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oipigface

How to unplug sticky wings?

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oipigface
4 hours ago, pete beadle said:

When the airframe was returned to you, was it covered in dirt and grime? but particularly were there any GREEN marks indicating plant growth, mould etc?

Did you clean it up first, to be better able to inspect the damage?

I'm trying to account for this stickiness by thinking that perhaps there is some sort of vegetation growth starting in the cracks activated by the soap and water(?) used to clean it?

I have only cleaned the tailplanes, to see if they would ever fly again. I think they would, but I think the plane would be better with new ones.

I haven't tried cleaning off what dirt there is on it, and I don't know what the finder cleaned off it. This is mostly sort of muddy dust, and pine needles. I suspect it might have spent most of its time under the mulch that you see on a forest floor. There is no obvious sign of algal growth or mould, but then such things are very often microscopic.

I've looked out some threaded rod, and I'm going to buy some iron angle and a couple of steel rules, to make a more robust version of my wooden device. In the meantime the plane is in a spare bedroom near a radiator, and the Dremel is waiting....

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isoaritfirst

Calm down Pete! 😚

John knows what he is doing - he's done enough repairs to know whats involved if he does slice and dice.

Its not an Extreme measure at all , its not irreversible, (with the exception of needing a new joiner) its just a simple repair. I've done more as a field repair.

The model has a hole in the wing that needs a repair as well, and this will not phase John at all.

Sometimes cutting out can give you a simple quick repair, with significantly less hassle and without the risk of doing unknown damage by poking and pushing for days with a less structure plan.

Which will give first with a push/pull on the wing root?

The joiner loosening, or the wing root collapsing, or possibly damage to the joiner box. As well as dents in the wing skins.

If this was a wood fuselage would you not cut it out and get  on with the job,

To those of us used to working with epoxies - its no different, splicing in, is easy and successful. 

Its not sacrilege it not against any engineering principals its just a day to day repair, that once completed will be invisible and as strong as the original. 

 

 

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pete beadle

Hi Mike

Thank you for your reply

I stand corrected, but have to say that what you describe as everyday repairs scares me stiff at the thought of it

I find that, usually, mouldie users seem to be turning to replacement parts from the manufacturers rather than repairs in most cases, and considerations like cost seem to be largely secondary

When I built my own gliders I happily worked with wood and glass fibre, but the thought of doing what I did with those planes simply doesn't extend to my moulded ones

I never intended to imply that John wasn't capable of this type of major repair, just that I wasn't, and wouldn't even consider doing this the way you describe, I was trying to be helpful but, if my comments have offended I will now stop and leave the whole thing to John, as you say, I'm sure he  knows best

Regards

Pete

BARCS1702

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Phil.Taylor

hacksaw through the incidence pins first, before the joiner - then you'll know if it really is the joiner that's stuck

Phil.

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isoaritfirst

Not offended Pete - your experiences differ.

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Bobbyr

If its hydro locked , as said it wont come off ,

                      so drill a small hole through the wing at the end of the joiner box , 4 mm Diameter will do ,  this will allow any water trapped inside to come out and Air in to allow separation at the end of the joiner , and a small hole will be easily filled , just an idea Mate , not very destructive either . Incidence pins are usually ST/ST or Tool steel , doubt they would rust to be honest

 

                                     Bob

 

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isoaritfirst

IMG_1297.jpg.c6a79d18d47c6a82633f067c4f596a38.jpg

wing joiner is hollow so hydro lock would seem less likely. but could be released by drilling into joiner at the centre.

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isoaritfirst

I recall when I had my Jaro Muller Elita, I was convinced that Muller quality would not require the joiner to be fettled so I pushed it harder into the wing than I should. 

I could not pull it back out.

Eventually as it was just one panel I clamped the joiner into my wood vice and pulled/tapped.

No hydro lock just good old friction, can be tuff.

 

Pulling may well be imparting a degree of sticktion as the pull is unlikley to be square. again I have experience pulling hard to no avail then a lighter but more controlled square pull releasing items like this. 

Tapping is a far better way. it will not suffer from the same side loads, or cause gather in the materials. 

Not sure if "gather"  would be a problem with a carbon joiner but thinking about rubber handlebar grips, trying to pull them off is hopeless but tapping a spanner on the inner edge will remove them effortlessly.

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oipigface

Meanwhile, I am in a pub recalling today’s visit to B&Q, where I bought 1m each of steel I-beam and  20mm square section tube and two steel rules. 

From these and some bits of threaded rod I hope to devise a machine that will deliver a straight and controlled pull on the wing. Before I use it though I’m going to see if I can’t drill a hole in the joiner tube through the servo cavity. That way, I don’t need to damage any visible surfaces.

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Frosty

Have a look at screw fix hedgehog easy air wedge 140Kg of push and no damage 

 

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oipigface
3 hours ago, Frosty said:

Have a look at screw fix hedgehog easy air wedge 140Kg of push and no damage 

 

Looks like they are 2mm thick before inflation, and I've got only 1.5mm. Good idea, though, which may be useful if I can get the extra 0.5mm! I wonder how accurate that 2mm is?

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Frosty

Found this on you tube 

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Scram

Those Winbag type "tools" are great.  I have a couple and they make removing/replacing doors a doddle.  Amazing what you can lift with them.

John, if the load you apply to the wing root face is right up against the joiner you will be applying force down the joiner box structure rather than the root rib.  Probably difficult to achieve effectively but less likely to break that rib.

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oipigface

Can you measure how thick yours is (deflated), please, Jerry? I've only got 1.5mm at the moment, and I'm reluctant to fork out on a bag or two unless I can be sure that I can get it into place.

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Tone-the-glider

If you have a gap between the wing roots and the fuz? even a small one. could even file a bit off the fuz the make the gap wider. 

Then try sliding in as  wide as possible flat steel plate in both sides  (something hard like spring  steel)

Then  using a pair of (the sliding the type that can have the plastic faces reversed)  clamps between both plates to slowly ease the wings appart.

image.thumb.png.f1c73efc7151631cb5e499dc65995eb7.png

 

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Tone-the-glider

Here is a better pic.

 

image.png.673c756e6f375f0c109047a5b3ec453f.png

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Tone-the-glider
12 minutes ago, Tone-the-glider said:

Here is a better pic.

On second thoughts, I dont think you will find  clamps that will close down small enough to fit between the  steel plates.

A hole drilled through each of  the plates with a nut against the inner side, with a bolt through against the opposite plate. Then slowly and evenly tighten the nut to ease the plates apart  

image.png.673c756e6f375f0c109047a5b3ec453f.png

 

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oipigface

Thanks for your suggestion Tony. It is more or less what I have been using unsuccessfully, only I've used screw clamps. The force I need seems to be greater than normal for the problem to be solved simply. Very rigid supports for the blades are also necessary. I've put the plane next to a radiator in a spare bedroom in the hope that dryness might be part of the solution, and in the meantime I'm fitting the lighting in the back of my van.

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Scram

Hi John, sorry for the tardy response to your request - just seen it.

Thickness varies a bit.  I squeezed it with my digital caliper and got 2 adjacent edges down to about 1.6mm.  I would not want to say it will go much thinner but with some lube may be persuaded into the gap.

The bag is made from a single sheet folded over and welded on 3 sides.  One side weld is definitely 2+mm thick at the edge but you may well get the corner in or could maybe shave the thick weld down a bit.

You can borrow one if needs be.

 

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Scram

Have you got 'em off yet, John?

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