Bows that bend against the growth rings? Scythian bow?

[Tom Dulaney]

Hello,

Is there such a thing as a bow that bends perpendicular to the growth rings? The cross sectuons of most bows look like figure (a) of the following picture. I want to know if it is possible to build a bow with the growth rings oriented like figure (c). We could think of this as being like the way the growth rings are oriented on a siyah.




Am I wrong for thinking this is how the the lower bending wooden "cores" of the Scythian bows from Xinjiang were built?

http://www.atarn.org/chinese/Yanghai/Scythian_bow_ATARN.pdf

[Pat B]

Board bows have all three ring configurations.

[Tom Dulaney]

Board bows have all three ring configurations.

Interesting! I am ignorant about board bows. I was predicting that someone would tell me that a long, narrow bow (narrower than it is thick) would be too unstable, but the lower bending portion of those Scythian bows were narrower than they were thick. They had a reinforcing horn laminate in addition to a hidden horn core. So I guess it is feasible, then. Wow, I never knew this... Blows all my suspicions away...

[High-Desert]

The oldest bows found in Europe were configured like that.  A limb split, and that used as the back as opposed to the first ring under the bark. The stellmoore and holmgaard bows.

[PatM]

Board bows have all three ring configurations.

Interesting! I am ignorant about board bows. I was predicting that someone would tell me that a long, narrow bow (narrower than it is thick) would be too unstable, but the lower bending portion of those Scythian bows were narrower than they were thick. They had a reinforcing horn laminate in addition to a hidden horn core. So I guess it is feasible, then. Wow, I never knew this... Blows all my suspicions away...

  You can't view the deflexed inner limb of the Scythian bow in the same manner as a bow of regular configuration. They are pre-bent so that the curve is  much more established before the bow is even strung.

[Holten101]

The oldest bows found in Europe were configured like that.  A limb split, and that used as the back as opposed to the first ring under the bark. The stellmoore and holmgaard bows.

That is a common misunderstanding, but the Holmegaard bows were not "backwards". The misunderstanding originates from misinterpretations of the archelogical drawings of the artefacts (Bowyers Bible got it wrong, but so have many others). There is absolutly no reason to belive that the barkside was not the back of those bows.

Cheers

[bradsmith2010]

 

[Pat B]

 

[PatM]

If you look at the actual artifact it's just a normal bow.

 Undoubtedly decrowned bows were made and a decrowned sapling turns into a double bias or edge ringed stave as soon as you do that.

[Del the cat]

WOAH!
You asked about grain orientation, then suddenly you are talking about narrower than thick
"I was predicting that someone would tell me that a long, narrow bow (narrower than it is thick) would be too unstable"
Those two concepts have nothing what so ever to do with each other.
Of course narrower than thick is unstable, and that's why it tends to only used for non bending levers.
An English longbow is relatively unstable due to the aspect ratio (pretty narrow relative to thickness) and because of that needs some careful tillering in the early stages.
Del

[mikekeswick]

As long as the grain is straight the orientation of the rings doesn't matter in a wooden bow.
For a hornbow core you should use flat ringed pieces as wood is stiffer laterally in this orientation.
Hornbow cores and selfbows have very little in common

[Tom Dulaney]

WOAH!
You asked about grain orientation, then suddenly you are talking about narrower than thick
"I was predicting that someone would tell me that a long, narrow bow (narrower than it is thick) would be too unstable"
Those two concepts have nothing what so ever to do with each other.

This is true, but if you look at the diagram I posted, you will see that it is a specimen of those dimensions.

And this is also the case in Scythian bows. I simply found it difficult to believe that a bow of this shape could have the the growth rings oriented in that direction, on a bending limb.

Although Pat pointed out that the limbs are deflexed, the Xinjiang-type Scythian bow is still under more pressure than other bows, despite this.

[bradsmith2010]

more pressure,,?

[Del the cat]

"... but if you look at the diagram I posted, you will see that it is a specimen of those dimensions".

Nope. I see an inadequately labelled and ambiguous diagram.
It takes a lot of imagination to make a) look like the cross section of "most bows"... in fact one has to totally ignore the dimensions to make it look like the cross section of almost any bow...
I'm not trying to be argumentative, but one need to explain carefully if one is to get sensible responses.
Del

[davidjw]

The article says that the core was made from saplings that were then split to add the central horn strip, so I think one can assume that the grain was pretty vertical.  As Mike said, flat grain is typically preferable in horn bow cores for stability, so perhaps the central horn strip helped with the stability issues of having vertical grain in the core.  I don't think grain orientation would have much effect on the amount of stress the wood in a horn bow core can take, if this is what you meant by being 'under more pressure,' it is more of a stability issue.