EFOC

[Pine]

I have been experimenting with my arrow setup .
This one 50# bow likes 2117 29" long arrows with 30 gr. Broadhead adapters and 125 gr. Field points for a total of 155 gr. They fly perfect .
Now the experiment .
Have 185 gr. Broadhead adapters with 125 gr. Field points for a total of 310 gr. Went up to a 2216 29" long arrow and they fly. like a train wreck . Show very spine light .
I guess my question is how much heavier do I need to go or should I just not try to mess with that much weight forward  ?

[halfseminole]

Try adding some nock weight.  Seems counterintuitive but it will stiffen the spine up.  It's also easy to remove if you find another tactic will work better.

[Pine]

Well I have arrows that go up to 105# spine but that seems ridiculous heavy for a 50# bow .
It is just a curiosity thing because so many archers are leaning toward the efoc setups and I thought I would try it .

[ranger 3]

You doubled you front weight and in turn you lighted your spine, if you want to add more weight to the front you have to go with a heaver spine.

[JimB]

Changing point weight,changes dynamic spine.I never heard of a 185 gr broadhead adapter.Where do you get them.

People that chose to strive for EFOC plan for it before building.This means using a very stiff shaft to start out and this means usually jumping 2 spine groups like from .500 to .340 at least.

In order to keep that arrow from being monstrously heavy,that stiff shaft needs to be made from a very light material.This makes a light carbon the shaft of choice for that endeavor.Because of the GPI weight of aluminums,they aren't the best choice for an EFOC arrow because when you find one stiff enough,you end up with a total arrow weight that most people wouldn't like.

It is tough to get much over the low 20% FOC with aluminum.With wood,that number would be even less.
With carbon,it's possible to reach levels of 35% and more.

[halfseminole]

Not so.  Some of those heads top 600 grains.  The shoulder of those will fit a standard arrow.  I have some of the first one and will post my results when they get here.

With a glue on head, no.  With a tanged head that has a fair bit of its weight behind the head but still well forward of center it's possible.  It's just not a solution we think of readily.  My experience in historical archer, specifically Asian archery has taught me that we are nowhere near our forebears in the skill of tuning arrows.  I know a LOT about arrow manufacture as it was, and some of those could approach 50% EFOC, through very careful manufacture and setup.

There are plenty of 30% EFOC wood and cane arrows in museum and private collection.  I look to those when I create my own arrows.

[Pine]

The 185gr. Adapters were made from stainless steel and are solid . One of the perks of being a tool maker .

[JimB]

Originally posted by halfseminole:
 

Not so.  Some of those heads top 600 grains.  The shoulder of those will fit a standard arrow.  I have some of the first one and will post my results when they get here.

With a glue on head, no.  With a tanged head that has a fair bit of its weight behind the head but still well forward of center it's possible.  It's just not a solution we think of readily.  My experience in historical archer, specifically Asian archery has taught me that we are nowhere near our forebears in the skill of tuning arrows.  I know a LOT about arrow manufacture as it was, and some of those could approach 50% EFOC, through very careful manufacture and setup.

There are plenty of 30% EFOC wood and cane arrows in museum and private collection.  I look to those when I create my own arrows.

No,I'm talking about FOC on arrows that our modern archers would consider of an acceptable weight for hunting or and will TUNE on their bows.Many don't want to go over 10 GPP of bow weight.Polls on this site have shown that hunters using 14-15 GPP arrows are in the minority.

Graps,that's cool on the 185 gr adapter.

[halfseminole]

I do understand.  I just felt that saying it's impossible is fudging it a bit.  And I don't mean that you meant to do it either-not to many of us shoot historical equipment.  I've often thought about making arrowheads that will work like that for modern wood or cane arrows.  This summer I may try it.

That said, I'm pulling about 90#-the GPP is lower at my range than say a 45-50# bow.  I still think these could be adapted to regular arrows, but I'm still working on that.

[McDave]

Arrows should be designed to most effectively accomplish the task for which they are needed.  For example, if the purpose is to pierce armor, maybe a 600 grain bodkin point is needed.  If the armor that needs to be pierced is 200 yards away, then the bow needs to be strong enough to get it there.  Examining the bones of archers from the 14th and 15th centuries shows the results of doing that with 100+# bows, which aren't pleasant.  Of course, the results of war, whether from the 14th century or the 21st century, are rarely pleasant.

Fortunately, our decision today needn't be quite so dire. We just have to decide how far away we want to kill a deer, and whether we have the skill to do it.  We can increase our odds a little by using a heavier point, at the expense of reducing our effective range.  If we know we are going to kill all our deer inside of 25 yards, we can use the heaviest head that will allow us to do that, at the bow weight we feel comfortable shooting.  For most of us, that is going to be considerably less than 600 grains. If we're going to take shots further than 25 yards, we have to either increase our skill, get stronger, or use less arrow weight.

[Pine]

Played around with it again today . I have been shooting the way I do for over 50 years , I think I will stick with it .
Like the old saying goes , If it ain't broke , don't fix it .
That EFOC is a tuning nightmare .

[njloco]

I shoot a GT 1535, 29" long out of a 50# R/D LB with 100gr insert, 100gr adapter, and 160gr Grizzly right bevel BH. Very good flying arrow.

[Sapcut]

Tuning nightmare??

I found arrow tuning to be much easier when above 30% FOC. Much wider spine window and forgiveness....if built correctly.

[JimB]

I agree.The tuning principles are exactly the same as for tuning any arrow.Having a wide array of screw in point weights makes sorting it out go much more quickly.

It is different in that you are drastically changing the balance of the arrow and that requires planning,using a very light and stiff shaft and then finding the right front end weight that works.

I fumbled with it at first but once I quit trying to use what I had and bought what I really needed,I got it figured out.I now know which spine group I need and just by using assorted weight field points,I can dial a set in,in about 15 minutes.

[olddogrib]

IMHO, I don't think it was so much that EFOC tuning was a nightmare, it just caused people to revisit the conventional wisdom of the time. Far less people now argue that weight has an identical effect on spine regardless of whether it's on the end of the shaft or embedded down in it. They found that long, heavy 100gr. inserts had a stiffening effect when they're taking up 2" or more in the end of the shaft, reducing the flexing portion, much like footing.  If you want to "fry some brain cells" start studying some of the research papers written by Phd's on the nodes of arrow flexing.  To target archers it might as well be a religion.

[Sapcut]

The perfect oxymoron known as...."the stiffening affect of the added weight up front"... is the magic that creates the best flying and penetrating arrows built these days.  It is the perfect recipe for a perfect arrow.

[Kris]

It is tough front loading aluminum and getting the same performance that you would with carbon...same goes for wood.  

When we speak of FoC and EFoC and UEFoC we assuming carbon use for the most part.

Kris

[Bladepeek]

If those 2216s are flying weak for you, you might want to try some 2219s.

I had a 58" Lost Creek Life Ender that was marked (and felt about right) 48# @ 28". I went to our local trad shop (now sadly gone) and the owner worked with me on some bare shafts. He said 2117s would probably be too stiff, but they flew like wet noodles. He pulled out a 2219 shaft that he knew would be way too stiff and had me try it with the idea we'd have the spine bracketed and could work back down. Those 2219 bareshafts hit dead on at 20 yards and without a wiggle, wobble or even a tremor. WAY over-spined for a 48# bow, but that's what the bow wanted. Back then I was shooting right-handed and probably over-extending just a bit for about a 29 1/4" draw, but still 2219s?