Scary wing covering …. I love Oratex !

This was one of those evenings that you skirt around for ages and in the end think … well “No one else is going to do it for you” !

So I took the big 1.8m roll of Oratex out of its protective covering and unrolled it over the prepared underside of the Top Port wing. Trimmed to length and let it hang out over the sides. You then need to set an alignment level on the leading edge .. following PHS expert advice 🙂

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You need to pre glue both the wing and the material and then leave for 24 hours to go off. Use the alignment notes below to lightly mark the underside of the material so you know wher to glue up to. NOTE A biro WILL show through for ever more ! so light pencil is best

Also – try not to over glue as this will inevitably show at the overlaps.

As noted below – the leading edge p,y sheeting and trailing edge give a good sized surface to prepare BUT it’s well worth making sure you don’t leave bubbles of glue to dry .. These don’t flatten easily when ironing and, on the slightly bigger surface areas like the leading edge can show through as air bubbles … A pain to work out after the event ..

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Once your 24 hours drying is up re present the covering to the wing ….use masking tape if you don’t have spare hands as I didn’t … Spare hands are MUCH better .. Cos they respond to comments like .. Can you pull that at 45 degrees !

The lower covering wraps just over the midpoint of the ply covered leading edge. As the full leading edge ply has been glued it provides a lot of surface area grab. The leading edge is then ironed into position using masking tape securing points across the full leading edge to make sure the material doesn’t slip during fixing. It’s also good practice to clamp the trailing edge where you can to get the whole covering as flat as possible before fixing the leading edge.

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Once the initial line is set and ironed and cooled you can bring the heat gun into play (130 degrees not 150 as its wood which doesn’t conduct the heat away to any degree). This is where the funny little Oratex pad comes massively into play. As you heat the material and the glue starts to react, it also heats up the glue surface on the ply leading edge underneath. The Oratex felt mat lets you work relatively small areas to ensure you are bubble free and get a really solid bond as you work it back to the trailing edge of the underside leading edge.

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Leave the whole lot to cool at the leading edge and trailing edge joints .. If you start to get excited and try to shrink it in the same evening it can pull away … Shrink rate of 20% makes it pretty tough

The next evening .. You can start the shrinking exercise .. And boy this is where you just fall in love with this material … Such a joy as all those saggy bits and wrinkles fall away and leave a fantastic sheen and tight finish.

Again I left it to ‘settle’ so that I could do a little more heat gun before masking up again ready for the top layer of Oratex .. Mask so that you get a good overlay AND the finished edge is well in the ‘downstream’ of the planned airflow.

NOTE – the finish you leave on your first (underside) layer shows right through the top layer .. So .. Put a wobbly first line and you will be looking at it forever ! even through the pinked 4″ doubler tape !

Bring the top sheet over the lower sheet and use masking tape again if your ‘talking hands’ aren’t available …

This means you effectively butt the top layer against the nice straight edge of the lower layer and then cover with a 4″ reenforcing strip.

One admission here ! – I had felt that the leading edge was very smooth BUT … any small pimple of glue of polyuerthane will show through the top surface so well worth a very light pre sand to ensure that is smooth as the proverbial ….

Wing glueing

Preparation for tonight’s first wing covering panel

Had a chat with Paul re the best way of covering the wing ie where the joints should go and where the overlap fits etc so you don’t have VPL ! (Visible (panty) Precision Lines !)

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Will add pictures as I unroll all that Cub Yellow and start fitting 🙂

Busy night last night – Wing covering prep …

Its only when you step back to minutely review things that you spot bits ! ‘walking’ through the first plan to cover one of the wings undersides and I realised I had missed making and fitting two material landing ply plates around the bracing wire supports on both upper wings !

Quickly re-found the template and made two up last night. Fitted in place, feathered, treated with thinned polyurethane.

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Then, as the covering will wrap around the wing tips I need to make sure the tips are a good ‘easy but tight’ fit so that the material doesn’t prevent a good fit.

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A small amount of trimming was required and I reckon the material will make it a comfortable fit

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The bolts showing upper right picture are for the small angle brackets I made to allow tips to be screwed on and so removable for later inspections.

Also covered last tailplane surface last night – ready for pinked edging now

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Port Tailplane

Second tailplane underway last night … noticed the small shoe iron seemed a bit colder so started using the heavier duty iron which seemed to do the trick

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Published these pictures so that others dont panic when the material looks creased on application

Port upper aileron …

Slow but steady progress ! Just wish I had the work and life time to spend the next 2 weeks just finishing !

Anyway …

First aileron laid out, and material marked and cut and pre glued for tonight … will get into a sequence of prepping and gluing then heating 24 hours later so all 4 ailerons by the weekend.

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You also realise that what you thought was a nice smooth aileron has little bits here and there that you need a fine rub down so that nothing shows through the covering. The ailerons had already been prepared some months ago with a thinned polyurethane so ready to take the Hotmelt glue.

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First tailplane covered

Been a busy week with lots of other flying going on – pups from Lydd, pups from Southampton, double early drop offs in Alderney this morning ….

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Managed to get the first tailplane covered last night .. definately an art to get the material nice and warmed so that it goes around the curves nicely !

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Once the heatgun has taken a little out the flat iron works a treat to finish it off

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Panel wiring and prep and Fuel tank cable run

Decided to run these back to the panel last night but sheath it first to keep it tidy.

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Also, having tried a couple of routing options, I decided to ‘hide’ it under the longerons so that the passenger didn’t see a cable running alongside them ! and feel the need to play with it !

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More dismantling last night – Tailplane

Having completed the rudder and elevators I started removing all the tail fin wire bracing and took off the starboard tailplane, having first marked up all the cables I lovingly crafted so many months ago

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I could then see I had missed one piece of waxoyl on a joint .. this could now be covered ready for the re-assembly.

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Now I could complete those small ply material covering landing plates at the leading edge of the tailplane.

‘Plane looks quite ’empty’ with no tail feathers now 😦

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Made me realise the re-assembly sequence is going to be interesting … not sure how that might work so will need to call Paul in Norfolk !

Oratex – ongoing – getting the hang of it now :-)

I have been a little quiet on the blog front but like all swans .. frantically peddling away under the surface !!

Having now completed 3 surfaces of Oratex (rudder both sides and one lower elevator covering) I think I am finally getting the hang of things … It may mean a week offline in the winter clag to recover the rudder as I’m not 100% happy with the finish having managed to get a large wrinkle in that even 18% shrinkage wouldn’t pull out – leaving me with a small (but noticeable) crease by the rudder post. Yes I could lose it by putting the pinked capping tape over it but I know it’s there !!

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The elevators, completed in the wee hours this morning, have helped me get a routine that makes the pre shrinked finish much much tighter and on first application of the heat gun your get a fantastic taught sheen finish !

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Next steps – Tailplane …. before the larger wing and body rolls arrive 🙂

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