Primitive Archer
Main Discussion Area => Bows => Topic started by: arachnid on September 12, 2016, 03:42:10 pm
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Hi guys.
Long time since I posted something.
I`ve been shooting my BBI R/D longbow for about a year and a half now, and I`m really pleased with it.
I want to make another one like it, only better. I want to get more arrow speed (although I have not measured the speed
on this bow- don't have a chrony...) and better performance.
Here are the specs of my current bow:
66" long
1.4" wide at the fade, parallel limb for a about 2/3 of the way, then taper to 1/2" tip.
1/8" thick bamboo backing
reflex deflex design
42#@26"
14 strand B50 flemish twist string
What I`m looking for is the little tweeks and modifications in the design that make all the difference in performence (along with a good tiller, of course).
Looking forward for your wisdom.
Thanks
Dor
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Honestly you should have a chronograph to compare but just using 8 or 9 strands of fast flight for string will give you maybe a good 8 fps increase right off the bat.Increasing performance is done here and there in little bits to get an overall goal.You might try reducing weight on your outside 10" of the tips if possible.I've read every 65 grains taken off tips increases 1 fps.I can vouch for that on a couple of my bows.Readjusting stable good shooting bows long after shooting in is'nt advised too much by me.Leaving good enough alone so to speak.If your really pleased with it you might want to leave it alone.Increasing performance is done making more bows and trial and error.Different designs and above all good tillering like you said.Maybe just ,make another bow a little different.Some other ideas might get shot at ya on here too.That's just my 2 cents worth.
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So your looking for speed?
The only thing I can think of at the moment, narrow the nocks some more. Switch to a 8- 12 strand fast flight string (like beadman said) and lighter weight arrows.
But the best thing for performance is a tiller that tells no lies and is using all the wood to its maximum ability:)
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Thanks guys.
But, as I said, I`m not looking to make modifications on this bow. I want to make a new one and I`m looking for things to change and tweek on this design and apply on my next bow. It`s better then just guessing (I guess... ;))
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Make a recurve obviously. That's why they were invented. ;)
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Do you have a braced,unbraced and a full draw pic?
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Do you have a braced,unbraced and a full draw pic?
It`s kinda late night now, here in Israel.... I`ll try to take some pics tomorow...
BTW, which wood is better to use as a belly with boo backing- Ipe (board) or Mulberry (self cut, 2 year seasoning) ?
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Ipe by miles.
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Ok, here are some pics... notice how the upper limb has a bit less reflex then the lower. I had a bit of de-lamination and I didn`t pay attantion to it and drew the bow- BAD IDEA. Anyway... I wraped it with FG cloth and epoxy (I know Iknow... not primitive. But it`s the best thing I had at the moment). The tiller is far from perfect, I made some improvments lately, causing a 3# drop in draw waight.
(https://lh3.googleusercontent.com/sF7K8LArp4UImNRSVatdfeZAd3vtGhJzlaxEIMC0nOh2TRQCYK52z2mK-kLOPS6Bl-qs5t_HpS_Kpu5uZWWrYMj_vdI33-Z54c0ttoPqZdKqigEvhYfI3biMHDctc8TUYO1AGLucbSmAtTG5qwu4OsCY6eUJe-OnfpCAqC6WvUsi5PjV6UMa4JGWjHXjD8Nl4cKLvW7WdJ3B8X8qPEr1aYmnSqwYevQkQKEYiOBEAiapd9ODLDNYLtaMA3FDAi0dCGRG2Gx9KrFTXFK9FYcZLq6MkTCn8Zxdtv6FJFu5NzOyhC5vBu-y5ZrJj5UfFB4PNgv9E9cJDfqhIGnc5EWPbM7L_EGvzFvS1ZXfUbVFd39PifFKtIqi5BugMnki2EGpkaw4hS_MHxtwdOsWG-BbuJQVB2XG4KUgHXOqLYboCQH4dFxzA9Y3qfrE7Lobqpl1rHSSakIdd2W8sltp3dDRG3AokH_XlsCrstWzYRVRiOIqLC3Bhj9gHgTv7_7PujqBhBvq-pM24bp8igIuGaeh0U80adO5We6LmxTUxdJVW2HHwcTlOomRLYrGKlOR338OYGComEQb4NTrlB6eOK25HDIk4HiKWdr9OQuFPPZeDkYAK-dc=w1135-h638-no)
(https://lh3.googleusercontent.com/f_OWDRJ9Py0gpx71DudD52f6Rm2e2sHoESxG212NM9UaoD_TGH-j5n2OOuCV0SuCx_7oap1z7Wejmcq0ptyxXMwnw23zo7SwCJleNPzdhslX8fY6UwVtIa_x5zNvUeNbD2LrqR2rjkvq8jz5fYZgKFZ5h7owDa4a1Ov-22izA3tWw1c1gxoX4IYaf2PIgOdjQNvfhZquuUXliyKOelikPyaFAdpBl14tZdV-W4J_wAnHGNeEiqDRYMPXn7Le30UQS7c5KE2Xb3yzmd_nYwC3mhnz57OxcEoNjS9FfsLxktzBVpn23ZLkOlaOXvOd-S16e0Ow3lZF7xJ_y4HCr2USyJ0fr0Yi14snb9O2rUI4WqQ6jojNcN_dX6tDmarByil-kJaZ6rN1GGeZZQvjzKtn5-rAH6FyZvO5IiNZrcU25O7JilIkhwAjzspkEseX0BDxUjfA6aS0QTMX5mYYqQkm-PyoVGnl3Ud68g1FBMeNIjUSKbNe3eWUg86Q0-oyfLKMSVFhmhQ6VZGu3qEkDZvCMybtaKT1qOfeluZsQE24Fqw1SLmJ1POIukG8YScP-HsicOdbZMsa0E2OL6rgupbLi_pRlkAxWKaqeA46Ooeaoj9XFghf=w1135-h638-no)
(https://lh3.googleusercontent.com/p8iduiFUPlW6JIG40MBQMlz9HN3Sit3AuWZSoC8qTETHXhGsojLprPb_OlzTBC8B-MM2DatjRE2NLWlZBP8ccgq6ot0qhWo-V-hYAJ2HsFeBiPmlAYmnHDnw4orbIy9zcRrJagzYPREEkaBOSATcN70k31zfGku9HZYloasYCT2TeFFRc_mnW2SCDqsOk2MLLsB5YSZYOYQ_sqz6fvNjOykeIe0yrx1NW5nKhtQhuK75p1u4_nnlZLMwF-iK__LwyLq5vXofajZVVf5tY26f-WDBG_zoijxfeBLd2yuzgcRH_3cyi-vfXkdY847fPIuiDuTuETD-ZiWGx_L90Pz7FD7KMJ_6aVH3qUFR4TywrT3OlbAx1yk-kbynDhQu7GWeO3_GtQxG31GKtUk5MwlTEI32tSImjAJmn93Z6ZiDZtrvmwBdsx7-PKcJx4heq4wFz-7F14dfx-K_l5nO-Ju3anv5l3S-8Oy6VWjHBYyymo8qRZH0zHiR2BGFMKLQF1zogNTzHuqyJ_H1M2DcO_utAm9TEn_6t38d7fnBWXcCEHgqOZVPaEB1L5DIDNee03p26DpGb0zHL7PYGN7w5NIg6nweTWd58bGmQ_aUylPER97ovts7=w359-h638-no)
(https://lh3.googleusercontent.com/bttL_UukGdPcM69iVpIR7TPpTKWjDysUv4eBnL5ski85R4A7ttkY8jBmIXLNXSRXzZNQal1fU8RqxLQvzq4r5ORpLAqIGN1amrCdJPbtNLaOoa8ggF6LwP0zXy_qDZLxFv4ne9uGzuTkR6sBmYo5kcuXlUpPqI07gh7WYo_RBh-m3jLKfm76Um6kw_G9qb5Fq8lhsPDVsJM20YhfaUyksYeGYbMLp88jhuW3E2aLxPesylIkU626FFTHX6xRXS9M9kZrkW3Ybf49Q8echeDVbNsFdylnnJSAVdSPj8szi2J-g90skuYlWXnypDDfmwCvSVMzwjpAnqAQ7GCO98rebEjGlUaxNE3nCkF571V09erAyTcHOHdnNPXYgL4JTXO757UOhv-l5XOXqaEcoIqh8P91PUmEfbm8I0ruyzMS4Xy66dDH1XkJw9yvTgzzUtvMfeVQyRz34e86RyJHqO_On1sQkz5Vnz6Ke9k5J1sh5kUbSwFGbUejmHEg9fXYVMkF0cDlyIFl8olipE6VSsZVSOwjR0-oC0raAARgq0BCawb73bS-Tm9uNulihqXldIaQy2rSsRRcgTMsY1GWKuHk8ebIqAbSgIb8VhdDyaAUeaBNfFOr=w1135-h638-no)
So, back to my question- what will be the best design improvments I can make in my NEXT BBI longbow?
And, If I want to make a tri-lam- mulberry belly, ipe core, boo back (I`ve read a few years back that Adam [a.k.a adb] made great shooting bows with osage belly, ipe core and hickory back)- will I get good performens?
Thanks
Dor
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As far as improvements go I can't see your pics. But I would use about 3" reflex and try to finish with 2". Most of your improvements will come in the way of tecnique used to tiller. I like to use the least amount of bending limb that I can get away with but at the same time I don't want t use less than what I need to avoid set. In the case of your bow this would usually mean keep the outer 8" of the limb stiff. I favor using a no set tillering tecnique. If you don't know what that is we can explain it.
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as stated,, string and narrow tips will help alot,, ,, then it becomes more complicated,, :)
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As far as improvements go I can't see your pics. But I would use about 3" reflex and try to finish with 2". Most of your improvements will come in the way of tecnique used to tiller. I like to use the least amount of bending limb that I can get away with but at the same time I don't want t use less than what I need to avoid set. In the case of your bow this would usually mean keep the outer 8" of the limb stiff. I favor using a no set tillering tecnique. If you don't know what that is we can explain it.
Yes please or pm me or I dunno trying not to steal his thunder but I'm reeeallly interested
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Also your bow is too long for a 26" draw. Go down to 62 or 63" max
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found his thread on no set tillering - http://www.primitivearcher.com/smf/index.php?topic=17294.0
the last paragraph of the first post explains it
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I've posted the pics using google drive but I don't know why you can't see them.
Anyway, I've read the post on no set tillering but I didn't quite get it. So if you can explain a bit more clearly- that'll be great.
Thanks.
Dor
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What Beadman said will help a lot. Arvin
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I've posted the pics using google drive but I don't know why you can't see them.
Anyway, I've read the post on no set tillering but I didn't quite get it. So if you can explain a bit more clearly- that'll be great.
Thanks.
Dor
I think maybe they aren't in a public folder, or...
try this
https://stackoverflow.com/questions/15557392/how-do-i-display-images-from-google-drive-on-a-website
Hosting on Google Drive won't work anymore...
I should probably try Google+ Photos, not sure if I should recommend it
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What Beadman said will help a lot. Arvin
My nocks are wood.. Not horn so I can't use fast flight.
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Not at all true in my experience. Many of my string knocks are wood and all my strings are FastFlite. I pad the loops to fatten them up but nothing more.
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I do the same. Although I just use Dacron B50. I like a little extra cushion on the loops more so when the bows have a sinew wrapping.
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Well, aside from string and thinner/narrower tips, length (thanks Marc. I always make my bows 66" just in case) any more design modifications? How about limb profile and dimention? What will be best for BBI?
Oh, Badger, if you can explain the 'no set tillering' technique that'll be great!
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no need to design your bow poorly just in case,,Marcs advise would make quite a positive difference in your cast,,
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I would try to make the working limbs thinner and wider. Within reason of course. Experts here appear to prefer rather narrow limbs for speed. If you are not willing to make the bow shorter, you can always make the handle longer, making the working limbs shorter.
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As far as I know, with dense tropical woods like ipe, a narrow deeper limb is better. This bow is 1 1/4" wide at the fades. I've gone even 1" wide on one BBI I've made.
As for length, if my draw is 26" times 2- that's 52". Plus 8" handle and fades- that gives me a minimum of 60" total length. So I guess 62" ttt will give me about 60" ntn.
Is that for boo backed ipe or can I use this length with less dense woods? I also use white oak and it tend to take a lot of set. If I make it shorter.....
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It depends on how thin you are willing to go. I don't find it "primitive" enough to make the limbs as thin as fiberglass recurves, but sometime go as thin as 1/4 inch, but 2 inches wide working limbs.
I prefer long stiff handles, usually as long as 12 inches or even longer. I read somewhere a physicist likes it that way as well. Many European flat bows have very long handles. That means my flat bows are often 66 to 72 inches long.
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It depends on how thin you are willing to go. I don't find it "primitive" enough to make the limbs as thin as fiberglass recurves, but sometime go as thin as 1/4 inch, but 2 inches wide working limbs.
I prefer long stiff handles, usually as long as 12 inches or even longer. I read somewhere a physicist likes it that way as well. Many European flat bows have very long handles. That means my flat bows are often 66 to 72 inches long.
What is the benefit of having a longer handle? It`s not a working part
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A long handle makes the limbs relatively shorter per bow length which increases their speed potential.
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A long handle makes the limbs relatively shorter per bow length which increases their speed potential.
So I guess it's just like making a shorter bow.
And while on that topic- why does a shorter limb has higher speed potential? Is it because the "load" spreads over less material, making every inch work harder and thus store more energy?
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A long handle makes the limbs relatively shorter per bow length which increases their speed potential.
So I guess it's just like making a shorter bow.
And while on that topic- why does a shorter limb has higher speed potential? Is it because the "load" spreads over less material, making every inch work harder and thus store more energy?
This is a debatable question. It wouldn't be hard for using a controlled test to settle the issue once and for all. A shorter limb has less limb available to vibrate and distort durring the shot sequence but is not the highest energy storing feature. It can store decent energy ratios and excel in efficiency. I think this is what makes it faster.
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A long handle makes the limbs relatively shorter per bow length which increases their speed potential.
So I guess it's just like making a shorter bow.
And while on that topic- why does a shorter limb has higher speed potential? Is it because the "load" spreads over less material, making every inch work harder and thus store more energy?
This is a debatable question. It wouldn't be hard for using a controlled test to settle the issue once and for all. A shorter limb has less limb available to vibrate and distort durring the shot sequence but is not the highest energy storing feature. It can store decent energy ratios and excel in efficiency. I think this is what makes it faster.
Steve, can you explain? I didn`t quite get it....
P.S
Can you explain the no set tillering ?
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Well if I sum things up-
Shorter limbs
Thinner tip
Less strands in the string
How about multiple lamination (say a tri-lam instead of a dual lam)? Will that help performance?
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IMHO "no set tillering" is just a catchphrase to remind ourselves that we should never overstress the stave while tillering. At least never pull on it more than your intended draw weight. I would add never pull on it while too damp, while there is a hinge developing, while too hot after heat treating, etc. This is probably why some experienced native American bowyers never even string up a bow while tillering.
I floor tiller and string up the stave and just use the curvature for tillering. I do pull on the bow a dozen times or so after scraping, but usually for much less than my intended draw weight. I use rather short arrows to shoot it for the wood removal to show up.
As for the shorter limbs, the easiest way to think about it is to see if the longer limbs are not fast enough by cutting the tips a little and scrape the limbs a little to make the draw weight same. If no set is induced in the process, the "shorter limbs" must be faster because we just made them lighter.
Come to think of it, shorter limbs of same draw weight is always lighter than the longer limbs, so long as no set is induced in making them shorter.
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Ok, thanks for the info guys.
I'll just add one more question- if I decide to make a recurve, I want make it like this guy:
https://m.youtube.com/watch?v=mBN6eSwTi00
Looks like he cut a kerf along the te outer limb and added anothe lam in between.
If someone can explain how it is done- that'll be great.
Thanks
Dor