EFOC bows

[ozzyshane]

#4919

Hey Troy

With all the great talk about EFOC it has got me thinking about the bows we use and what the EFOC arrows was designed for in the first place .

I think Troy and David have gone a long way with the arrow with bows under 60lb but this is were my Qs come from.

The EFOC arrow that Dr started with were for hunting buff 65lb and up ..

But with most bows cut past centre you have to build them out like troy has done but there is going to be a saturations point with most modern curves.

So this is the money Q what is the best bow design for the EFOC arrow for hunting buff????? is it a ILF metal handle with a centre rest and wind it way out or a modern long bow like David shoots cut over centre shot like a D handle long bows have .

Thanks Shane

[Troy Breeding]

#35244

Shane,

EFOC, UEFOC and shhhhhhhh BHFOC arrows aren’t just for Buff or super big game. Yes, Ed did hid test on Buff, but thats what he had handy at the time. His findings will aid anyone.

Increasing FOC aids in bone penetration and flight without having to use such a heavy arrow.

If you read his report you remember that he did test different bows with some of his same arrows…i.e. He tested his 80 something pound Hill longbow and his Adcock ACS 67# (I believe) and found that both bows shot the same speed with the same weight arrow. Thus making the ACS equal to the much heavier Hill bow.

If I were going to hunt Buff, I’d check into the most efficient ( I think thats the word I need to use here) bow with the most weight that I could properly handle.

Repeat,,, the most weight I could properly handle. Not just pull and shoot.

As for how the sight window/rest is set or cut depends on the arrow and proper tuning.

Hopefully I answered your question.

Troy

[Ed Ashby]

#35257

Troy has it. The closer to centershot the bow the more difficult it is to build EFOC, UEFOC or …. the unmentionable FOC arrows. Whatever your bow type, the highest FOC arrow you can use with it will yield increased penetration (and arrow flight) benefits. So far there appears to be no upper limit on FOC, as far as giving increased penetration and arrow flight benefits.

Ed

[Troy Breeding]

#35264

Thanks Ed,

I was hoping I said that right.:D

Troy

[sapcut]

#35808

The closer to centershot the bow the more difficult it is to build EFOC, UEFOC or …. the unmentionable FOC arrows.

That’s my dilema when shooting a 71@31 Widow recurve. Not only close to center shot (have already built plate out a bit) but I don’t want to give up bow weight or draw length.

The best UEFOC arrow I have gotten so far is 1050 grains and 38% FOC….and a very quiet bow.

[Troy Breeding]

#35875

Sap,

I’ll be building myself a new bow in the spring. (Can’t ever have too many bows). My design right now has the sight window at no less than 1/8″ before center. I also plan to build the shelf out further to allow plenty of area for the shaft to sit on.

Widow bows have shallow shelfs if I remember right. You might consider building it out as well.

Troy

[Jason Wesbrock]

#36003

Ozzyshane,

From a tuning perspective, moving your arrow further away from centershot accomplishes one goal. It makes a weak arrow act stiffer. Unfortunately, doing so also comes with the drawback of making your setup less forgiving to shoot. This is why you won’t see top target shooters (there may be an exception or two) building out their strike plates unless their shooting class mandates it. Is the loss of forgiveness significant enough to matter on big game at your chosen effective range? That’s something only you could answer. Regardless, you don’t have to start pushing out your strike plate just because you want to build an arrow with x-amount of FOC. A couple years ago I built a set of EFOC arrows to test a hypothesis that had been floating around. I had no problem shooting them out of my ILF riser with a plunger tip somewhere around 1/8” in from center

[Bruce Smithhammer]

#36095

This is interesting, and something I hadn’t really pondered all that much before. I’m shooting 24% EFOC out of two different bows that are 1/8″ past center. It hasn’t seemed to lead to any noticeable tuning issues, but it’s also something I admittedly haven’t played around with that much as far as adjusting strike plate, etc. What you’re saying makes sense, J.

[Troy Breeding]

#36167

I could easily shoot low to mid EFOC off my bow when it was cut past center. Now that I’ve grown to understand UEFOC and the shhhhhhh foc I can tell you building out the strike plate is the only way you will be able to get proper flight. That is, if you have a longer draw or shoot a bow with some poundage. Combine the two and not building out the strike plate is out of the question.

Troy

[sapcut]

#36199

I have built it out some. But what helps me is the stiffening affect of the external 2117 footing.

[Troy Breeding]

#36277

Troy Breeding wrote: I could easily shoot low to mid EFOC off my bow when it was cut past center. Now that I’ve grown to understand UEFOC and the shhhhhhh foc I can tell you building out the strike plate is the only way you will be able to get proper flight. That is, if you have a longer draw or shoot a bow with some poundage. Combine the two and not building out the strike plate is out of the question.

Troy

Let me add in something I missed typing in on my past post. It should read:

Now that I’ve grown to understand UEFOC and shhhhhh foc I can tell you building out the strike plate is the only way you be able to get proper flight when shooting shafts that have FOC above 30%.

Sorry, my finger can’t always keep up with my mind.

Troy

[ozzyshane]

#36403

Lots of good info coming up now

Sap guys like you with a big DL (im 29.5)can only go to a certain % and get an arrow that we will be able to hunt with.

Troy your last post is were i was headed with this thread

Now with your next bow you are building with the info you have about UEFOC what is your plane of attack with it .

I think the best design for the perfect UEFOC bow would be a one peice 50s style recurve bow made with carbon,foam and a good grip cut way out from centre .

Thanks Shane

[Troy Breeding]

#36415

Shane,

I use three piece takedown recurves and three piece takedown longbows.

I don’t think the style of the bow is that important as long as it’s one of the new style R/D longbows or a recurve.

Ed’s reports proved that. He found that his lower weight Adcock bow shot the same arrow the same speed as his much heavier Hill bow.

My next bow will be another three piece recurve. I may do a little more checking into the foam core material. From what I have read and heard so far the foam core doesn’t add that much speed but does smooth out the bow and add stability to the limbs. Others may say different.

If I were going to buy instead of build, I think I would build an arrow with heavy weight and test shoot as many different styles and make bows through the chronograph as I coud get my hands on.

Only you can decide what bow you like. You have to remember, speed isn’t the only factor. Some fast bows are hard to control even with a heavy arrow.

Troy

[Ed Ashby]

#36494

Troy Breeding wrote: Some fast bows are hard to control even with a heavy arrow.

Ditto that! Stability from my bow is more important to me than is speed. If you have a bad release, as I do, a bow with heavier limbs (physical weight) moves slower, but the heavy limbs and slow limb recovery allows more time for the bow to correct from the poor release, assuming you have a good follow through. That’s a tip I picked up from Ben Pearson, personally. His words were,”Don’t worry about your release. Just use a longer length bow with thick, heavy limbs and concentrate on your follow through. The heavy limbs will whip the string back into alignment long before the arrow is off the string”.

Ed

[kirkll]

#60356

Howdy guys! I just registered here & thought i’d jump right into it. For those who don’t know me, my name is Kirk, and i’ve been building composite bows professionally for a few years now. I take great pride in building high performance bows of very high quality.

Some fast bows are hard to control even with a heavy arrow.

I have to agree with this statement, but not the solution Ben Pearson chose. Why shoot an 80# heavy limb long bow when you can get a good shooting R/D with the same performance using the same arrow at 65#’s.

The key to having a high performance bow shoot well is stability. Vertical stability is not as critical as torsional stability, but desirable never the less. Torsional stability in a high performance bow is absolutely critical. This is what keeps those limbs tracking straight.

With a well built bow with excellent stability, you can have the best of both worlds. I typically cut all my shelfs right to center & use a velcro pad to start out unless requested otherwise…. there are competition shooters who do prefer a 3/16″ past center cut, but it would be a waste using EFOC arrows. you’d just have to pad it back out to before center again.

[Ed Ashby]

#62201

kirkll wrote: The key to having a high performance bow shoot well is stability. Vertical stability is not as critical as torsional stability, but desirable never the less. Torsional stability in a high performance bow is absolutely critical. This is what keeps those limbs tracking straight.

That’s spot-on. Todays choices in in high performance bows can offer the best of both worlds. That wasn’t the case ‘back when’. I was very impressed with the stability, and the ease with which I could shoot, the ACS-CX I was loaned for use in the testing. Couldn’t fault the stability of that bow at all.

Ed

[kirkll]

#62258

Dr. Ed Ashby wrote: [quote=kirkll]The key to having a high performance bow shoot well is stability. Vertical stability is not as critical as torsional stability, but desirable never the less. Torsional stability in a high performance bow is absolutely critical. This is what keeps those limbs tracking straight.

That’s spot-on. Todays choices in in high performance bows can offer the best of both worlds. That wasn’t the case ‘back when’. I was very impressed with the stability, and the ease with which I could shoot, the ACS-CX I was loaned for use in the testing. Couldn’t fault the stability of that bow at all.

Ed

The ACS-CX is a perfect example of a torsionally stable bow that has questionably poor vertical stability. The radius cross section adds incredible strength to the limb in one direction. but it’s rather limp in the other direction.

A good example would be a common metal tape measure. It has a cup to it and can be extended 8-10′ out before it folds over. But turn it upside down and it wont extend 2 feet.

Limb design has come a long way since the ACS-CX took the lead in high performance bows years ago. There are glass bows available now that meet or exceed the performance levels of the XX carbon ACX and have excellent stability both vertical and torsional…..

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