carbon/glass perry reflex bow experiment

[limbcracker]

I built my first carbon glass bow and couldn't help experimenting a bit. I build I straight profile longbow, with pyramid taper, 62" long, 1.5 wide handle tapering to 3/8 tips. I used a .02 carbon back, maple parrallel .18 thick, and a .12 cherry with .002 taper on the belly, with .04 clear glass over the belly. I first glued the backing on with a form with 4" of reflex. Then glued the belly on on a flat form. (using smooth on and heat box both times) after tillering and shooting in,the bow came out with about 3/4 reflex. It has a draw weight of 50lbs at 28" and shoots a 510 grain arrow right around 170fps. I'm wondering how this stacks up to glass bows of similiar length and design as it took a lot of extra time to do this two stage glue up, so I don't intend to repeat the process unless it provides some benefits. I will try to post some pics of the bow.

[Dano]

I look forward to the pictures, it don't sound like the experiment went too bad that kinda speed is respectable.

[Apex Predator]

That's very respectable speed, which will hang with many fast customs, if that was shooting by hand with a finger release.  Some of the fastest ones are probably around 180-185 under same conditions.

[limbcracker]

Will try to post a link to bow picshttp://s991.photobucket.com/albums/af37/kirkarndt/?action=view¤t=copperheadpics003.jpg" target="_blank">http://i991.photobucket.com/albums/af37/kirkarndt/copperheadpics003.jpg" border="0" alt="Photobucket">

[limbcracker]

Trying to post links to pics of bow again.

 http://s991.photobucket.com/albums/af37/kirkarndt/?action=view¤t=copperheadpics001.jpg

[limbcracker]

Thanks for the unput guys. I was finger shooting with a 16 strand fast flight string to get the numbers above. Any more input would be appreciated. Does anyone think I would get similiar results with a simpler one stage glue up, with say 2" of reflex. Kirk

[ChristopherO]

In my way of thining with fiberglass you aren't really getting the "Perry Reflex" results that Dan Perry designed into his all wood laminated flight bows.  I say that because, unless you are a complete master, even wood laminated bows will take a set.  The Perry Reflex glue up method helps to negate the wood fiber compression by building in to the bow the reflex:  Sort of like heating a self bow into reflex so the tillered limbs will still have some reflex in them, or still be at least straight when finished.  
A good fiberglass bow can come out of the form and stay strung for years and not experience any of the compression/set problems that an all wood bow.  Fiberglass bow with reflex built into them, like the Martin Pioneer I have, are basically reflex longbows.  
JMHO.  Someone feel free to correct me if I'm wrong here.

[monterey]

  I first glued the backing on with a form with 4" of reflex. Then glued the belly on on a flat form.

Maybe I'm misunderstanding what you did, but it looks like you did it in the reverse of a Perry Reflex glue up.

It seems like you should have added the back at the end to a flat belly section that was then pulled into reflex before glueing the back portion.  Maybe that is what you did?

[limbcracker]

I did do the glue up in the reverse order of the way perry describes, only for convenience,  because I think the effect is the same whichever way you do it: the belly of the bow is pulling the 4" reflexed back into an end profile of 3/4" reflexed, so the belly and back are in a dynamic tension, pulling against each other even when the bow is unstrung. My theory of how it works is that the thicker belly his effectively holding the bow partly drawn,at say 5 lbs at 3.25 inches(dif. between reflexed 4" and final profile 3/4", which adds early draw weight without extra limb weight.  At least that's my theory, others like chrisO above, think it works by protecting the belly from compression. Anyway, it seems to shoot pretty fast for the design, but I would have to build an identical bow with 4" regular reflex and test it to see how much difference there really is. I may do that soon. If so I'll post the results. Kirk