# Straight longbow design considerations?



## Apex Predator (Aug 5, 2008)

I have built two fiberglass laminated longbows.  They are both 66" between nocks.  These are the differences:

Bow #1- This one draws 50@28.  She is 1 5/16" wide narrowing to 9/16" tips.  The bottom limb is 2" shorter than the top.  The arrow pass is 1" above center of the bow.  Construction is of three parallel lams and one .002 per inch tapered lam.  It has 3/16" positive tiller, but I shoot three under.  This one has maple core lams and red cedar lams on the faces.  The red cedar on the bow's back is the tapered lam.  I used .050 clear glass and smooth on for epoxy. I feel that this one has tip overlays that are a little too thick, and could stand some narrower tips.

Bow #2- This one draws 49@28.  She is 1 3/8" wide narrowing to 7/16" tips.  The bottom limb is 1" shorter than the top.  The arrow pass is 2" above center of the bow.  Construction is of two parallel lams and two .002 per inch tapered lams.  It has 3/16" positive tiller, but I shoot three under.  This one has two maple .002 tapered core lams and parallel walnut lams on the faces.  I used .050 clear glass and smooth on for epoxy.

Between the two you can see that the #1 bow bends slightly more out side the fades and less at the tips, compared to bow #2.  Bow #1 is in the first photo.












I've shot both bows quite a bit with 10 grain per pound arrows and 13 gpp (which I prefer for hunting).  With the heavier arrows the difference in handshock and noise was not noticible to me.  When shooting the lighter arrows, bow #2 had noticeably less shock and noise.  Brace height on both is the same at 6 1/2".  They both have the best manners at this brace.  My nock set is similarly 3/4" above sqaure.

Here you can see some side by side photos.
















In that last photo of both bottom limbs, you can see that bow #1 is bending more at the fades and less at the tips.  I don't own a chronograph, but believe that bow #1 is a better performer, and expected that.  

What other considerations should I be giving to my design?  Should I be tillering them even for three under?  I'm very pleased with both bows, and neither has more shock than the Hills that I have owned.


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## hogdgz (Aug 5, 2008)

COOL Marty, but way over my head!!!


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## SOS (Aug 5, 2008)

Why a 2" longer limb?  That's a lot, with the heavier tips and off center may lead to some shock - limbs returning at a different time.  I would say bow 2 with the arrow shelf less than 1.25 about center would be real close.  2 inches seems high.  But then again, I've only built one bow!


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## Apex Predator (Aug 6, 2008)

Steve, 2" is on the edge of what is considered normal.  There are trade-offs with every design characteristic.  Getting the arrow to pass as close to center of the bow as possible is desirable, but the limbs must be tillered to bend close to the same even if they are different lengths.  Both of these are good shooters, but I like the second one better.


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