pcsol

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Although I have been a builder for more years I care to reveal , I have never focused on a WWI subject seriously until now. I am in the process of building a 1/3 scale Pup and a debate has come up amongst my cronies about the correct method for scale rib stitching on a WWI fighter. The question is this:
Did the builders of Ally fighters (Sopwith and their sub contractors) use a cloth strip over or under (or both) on the rib stitching as in the more modern day cloth covered aircraft ? I have seen several beautiful WWI scale models with the "pink" tape method used and doubt that such a technique was used on these most early of warbirds. Am I wrong? Perhaps a plain edged strip was used to cover the stitching? anyhow, I know somebody out there must have the real answer to this! And I would greatly appreciate it !

PS: I have also seen a few full scale reproductions of Sopwiths with the modern method used that don’t really qualify for true scale subjects.

BigglesFliesUndone

Hi pcsol, You are correct in that pinking tape was not used on WWI aircraft. I have attached a picture of Hendon's (UK museum) Sopwith Camel .. which I believe is correct , You should be able to work out the stitching spacing from the pic too.

BobH

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The good part about the stitching tape is that it wasn't pinked as biggles has stated. So this means you can tear strips of cloth and not have to worry about the "pinking". I do believe that the tape is torn along the bias (?) to prevent unraveling of the threads. I found an interesting series on the net that deals with fabric covering. It has a lot more information than you probably want to know but it never hurts to learn huh lol.
http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/99c827db9baac81b86256b4500596c4e/$FILE/Chapter%2002.pdf

Hurri

I have a 1/3rd Pup & done proper rib stitching , took a while but was concerned that over the years if the pup survived - was worried if only glued to undercamber it might get unglued , so stitching makes sure it stays put . Re; the pinking , I read that early on pinking type was used
but sometime in WW1 they changed to just straight tape . Think the full size stitches are every 3" , so Think I done one every inch , was every 3/4" on my 1/4 scale planes

pcsol

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Thanks Gents.
Good point about the undercamber Hurri.
Great pic Biggles!
Certainly proves the point. Although I lose the argument to my friends :-( ( I had argued that they used nothing at all to cover the stitching) it certainly does appear that a strip of material was indeed doped over the stitching. It would be interesting to know who first created this technique since it was such a short time from the very first aircraft up to the early fighters of the war.
Bob,
Interesting to note that in the covering doc you linked too they describe 4 stitches per inch ! guess back in the big one the rule was more like a stitch every three to four inches ! safety not a factor...

abufletcher

Bob, interesting document. I had always been a little unclear on the actual function of rib stitching -- i just figured it was something do to punish scale modelers! Anyway, this document answered that question: "Fabric should be attached to aircraft components to prevent ballooning due to aerodynamic forces..."

I'm glad all WE have to do it SIMULATE it!

BigglesFliesUndone

You havn't entirely lost the argument I believe the tail end of a few aircraft ..think mostly German ..didnt have tapes
Thats the problem and beauty of this era ..you have to dig deep in your research ..even then most is "speculation". Example is Pinking tape. Its commonly recognised that the French started using it in early 1920's ..however pinking scissors were around long before then .. some folks think a few later WW1 Fokker's had pinking tape .. and they may or may not have , but noone as far as I am aware has produced photographic or remenant proof (hard evidence) There is plenty original pics of straight tape .. or no tape as case may be

I have built many undercamber wings and covered with solartex only, no balsa loc etc. It has never come unstuck, however I appreciate I live in a climate best described as "moderate". I cant answer for hot humid climates

Hurri

One of the main reasons for the tape over the rib tops was that there was a double thickness of cloth on ribs , if only one & the cloth wore thru thu the rubbing contact on rib then the extra was an extra precaution of the whole sheet of covering letting go !