« Archives in November, 2009

Canopy handle stuff

2 hours.
lined up and drilled the attach holes for the canopy using the template on DWG 48. I think I get it. But the plans say ‘work carefully’ because they have you drilling holes and cutting slots in the left side skin. I did a great job of measuring and cutting the slots, but of course, in my attempts to file the edges and square them off, I managed to rake the skin with a file.. Should have worked on it from the inside. But I was able to move on to fabbing the bracket for the release handle and ratchet. I skipped a step: I didn’t rivet the subpanel to the fuse because I need to paint the subpanel parts first. I need to get down to B & B and pick up some gloss battleship gray before that happens. Some gray, and some white, because the canopy latch bits are powder coated white from Van’s. There’s other stuff hanging in the breeze, I still waiting on some stainless plumbing fittings from Earl’s, then I can finish the cabin-side fuel system.

The last fuel tube, and some canopy.

4 hours.
It’s always exciting when I get to transition from one set of plans to the next one in the sequence. It feels like progress. Not that there aren’t details to attend to later, little things like wing mating, for instance. But that’s going to be such a mission, and I need to prep for that, and I need as few loose ends and as much structural integrity as possible. But I did finish the bend for the pump-to-firewall section of the fuel line. I’m currently waiting on a stainless steel bulkhead elbow from anplumbing.com for the actual firewall interface, and it looks like I’ll need two SS elbows for the brake lines just to be safe, but the only nagging little bit left with the fuel plumbing is an Adel clamp on the left front gusset for the vent line.
The project at hand was the construction and installation of the hinge blocks. The C-617 and C-618 hinge blocks are made of UHMW plastic and they get sandwiched between the F-745 and F-644 ribs on the front deck.

This pic shows the clecoed subpanel and ribs sitting on the bench, where I begin to puzzle out the mechanics of getting holes drilled all the way through to the attached F-644 ribs. Those are the little short things next to the ribs with the 3 big lightening holes in them, the F-745’s. What you have to do is this: You have to take the subpanel assembly apart, and I’m really glad I didn’t jump the gun and rivet that whole thing together right after I’d gotten the brake pedals in. Basically, you have to use the F-745’s as drill guides for the UHMW blocks, then use those to match-drill a 1/4″ aluminum spacer, then put that whole assembly together along with the upper deck skin to match drill all the holes through the F-644 ribs. The reason you need the F-745 ribs off the assembly is because the holes in the UHMW blocks and the C-619 aluminum spacer need to be done with a drill press, so you get a straight, even hole. This is your canopy attach point, so it behooves you not to fark this up. The RV-7 was not designed for open-cockpit operations.

Here’s the midpoint of the process. I thought I could be clever and match drill a temporary plate to take the place of the forward deck skin, allowing easier access. A nice theory, but theory doesn’t count for squat when it comes time to fit parts.

Here’s the other side. This has the canopy frame wedged in there to test the fit. Good thing I checked this. The C-619 spacer had to be filed down in order to allow the hinge to pivot around wheere the 1/4″ pivot hole is going to be with enough edge distance. Scary stuff.

A wider view, showing the canopy frame sitting in place.

The forward deck skin is nw clecoed on, and the green masking tape is suspending the ends so I can get a drill in there and drill the 1/4″ canopy hinge pin holes. These hinge pins are part of an elaborate canopy release mechanism that looks to be more trouble than it’s worth, and quite a few guys have eliminated it altogether. The most elegant solution I’ve seen is where the release arms are Adel-clamped to the F-745 ribs instead of going all the way to the torsion mechanism. This allows for release of the canopy for maintenance and upgrades, but secures the pins tightly in place during flight.
As far as I know, the next phase of this fracas is going to be the initial work on the canopy frame.