« Archives in June, 2009

Subpanel and forward top skin

4 hours.
Drilled deburred, dimpled F-711 skin, matchdrilling to the firewall flange. Stainless steel is a bitch. It’s really not advisable to run your finger along the underside of the holes to feel for burrs. That stuff is sharp, and it has a taste for fingertips. Imagine what it could do to your eyes. Even so, I managed to get it all debured and dimpled, as well as drilling the center subpanel rib attach angle. The skin is now off and put safely away while I go to town on the remaining bits. I’m also entertaining the idea of not painting most of the interior and going with a Classic Aero Designs interior, which should give the ship a more polished aspect. Of course, that stuff is heavy, but if I’m going to be riding in it for significant lengths of time, I want a nice, comfy ride. Check out their stuff!

Eyeballs and dimples.

6 hours.
The fresh air vents take in air from two NACA scoops, one on each side, just forward of the panel. Each one feeds a length of 2″ tubing that ends in an eyeball vent, similar to the ones on commercial airliners, the overhead ones that the inconsiderate nong next to you insists on keeping open and blowing frigid air into your ear while you’re trying to read or sleep. Rather than use the cheap plastic ones from the kit, I opted to spend the cabbage on the nice machined aluminum ones from SteinAir. The SteinAir vents are different in that they mount in a 2″ hole and are held fast by a threaded ring, while the Van’s ones are square and have four AN3 bolt holes designed to grip an angle bracket and a point on the panel. What this means is the mounting needs to be a custom fab, like so:

The next thing to do was dimple the angle for mounting to the side skin. Once that was done, and the part clecoed on, I could match-drill the panel attach hole, then put a nutplate on it. This took lots of measuring, then a bend, then some more measuring, then a few cuts, some drilling, and presto, it’s done.

The second one was easy, all I had to do was make the 90 degree bend at the right distance from the edge of a piece of scrap, then trace the outline from the original part on the opposite side from the bend. Some bandsaw and hole saw work and I got a mirror of the first one. Repeat dimpling/nutplate process.

With the eyeball mounted, it looks pretty sweet.

The only issue here is that the threads on the eyeball don’t go far enough. Minimum thickness this thing can clamp down on is about 3/32″, and my aluminum bracket is maybe half that, so I need to find or make a bushing for the backside so the eyeball can be screwed in tight.
After that, I deburred and dimpled the rest of the subpanel, plus I finished riveting on the weather seal angles. The left-side panel support rib, F-745-L has been truncated at the subpanel to make room for the EFIS. This is a common mod, and the F-745 ribs aren’t structural, so I figured I’d go ahead and do it. If you ask me, putting a panel support rib right down the centerline of the pilot seat is kind of dumb, but I can see where it maximizes efficiency in manufacturing, and it does stiffen the panel. The piece sitting on top of the subpanel in the photo is the aft-of-subpanel piece of the F-745-L rib. I’ll figure out another way to stiffen the panel.

Of course, the skin will have to go back on so I can matchdrill the firewall, as well as the center rib to firewall angle. I wasn’t quite ready to mess with the skin.. That forward top skin is a pain in the butt, so I decided to do something completely different: Start playing with the placement of the throttle quadrant!

The idea is to get the quadrant centered, and I figured I could mock that up by cleco-clamping it to some angle, then try it on for size. It’s easy to reach, doesn’t block the view of anything, and once it’s all bolted in with cables attached, should be solid. Not only that, the aluminum angle strung between the panel and the subpanel for the mount should help stiffen the panel.

This shows the placement relative to the pilot in fore and aft direction.

I have to consult the oracle of VAF to see if I’m even remotely on target with this quadrant thing, But it looks like it should be fine. I’m still avoiding painting the interior, go figure. But there’s plenty to do, like rivet on the firewall recess, fabricate the quadrant mounts, and maybe even do a couple of firewall-mounted items before I need to have a paint day. Then the next discrete step is that engine conversion, which, I gotta tell you, makes me nervous. More on that later.

Subpanel work.

4 hours.

The subject of todays efforts was the subpanel. When I had it all clecoed to the airframe, I drilled the F-644 and F-643 ribs to the skin. as well as the F-643B angle that attaches to the firewall. I’m not being to squirrelly about primer, most of these parts are alclad, and even the ones that arent will probably get a coat of gray paint, assuming I have enough left over from doing the interior. If not, big whoop. This is a sction of the plane nobody will ever see. In the plus column for painting is insulation. There’s going to be a buttload of wiring under here, and if something chafes or comes loose, contact with paint is going to make fewer sparks than contact with metal. In the minus column is that painting is a pain in the ass. In any event, today saw the riveting of the center subpanel, and for anybody playing at home or at work at the FAA, here’s a photo of me riveting the thing together. Not the most flattering pic in the world, but it’ll do.

The other thing that got done today was a loose end that’s been bugging me for a while. I got the brake pedal bracket riveted to the firewall recess angles. I hadn’t done it before because I needed to paint it first. It is now painted.

Speaking of paint, here’s a current state of the nation. The weather’s been gloomy, salt-damp, and cool, suboptimal paint conditions at best, so this is as far as it’s gone. The uneven splotch on the baggage compartment bulkhead is just an exploratory shot with the paint gun, just to see the effects of paint on a completely unprepared surface. Big surprise, it looks like ass.

I still have to fabricate mounts for the eyeball vents, then put in the NACA scoops for fresh air. That involves Proseal or RTV, and I’m leaning towards RTV. But I realized today, dude, you’re about ready to order electric bits. Of course, I still have to finish painting the interior, do the canopy, run fuel lines, and install the autopilot pitch servo before there’s much point in that. But at least things are happening.