Rebuild Thread - EF 104 Extra

As mentioned, I realised I needed to repair the bottom skin, so stripped the film covering from the bottom, this revealed 2 main areas of damage near the wing root. I cut out tapered pieces of new skin which covered the damaged areas, squared the edges with a Permagrit sanding block, then cut through the existing skin using the new bits as a guide. By making them tapered in width meant that they can be adjusted by pushing them in from the root ensuring a tight joint, once happy with the fit, I used pva to the ribs and spar then with the new sheet in position, thin CA run along the joints

Next I repared the wing tip and patched the bottom skin, again just using the old parts as patterns where possible, with measurements taken from the other wing.

Although I don't use them, I had to replace the blind nut and reinforcing plate at the front of the tip that is used to secure the SFG's, I might want to try them again in the future.

Bottom of the wing finished

Really good work Jon. Hand cutting bits out is slog work but necessary evil. I too was surprised that CA finds it's way through grease. I use Vaseline on the edges of surfaces when I am CAing hairy hinges, that seems to stop it sticking the control surface to whatever especially when a close fit is required and I have over done the "few drops" required.

I notice that your wings have square carbon tube installed. I might try that idea myself when beefing up a repair.

to the top of the wing, I have made a complete new wing skin from various 3in sheets of 1/8in balsa. Unfortunately I had to use a bit of lightweight filler as the sheets I bought were not very consistent in thickness.

The sheets are joined by edging with my trusty 24in Permagrit sanding block, course side followed by fine, the sheet is laid onto another sheet to raise it up a bit which gives a really straight square edge.

Once edged, I lay the sheets edge to edge face down, then working from one end, push the edges together and run thin CA along the joint using a fine tip on the bottle, I do about 2in at a time immediately removing excess with kitchen towel, I keep moving the sheet to make sure it isn't sticking to the bench. This is a really quick process as the CA goes off very quickly because of the tight joint. It typically takes a couple of minutes to do a full 36in sheet joint.

That's where I have got to so far. Next job is to jig the wing up to make sure there is no twist in it, i.e. the centre lines of the root and tip rib are parallel, then attach the new skin.

Good work Jon. I remember saying that after doing a job like this the realisation dawns that it would have been quicker to build a new one!

That thought struck me when I'd done a similar repair on my Impressivo after some gent had flown it through the hedge for me. He said he'd had a brown out but they all say that don't they?

No tasteless remarks please, Mr Bright.