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.
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.
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.
I finish sanded the horizontal stabilizer fairings to 180 grit, so they’re ready for a coat of primer.
I temporarily bolted the horizontal stabilizer back in place and then added the upper empennage fairing so that I could begin positioning the lower empennage fairing.
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.
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.
Since the wingtip is held on with hinges, I needed a method to secure the hinge pins so that they can’t come out. I fabricated these retaining blocks out of a chunk of Delrin that I machined down to fit inside the trailing edge of the wingtip rib. It’s held on by an AN509-8 screw.
The screw screws into a nutplate mounted on the back of the rib and through the tooling hole that was already present in the rib.
In the sides of the blocks, I drilled a #43 hole and machined grooves aligned with the holes to capture the hinge pins. I bent the aft ends of the hinge pins 90º so that they will go into the holes.
Here’s how they look when installed. The hinge pins can’t back out of the block because they’re trapped by the flange of the rib. The block also provides a convenient handle to extract the pins.
With those done, I primed the backside of the ribs and installed them with epoxy/flox and soft rivets.
I also sanded down the additional filler I applied yesterday. I still need to apply some filler inside the gap, but the outside shape looks great.
I finished up the last of the wingtip reinforcement. I’m super happy with how this has turned out. It’s very light and the tips are substantially stiffer.
I needed to start fairing the rudder and vertical stabilizer, but I wanted to do it on the plane since it will be at a more comfortable working height. With the rudder bottom fairing in place though, the rudder couldn’t be mounted since the fairing hits the tailwheel spring. I measured and chopped off a chunk of the fairing.
This fits a little too tight at the front, so I’ll cut off more later. I can’t just parallel the tailwheel spring though since the spring can flex quite a bit. I need more room at the back to account for this.
I started fairing in the rudder and vertical stabilizer. You can see that there is now a continuous curve along the top and the sides match nicely. I need to add a little more filler in a few low spots, but this is turning out very nice.
You can clearly see the profile of the vertical stabilizer tip and rudder tip together don’t form a single continuous curve.
You can also see that the gap between them isn’t uniform. I’ll fill this later to create a uniform 3/16″ gap which is the same as the lower horizontal gap.
I mixed up some filler and applied it to both fairings. You can see that I built up the rudder tip quite a bit. I also widened the rudder horn about 1/16″. I’ll sand all this down with the rudder clamped in trail so that they’re perfectly faired together.
With the internal stiffeners glassed in, I could glue the trailing edge back together. I mixed up some epoxy/flox and put a bead down the back. I used a bunch of small spring clamps to hold the trailing edge closed while the epoxy cures. The clamp in the back is holding a couple of scrap pieces of aluminum angles and span the gap between the aileron and wingtip ensuring that the wingtip perfectly follows the edges of the aileron.
You can also see some epoxy/flox on the outer edge of the wingtip. I needed to add a little bit so that the outer edge of the wingtip could be filed to a straight line.
Here’s the cured fiberglass over the foam rod. This worked great. It’s incredibly light (just a couple of ounces per rod at the most), and added a surprising amount of stiffness to the wingtip. The Coremat I was going to add would have made it stiffer for sure (probably close to the stiffness of the cowl), but that would have been overkill. The wingtips simply do not need to be that strong and the weight penalty was excessive.
I’ve been meaning to reshape the vertical stabilizer fairing for some time. I originally installed the foam rib based on the shape of the tip right out of the box, and not how it looked relative to the rudder horn. Unfortunately, it turned out fatter and shorter than the rudder horn, so I needed to reshape it. I removed the old foam rib and used a clamp to squeeze it (making it both narrower and taller). I then used a heat gun to soften the epoxy so that it would take the new shape. I wrapped the rib in some fiberglass which will stiffen everything up a lot. I’ll still need to add a bunch of filler to both the fairing and rudder horn and sand them at the same time to fair them together.
While that’s curing, I added some foam rod and glass to the upper side of the right wingtip and then reinstalled it on the plane to set the curvature.