"Stealth Pilot" wrote in message
...

the items in question are the tailfeathers of a 4 seat radial engined
Yak. (yak 18T I think it is)

we're not sure whether we are following original factory work or
someones abortion.

the rib caps have a section like ----v----
in the centre of the v there is a hole every inch.
it appears that instead of following english/american practise of
tying the ribstitch around the rib from top to bottom and tying off
each loop individually the ruskies have taken two adjoining holes and
stitched button style around and around, then moved to the next pair
and stitched around and around and so on.
the top stitching is only along the top rib cap.
the bottom rib stitching is only along the bottom rib cap.

are we looking at factory original stitching or is this something that
subsequent refabric work has done?

if it is the original ruskie system it produces a very neat rib
treatment.

Stealth Pilot

I admit that my personal knowledge of rib stitching is essentially nil, but:
1) what you describe could be done easily with a "sail needle"
2) it would give the "benefit" of a clear area and no risk of fouling, and
3) as Veeduber pointed out in an adjacent thread, the loads are small.

So, I don't know either, but it could very well be a factory solution:.

There was a two seat YAK in the local EAA chapter, so I'll try to ask.

Peter