Another article on the Steppenkrieger bows

That's cool. Did I understand correctly that one has to send the snailmail orderform to have a copy of the magazine? I did not find it in the online webshop.

The webshop doesn't include this edition, so I would simply write an email to them. verlag(at)rgzm.de (just change the "(at)" to the a with the circle arround it).

The snailmailsheet is for a subscription of the magazine, to recieve upcoming editions, so I can't imagine why they won't help via email.

thank you for the link !

Thanks Amarutu! I just sent an e-mail. I will report on what to do to get a copy of the article :)

So, it turns out one can simply send an email to verlag(at)rgzm.de as Amarutu suggested, and ask for a copy of the magazine. It costs 14 euros, plus 5,5 euro for shipping abroad.

For those of you reading the article, I have noticed something that is important to bow builders. Each bow has two tables relating to it. One has general dimensions and proportions such as total length and how long each section of the arm is. the second is detailed breadth and depth measurements done with calipers and the using the CT scan.

The problem arises because the bows are not straight objects aligned with the axis of the scan. As you will see from the cross sections, the scans are sometimes through the limbs at an angle. This means mathematical corrections will need to be applied to the depth measurements on any part of the limbs that are not at right angles to the direction of the scan. In the accompanying photographs, the horizontal lines showing the position of each numbered scan also allow you to judge the angle. On the two Old Turkish bows, the variations are smaller, but on the Mongol bow, the tips are especially distorted.

Some of the drawn cross-sections may have been adjusted, but I think it would be best to check them yourself. The angles can be measured on the photographs and the actual depth can be calculated using trigonometry. Those of you that read the catalogue of the exhibition will remember that the measurements printed with the CT scan did not add up.

I haven't read the text yet in detail so this may be discussed somewhere. I was alerted by the cross sections of the tips of the Mongol period bow which showed the nock in one and seemed much too deep compared to the photograph next to them.

This is a valid point, but the tables show the measurements with a caliper as well, which had to be done across the sections correctly. Then the thickness of the bark wrapping can be subtracted. Actually, looking at the numbers the software corrections were probably made already, and the critical sections at the bending arms did not need them anyway. I would just take the total CT scan thickness/width for replicas. As I understand it, the CT total measurements are without the bark that could not be seen on the scans.

One number that is missing is the thickness of the Zargalant bow at the thinnest spot below the siyah. This measurement is not so important in the other two bows, unlike in the Zargalant, as their arms thicken past the midpoints of the arms. I also hoped to have the lengths measured at the sides of the bows, not over the backs again, which introduces errors depending on reflex or deflex.

It seems the heaviest bow might be the Chonot Uul with the arm nearly 17mm thick at middle and the greater grip reflex (100+lb?). The Cagaan Chad probably the weakest (70-80lb?).

Adam

Eagle eye Bede :wink:
I have read the manuscript again and they say that

- glue lines and bark cover are not covered in the CT measurements
- so the sum of CT thickness is always less than the caliper measurement

- the CT scans were 3D reconstructed (which is acutally an "easy" standard operation in medical CTs)
- they do not specifically mention this adjustment for thickness measurement, but write it done for angles of grip + sihays

so in summary I suppose the figures should be ok


Adam: so the heaviest bow was made from willow wood ? interesting.

8)

I am still also worried that where the CT scans are shown the diagrams do not match the scans. This was a problem in the catalogue too.

I have a program where I could scan in the photograph, match the measurement along the back and then rescale and measure the edge dimension. However, I think that Adam is probably right and there is no need to be so precise.

Bearing in mind that these are individually made bows, at best they can only give us guidelines for the correct dimensions. Each bowyer would have varied them depending on circumstances and the availability of materials. This might be the reason for the odd relationship between the ears and bending arms in the third bow. What also struck me was that the three bows were so close in overall length and that the handles also were within a couple of millimetres of each other.

I had same thoughts. the overall length is about same,
and there is slight asymmetry which is probably not intentional.

It also interesting that the horn-wood joint is flat (not convex-concave), and the sinew encases the wood in all 3 bows. there is a change from lenticular to semi-convex shape with the Tsagaan Khad bow.

I would really like to see the original CT scans. The one on page 184 of the catalogue shows a slight convexity in the core, which was neither used in the reconstructions nor reproduced clearly in the cross sections. Slight changes of curvature may not have been reproducible in the method they used for the drawings.

The ?argalant bow shows slight curvature on the core in the diagrams, but it and the other bows have pronounced convex bellies on the horn, which would give the advantage Adam writes about when gluing the horn to the core by providing more pressure in the centre of the lathe of horn and allowing the thinner edges to pushed in against the core.

The cross sectional drawings of the other bows are not really precise enough to find out how much if any curvature there is in the cross section of the core.