Dave’s RV-7A Building Log

With the canopy sitting on the fuselage, it was obvious that more needed to come off the corners. I initially left some of the flange on, but it all needs to be removed. After all of that trimming there was still a little bit of a gap up front–maybe 1/8″.

While waiting for Julie to help me put the canopy back on the fuse, I marked the centerline on the roll bar. Do this with a dark marker. I used a blue pen on blue tape, and it was very difficult to see through the canopy.

I set up in the garage for a major cutting session. Temp was 77F. I used the respirator this time, which was much more pleasant. Keeping the die grinder steady really helps. If the disc gets crooked even slightly in the slot, it tends to bind up. I cut about a foot at a time, stopped, taped the scrap in place, and let the compressor catch up and rest for a second. Here’s an action shot courtesy of Julie.

This picture shows the canopy after trimming the side. The scrap is still taped in position. The ends of the saw horses had a little lip that the canopy was hooked on, but I used the clamps just as a safety measure. For the remaining cuts I think I’ll put a sheet of particle board on the saw horses to make things a bit more stable.

On the sides and back, I trimmed just above the clamping marks from the molding process. There’s a faint line above the clamp marks, but I decided to ignore that for the first round. Along the front, I followed the advice on someone else’s web site, trimming right where the canopy makes the transition from the horizontal flange to the upward slope. I was a little conservative at the front corners, leaving some of the flange in place. Here’s the scrap.

After trimming all the way around, Julie helped me move the canopy to the plane. I made a mark 1.75 inches aft of the forward edge of the canopy frame skin. I spent a few minutes centering the canopy using the sides as reference. The centerline I drew down the canopy ended up being slightly off, probably because the clamp marks weren’t symmetrical with respect to the sides. I figured the clamp marks are more significant. The plane looks very cool with the canopy on top of it. Julie even said, “Wow!”

Now for the result. Leaning into the fuselage from the back (I left off the top skin), I measured from the top of the roll bar to the canopy. I couldn’t believe it. 1/2 inch. I went all the way around making sure I hadn’t screwed something up. Nope. That is incredibly close. I was expecting something more like 1 to 1.5 inches. The front edge looks really good with just a slight gap in the center. I’m going to trim off more of the front corners and that will probably be it!!

I also did a little experiment on one of the pieces of scrap. I’ve seen a few people say they’ve been able to drill with regular drill bits (not that I’m going to–I have plastic bits on order) and not have any problem. So I took out a #30 drill bit and drilled close to one of the edges. It didn’t crack, but the plastic chipped out on the back side. You can sort of see it in this picture. I’ll definitely be using the plastic drill bits.

The weather warmed up nicely into the 70’s, so it was time to dive into the plastic cutting. I set up outside with two saw horses, an air line, and my angle die grinder with the special plastic disc that shipped in the finish kit. Julie helped me move the canopy out of the guest room. I decided to just do one cut for starters. I cut the clamp marks off the back of the canopy. Following Dan’s method, I peeled back the plastic, cut it back a bit, and applied tape to the edge to keep the dust from going up inside the plastic.

As others have said, cutting the canopy makes a nasty white snow. However, it didn’t make nearly as much as I expected. I make more sawdust cutting up plywood in the driveway. While you’re cutting, it definitely emits a nasty plastic odor. I might try the organic respirator next time. I noticed that depending on whether I used the upward or downward spinning edge of the disc determined whether I got completely covered in the nasty snow or it just covered my sandals. Definitely having it go downward was preferable. Julie said she could hear the die grinder a block away in the park, so I might do the remaining cuts inside with the door closed. My compressor is barely able to keep up with the die grinder. I’ll just have to take 5 minute breaks occasionally to let it cool down.

I taped the scrap in place with duct tape as I went along. That helped quite a bit. I didn’t make the straightest line possible, but I got better as I went along. The aft edge also doesn’t matter much as it gets trimmed back again later. The plastic has very similar sanding properties to a soft wood. I used an 80 grit disc on my sander and it cleaned up the edge very nicely.

Overall it was a very positive experience. After dreading the canopy for so long, now I’m excited to really dive into cutting this weekend when the temps outside should be 80-90F.

I didn’t get too much done. I clecoed on the forward top and canopy skins in preparation for fitting the plexiglass. I was planning on starting on the cutting, but the weather has cooled off quite a bit for a few days. This weekend should be perfect for working on the plastic. Instead I read ahead in the instructions and tried to visualize the next few steps.

I also had a new builder stop by to check on the project. Steve Tilford is building a 7A just a few minutes from where I live. His QuickBuild will be showing up next month. It was great to get an infusion of enthusiasm. He is definitely excited about jumping into the build process.

Reading Walter Tondu’s site and another (that I can’t remember right now), they suggested not jamming the wedges into place. I had kind of jammed them in there and was worried they would affect the fit of the frame to the canopy decks. I took the wedges out and sanded them down some more on the belt sander. They seemed to fit much better after that. I re-primed them and while waiting for that to dry, I riveted the splice plates to the side channels. I then put the wedges in place and riveted it all together. Looks slick. From the pictures, you can see that the left side looks perfect. The right side raised up a tiny bit at the front, but I’m sure I can persuade it to return to the right shape.

I didn’t get anything done over the weekend, as it was the annual guy’s trip to Leavenworth for camping, biking, and golfing. This was the weekend that started this whole project two years ago when I learned that my buddy Jeff was building an airplane.

I got back mid-day Sunday, and managed to get quite a bit done on the canopy frame in between naps. I tweaked the position of the side rails a bit. The angle at the back of the side rails bulges out a bit. Dan trimmed that off, but I think the aft channels will eventually be short enough that it won’t matter. I temporarily located the aft channels a bit higher in order to get the correct placement for the side rails.

I drilled the side splice plates to the front part of the canopy frame, first with #40 and then to #30.

I removed the frame and then drilled the holes in the bottom of the splice plate, putting the wedges in that I previously fabricated. I unclecoed everything, deburred, and countersunk where needed.

I finished riveting the canopy frame around the hinge points using a flat set in the 3X rivet gun. The retainer spring was getting in the way, so I removed it and duct taped the rivet set in place.

I also drilled the side splice plates to the side channels of the frame. I clamped the frame back in place, moving some of the clamps so they won’t be in the way of the plexiglass when I get to that stage.

I haven’t had much time for the plane this week, but I’ve been trying to get in little stuff here and there. In my priming batch yesterday, I left out the side rails. I deburred, cleaned, and primed those today. I also started riveting the canopy frame together, starting with the splice plate in the middle. I tried riveting the 4 rivets around the hinge points, but I couldn’t get a squeezer in there. I’ll have to shoot those.

I cleaned and primed the canopy frame along with the splice plates. The frame has lots of nooks and crannies, but I think I hit them all.

I did a bunch more deburring and smoothing of edges on the canopy frame. It’s definitely very rough right out of the box. However, I wouldn’t want to assemble and weld the thing myself. I got it looking really good. I also countersunk the rivet holes along the front. The plan is to prime it and then do some riveting.