Wing is now well under way - and I decided to up the pic resolution a bit
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2" extra thick boxing tape on the outside of all bend lines - I've decided this will also have to act as spar for any negative G's.
And Iv'e done my experiment with the Strapping material as spar. Ended up OK, but there were a few leaning experiences involved:
1) Hotglue applied to the strip should be spread instantly to rather thin a layer as fast as possible. I did a bead down the middle, and result was that I had to heat the strapping so much that it started shrinking a bit! You can see the warpage at one of the ends. I managed to keep it to a minimum by sort of balancing the heat constantly moving the covering iron from place to place while slowly stepwise making the hotglue melt and spread out under the strip, but it was too tricky to call a recommendable method. At one of the ends I had tried spreading the glue first with mixed success (waited too long before trying to spread it), and that went on far easier.
2) The panel warped a bit due to the shrinkage. I ran the covering iron across the strip again in a very slow fluid motion from the center outwards, and that relieved the tension and let the panel go perfectly flat again very nicely.
3) The covering iron was a bit of a mess of hot glue afterwards, but a thourough rubbing with some paper towel took care of that ever so nicely.
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Then I creased and folded over the LE. First crease by pressing a ruler edge into the fold line, really get that sucker in there with force, the panel should lift it's outer edges from this. I went and creased the 2 wing top fold lines right away as well, as I was not sure whether they would be fully accessible after bending the LE. Then I flipped the wing panel over with the top side up and hung the bottom side out over the table with the LE over the table edge, stacked a bunch of books on the wing top part to keep it in place and very slowly bent down the bottom side panel to 90° doing my best to apply the force evenly along the length of the panel. You only bend it, say, 10-20° a time and you can sort of feel the foam giving in to the force applied after a bit of time; then you can give it another 10-20°. If you rush it the tape will split and the foam will crack.
The I removed the books, flipped the panel over again and continued to fold the bottom panel over till the top and bottom panel were flat on top of each other. Then I put the book back on top and let it sit overnight. Could have had taken more pics of this process, but was clear out of extra hands folding the foam.....
But here's a pic of the resulting leading edge:
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This morning I removed the books.
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I got the shown piece of wood from the shed and used it to do a bit of pre bending on the 2 wing top bends.
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I glued the spar in - smear, wait to tack, lay down and apply pressure while the glue cures - last I did by laying the wood piece on top of the spar and stacking books along the length of it. Gave it a couple of hours to cure.
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Then I applied a bead of glue inside the LE, smeared glue on the spar and wing top underside and closed the wing. Wood on top(moved it bit back to get the wing top to be perfectly flat on the spar) and book to keep it in place.....the another couple of hours of curing time.
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Finally, I've just glued the rear edge of the bottom panel. I decided to use a different glue for this, as UHU-por is best when there is a lot of surface to make the bond. I used PATTEX 100%, You can see the bottle on the table behind the wing.
Here are a couple of pics of the final panel airfoil and leading edge:
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I had expected the bottom to be more flat, but this slight upwards rounded lower front could very likely cause the wing to have a greater speed range and glide ratio than I would have first expected - again, can't wait to fly it. And I am quite satisfied with the straightness of same LE.
Next is the polyhedral, a fast radio install and then it's hopefully finally time for maiden!!