It’s been another bruising, tiring week in Dorset.
The plan was to get all the fabric attached to the flying surfaces and the ribstitching done, since a good deal of the ribstitching is a two-man job.
But it’s a bit more complicated than that. There are 11 surfaces; four wings, four ailerons, two elevators and a tailplane that my true love gave to me…
The previous week we’d also applied Waxoyl (which is based on lanolin, which they’d used originally) to the internal steel stuff. We’d used it originally and were delighted to find no deterioration in four years.
The actual flying fabric mustn’t touch metal at all, otherwise the metal will rust, and chafe through the fabric, so the leading and trailing edges had been re-wrapped wrapped with fabric, and the wood contact surfaces had had 1/2in tape glued to them – again, to stop any risk of chafing.
So this week, before we closed the frame off, they were very carefully examined, since you won’t be seeing them again for another ten years, with any luck.
The tail surfaces are closed off with hand stitching; Sue did the elevators as you saw here, and this week Theo’s brother Noel did the honours on the tailplane.
The wings and ailerons are closed by gluing the fabric to the structure (originally they used loads of carpet tacks, but they weren’t expecting their handiwork to last more than a few months). Getting the fabric to lie nicely against the surface you’re gluing to is time-consuming; inevitably it has to be led over a curve first, and the surface itself has cutouts and obstructions like aileron hinges. So it takes a while to work out how to cut the fabric to provide full cover, and the glue itself (called Super Seam) is not easy to work with. Inevitably you end up with a short temper and fingertips entirely encased in glue!
The next phase is ironing, which we also covered in the previous entry, and it’s generally rather satisfactory. It also enables you to iron out most of the mistakes you made at the gluing stage…
At this point, we tried applying dope to the elevators, and were horrified to find a ‘bloom’ appearing. It’s hard to see here, but the conditions were sufficiently damp that the clear dope picked up some moisture while drying and ended up with whitish stripes.
It was possible to remove them with liberal amounts of thinners in warm dry conditions, but we were very concerned that this would put paid to any further doping during the winter. we invested in a hired heater, and thankfully all went well after that, but it caused both of us a sleepless night, I can tell you.
We applied two coats of dope; the first is thinned 50:50 with thinners in order to ensure it penetrated the pretty tight weave of the fabric. we used a small 3 in roller and this seemed to apply just enough fabric to penetrate without causing drips on the inside. Theo had a couple of fancy face masks he’d acquired from somewhere and they proved invaluable in keeping us conscious despite the atmosphere thick with thinners. The second coat was full strength, and we used it to stick 1/2 in tapes to each of the ribs. These are needed for the ribstitching as you’ll see.
Ribstitching took place in the living room, and is a very long-winded process. The purpose is to positively secure the fabric to the frame, and involves using thick waxed thread (minimum breaking strength 14lb) to tie a series of loop round each rib at 2 1/2 in intervals. the tape we stuck on earlier makes sure the thread doesn’t simply pull through the fabric. Each loop has to be secured with a seine knot, which is the one fishermen use for making and repairing their nets.
First of all, you have to mark off the 2 1/2 in intervals down each rib, on both sides, ensuring that matching holes are opposite each other. then you start stitching with a giant needle, long enough to reach right through from top to bottom of the wing.
You push the needle through the first hole and then have to fidget carefully until the tip of the needle lines up with the hole on the other side. And once you get into the middle of the wing and can’t peer over the top, you need someone else to guide you.
Sometimes the holes line up with the internal bracing wires or other internal structure; if you’re not careful, the aileron cable, which is lying slack inside the wing, ends up on the wrong side of the stitches.
A seine knot is fiendishly simple, the operative word being ‘fiendish’. I’ve never heard Theo swear as much, nor he me. And it is a long, long process. The last two wings were done on Friday, and took the two of us 12 hours, only to find the aileron cables were on the wrong side of some stitches, so we had to redo those ones, which took another couple of hours.
But, finally it was done, and on Saturday we could concentrate on doping the ailerons and tail surfaces, and the stitching was finished on Sunday. Phew!