Bow Design Epiphany... sorta

[Kegan]

Goofing around, I picked up the old fiberglass recurve we had knocking around. Didn't like it, couldn't hit a paper plate at ten yards- but when I picked up my white oak and sinew hunting bow, I suddenly realized how slow and handshock-y my beloved bow was ! And with the cooler weather setting in pulling 80# is just tiring, to put it mildly. So, off to our archery library.

Going through Traditional Bowyer's Bible Vol. 4, I started realizing just just what aspects affected performance- most noteably stiff tips, tip weight in relation to arrow weight, enough mass on the inner limbs to prevent excessive set, and a light string. It hit me that's why modern straight bows like Hill bows are slow compared to others, or why my beloved hunting bow isn't as good as it could be- despite the material advantages of a Hill and my bow (fiberglass, tempering, sinew). Not really an epiphany since I'm just using other bowyers' knowledge, but I've always been a little slow to catch on .

Anyway. I went in with that firmly in mind last night and went about working on some bows. The one closest to shooting was a bamboo backed red oak board bow. This morning I finished tillering to full draw 45# @ 28". It took about 1 1/2" set, and had a nice high pitched 'thrum' when I plucked the string- but quite light compared to what I'm used to. I grabbed a handful of my brother's 28" cedar arrows, 550 gr. to test it out. I was figuring it would have a nice, soft cast- like some red oak selfbows I'd finished earlier in similiar designs to my hunting bow.

HOLY SMOKES!!! Smooth, fast, no handshock. That little 45# bow shot better than the recurve! I tested the speed compared to my other bows- and with the 12 gpp arrow it had a point on distance of 55 yards... that's the same as my 80# bow shooting a 7.5 gpp arrow! The bow didn't move in the hand at all. That little 45# stick was a serious hunting weapon, just because of a little attention to the outter limbs and some mindful tillering.

So I've learned a few things:
1. Building a good bow is just as easy as building a bad one. But a good one is much easier to shoot.
2. Always read your Bible. There are valauble, timeless truths in it.
3. Until now I've spent too much time on tempering, sinew backing, and sheer bow weight- when design was easier and much more effective.
4. My bows should start getting even better!

I'll have photos of the boo backed oak soon, as well as some other new bows that follow proper design. I just had to rant, I'm tickled pink and quite excited . Hopefully other newbies benefit from this; boy was I wasting time !

[Pat B]

Kegan, You have learned wood bow building the way most of us oldie's learned...by trial and error! You took what you had and made bows. You learned how to tiller well and finally you have learned that a 45# bow is an efficient killing machine...if designed properly. I'm gonna miss your crude but well tillered 80#+  bows but am looking forward to your Renaissance bows of the near future!   

[radius]

i found the same as you, Kegan.  Disappointing when my "special" turns out to be a flop compared to some simple stick with light tips.

[Kegan]

Pat, the next logical step is of course a 70#, 80#, and then 90# version with these characteristics. Then finish it with a crude handle wrap and maybe some character knots. "The Sleeper"... hehehehe...

I have another one shooting- this one was supposed to be heavy, but I got a little excited with the vixen file and it's only about 55#. The tips are still a little heavy yet. Both of these bows should make great gifts .

[Ryano]

Kegan, I've been telling people this for years.....With the added mass it takes to make a 70 or 80# self bow a 50-55# bow with out shoot it speed wise with hunting weight arrows any day. To me any wood bow over 60# is just a waste.....There's no advantage to it, Unless of course hunting armor plated deer and shooting 200 yards with 1500 grain arrows..... point being really heavy heavy draw weight doesn't help unless your shooting really heavy arrows. My fastest bows have always been right around the 50# range.

[Keenan]

 Words of wisdom for sure. If the wood is not working wood then it is dead weight. Tip weight is the most critical, and the right design for the wood that you are using equals performance. 

[NTProf]

I can't wait to see your boo-backed red oak. How is the red oak holding up with the boo backing? Thanks for sharing your experience with us. Now I am excited to build another one while giving attention to the details you mentioned.

[Kegan]

Ryano- Of course, this just means I need to apply this to heavier bows also, but that's only because I'm completely insane .

Keenan- that's another thing I forgot to mention: I've been abusing the woods I have available. Given 2" wide limbs and enough length to handle the draw/design, my hickory and white oak bows would be happiest around 70-75#... not 80+# and with less width. I'd alsways had issue during early stages of tillering with these woods suddenly having too much set on extra heavy bows. Well, now I can see why . Of course, it's only after I admitted I'd be happier with 70#-75# bows that this final clicked, but still

NTProf- I should have photos tonight or tomarrow. I have a physical right after school, but the bow is finished out. At ony 45#, 1 3/4" wide with a crowned back, the 68" bow is showing almost no string follow and no signs of undo stress. For the bow weight, red oak and boo seem to be a good combo .

[The Gopher]

So let me see if i have this right. If i wanted to design the highest performing straight limbed, unbacked bow that i could it would have these attributes:
 - Long limbs for smooth draw and lower string angle.
 - stiff narrow tips for low mass.
 - stiff handle section for less hand shock
 - i could add a bit of reflex that would store a bit more energy?
 - light string, possibly use fastflight?

basically you end up with a stretched out holmegaard like the pecan bow that Baker built in TBB4?

or am i way off?

thanks, Dan.

[Kegan]

Yup! Actual "lightness" on the tips seems to be less important with heavier arrows, and more important with lighter ones. Either way, you covered all the key points that vol. 4 layed out