Primitive Archer
Main Discussion Area => Bows => Topic started by: BowEd on March 06, 2022, 02:50:19 pm
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Just got through shooting this straight tipped sinewed winged elm bow through the chronograph.It pulls a touch over 47#'s @ 28"so I used a 475 grain bamboo arrow.I got two identical shots through it at 186 fps.62" TTT.
I must mention that I used a 9 strand 70 grain string also and I used Robin as a spotter while shooting.
(https://i.imgur.com/k2FcSIR.jpg)
slight opposing propellers on this bow.
(https://i.imgur.com/MIepykf.jpg)
(https://i.imgur.com/ZrllfuT.jpg)
(https://i.imgur.com/fV66AXF.jpg)
I'll doll her up and show the rest of the story over the next few weeks.I see I did'nt quite get it to full draw in the picture or I did but the slow camera shutter action of the camera did'nt catch it right.
I thought I would post this to prove my observations on a subject.There was a discussion some time ago on a thread called "The mass principle question" started by freke about it's relation to sinewed bows.The disussion migrated to comparing recurves to straight tipped wooden bows' performances.
This bow is not an anomaly as I've seen this before over the years with other woods like KCT and hickory.Here's the discussion about it some time ago.
http://www.primitivearcher.com/smf/index.php/topic,70936.0.html
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Love the tiller shape. Can’t wait to hear more.
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You can't post such a "killer tiller" and such great numbers without filling us in on the rest of the story...and pictures are a MUST... :OK
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Thanks Ryan.It's different than the usual bow profiles working in such a shorter section of the bow and has been shown before.A fella not on here for a while called "bushboy" used to show some real dandies.
It was the performance thing that prompted me to post this.Far as I can see examining it it's got 45% working limbs and 55% stiffish outer limbs.The 3" fade into the lever does'nt bend much either with the bow having around 11" working limbs and around 15" stiff levers.
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Thanks.I'm getting older Bob but I'll get er done.
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Nice one ED, and at 186 sounds like ya got a keeper. Bob
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That is an acceptable fps! Nice. looking bow!
Hawkdancer
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I could hunt with that bow…nice everything! Just out of curiosity, what’s the mass weight?
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Wow that thing is smoking. Lovely tiller
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Thanks fellas.
Nonbacked....I did give the bow an 8" handle and fades.The mass weight on it is 17.50 ounces.With the lightened up outer limbs and tips many times these come in under weight even as a self bow.It can depend on how long handle and fades are.
(https://i.imgur.com/b5sDtxW.jpg)
Being sinew backed I don't think it conforms to the mass principle of self bows.At least it never has in the past for me.With it's reflex according to the table it should weigh at least 22 ounces as a self bow.
(https://i.imgur.com/sG2WDaB.jpg)
The way I see it I replaced wood with denser material [sinew] in the right places,and made it work for it's living stretching in the profile I applied it in.This bow shows that per gram weight wise a person can get a lot more efficient power and speed per gram from sinew than you can wood if it's applied properly in the right profile on only the inner limbs on some designs.
Hawkdancer.....All of acceptable Jerry.
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Very impressed Ed, I value your test results also.
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thank you for posting,, I have always felt straight tip sinew bows were underrated,, this one being a little long by conventional standard,, shows they can really shoot and also that sinew does not weigh a bow down,, )P( great work congrats on a really nice bow,,,
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Steve....Thanks.Just trying not to get bored over here.
Brad...I chose a medium length bow.Starting out width dimensions and my normal thickness for a flat bow working limb on this bow being winged elm and the density that it is dictated the length for my needed draw weight.I gained around 10#'s by cutting off 4".The rest of the draw weight gained I got using the sinew.
The sinewing is crowned very well also and only on the inner limbs and handle.
Without shortening it and sinewing it would of made about a 35# bow at best at the width that it was.
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Nice bow Ed! That’s an impressive result. Always love seeing your bows posted here.
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Thanks Will.....I don't make as many per year any more so I try to focus on harder challenges.
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Do the fletchin start smokin before or after impact ;)
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Wish I could fling a few arrows out if that one, and watch them zip to the target.
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Thanks fellas.
I wanted to show to some extent what sinew can do to self bows on some designs on bows.
Shooting it is fun.Got it pretty much dialed in now.It's holding up well.I'll get around to finishing it in a few weeks.
I expect to use it when hunting season for deer rolls around again.
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that is mighty impressive... gut
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Nice. I have not sinew backed a bow yet. I was on a mission to get the mass principal down but it's been to cold to try and heat the shop.
I'm looking forward to the rest of the story
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Smoking hot Ed ! I like it.
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Nice bow Ed.
I’ve often thought that would be a good design for sinew.
Bjrogg
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Thanks fellas.
It's a good design as a self bow too.
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Very cool Ed! I love it. Sinew in the right places is exactly what you got there. Thanks for sharing. Awesome performer too. Nicely done. Question… did you wrap the sinew at the ends at your levers it’s hard to tell from the pics. I’m doing one similar to this and I ended up wrapping mine but wondering if it was necessary.
Cheers
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It usually was'nt neccessary to hold the sinew ends down on previous bows while shooting it in.The sinew fades out far enough into the levers' fade that is'nt bending.
I heat tempered the belly of the levers during tillering to be sure they were stiffened up good as they are kinda narrow.It got a bit hot where the sinew ends on the working limb.The sinew curled a bit on the edges because of that.So I wrapped them with sinew on this bow.
I'm putting a snake skin on the working limbs anyway wrapping the ends with silk or possibly sewing on a deer rawhide wrap.This wrapping helps relieve wear and tear or abuse from the string loop always running into the front edge of the snake skin too when unbraced.
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Nice profile, and good speed. Elm with sinew is a great combination. That one should last forever.
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Congratulations! Very nicely done. Jawge
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Thanks fellas.
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Added mass on the inner limbs is not hat big a deal. My 2-3/8 fades on some of my Osage bows proved that to me. The outer half a s where less mass pays off. Good design Ed . I would like to shoot against that one my friend. Maybe we can someday. 🤠🤠🤠
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Added mass on the inner limbs is not hat big a deal. My 2-3/8 fades on some of my Osage bows proved that to me. The outer half a s where less mass pays off. Good design Ed . I would like to shoot against that one my friend. Maybe we can someday. 🤠🤠🤠
Thanks Arvin....Yes I've known that for quite some time too.
I've reduced the poundage on the bow a little bit like I said I might,but it might gain a little more from curing yet.Still shoots a 13 grain arrow a good clip though for hunting.Hav'nt distance shot it yet with a 10 grain arrow.
I should be at Mo jam.
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Well Ed, old boy. Keep it up, it seems like you are starting to get the hang of this bow making business!
Just a friendly hint: You might wanna make the next one a little bit more sluggish. You see, this one is liable to set the fletchings on fire and you don't wanna start a nasty ol' fire in yer straw bales! (=)
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Thanks JW....A long long time ago I had a FG bow maker tell me"you know if you want to get what these FG bows got you might want to put a strip of FG in your bows".
I've shot with him for years as a group at 3D shoots.He's had to back pedal on those remarks.
He makes very nice bows himself and other than being outspoken at times we enjoy each others company.
It seems it's hard for people to get out of the modern main stream.