A couple of days to catch up on...
Rose helped me pull the canopy off and get it to the bench so I could see what kind of a mess I'd made with the Sika. For the most part, it turned out pretty well. As expected, most of the joints still need to have a finishing bead of Sika put on them just to give a more even line though. I taped up the aft canopy brace on both sides and ran a new bead on each side. That made a big difference and gave it a nicer finished look. The canopy side skirts and the inside canopy to frame joint is a little messier and harder to deal with because it's already a pretty tight joint. It's just wide enough that I do need to fill it with a tiny bead of Sika though. The Sika had gotten underneath the tape on the outside, so I had to spend quite a while cleaning it off of the plexi. Luckily it doesn't stick very well to areas that weren't primed (but boy does it stick to anything that got primer!). I think eventually I'll need to use a little polish on the plexi around those side skirts. Just in cleaning up the Sika I managed to get some tiny scratches. At least they're barely noticeable and nothing that some polish won't clean up. I think I'll have to get used to polishing out scratches on the canopy every handful of years. It's not exactly like a Cessna where you can just pop in a new window when one gets old! I ran out of the glue, so can't finish the side skirts until I get more.
With the canopy off, it's a good time to cut the holes in the glare shield for the defroster fans. I waffled on putting fans in, since they are so small and won't really move a ton of air, but I finally decided that it's so easy to put them in now that I may as well. Even if they don't actually work for defogging the canopy when on the ground, they'll be great for pulling hot air away from the back side of the panel and keeping the avionics a little cooler. I ordered two 50mm CPU fans on Amazon, thankful for experimental aviation. I'm sure if I needed a fan for a certified plane, I'd be out hundreds of dollars, not $8 for two!
Considering I'm drilling into a finished canopy frame that took months of work, I decided to draw up a drilling template in Fusion 360 vs just marking sharpie lines on the glare shield and hoping I was close enough.
The slider canopy frames allow for much larger fans to be used, but the tipup has a very small space between where the panel sets and where the canopy frame braces are. That's why 50mm is about as big as I could go. Most fans that size are only 10mm deep, but I found some that are 20mm deep and move a lot more air because of it. The drilling was pretty uneventful. The large hole is an odd size though, so I had to use a fly cutter in a hand drill to make it. That's actually very easy to do, and a lot less scary than using a fly cutter in the drill press. I just went very, very slowly and with very little pressure on each pass.
Since I had already drawn up the basic dimensions in Fusion 360, I had a little fun and made a quick design for a fan grill and 3D printed them. They will go on top of the glare shield and be held in place by the screws that mount the fans. I have a feeling the filament I used may not be up able to stand up to the heat of a cockpit sitting on a hot ramp during the day, but we'll see. I used PETG, which starts to deform around 160 degrees. If I find it gets soft, I may just send the file over to sendcutsend.com and have it cut out of aluminum. I loaded the file for a quote, and it's only $5 for each grill to do that (except $20 in shipping of course, unless I come up with another $20 in stuff I want them to make - I'll sit on it and see what else I come up with before I'm done).
The next thing I need to figure out is where to make the cutouts for the center stack audio panel and GPS in the subpanel. Those two units are too deep to fit in between the panel and subpanel. Avionics have changed a bit in the 25 years since Van's designed the RV9! I measured about 100 times and marked where I think the hole in the subpanel needs to be. I'll cut the hole and then put some angle bracing around it. I do still need to cut the panel for the IFR GPS as well. I'm really waffling on that - I hate to cut it, not knowing for sure if I'll ever get my IFR ticket or not. But I think I'll hate it even more if one day I decide to put an IFR GPS in and have to pull the whole panel out to cut a new hole!
