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158. Blowing Bubbles and Trailing Along

25/04/2015

Most of the week has been concerned with getting the fuselage fabric ready for doping, but now that’s done, we’ve been able to make more progress with other things.

First was to check the fuselage internally. Once the fabric’s laced up an doped, you really don’t want to remove it. It’s very difficult to get the tension exactly as it had been, and the fabric shrinks when you take the tension off it, meaning that if you leave it loose overnight, you may never get it back on again!

So I waited until Rick was available, and we went through it carefully, bolt by bolt, wire by wire, strainer by strainer. I would have said that there was nothing left to do, but we found at least half a dozen bolts with nuts missing, or of the incorrect type, or not sufficiently tight, so it was a very valuable exercise indeed!

We then applied Waxoyl to all the bolts, wires, cables and so on in the rear fuselage in a bid to limit the onset of rust. Originally it would have been lanolin, but Waxoyl looks identical and has better preservative properties, we’re told.

With that done it was time to put the fabric on for the final time. I’d also fitted the ply hoops round the footholes, and these look great.

The foothole in place

The foothole in place

Then today we moved on to checking the fuel and oil systems for leaks. You do this with an air and soapy water test. We made a little adapter plate to sit on top of the filler caps with a short copper tube that Rick could blow into, while I used a paintbrush to apply a 50:50 mixture of Fairy Liquid and water round all the joints in the each system in turn. If you agitate the brush well in contact with the surface, it forms a skin of bubbles that will immediately blow big bubbles in the presence of a leak.

Pressurising the fuel system. Despite what the picture shows, this is a test of the fuel system, not the blower!

Pressurising the fuel system. Despite what the picture shows, this is a test of the fuel system, not the blower!

We found two or three leaks this way, so once again it was a very satisfying and useful exercise. Think how much harder it would have been to fix the leaks once it was full of petrol and oil!

And then the trailer arrived.

2015-04-25 Trailer outside

Keith and Kevin Edwards have done a magnificent job on it, and we are absolutely delighted with it, and spent the rest of the afternoon fixing the frames in the side doors which will hold the wings. We didn’t quite manage to finish it this evening, but we’re very close and another hour or so on Monday morning will see the job done. The enormous rear door is nicely balanced with a spring and works fine. The side doors are very heavy, and we expect we’ll need some sort of assistance to be able to operate them safely, but until we get the frames in place and loaded up with wings, it’s hard to say what will be needed.

Finally, we successfully managed to manoeuvre it inside the hangar, which was part of the plan, but it’s always a nice surprise when it works out.

2015-04-25 Trailer in the hangar

It can wait for a week or so, as this next week is a last all-out effort to get the aircraft complete and ready for engine runs. The dope for the fuselage will arrive (fingers crossed!) on Monday, and we’ll be splashing loads of coats on there. We need to apply the roundels to the wings and the stripes to the rudder. On Wednesday the film crew will film the assembly of the whole aircraft as a time lapse, and thereafter we’ll need to check the fuel flowrate.

And then roll it out and see if we can start the engine…

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From → Building, Technical

3 Comments
  1. As I recall from my industrial chemistry days some 30 plus years ago the likes of Waxoyl are (or at least used to be then(!)) predominantly lanolin with various additives to make it work/behave better. So you’re pretty much in the right spot anyway.

    We recently found some fragmentary records which suggest my grandfather used to work on Scouts amongst others in France. If only he were here I’m sure he’d love to see your plane and be able answer some questions, but I bet you say that yourselves often enough…

  2. Wan Berasategui permalink

    waiting for the dope, it will be great!

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