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O-Yumi?
May 7, 2006 18:17:09 GMT -5
Post by Hosokawa Sanosuke on May 7, 2006 18:17:09 GMT -5
anyone know anything about japanese ballistae? I always wanted to make a ballista but never had the chance until now, and since im aspiring japanese i figure I ought to see if there was anything like it on the nippon side of the equation.
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O-Yumi?
May 7, 2006 22:12:43 GMT -5
Post by liangjieming on May 7, 2006 22:12:43 GMT -5
No one knows for sure how the o-yumi looked like despite many, many references to it in japanese records.
I have written a short 1 page summary on the oyumi in my book if you like to read it.
Jieming
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O-Yumi?
May 9, 2006 22:12:34 GMT -5
Post by Hosokawa Sanosuke on May 9, 2006 22:12:34 GMT -5
arigatou!
I am even more mystefied by it now, i must make one.
I thought i had read somewhere about someone finding a firing mechanism of an O-yumi, anyone know about that?
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O-Yumi?
May 9, 2006 22:37:13 GMT -5
Post by liangjieming on May 9, 2006 22:37:13 GMT -5
Really? If someone has found an Oyumi firing mechanism, please, please let me know.
Jieming
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O-Yumi?
May 9, 2006 23:01:20 GMT -5
Post by Otagiri Tatsuzou on May 9, 2006 23:01:20 GMT -5
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O-Yumi?
May 10, 2006 9:10:40 GMT -5
Post by Otagiri Tatsuzou on May 10, 2006 9:10:40 GMT -5
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O-Yumi?
May 12, 2006 13:02:16 GMT -5
Post by liangjieming on May 12, 2006 13:02:16 GMT -5
Image 21.jpg is a modern sketch of the Sangong Chuangzi Nu (Triple-bow Little Bed Crossbow). This sketch has the winch afixed on extended upright rear legs, something which is not found in any of the source illustrations I've seen to date. (If anyone can find the source illustration this is based on, please let me know. I'm very curious to see where they got this from. A full sized replica of this is can be found in the Beijing Military Museum.)
In my book, I've done a short analysis of the stresses involved when the bowstring of the Sangong Chuangzi Nu is drawn, based on figures of draw strength given in source material, and I've shown that the winch on the upright configuration is not practical or feasible unless the frame is made very thick. Placing the winch directly onto the horizontal as can be seen in the illustration in 19.jpg is more practical.
Not sure how accurate Turnbull is, but he believes the Oyumi to have been a single bow affair and not a multiple bow arcuballista like the chinese arcuballistas.
Jieming
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O-Yumi?
May 12, 2006 19:39:06 GMT -5
Post by solveig on May 12, 2006 19:39:06 GMT -5
Noble Cousin!
Greetings from Solveig! Current Japanese scholarship about the oyumi appears in the book: Zusetsu Nihon Kasen Bugu Jiten ISBN: 4760125337 This book illustrates both Chinese and Japanese versions of the oyumi.
Historically, the term oyumi covers a range of crossbow like devices which fired either bolts or pellets. Infantry of the Chinese style imperial armies of the Nara and early Heian period were supposed to have been armed with the things.
Your Humble Servant
Solveig Throndardottir
Amateur Scholar
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O-Yumi?
May 12, 2006 22:49:09 GMT -5
Post by Hosokawa Sanosuke on May 12, 2006 22:49:09 GMT -5
what does the backward facing bow do in an arcubalista(sp)?
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O-Yumi?
May 13, 2006 11:47:50 GMT -5
Post by liangjieming on May 13, 2006 11:47:50 GMT -5
The backward facing bow helps increase the power of the bow. This innovation is what allowed East Asian armies to build arcuballistas that have been recorded to reach maximum ranges of 1000m. They built double-bow arcuballistas and then triple-bow arcuballistas. Incidently, Greco-Roman armies never learnt this trick and went the way of the torsioned sinew to achieve the same results.
How the backward facing bow increases bow power is dependant on the way the bows are strung. Joseph Needham's volume on Siege Warfare has a sketch showing the theorectical methods of stringing. I've done a similar sketch in my book but I differ from Needham's sketch slightly in one of the ways the triple-bow may have been strung, mainly from having experimented with a model and finding some ways more practical than others.
Jieming
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O-Yumi?
May 13, 2006 11:50:07 GMT -5
Post by liangjieming on May 13, 2006 11:50:07 GMT -5
I replied to this in the other thread. From the dimensions given on the excavated trigger, the overall length is only 6cm, the size of handheld crossbow triggers. An excavated arcuballista trigger from the Northern and Southern dynasties period found in China measured 39cm in overall length. I've posted a picture of it in the other thread, or you can find it in my book too.  Jieming |
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O-Yumi?
May 13, 2006 18:32:22 GMT -5
Post by solveig on May 13, 2006 18:32:22 GMT -5
Noble Cousin! Greetings from Solveig! The backward facing bow helps increase the power of the bow. I fail to see how the backward facing prod applies a forward force on either a bolt or a pellet. It appears to be coupled to the forward prods by a pair of chains. When the forward prods are in the cocked position, the chains should become loose. I expect that the rear prod is a kind of anti kickback mechanism on the forward prods allowing the use of heavier forward prods. Your Humble Servant Solveig Throndardottir Amateur Scholar |
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O-Yumi?
May 13, 2006 23:52:23 GMT -5
Post by Hosokawa Sanosuke on May 13, 2006 23:52:23 GMT -5
actually I think i understand it now, you are not using it for foreward thrust, if you string too many bows in series you would have to start decreasing the length of the bows, instead you are using it for outward force, away from the center, as this is what makes the string move foreward. you could technically speaking face the bow in any direction, its just the string that needs to be facing foreward.
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O-Yumi?
May 14, 2006 11:47:34 GMT -5
Post by liangjieming on May 14, 2006 11:47:34 GMT -5
Here's a sketch. Hope this helps.  |
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