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Chips with everything


Nev
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I bet everybody with the CNC wood kit has assembled these 4 bits of wood and thought Hmm ! Me too, they are very loose fit.

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Having decided on a 3 part wing build however I had to make a centre section. So spent quite a bit of time drawing vertical lines on everything and making a nice square jig. Then taking a deep breath, take the already assembled bits in one hand and apply glue with the other. Smartly putting it back on the jig to square it up before the glue start to go off. I used a polyurethane adhesive so it foamed into the joints. Now it’s done I’m pleased with it, although it was a bit of a faff. I also added a temporary brace across the back to set the height and hopefully to stop me braking it again.

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So now I have these bits all ready and can do this.

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It’s not glued up yet, just checking it all fits. I want to do a bit more on the wing panels, fit servos and make flaps before permanently fitting them together. But it looks like it’s going to work and I should be able to jig it straight, so feeling a lot more confident.

Nev.

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  • 2 weeks later...

These are fiddly things too put together, didn’t particularly enjoy this bit. All the ribs are set at a different angle ( apart from one, which was much too big ) which means you have to twist the leading edge down onto the rib as the angle gets more acute as it gets toward the tip.

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Never made flaps / ailerons like this before, so presume this is normal. When you unpin it from the board the leading edge straitens out and puts a twists on the aileron. I was a bit worried by this as I was building it, convinced it was all going to go in the bin. I am not sure if the twist is for some form of washout, it has that effect, or if it just follows the shape of the wing as the ribs get narrower.

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But it all seems to line up and follow the wing shape. So now I’ll do the other side and if I get 2 the same I’ll assume it was all some sort of clever design and get on with the next bit. Not getting much time on it now though, must be the time of year.

Nev.

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Hi. It's hard to describe, every rib has a different leading edge angle and the angle gets more acute as you get to the tip. Cut parts match the plan both are the same, try overlaying the last on the first, it's about 2 degrees rout to tip. I'll try and measure it later but it is intentional. I only noticed it when I stacked the ribs together and you can see a progressive change.

I built it pined to the board until all the cap strips were on but you either get a twist in the aileron or if you built it rock solid you would set the twist in the leading edge. Now it's built it looks right because as the ribs get thinner the trailing edge of the aileron lifts to match the line following the underside of the rib. It "looks" like washout.

Not describing this well, I'll try and take photos.

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I understand you too Nev, and immediately went and looked at the ribs on the plan, and as you say they do alter as far as the leading edge goes from root to tip. Perhaps the wood I used was very soft as I didn't have to exerpt much pressure to bring the leading edge into contact with the ribs, in fact I don't recall any pressure. Relying on the twist of the leading edge would be too hit and miss for a designer, as this would depend on the stiffness of the wood used. As I said mine was very soft. The best way is to build the ailerons with the wings and only seperate them once sheeted. This is a common method of ensuring the washout in the wing matches that of the aileron.

However as long as the twist is the same you will be fine, it is acting as washout which is no bad thing. Provided the sides match

Cheers

Danny

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Thanks chaps. I think a lot of this is optical illusion and a bit of my inexperience.

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This is what got me worried, if it shows up. Built up I saw what I was expecting, a twisted aileron.

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I tried to line this one up a bit better and the bottom is flat, the top leading edge tapers in toward the tip so enhances any twisting.

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I still think there is a twist, maybe not as much as I imagine, intentional or not I don’t know but like you say if they both come out the same I’m happy to use them.

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smiley Before this the only built up ailerons I have made have been dead flat built out of 1/4 square, so this is a bit of a change. Luckily I cut all the wood for both sides at the same time, from the same sheet, so they should be the same.

Apart from moving a rib or two so I can reposition the horn to match my servos that is devil

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Cheers Charles.

I think that is exactly the problem with this plan. If it had a few notes just to let you know what the end result should be, most folk would be happy to just get on with it in there own way. Don't get me wrong I'm not criticizing, I couldn't draw it, but I have to spend twice as long thinking as I do building.

Having said that, after this I don't think there is anything I wouldn't consider. Assuming I could get it in the shred devil

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  • 3 weeks later...

Hi all, I hope everybody has had a good start to the New Year and long may it continue.

Not much building for me, well actually that’s not quite true, maybe I mean not much to show for it.

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Did have a day or so off though and managed to get into the garage in daylight so got the metalwork done. I found some thin steel sheet, 0.6mm thick, a bit more substantial than a bean can but still workable.

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Servos are in so its only a bit of sheeting and a couple of hinges to go !! Soon be on to the fuselage. Nev.

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  • 2 weeks later...

Enjoy the fuz he said, I’m sure I will when I get to it. Actually I’m not rushing into that bit, want to get as much of the wing done as I can. If anybody thought they were short of space…

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Anything’s possible. Had to borrow the dining room table to sheet the underside.

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It may look precarious but its well nailed down.

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Which all helped to get a dead straight wing, no twists and equal dihedral (ok about 4 mm out but that’s good enough for me). Port side one day, stbd the next and back up in the office today before anybody noticed.

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I know its not correct for scale but an 8mm LED is about the right size for the navigation lights, needs a bit of work to make them look right.

Fuselage by the weekend I think John, then I can catch Nigel up.

Nev.

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