I have been studying the section in Adam?s book where he documented the different measurements of old bows. I am starting a turkish bow project and have just finished shaping the bow and am now going to apply sinew. I though I was ready until I weighted the bow. With out sinew the bow came in at 295g. If the sinew/glue should be 1/3 of the mass this was going to be one heavy bow and I would guess heavy = slow as I am aiming for just a 50-60 pound bow. I worked the bow down to 245g which after sinew/glue the bow should come around 370g. Should I take more material off? The bows length is 34 inches with 3mm horn. In Adam?s book it appeared that bows weighing less than 100 pounds had a mass under 300g. Has anyone weighed their bow? I would like to compare different bow lengths, mass, and their weight.
Stephen Selby
I have had a chance to examine some Han to Yuan period bows in China last week. I am struck by the fact that the ancient bowyers kept their siyahs much narrower and lighter than most modern work being displayed by friends on ATARN. I think this is an area where our bow-makers need to focus their skills and increase their confidence.
In early (pre-Ming) bows, I see a lot of use of sinew wound obliquely around the limbs at the splices, or even throughout the whole bow. That suggests a line of exploration: that wound sinew provides a lighter-weight route to structural strength than massive components and long glued splices.
jkekoni
I would sat that the ears were lighter, since the professional bowyers had spent much more time collecting skill than the hobbyists of this day. Narrow ears are more prone to sideway bending etc... It also may be that the bowyers of today favor lighter woods.
Alternatively theory is that you compare real bows with pictures and they do not look the same..
Sinew has lower elastic modulus (stifness) than wood, so I fail to see reason to put it much longer than what is used to reinforce splice joint... unless the bow has bending ears.
Alex S.
Stephen would the bows you are describing have short splice than what you see modern bowyer using?
I understand the use of narrower ear, the alignment must be perfect and cross section well thought to create strongest but lightest ear. If alignment is not perfect it almost does not matter how good the cross section design is, it must be made more massive to resist side ways bend. Probably why modern bowyer makes them bigger since they are more forgiving to this.
I became interested in the limb wrapping after seeing the reproductions of the Scythian bows. If such narrow cross section can resist this side ways bend by simple wrappings, I think it should be looked into more, possible secret into making lighter joint between the limb and ear.
Stephen Selby
Yes, the overlaps at the splices were probably shorter. I think the issue of over-built siyahs is not a lack of skill but a lack of confidence. A lot of thought is being put into places where bows commonly fail (the splice adjacent to the grip or the splice adjacent to the siyah) and the quality of the gluing and sinewing. That is all correct; but the outcome will not be pleasing if the siyahs are over-weight.
Bow-making is not easy. You can't drop your attention to anything. :cry:
jkekoni
Stephen Selby wrote:
I think the issue of over-built siyahs is not a lack of skill but a lack of confidence.
...yes, both are related the amount of time spent/ number of bows made...
Bow-making is not easy. ... :cry:
Composite bow making, that is...
jkekoni
The scythian design did not survive the test of time. I think this not a coninsidence.
All the designs that survived until the era of gunpowder follow the same pattern:
1. recurve ear
2. horn belly in sal
3. sinew backing
4. rigid handle
T?rkish,tatar,qing,korean,crab,persian. I think they are all the same, just with different details.
... Except ...
Native american non core horn bows and Javanese horn self bows...
Native american ones survived due to lack of competition, tool techology and decent horn availability.
Javanese full horn bows survived due to climate uncompatible with sinew.
Adam Karpowicz
Perhaps the ancient bowyers did not have to be concerned with the liability insurance and could afford to relay on the archers' skill in the use of the bows?
As to the mass of bows: a lighter draw weight bows will not follow the 1:3 ratio of draw weight to mass. This ratio applies to the shorter 42-3 in ntn bows of heavier weight. Bows below some 60-70lb had more mass.
Adam
Stephen Selby
Adam Karpowicz wrote:
Perhaps the ancient bowyers did not have to be concerned with the liability insurance and could afford to relay on the archers' skill in the use of the bows?
Adam
Good point. Lucas Novotny (the US one) makes horn bows to fine tolerances and won't agree to sell to people who he considers don't know how to use them.
