Category: Cabin Top

With the cabin top basically fitted, I finally gathered my courage and started to drill the aft end of the cabin to the top skin. I had a small mental block as this seemed like permanent step and I really wanted everything to line up perfectly. Finally got to the point where I had to get over myself.

Some small notes: the mid fuse skins did not fully touch the top of the joggle on the cabin top. This was not due to hitting the longerons but due to the door sills needing to be sanded more I guess. I basically had the door sills sanded flush, so I made the decision that it was good enough and I would fair it out with epoxy/flox/micro. We are talking about maybe a 1/16″ gap.

I use some scrap 2×4’s and a reversible clamp and apply some upward pressure on the cabin top so it is tight against the top skin. I then start at the center of the cabin top, and match drill #40 all the holes between the three top longerons. I clean out any trapped dust, then go back to the center and up-drill the holes to #30. This reduced the dust that got between the cabin top and the skin as I drilled at the expense of taking a little longer. Maybe a wash on time/effort.

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With the top holes drilled I reposition the wood and clamps so I am appying pressure to the sides of the cabin top and I repeat the same process along the rest of the aft end of the cabin top. Things got progressively easier as I went along and only had to stop a few times to clear out dust between the parts. I then shift my wood shims and drill every 8th hole down the side of the mid-fuse skin into the cabin. Same process. Drill #40, then updrill to #30.

Next was drilling the screw holes into the door sides. I lined up the cabin top per the plans and clamped into place. Using a 90 degree drill, I make the initial #30 hole clecoing as I go. Then up-drill using my regular drill to #12 and using my 3/16 clecos to keep everything in place. To countersink the holes, I end up using my 90 degree drill with the countersink bit in it as I didn’t have a threaded to chucking adapter. I had to free-hand countersink the holes to fit the screws and installed 2-3 screws on each side to keep things in line.

Next I transfer the markings from earlier in the chapter to the cabin door sill and drill the holes up to #19. With a few screws installed the door is pretty solid so I then begin to install the front cabin brace. I then measured and marked the centerline of the cabin top to help align the cabin brace.

With most of the interior completed, I was eager to finally get the Cabin top. Honestly pulling the cabin top down has been one of my “goals” for a while. I was originally hoping to have the cabin top started in December of 2019, but hey, stuff happens.

With the assistance of my wife, we get the cabin top off the ceiling and on to my work bench. I inspect the scribe lines and find the a number of them are a bit off compared to the plans. Using my calipers, I re-scribe lines and mark them with my sharpie. Then it’s time to start trimming.

Ok, so this part kinda sucks. I tried a few different tools with different levels of success. First was the oscillating multi-tool that was recommended in the fiberglass class. This is pretty light on dust, but it’s loud, hard on your hands and cuts SO SLOW!. Also the tool was a bit heavy and I got tired before I finished my first cut line. I then decided to switch to the Dremel tool with a cutoff wheel. I moved the cabin outside and started it up and it cut pretty good. It did EAT a lot of those tiny disks and my lines were really that straight, but it worked. I had enough disks to at least cut the door sill, under the rear windows and the aft end of the cabin top.

With these done, I enlisted the help of my wife and two girls. Let’s just say that my girls were more excited to help than I expected. They absolutely loved to climb into the cabin and crawl around to help out. With their help holding the weight on the rear of the cabin top, my wife and I tried to slide the door frames between the cabin pillars.

I REALLY didn’t want to sand too much off, so we did this 5-6 times with me sanding a little each time before we could get the cabin top to bottom out. Then I had to mark where I had interference, both in the door frames and under the rear windows where the cabin top hit the longerons. To sand things down at this point I used a Ryobi belt sander from Home Deopt with some 40 grit sand paper. The belt sander could chew through the fiberglass with a little pressure, or just lightly sand if needed.

On and off another 4-5 times as I sand a little here, a little there, I finally felt like I had things almost perfect. The frame is thin in a few places, but looking at posts from others, this really isn’t unusual. I can build it up with some epoxy and flox without too much issue.

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Added a few photos to show examples of how close a fit I got. This was hard to visualize so I ended up sanding a little too much in a few places. Not the end of the world. Overall really happy with how it turned out so far. I will say that making the cuts, and then eventually drilling the holes in the canopy top is scary the first time you do it! All went well – no regrets.