14th August 2014 - Spats and brakes

The Tailwind has taken something of a back seat recently however, finally some progress.
Some time ago I bought a pair of second hand Vans' spats. These are the original non-pressure-recovery versions. These were drilled for fastening to some sort of mount on the inner side of the wheel and onto the axle nut on the outside. The challenge then was to fabricate some sort of mounting bracket and fasten it to the airframe in some way.
Before I could start I needed to find some way of jacking up the wheel so I could work on the axle. I found a bit of spare steel tubing of about the same diameter as the undercarriage leg. This was cut in half and some scrap plate welded on and drilled so it could be clamped to the leg. Then a bit of angle iron was welded on at an angle so that a car jack could be used to lift the wheel. This works well but marks the paint so I will have to line the inside with some rubber.
The spat mounting plate needed to be kept clear of the brake disc so 1/2"-long spacers were cut out of some steel tubing. The 1/4" bolts that secured the brake mounts were then replaced with longer ones to take the spacers. A bit of scrap aluminium was then progressively cut to fit the bolts and clear the brake caliper. The wheel was then replaced and  the spat test fit. Holes were drilled in the mounting plate and the spat clecoed into place. This was then repeated for the second gear leg. The spats were positioned so that they were horizontal with the aircraft in normal flying pitch.
The development mounting plates were then removed and a final version drawn up on the computer in Cambam. Then the CNC router was used to cut final versions out of some 2mm 6061-T6 aluminium sheet.  Nut-plates were riveted into place for the spat mounting screws and the plates mounted in place. They will have to come off again to be painted.
AN822-4D right angle fittings were installed in the top of the brake calipers . Finally, some 1/4" soft aluminium tubing was bent and cut to make the brake pipe. The ends were flared, making sure that the AN nuts and sleeves were in place first. The brake pipe will be taped to the rear of the undercarriage leg and covered by the leg spat. The loop of pipe is to ensure that flexing of the leg will not break it.

11th November 2013 - Painting, painting, painting...

Despite the lack of posts I have been working over the last few weeks. The left wing has been completely painted and once fully hardened wrapped in bubble wrap and transported to my friend Paul's house for storage. The doors have been finished inside and out. Also, all the flying surfaces have now been finished to a good standard.
The learning points from doing this are interesting, First, the EkoPoly has a very definite shelf life. Trying to use it beyond this is doomed to failure! The newer EkoPoly Premium paint is much easier to apply without runs.
I'm painting in Insignia white, it is hard to get a full colour coverage over the grey EkoFill or charcoal grey EkoPrime. However, a thin coat of the smoke grey EkoPrime makes it much easier to get an even, high gloss, white finish.

11th October 2013 - Left Wing Painted

Over the last few days I have finished applying the EkoFill and EkoPrime to the left wing and have now sprayed it with the white EkoPoly. This hasn't been simple, it seems that as soon as I get enough paint on to get a gloss runs start to appear. The bottom of the wing actually sprayed up quite nicely but my first attempt at the top was so bad with multiple runs that I washed the paint off completely before it had time to harden - thank goodness for water based paint!

Thinking about it, my suspicion is that there had been some surface contamination in areas of the surface. So I sanded the whole wing with 320 grit open coat sandpaper and then washed and rinsed it thoroughly. My next attempt at the top surface was better but I was too sparing with the paint and didn't get a full gloss so this was cut back with the sandpaper to create a key, cleaned with isopropyl alchohol, and then today another coat was applied. This time I got a good gloss. Note the way in which all the fabric edges have completely disappeared. There are a couple of small runs that will need sanding and polishing out but basically the left wing is now finished. I'll let the paint harden for a few days and then I can get on with the right wing.

28th September 2013 - Left Wing Top Surface UV protected and Primed

Today I started the task of painting the wings. As I've covered in ceconite I need to hide the fabric edges. The picture shows the way the lower fabric wraps round the wingtip. This creates an edge along the cut surface. Following advice from Jason at Stewart, I started by appying the usual three cross coats of EkoFill which provides the UV protection to the fabric (I'll reduce this to 2 on the underside of the wings). Then EkoPrime was applied along the leading edge and sanded, prime and sand, prime and sand... until the edge of the fabric was completely masked. The rear joint in
the fabric is on the trailing edge behind the flap/aileron so that needs no particular attention.

27th September 2013 - Left Wing Covering Complete

I decided that I would try and get the second wing covered as quickly as possible - so I put in a 10 hour day today and it is finished! - next to paint the wings.

26th September 2013 - Right Wing Covered, Left Started

I finished off the right wing today and then it was my wife's turn to help me re-organise the garage. The wings are awkward but not too heavy. First the left wing was removed from the garage, then right wing was stored against the wall, finally the left wing could be placed on the saw horses for covering.
I won't bother repeating the same pictures for the covering of this wing so it will be a few days before the next post.

25th September 2013 - Right Wing Bottom Covering Glued

Today I shrunk the bottom covering into place and then glued it in the same way as the top. The tips and trailing edges have been made off so tomorrow I can finish the leading edges.