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Main Boards => PowWow => Topic started by: Zradix on January 11, 2011, 08:19:00 AM

Title: SOLID carbon fiber limbs?
Post by: Zradix on January 11, 2011, 08:19:00 AM

I've never seen a bow with solid carbon fiber limbs.
Anyone ever tried this?
Seems like it would be a good idea.

Is it just cost?
Or maybe something else.

What do you think?

Thanks

Title: Re: SOLID carbon fiber limbs?
Post by: JamesV on January 11, 2011, 11:12:00 AM

Some compound bows have solid carbon limbs. Never saw a recurve or longbow with solid carbon limbs but they may exist.

Title: Re: SOLID carbon fiber limbs?
Post by: Blackhawk on January 11, 2011, 01:02:00 PM

Some time ago I heard that Earl Hoyt Jr. made a few sets (about 10) of all-carbon limbs for the Sky Hawk recurve which were sold in the '90's.

Anyone see these?  

Earl seemed to be ahead of his time, so their existence would not surprise me

Title: Re: SOLID carbon fiber limbs?
Post by: vermonster13 on January 11, 2011, 02:12:00 PM

Can you say crrraacccckkkkkk?

Title: Re: SOLID carbon fiber limbs?
Post by: Rob DiStefano on January 11, 2011, 02:58:00 PM

i'll take a little assistance from technology (glass backing over grass or wood) but a bow with a lotta 'space age whatever' materials for the limbs and riser just turns me off.  ymmv.

Title: Re: SOLID carbon fiber limbs?
Post by: Longbowz on January 11, 2011, 03:04:00 PM

Of course some ILF limbs are carbon with foam or wood cores.  I would assume there is a need to seperate the tension from the compression side which is the reason for the core materials.  Many compounds have used solid compression molded carbon limbs for some time.  But they are little more then a fairly crude spring.  Feel & cast plays little into this type of limb design.

The problem with using carbon fibers is mainly cost to manufacture a satisfactory limb.  It would require pretty spendy curing equipment to take full advantage of the materials properties.  Far beyond the small custom bowyer.  This is why some who have tried to use carbon in their designs find little advantage.  It's not the material, it's their inability to use it to it's full advantage.  

In the end I would think it possible to design a limb better in every way then any wood limb made.  All it takes is money!

Title: Re: SOLID carbon fiber limbs?
Post by: BenBow on January 11, 2011, 03:06:00 PM

Remember all fiberglass bows?     :rolleyes:        I also ran supertiller with a design that I worked out that was 53#. When I changed the materials to all carbon the weight went to 277#. To get the weight down to a shootable number there wouldn't be enough carbon to keep the limbs stable. In other words it won't work.

Title: Re: SOLID carbon fiber limbs?
Post by: Andy Cooper on January 11, 2011, 03:19:00 PM

Quote

Originally posted by BenBow:
Remember all fiberglass bows?       :rolleyes:              I also ran supertiller with a design that I worked out that was 53#. When I changed the materials to all carbon the weight went to 277#. To get the weight down to a shootable number there wouldn't be enough carbon to keep the limbs stable. In other words it won't work.

Raging Water would have taken if off your hands if it was only 277#!   :eek:      :D

Title: Re: SOLID carbon fiber limbs?
Post by: HATCHCHASER on January 11, 2011, 06:44:00 PM

More like explode. Carbon is extremely brittle.

Title: Re: SOLID carbon fiber limbs?
Post by: chanumpa on January 11, 2011, 08:14:00 PM

Andy McCoy of Bezaleel Bows made one for himself.that is really a cool one.Check out his website and ask him for a picture of it as he is a master bowyer and great guy.It is an extreamly fast bow to boot,as are all of his.

Title: Re: SOLID carbon fiber limbs?
Post by: chanumpa on January 11, 2011, 08:17:00 PM

Maybe Andys bow limbs on the one I spoke of arent 100 percent carbon ,but he left the top sheet carbon on the back of the bow and it is pretty neat looking.

Title: Re: SOLID carbon fiber limbs?
Post by: Zradix on January 12, 2011, 08:22:00 AM

OK I understand now.

The farther from the center of the limb the more stress there is when the limb is bent.

Carbon fiber laminate is 2-3 times as dense as wood.
Having that dense CFL in the core ( not doing much work ) just weighs down the limb too much.

So, you need to build a limb with a light core and put the stiff and heavy CFL on in a thin layer as far from the center of the limb ( within reason) as you can.

A solid 3 layer CFL strip weighing 10oz will bend easier than say 2 layers of CFL sandwiching 1" of bubble wrap with the sandwich totaling 10oz.

Someone needs to invent a better core material and a lighter resin for the carbon fiber..

Title: Re: SOLID carbon fiber limbs?
Post by: Mudd on January 12, 2011, 08:35:00 AM

If I am not mistaken there is a tiny little horse bow from Korea that has carbon limbs that are covered with birch bark.

It feels like a toy, feels like your holding a pencil in your bow hand. I think you could pull it back to the mid 30's without any problems or issues.

I was absolutely astounded at the speed this little bow spit out the arrow.

I may end up owning it since the guy wants to sell it.

It's about as far away from my beloved Hill styled bows as you could get but it was fun to shoot.

God bless,Mudd

Title: Re: SOLID carbon fiber limbs?
Post by: Lee Robinson . on January 12, 2011, 09:40:00 AM

I don't think carbon does much good if it is in the core, and I know of a few bows that broke when it was used on the belly/compression side. That said, carbon has EXCELLENT tension strength and works great on the back side but it should be covered with glass imo to protect it from being banged on.

Most of us have tested it to some degree. Although this "test" is way over simplified, it illustrates a similar observation I have seen in bows that have used carbon. Imagine your old carbon fishing rods. You can pull on them hard without any problem. Yet, if you lay it on the ground and step on it, it will crack. Supposedly it has decent compression strength in some tests, but for some reason in the real world of use it is my opinion that it should only be used as a tension material. I may change my mind some day if I do some testing myself with it on the belly (again covered with thin glass), but I am not going to get into unknowns just yet. As Terry says, "stick with meat and potatos and you won't go hungry." What that means to me is there is nothing wrong with doing research and testing, but don't put those tests in the hands of customers until things are proven out.

Title: Re: SOLID carbon fiber limbs?
Post by: 2 Barrels on January 12, 2011, 01:19:00 PM

Give Bob Morrison a call.He seems to have the whole carbon thing figured out.I think alot of guy's have a misunderstanding of what carbon is good for.It make for a very stable limb.And speed is a by product of it's light weight.

Title: Re: SOLID carbon fiber limbs?
Post by: vermonster13 on January 12, 2011, 01:21:00 PM

Arvid has done a lot of work with carbon from the very beginning. It is an excellent back of the limb material. His carbon foam is an excellent core material. The belly is where carbon is most likely to fail and other materials are better suited for use there. Compression is not a strength of carbon.

Title: Re: SOLID carbon fiber limbs?
Post by: ryan brodrick on January 12, 2011, 02:58:00 PM

www.uukha.com (http://www.uukha.com)

Title: Re: SOLID carbon fiber limbs?
Post by: Zradix on January 12, 2011, 03:53:00 PM

Quote

Originally posted by ryan brodrick:
 www.uukha.com (http://www.uukha.com)  

SUPER COOL!