I prepared the four wing joiners four our Elfe S3 last winter already. Now that we have the fuselage sizes I could do the sleeves around the joiner, that will go into the wings. These are made of woven kevlar, with a second string of kevlar wound lightly around it. I first made the wing joiner nice and greasy using bicycle grease (a really thick coat), followed by 1.5 rounds of clingfilm or thing plastic vegetable bag. The kevlar sleeve is epoxied around that. I then apply tear-off tape and hang a weight at the bottom of the sleeve and let it cure. Once cured, repeat that for the other side of the joiner.

I’ve started building the horizontal stabiliser. Although the stabiliser will be in two parts, we built is as one – including most joiners – separating it afterwards.

We cut the foam a few weeks ago and Georg made a great plan for building the stabiliser – as usual (all by hand – see the last picture below). I prepared the carbon and glass layup, to be placed between the foam and ebechi, applied the epoxy and put the first side in a vacuum bag for 11 hours. I then cut out the various openings for the 10×1 carbon tube with glass sleeve (main joiner for the two halves), balsa where the 4mm steel pin joining the two halves will come, as well as small brass tubes with the 2mm steel pin for the elevator control. I also cut out a foam strip, inserted it into a carbon sleeve, which will be where the elevator will separate from the tailplane. Also make sure you remove a bit of foam from the leading edge and add in some thickened epoxy, so that you can sand it into a nice leading edge afterwards. Plus I inserted small bits of plywood at the end of all three pins connecting the two halves to prevent that these pins are pushed through into the foam when building up the plane later on. Then I epoxied the carbon and glass inserts onto the ebechi, closed the stabiliser and again put it into vacuum for 11 hours.

Once fully cured, I carefully separated the two halves of the stabiliser and sanded back the ebechi and the leading edge into shape.