Gansu, Niya

Redhorse · Post by **Redhorse** » Tue Oct 28, 2008 1:18 pm

When working on the f-d curve I remember the Gansu bow. It has two bending parts.
My thinking is, if the limb bends in the beginning and store heavy weight till the ear start to come around and the draw length is normally reached, if we draw more the bow explode. But if the other bending part in the siyahs starts to bend and give longer draw length, would we not have a longer power stroke and store more energy?

Stephen Selby · Post by **Stephen Selby** » Wed Oct 29, 2008 3:57 am

After having seen and handled many of these Niya-type bows, I can now say that there was only one working part of the limb.

Grozer has made an exact replica. Its effective draw-length would not be more than 30". The arrows with it bear this out.

S

Redhorse · Post by **Redhorse** » Wed Oct 29, 2008 7:17 am

Ok, but would it have work if it had two working parts?

Dwanyin · Post by **Dwanyin** » Wed Oct 29, 2008 4:12 pm

Stephen Selby wrote:After having seen and handled many of these Niya-type bows, I can now say that there was only one working part of the limb.

Grozer has made an exact replica. Its effective draw-length would not be more than 30". The arrows with it bear this out.

S

The picture from http://www.atarn.org/magyar/niya.htm showed that the Niya bow had two working parts though.

Stephen Selby · Post by **Stephen Selby** » Thu Oct 30, 2008 2:41 am

Dwanyin: yes it did say that. And I drew that picture, and it was wrong.

Back to the question: what if I had been right?

My view: it would not have been a bow with two working parts to each limb; but a bow with two working limbs with a useless bit of sold wood adding unecessary weight in between them.

What is of much greater interestis the width of the limbs, which exceeds anything that I have seen.

Redhorse · Post by **Redhorse** » Sat Nov 01, 2008 4:47 pm

But would it be totally wrong if bow had two working parts?
We been told that a Turkish bow should bend a little at the kasan eye. Can it be done more accurate? Say limbs bend to 80 lb and then the kasan eye starts to straighten. It would give longer power stroke, or?

Adam Karpowicz · Post by **Adam Karpowicz** » Sat Nov 01, 2008 8:50 pm

It an`interesting question. A bow with two bending parts would have the high string tension at brace = high early draw weight. But the transition to the onset of bending in the second part would be gradual, not abrupt, so the resulting f-d curve would not differ much from a bow with totally rigid siyahs. Actually I would expect such bow to stack earlier in the draw for less energy storage. It is beacause the second bending part is higher up in the limb and closer to the tips. A bow with bending more concentrated towards the grip will store more energy.

Adam

rwelch · Post by **rwelch** » Wed Nov 05, 2008 5:35 am

Wow ,how do you get a horn strip that wide ? or was it side by side strips on each limb? And do you have any idea what that bow's draw weight was ?

Stephen Selby · Post by **Stephen Selby** » Wed Nov 05, 2008 12:48 pm

It was five strips of horn. The draw weight of the exact reproduction was 50 lbs at 30"

S

Orda Khan · Post by **Orda Khan** » Wed Nov 05, 2008 5:00 pm

Are there any pictures of the reproduction?

Alex S. · Post by **Alex S.** » Wed Nov 05, 2008 6:29 pm

Mr Selby

Is it possible that a draw of longer length was used? The bow is quite long in length it seems at 162 cm, maybe they drew it to 34? I don't know, but it seem it would get more out of such design.

Redhorse · Post by **Redhorse** » Thu Nov 06, 2008 3:53 am

I have had my thought about that to, why put in so much effort in a bow that just draws 50 lb. It can be done with almost any stick.

jack farrell · Post by **jack farrell** » Thu Nov 06, 2008 4:03 am

A wood bow in the Taklamakan desert would be most unreliable. A #50 bow tested in HongKong might be a different animal in the desert. It would only have to be slightly better than your enemie's. -j-

Alex S. · Post by **Alex S.** » Thu Nov 06, 2008 11:34 am

Mr. Farrell

That is good point, I did not think of that!
Gansu would be very dry indeed, almost impossible for local woods to be durable, or at least more durable than a horn bow.

Though, I still believe this design could be taken a bit further. The wide limbs seem to be designed for lesser stress and the length would seem to lend itself to long draw.

Also, as you say the climate varies quite a bit between the two places. Right now, the humidity in Hong Kong is 92% while its only 15% in Gansu. Quite big difference, it equals to 21.6 EMC in Hong Kong while being as low as only 3.6 EMC in Gansun. At this level, I think the hickory would even fail. This would also make the sinew shrink much more, and make the bow much stiffer. Perhaps we would see some rise in draw weight, maybe 30#? more? I cannot say, I don't know enough about moisture change or the bows of composite.

Redhorse · Post by **Redhorse** » Thu Nov 06, 2008 1:43 pm

I see, environment. Can make big difference. How does a hornbow like temperature below freezing?