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Warped wings (and other Qs)


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About 17 years ago I started building a glider kit in the cellar workshop at my old house, but then lost interest in the hobby. The wings warped due to damp and I packed the thing away. I fished it out of the loft the other day in my renewed enthusiasm. It's funny.. I could have sworn it was a Multiplex Flamingo, but it's actually a lovely Sitar Special 100". Much too nice a model to give up on.

Anyway, the wings are warped, one not too badly but the other is warped badly along its trailing edge. Has anyone got any advice on how I might straighten it out? I was thinking I'd thoroughly dampen the wing with water from a plant-mister then clamp it along the trailing edge to a flat worktop for a week or so?

What do you think?

I've also lost the wing joiner. It was simply a flat blade of steel about 7/16" x 1/8" x ?". Where might I buy a strip of steel to cut a length off?

Also, I'm puzzled at the method of securing the wings (I've lost the instructions). In this pic you can see a screw-in eye and there's one on the other wing. How would they be secured?

http://i46.photobucket.com/albums/f103/Sloper59/IMG_1726.jpg

Cheers

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Hi Sloper

I Guess the wings are balsa sheets covering wing ribs ??

If they are and it was me i would cut the sheeting off the warped wing see if this helps if not i would cut out the ribs, trailing and leading edges until the warp is out then reglue and resheet it.

i know this sounds alot of work but its better to find the warp and correct it. also it shouldnt take you that long maybe a few days then you know for sure you will have a nice straight and true set of wings

By the picture looks like there is a rod or strip to locate the wings and the eyelet to me looks like you rubber band the wings together in the body of the plane but of course i havent seen what the body looks like so this couldnt help ??

Rob

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Hi Rob,

 Nope, the wings are foam and glassed under the veneer. I should have said, sorry. I wouldn't have thought a glassed wing would warp but there you go.

From left to right of the pic is a locating peg (incidence peg?), then the screw-in eye, then the slot for the wing-joiner, then a tube for ballast.

The fuz is accessible under the canopy at the front but not where the eyes on the wing-roots enter it

http://i46.photobucket.com/albums/f103/Sloper59/IMG_1730.jpg

Cheers

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Flat steel bar should be available from the DIY sheds - or builders merchant - or use hard grade aluminium from many online suppliers including RS. I would have thought the eyelets were for rubber bands too.

Many of these older types had nothing actually holding the wings together other than friction on the main steel rod wing spar /joiner.

My old SAS schizo had such a method, but I didnt fancy it and inserted two aluminium "tabs" one in each wing half, these overlap in the middle of the fuz and a bolt screws through them for extra security.

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Open up the eye into a cup-hook shape, then get a length of something like 12 swg wire or an old bike spoke. Bend a hook at one end to pass through the holes in the fuselage, and a loop to act as a handle in the other end.

on the slope, slide the first wing onto the joiner part way, pass your wire hook through the fus from the other side, and put bands between this and the wing hook . Pull the bands through the fus, which will pull the first wing tight against the fus on that side. Now lift the wire up so that you can slide on the second wing far enough to wriggle the bands from your wire hook onto the wing hook, disengage the wire and the second wing should be pulled into place by the bands. Alternately if the fuselage is wide enough, make a couple of small S hooks to join the rubber band and the hooks in your wing. You will still need something to stretch the bands through the fuselage though.

Easier done than described.

As for the warp, you could try spraying the balsa with dilute ammonia and weighting it down onto a flat surface, but if the veneer is glassed on it may be to rigid to work. Would it be worth trying a heat source to soften the resin through the balsa?

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I understood it too. That seems to be the only way to do it.. thanks.

Bob, what effect does dilute ammonia have? 

Good idea about using a heat source too. I'll go with the water or dilute ammonia first though.. it was damp that warped it in the first place so hopefully heat won't be necessary.

Cheers

Steve

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Eric Bray wrote (see)
Dilute ammonia - urine? Bit smelly, though!
Haha. That occurred to me too but I felt foolish to ask about it! I might try it if all else fails.. I'd just hope other flyers don't think the smell is from me.

Anyway, I soaked the trailing edge of one wing in the bath for a while earlier, and now it's clamped on the kitchen breakfast bar worktop. Good job I have an understanding missus

Cheers everyone

Steve
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