Tonight I finished drilling holes in the canopy, and then final-sized all of the holes to #27,
I only had one scary moment, when for some reason one of the pilot holes I drilled in the aft edge didn’t line up with the pre-punched hole I was shooting for. However, I was able to enlarge the pilot hole slightly to get it to line up, and then the final-sizing took care of the problem, leaving a nice round hole in the right place.
More drilling tonight. I’m going slowly, but so far everything is working out nicely.
Match drilling the side rails takes some care. Because the aluminum rail is pressed up against the Perspex, and there are no pilot holes, the Perspex drill bit doesn’t completely exit the Perspex before contacting the aluminum rail. Switching to a regular drill bit and drilling through the aluminum rail requires drilling through the last few millimeters of Perspex with a regular drill bit, which risks a crack on the backside of the Perspex. I don’t expect to find any issues, but I’ll carefully inspect it when I disassemble in a subsequent step.
The wooden structure inside the cockpit is providing great support for drilling the canopy rails.
Tonight I drilled the first set of holes in the canopy. Everything went well and the holes were as accurate as I could have hoped for.
I made a small sighting tool by bending a piece of aluminum to 90 degrees. I used this to sight a spot on the canopy that was directly over the hole in the underlying frame, then marked the spot with a sharpie. Then I taped it to the side of the hole to help me keep the drill square. Then I lined up the drill on the spot, checked the placement, and drilled the hole.
Life has gotten busy recently! Tonight I finally finished trimming the canopy, and got everything ready to start drilling the holes.
I used a ratchet strap to hold weight on the front of the canopy, and rigged up some blocks of wood on the inside to backstop the holes being drilled through the side rails.
I plan to start drilling tomorrow, as it’s late and I need to get some sleep tonight.
Tonight I messed around with the side skins on the canopy trying to see if I could minimize the gap between the canopy side skin and the fuselage side skin. Eventually I decided to just go with the existing skins and worry about the gap later, if it’s an issue.
I moved on and measured the thickness of the canopy on the sides to determine whether I needed the use the supplied shims. If the thickness is less than .17 of an inch the shims are required. On the right side I measured between .158 and .17, and on the left I measured between .147 and .158. The thickness varies along the edge, hence the ranges. So it looks like I’ll be using the shims.
Work has been keeping me busy in the evenings the last few weeks, but last night I was able to spend some time in the garage. I trimmed the canopy sides to get it to sit flush with the canopy rails, and to sit down correctly on the forward canopy frame skin. I used a combination of a diamond blade on the jug saw, a sanding block, and a burred edge on a small steel ruler to cut, sand and scrape the edges. It wasn’t my favorite thing to do, as the canopy is bulky, flimsy and awkward, but it came out ok. Most of these edges will be hidden by skins and fairing, so the straightness of these edges wasn’t critical.
Yesterday I primed the various cockpit covers and panels, and today I painted a finish coat. The finish coat came out looking good; I didn’t have any runs in the paint, and the finish is even and “wet” looking. It’s still drying, but I’m pleased with how it came out. Much easier to paint on the bench vs. inside the cockpit.
Tonight I spent time deburring parts for the cockpit. These are all the covers and plates that fit into the cockpit and make up the seats, center console cover, flap motor cover, and various panels in the baggage compartment. My plan is to get these primed tomorrow, and then finish chapter 42, and final paint them in the coming weeks. Then I’ll be back to the canopy, or maybe work on both chapters in parallel. I’ve found it’s good to have a couple of mini projects running concurrently, so I can switch between them if I need to pause one, or just need a change of scenery.
Over the course of the last week I have been making progress on fitting the canopy to the canopy frame. I marked out the amount that needed to be trimmed from the aft edge and then cut it using a jigsaw with a diamond blade. The blade melted it’s way through the canopy without any problems. With the cutting done I scraped the edge with a thin piece of metal to smooth out and round the edges.
Today I installed the finished canopy frame onto the fuselage and checked all the clearances. I was relieved, but not surprised, to see that the frame fit very well and had not discernible twist. The only real issue is the gap between the cockpit rail and the bottom of the canopy rail. For some reason the canopy rail is not completely flat, and the gap along the rail is not uniform. At either end it’s about 1/16 and in the middle it’s 1/8, and it’s the same on each side of the canopy.
It’s annoying because the skin will also be bowed and have the same gap when the canopy is closed. I pinged Vans, but there’s not much I can do at this point. I may try to make a new skin for each side to ensure the gap is uniform, but I’ll hold off until I’m completely done with the canopy.
