Sunday, 23 October 2016

More right wing wing

After much discussion with the airframe guys at work on drilling perspex, I was none the wiser about using specialist bits or what speed to drill at!  I couldn't locate any suitable drill bits in the UK but importing a $3 drill from the US meant a £35 freight charge!  I therefore decided I'd have a go at grinding 1/8th and 5/32nd drills to the recommended 60 degree end with zero rake and see how it would work on a piece of scrap (an old side-screen from my MG). Behold it worked perfectly!  So I took the plunge and started on the landing light lens.

After masking the main lens area to try and minimise scratching, I match-drilled the 8 fixing holes through the wing skin and then marked the overall size of the finished lens using the plans instructions.  Drilling the holes before trimming should minimise the risk of a crack running from a hole to the edge.  Then I trimmed the excess material to within about 0.5 mm of the required size using the high speed cutting disk.  So far so good.

 The trimmed lens with edges polished and holes countersunk.  I used a coarse  sanding block initially followed by wet'n'dry paper stuck down on a flat surface and finally fine paper on a hand block.  This took about 3 hours!

 Next the screw holes in the skin are dimpled to match the countersinks in the lens.  The brackets are riveted in place and the previously installed wiring is terminated.  All wiring will be identified using heat-shrink sleeves.

 This is the view from inside the wing looking forwards, with the landing light fixed to the bracket and all wired up.  Just need to test it!

Finally the lens is installed through the front of the wing, with great care to prevent cracking.  I was fortunate that I could get behind the lamp to assist in lining up the lens with the screw holes.  I hope it doesn't have to come out in the future as there's no rear access when the wing skins are installed!

Now I can move on and complete the the top of the right wing.  I first needed to prepare the skins - file and polish all the edges to remove cutting marks etc and then prime the inside and all mating surfaces.  I also took the opportunity to prepare the walkway doubler and the wingtip lower skin.

Here I'm painting the outer surface of the right wingtip lower skin - just the tabs that will mate to the outboard wing rib and trim panels.  The inside of the skin is fully painted.

Here all of the prepared and painted main skins are lying roughly in place ready to be installed.    You may just see some of the yellow edges that'll be overlapping the adjacent skins, so need some means of keeping trapped moisture from the skin to prevent corrosion.

 Right wing inboard top skin cleco'd and ready to rivet.

 Inboard skin now riveted (excluding the walk-way area) and outboard skin ready to secure.  The leading edge can't be finished until the final middle skin is installed.

All three main upper wing skins completed and the wing-walk doubler ready to rivet.
You can see the additional wing ribs which are closely spaced to take a person's weight from the extra rows of clecos.  The leading edge along the whole wing is also cleco'd in preparation for riveting.

 The wing walk doubler completed.  Now just the leading edge of all skins to finish.

And finally all main skins completed! 

Just the wing tip now to complete for the right wing.  All the parts are ready including the fibreglass nav. light mount, so hopefully it'll be pretty straightforward.  After the wing tip is finished, I start on the flaperons.

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