows and love them, but haven't narrowed down for sure whether carbon OR wood is my shaft of choice. I was wondering if I could get some info from those of us here who have made attempts at EFOC with wood arrows. Info needed: Bow weight, FOC % and total arrow grain weight and how the FOC was achieved (just a heavy head to has anyone gone the woody weight route). The trajectory issue come to mind as their should, theoretically, be a change in trajectory when going from something in the 500's to something in the upper 600 to 700 plus range, grain-wise. When running Stu's calculator, I'm seeing calculated weights of High FOC arrows in the 7's. Let me know, if you would, what you are seeing with your high FOC wood arrows. Thanks.
To get EFOC and still maintain a reasonable weight you really must use carbons. Tapered shafts and heavy points won't push it into the extreme weight forward.
big bad is right. I can get about 19% FOC by tapering a 11/32 shaft, putting on a hardwood foot and using a fairly heavy point -- 175 grains. That yields an arrow that weighs about 675 grains, plus or minus a little. They're spined at 85# and they shoot well out of my 52# and 56# ACSs. My draw is 28 inches
If you have a long draw and/or shoot a heavy bow, you simply will not be able to get wood in a spine heavy enough to accommodate extreme front loading.
The highest FOC is achieved by using extremely light and stiff shafts.
With wood,19% will be close to the top you can expect,possibly 20%-maybe.With aluminum,a little more,about 21% or so.With carbons normal to quite a bit higher.
With any of them,it doesn't take much to bump your arrow weight to 700 grs.You just have to decide what you want and build it.
Not sure if this qualifies as extreme FOC but I am shooting wood shafts 30" long and total arrow weight of 850 grains. I am using 160 grain points with 100 grain woodie weights for a total of 260 grains up front and getting EXCELLENT arrow flight out of my Northern Mist Classic.
I've managed to achieve 23.7% measured the AMO way. The arrow is tail tapered 23/64 Sitka Spruce, 85 lb spine, 29.5 BOP, wearing a 300 gr brass field point from Tuffhead. Total arrow weight is 715 gr. There was another arrow in the set that weighed 698 gr and would measure a slightly higher FOC.
I don't consider the AMO method of FOC measurement to be correct, but that is what most folks are currently using. For some reason, AMO doesn't consider the point length in the arrow length measurement. This is fine for making up arrows, but IMO, FOC needs to be figured using the arrow's full actual length to be truly relevant.
Steve are those the 120# shafts you got from Snag??
I dont know much on figuring FOC. But i shoot 55-60 parralell POC 29" with a 125gr snuffer and 125gr woody weight. finished weight of 624-655 out of my 63# longbow. To most it would seem very weak but it shoots very very well.
QuoteOriginally posted by WESTBROOK:
Steve are those the 120# shafts you got from Snag??
No, these are shafts I am shooting in my 83# NM Classic. The fly like they are on a string! I posted a video of them on my site. They are Douglas Fir shafts. The ones I got from Snag only have 190 up front, I tried increasing the point weight on those but with the bow I bought them for it made them too weak. I may try adding a woodie on them and seeing how they shoot from my 90# ML-10.
Fletcher..
I agree the common method doesn't really give the correct answer....it's kinda geared to give higher results.
I've had about the same findings as you.
60-70# spine Tapered spruce with 200 grain tips gives about a 600+- grain arrow with around 18% foc.
Varies quite a bit just from how heavy/dense each batch of wood is.
I have some MFX 400's with 75 gr. insert and 200 gr. head which calculates out to a bit over 20% FOC. I agree that wood shafts seem to be hard to get close to 20% without producing a 700+ grain arrow. As said, guess I just need to build a few and see how they shoot. I have to change my thinking from wheelie-land where it was almost effortless to get 15% + FOC. There's so much force behind a compound-ed arrow and now I have less push force and must go to momentum. I need to realize that the bottom line is straight flight and worry less about total arrow weight. Thanks for the replies and best of luck to all!
Question-what is the target species?? Is HFOC needed for a whitetail? Is wood the best material for a cape buffalo?