Empennage Fairings and Rear Window

The rudder bottom fairing patch has cured.  After filing down the high spots and giving it a quick sanding, I applied some epoxy/microlight filler.  The leading edge of the fairing also needs to be built up a bit to match the rolled leading edge of the rudder.

I also added some filler to fair in the horizontal stabilizer and elevators.  Here’s the right side.

…and here’s the left.

I removed the rear window because the masking tape I applied a few years ago was all dried out and stuck tight.  I used some mineral spirits to soften the adhesive and removed all of the tape.  This took much longer than expected, but I wanted to use a mild solvent to avoid damaging the plexiglass.  After reinstalling the window, I laid a line of tape to mark where the Sikaflex primer will go.

I’m going to paint the inside of the rear window where it passes over the roll bar support channel.  I’ve noticed on other planes that it’s often fairly dusty on top of the channel, and it’s pretty tight against the window, especially toward the back.

After the horizontal stabilizer and elevator filler cured, I filed and sanded it down so that they’re faired together nicely.

I needed just a little bit more along the leading edges of the elevators.

I also sanded down the filler I applied to the bottom of the rudder.  There were a couple of low spots, so I added a little bit more.

Skim Coated Empennage Fairings and Prepped Canopy Frame and Roll Bar for Painting

I skim coated most of the empennage fairings with straight epoxy to fill the pinholes and scratches from the sandpaper.

I then started prepping the canopy frame for painting.  First up is to rivet the canopy bow to the side channel.  I then bolted the canopy latches in place so that all of the hardware will get painted.

I masked off the areas that shouldn’t get any paint, then scotchbrited everything that needed paint.

I riveted the roll bar support channel onto the roll bar, then scotchbrited the whole thing.  I used the scotchbrite disc in the die grinder to make all of the rivets completely flush to the surface to make sure they can’t scratch the canopy.

Riveted Canopy Latch Handle Bracket and Lock, Drilled Lower Left Empennage Fairing

I riveted the mounting angles that hold the canopy latch handle as well as the lock.  I removed the lock’s cam so that it doesn’t get painted since it would just immediately get scratched up.  Afterward, I primed this area with some self-etching primer.

I also drilled the lower empennage fairing to the fuselage and horizontal stabilizer.  The two holes in the fuselage go through the longeron and replace a couple of rivets.  I’ll add standard nutplates here just like the forward holes in the upper empennage fairing.  The rear nutplate in the horizontal stabilizer goes through the flange of the rear spar, and I can use a standard nutplate there as well.  The forward hole just goes into the horizontal stabilizer skin, and the inner rib would make it a pain to install a nutplate there.  My plan is to order a couple of Click Bond adhesive mounted nutplates to install here.

Unfortunately, the fairing doesn’t fit perfectly.  The vertical flange fits nice and tight against the side of the fuselage, but there’s a fairly large gap in the middle between the fairing and the horizontal stabilizer.  I’m going to spend some time with a heat gun to see if I can reshape it to fit better.

Painted Remaining Interior Components

I thought I still had some interior paint left over, but it had gone bad in the can.  I called yesterday and had to have a quart overnighted to me.  It came today, so I wrapped up the painting.  Here’s the inside of the cabin where the sidewall will be visible behind the interior panel.

Here’s a bunch of the smaller parts with final paint.  I might end up having to reshoot the roll bar support channel cover since I think some dust settled on it.

Here’s the canopy frame.  The red stripe along the arch is some electrical tape that is masking off where the Sikaflex primer will go.

Here are the roll bar and support channel.

I also mixed up some epoxy and skim coated the final parts of the empennage.  Here’s the rudder bottom fairing.

And here’s the top of the vertical stabilizer.

4 Hours for 4 Ounces

I’ve tried to take every opportunity to shed weight out of the airplane.  The canopy latch was a solid bar of aluminum that is 5/8″ thick, so it was fairly heavy (nearly 10oz).  I stopped by the TechShop to try to lighten the part a bit.  You can see here that I machined out most of the structure. It’s now under 6 oz, so I saved about 1/4 lb. This is the bottom side, so the top looks untouched.

I was having a hard time keeping the latch handle clamped down since it’s such an awkward shape.  While machining the inside edge, the part shifted and I almost cut through one of the most visible faces.  It took nearly 4 hours to do this, almost half of which was spent trying various methods to clamp the parts down to keep them from moving.  1 oz per hour is easily the most time I’ve spent trying to save weight on any part of the airplane.

I also masked off around part of the floor that needs to be painted to match the carpet since parts of it is visible around the seats.  I’ll paint this first thing in the morning…

Painted Under Seat, Finished Sanding Control Surface Fairings, Finished Drilling Lower Empennage Fairings

Well, this sucks.  The replacement can of paint doesn’t remotely match the original color they sent me.  I’m going to have to call them tomorrow and probably send a sample down for them to match.  I was hoping to start installing the canopy today, but this probably delays that a week.  Oh well, I have plenty of other things to work on.

I painted the floor a dark color that pretty closely matches the carpet.  It doesn’t have to match exactly since you only see tiny bits of it.

I finished sanding all of the control surface fairings.  These are ready for a coat of primer.

Finally, I drilled the right side lower empennage fairing to the horizontal stabilizer and fuselage.

Sanded Canopy Components

I received the correct paint color from Stewart Systems (I hope), so I sanded down all of the components I previously painted.  Some of the components had some dust or overspray on them anyway since I sprayed them flat, so I’m glad I’m repainting them anyway.

The canopy frame was the worst to sand because there are so many nooks and crannies.  I still need to wipe everything down with solvent before spraying, and I’m sure I’ll need to put on at least a couple of coats, so painting is going to have to wait until tomorrow night.

Installed Roll Bar

I installed the roll bar for good tonight.

Remember to install the AN509-10R10 screws that are hidden behind this skin before installing the roll bar.  I only installed the lower AN509-8R8 screw completely since I need to be able to flex this skin back to install the rear window.

There are a bunch of fasteners to install inside the roll bar.  It’s a pain to reach in here, but I managed to get everything in place without too much trouble.

I also shot and bucked the rivets that attach the roll bar support channel to the aft fuselage.  There are 8 AN426AD4-7 rivets tying the top skin, baggage aft wall bulkhead and roll bar support channel together as well as a few more AN470AD4-4 rivets tying the channel to the bulkhead.

Finally, I installed the canopy support channel cover for good.  I need to paint a few of these AN509-8R8 (or shorter) screws and replace these at some point, but that can wait for now.