Primitive Archer
Main Discussion Area => Bows => Topic started by: blindarcher on July 28, 2019, 09:53:55 pm
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All,
I was wondering if anyone had done a study on expected differences in efficiency one might expect by using sinew versus no sinew on a given bow design. That is, is there an appreciable improvement in arrow speed of equivalent bows, differing only in that one is sinew backed? Has this difference been quantitatively measured?
Cheers!
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If its designed for sinew, it will work better with it. If sinew is used to save a self bow, it wont be as good as it was before the sinew.
All that is subject to so many variables, you may never experience any of what I just said to be true.
Hows that for small print?
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Sinew allows you to do things you can’t get away with on a self bow. So...2 identical bows, one sinew backed, one self backed...the sinew backed will be slower, all things equal. Stress the sinew backed bow to take advantage of the sinew and you change the equation.
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2x what both said.
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Yep. Close enough. X3
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for example if you had a 52 inch stave,, and it was wide enough to get two bows 1 1/4 wide
make one sinew backed and one self bow,,both bendy handle ,,straight tip
draw length 25 inches,,
if you put the right amount of sinew on,, it will hold some reflex and shoot in the 170's
ok now the self bow, even if you heat some reflex in,,most is probably gonna pull out,
but it will shoot hard,, pretty hard at first, but after 1000 shots and being left strung for hunting,, its probably gonna have a little set,, and not shoot as hard as when new,,
ok the sinew bow,, it will probably hold the same profile as new,,and shoot about the same,,as when new,, probably out shooting the self bow sister at this point,,by a little, not so much a deer could tell,, but through the chrono,,
now that being said,, if you had a good 66 inch stave for the self bow,, you could get it to shoot about as hard as the sinew bow,, and it would stabalize and shoot like that from now on,,
so on a short bow the sinew will have an advantage,,but on a longer self bow,, the self bow holds its own,, thats been my experience,, lots of variables, and there are exceptions to everything I said,,
on this site,,, if you say it cant be done, theres somebody doing it,, ;D
I will say I love both sinew bows and self bows,, so I am not that biased,, and love to hunt with both too,, Ok I pretty much love all bows,, (SH)
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First you have to define efficiency.
Power output/Power input, but at what arrow weight, draw length etc.
I'd imagine the efficiency is very similar, the difference being the sinew allows you to put in more power due to it allowing more reflex and more draw over a self bow. Of course more power in will give more power out.
Mind if by efficiency you include easiness and speed of manufacture... ::)
Del
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I've done no scientific testing, but I have made a few bows and shot a few bows. In my opinion a short sinewed bow is no faster or zippier than a properly built self bow of equal draw weight. Sinew basically allows a much shorter bow for the a given draw length, its about the only advantage I've noticed. I also believe short bows give us the illusion of speed, cant explain it, but I think we all have shot an extra short bow and thought it was faster than average when really it wasn't.
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Spot on Pearl! The Osage selfbow has ruled the distance shooting for some years now. But maybe the great sinew Bowyers have not found the interest. Mike Yancey builds a good looking sinew pyramid bow but I have never seen ones performance. I am curious though. Arvin
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The sinewed Osage bows of the great days of flight shooting actually did better than the selfbows. They did better than the bows of today too.
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Pat do you think that was because of recurving, design,, or what,, ?
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All of the features and materials combined.
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thats very interesting to know,, how would I look that up,,I would like to study that,,
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...but aren't sinew backed hunting bows vs. sinew backed flight bows apples vs. oranges?
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...but aren't sinew backed bows hunting bows vs. sinew backed flight bows apples vs. oranges?
One shoots a light arrow far, the other a heavy arrow far, both are not the same requirements from a bow design.
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...but aren't sinew backed hunting bows vs. sinew backed flight bows apples vs. oranges?
Not really. Plenty of folks back in the day hunted with their flight style bows. The style championed by Bob Martin and Nelson Hoffman was essentially a flight bow.
Also Chester Stevenson shot a broadhead over 300 yards with a more flight style bow at the inaugural Pope and Young shoot back in the 30s.
Now folks get giddy with over 200.
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I'd like to see what bow was used, or at least the style of bow. Was the arrow weight 10 gpp, or was it shot into a hurricane?
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:)
Some day we might just re-crack the illusive code to incredible, unbelievable numbers. Keep building, boys.
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:)
Some day we might just re-crack the illusive code to incredible, unbelievable numbers. Keep building, boys.
We already know the code, folks have just been scared off by the "save your bow from breakdown" fear mongering.
Back then guys shot them out and made another. The odd thing is that the people most into saving their bows from stress probably make and discard/retire more bows than anyone else.
Sleek, The bow Stevenson shot over 300 with was a heavyish draw Yew recurve. Likely of somewhat shorter length and probably overdrawn too. He liked heavy draw weight and heavier arrows but undoubtedly the arrow was still less than 10gpp.
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So saying he shot his heavy weight/over drawn bow 300 yards and we get excited about 50# bows shooting 200 yards isn't really a fair comparison.
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:)
Some day we might just re-crack the illusive code to incredible, unbelievable numbers. Keep building, boys.
We already know the code, folks have just been scared off by the "save your bow from breakdown" fear mongering.
Back then guys shot them out and made another. The odd thing is that the people most into saving their bows from stress probably make and discard/retire more bows than anyone else.
Sleek, The bow Stevenson shot over 300 with was a heavyish draw Yew recurve. Likely of somewhat shorter length and probably overdrawn too. He liked heavy draw weight and heavier arrows but undoubtedly the arrow was still less than 10gpp.
Thanks for the clarification Pat.
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So saying he shot his heavy weight/over drawn bow 300 yards and we get excited about 50# bows shooting 200 yards isn't really a fair comparison.
Perhaps not but it's also well beyond the current unlimited self bow record. ;)
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I found these numbers on-line. I see a lot of 300+ self bow numbers, unless I am reading it incorrectly?
Unl English Longbow 371-1-4 / 339.65m Alistair Aston 08/??/07 *
50lb English Longbow 318 - 2 - 5 / 291.52m Dan Perry 09/07/07
35lb English Longbow 259 - 0 - 3 / 236.92m Brian Perry (Youth) 09/07/07
Unl Primitive Self 350 - 0 - 11 / 320.31m Scot Perry (Youth) 09/08/07
50lb Primitive Self 340 - 0 - 6 / 311.05m Dan Perry 09/08/07
35lb Primitive Self 233-0-3 / 210.37m Scot Perry (Youth) 08/03/02
Unl Prim. Simple Composite 351-2-4 / 321.72m Dewayne Smith 09/06/03
50lb Prim. Simple Composite 326-1-11 /298.67m Bert McCune 10/08/94
Unl Prim. Complex Composite 619-1-7 / 566.50m Don Brown 10/07/95
50lb Prim. Complex Composite 321-0-8 / 293.74
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The Stevenson shot was a broadhead shot, not regular flight like the list you posted.
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Seems crazy that a broadhead can take a 150 +/- yards off a shot from the same bow and arrow? But, I'm a simple hunter and don't shoot arrows past 15-20 yards very often.
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A broad head arrow would weigh much more? About how much?
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The broadhead classes have weight, feather and head limits which have recently been tinkered with a bit but the regular flight class is less restrictive. That can and does drastically change distances.
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A sinew backing can improve performance. Design plays a part but so does moisture. I wouldn't use a sinew backed bow for hunting up here because it's too humid
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Pat the current unlimited broadhead class is 298 yds I think. Somewhere around a hundred pound bow I think. Just what was the sinew record in the thirty’s? 301,307, 327? This could get revisited in say 6 weeks! Ok I took the bate. Arvin
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Ok Pat here is the low down. I shot my 50# selfbow 239 yds to break my 223 record. I built some bows for others also. The best broadhead shot from a90# bow 287 yds.The young man lacked about 3/4-1” getting it all the way back. I built a 68# bow that a lady shot for the team . It shot a broadhead 288yds. 54 yds past my established record from last year. Go figure. Gets me . Maybe Chuck could shed some light on the sinew backed bows he shot there. I think he shot some 70# bows. Don’t remember his shot distances. I understand the stretch in the sinew and how it pulls the bow back in place and should put more tension on the belly. Just some test guys. :BB Arvin
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Good shots. What are the arrow weights for these classes? Is it a set weight regardless of bow weight?
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Pat the arrows had to way at least 450 grains. I think the 90# selfbow arrows would go 575 gr. To spine properly for the bow. The 70# selfbow arrows was probably closer to 450-470 gr. My 50# selfbow was close to 460 gr. Also the 70 # bow was heavy in mass compared to Chucks sinew backed bows. Oh well. Arvin
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congrats Arvin!
As far as the sinew backed vs selfbows...we decided at our local shoot to allow the backed bows in our selfbow class as long as the backing is 1/4 or less of the total limb thickness. I have made and shot both and don't see the sinew as a big advantage, but more as protection. My pre-profiled and thinned bamboo backing on an osage belly might be a different story, or at least it seems that way to me.
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congrats Arvin!
As far as the sinew backed vs selfbows...we decided at our local shoot to allow the backed bows in our selfbow class as long as the backing is 1/4 or less of the total limb thickness. I have made and shot both and don't see the sinew as a big advantage, but more as protection. My pre-profiled and thinned bamboo backing on an osage belly might be a different story, or at least it seems that way to me.
This caught my attention. It doesn't seem right to me at all. This is for flight shooting, right?
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congrats Arvin!
As far as the sinew backed vs selfbows...we decided at our local shoot to allow the backed bows in our selfbow class as long as the backing is 1/4 or less of the total limb thickness. I have made and shot both and don't see the sinew as a big advantage, but more as protection. My pre-profiled and thinned bamboo backing on an osage belly might be a different story, or at least it seems that way to me.
This caught my attention. It doesn't seem right to me at all. This is for flight shooting, right?
No DC this is target shooting
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congrats Arvin!
As far as the sinew backed vs selfbows...we decided at our local shoot to allow the backed bows in our selfbow class as long as the backing is 1/4 or less of the total limb thickness. I have made and shot both and don't see the sinew as a big advantage, but more as protection. My pre-profiled and thinned bamboo backing on an osage belly might be a different story, or at least it seems that way to me.
This caught my attention. It doesn't seem right to me at all. This is for flight shooting, right?
I mostly hunt with my bows, but a few times a year I 3D shoot with them and a couple of times a year I flight shoot with them... with my personal bows, I get more distance with the bamboo backed bows than I do with the selfbows or the sinew backed bows. This is just me and my personal bows. If I need a bow to grab, string, have morning coffee, and leave strung all day in most any weather...and never worry about drawing on a deer, I carry my bamboo backed bow osage bow. It always shoots the same and doesn't take time to return to the original unstrung profile... in heat and humidity, my sinew/snake backed bows might take an hour to return to the original unstrung profile...just my personal observations. My hunting BBO has been shot thousands of times but over a hundred people and still shot 211 yards at MoJam with a 10gpp arrow...
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congrats Arvin!
As far as the sinew backed vs selfbows...we decided at our local shoot to allow the backed bows in our selfbow class as long as the backing is 1/4 or less of the total limb thickness. I have made and shot both and don't see the sinew as a big advantage, but more as protection. My pre-profiled and thinned bamboo backing on an osage belly might be a different story, or at least it seems that way to me.
This caught my attention. It doesn't seem right to me at all. This is for flight shooting, right?
No DC this is target shooting
Ahh, now it's OK ;D ;D ;D
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I used a sinew backed Rocky Mt juniper sapwood bow this year and it holds the current record for 70# simple composite flight at about 343 yards( official measurement might be a couple yards off ) and 70# simple composite broadhead at about 262 yards. It's 59.5" ntn and draws 67# @ 28". Modified Ishi design. recessed handle, 2 3/8" wide above the handle tapering to 1/2" below the nock. Backed with 3.5 layers of elk sinew it holds a 5 3/4" unstring reflex. The bow is light weighing a total of 17 oz. Juniper is no match for bow woods like osage as a self bow, but Juniper and incense cedar are in my opinion the best compression woods out there. So with a sinew backing juniper goes from a brittle 2nd rate bow wood to a top bow wood/sinew combo. In my opinion juniper and incense cedar wood make the best examples of what sinew can do.
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Great shots Chuck . Glad you posted the distances. And yes the mass on the seventy pound Osage was almost twice that . Arvin