Matt's RV-7 Project

I spent several days fooling around trying to form a good set of aft canopy skirts out of aluminum, and finally gave up. So now I'll try making a set out of fiberglass. To keep glue off the fuselage and canopy, I taped down plastic sheeting everywhere except the aft skirt area.

I strung packing tape between the canopy and top fuselage skin. This will become the mold on which I'll lay up the fiberglass, thus hopefully making the new skirts fit the canopy nicely. Before I put the tape down, I sketched a line on the fuselage skin to give me something to aim at when laying up glass.

Clear things are hard to take pictures of. Here's another photo:

I cut out some pieces of 9- and 6-ounce bid cloth, using the metal canopy skirt pieces as a rough guide.

When I get a block of time I'll break out the epoxy and do a big huge layup.

I spent most of the weekend sweating profusely in the sweltering garage, trying to figure out a way to install a lock on the canopy. To keep unwanted visitors out of the airplane, I wanted a to use a small key lock that was simple, easily-obtainable, and reasonably secure. I have no illusions that I'll be able to keep a determined thief from getting into the airplane, but at least the presence of a simple lock on the canopy ought to help keep honest people honest when the plane is parked outside and unattended.

After examining various options available at the local hardware emporium, I picked the same chrome plated cabinet lock that's been used by other builders. For future reference (in case I have to replace it) the manufacturer is Prime Line and the model is U-9941.

Since the canopy skirts are only 0.032", I made this doubler for the lock out of the remains of a spare elevator rib I had laying around.

The doubler will be riveted to the side skirt in two places. The odd shape is to let it clear the C-791 skirt brace. You may notice that although the lock body has anti-rotation flats machined in it, I didn't bother to try making the odd-shaped hole required to make use of them. I found that in practice the nut alone is enough to keep the lock from rotating once it's tightened down. This probably means that you could pop the lock open with a big enough flat-bladed screwdriver, but then again I'm only doing this to keep kids out at airshows.

The flange on the doubler will also be pop-riveted to the underside of the canopy frame.

I trimmed away some of the C-791 skirt brace around the lock and doubler. It's tight but it all fits together.

Careful measuring beforehand ensured that there would be just enough room to get a 7/8" socket onto the nut. I want to be able to remove and replace the entire thing down the road, in case it gets rusty or I twist off the key.

Here's a view from the exterior side. I wish I could have found a more flush-fitting lock, but this one will probably not cost me more than 0.01 knots.

In the unlocked position, this latch arm will be parallel to the canopy track and generally out of the way.

In the locked position, the latch arm will be vertical and will fit into a small slot that I'll cut in the canopy track. I'll wait to cut the slot until after the canopy is completely assembled and fitted, since the spacers underneath the rear anchor blocks are distorting the canopy geometry at the moment.

It's crazy that I spent an entire afternoon working on this. Little custom side projects like consume a lot of build time.

Today I decided to install the Koger sunshade while I still have good access. The shade can be installed pretty easily on a flying airplane, but I figured why not do it now. Here's a shot taken while I was drilling and tapping the screw holes that attach the slide rail to the canopy frame:

The whole setup is very simple – just some fabric panels, wire ribs to give them some shape, and a sliding track to let you deploy or stow the shade as desired. Here's what it looks like fully unfurled:

Not visible is the thumbscrew that keeps it from sliding around on its own. When it's stowed, it folds up behind your head so it doesn't block the view:

I drilled and tapped the holes that help secure the little Velcro dots (located where the orange clamps are in a previous photo) but I'll wait to install them until after the canopy frame is painted.

Overall the sunshade took very little effort to install, and I know from experience that it really does help keep you from roasting under that big bubble when the sun is beating down. At $160 it's a little pricey for what you get, but then again I probably couldn't reproduce it myself for much less, even if I had the sewing skills.

After experimenting with various techniques using scrap plexiglass, I ended up using regular old three-flute cutters in a slow-turning electric drill to machine countersink the sliding portion of the canopy bubble. I countersunk slightly deeper than normal to leave room for the dimpled aluminum to "float" within the countersink as the plexiglass expands and contracts.

Doing all the holes took quite a while as I was going extra slow to try and avoid causing cracks. I still haven't drilled out any of the holes to make them oversize just yet. I also didn't touch the windshield yet, since I want to get the sliding canopy mostly done first.