March 13, 2010

Vent Plumbing - Continued - 4.5 hrs.

I got into a whole new ballgame today. Bending and working with this aluminum tubing is something you just can't jump in and do. There's definitely a learning curve here! I spent several hours working on this thing. This is the vent tube for the left side.

The first thing you need to do, though, is install the fittings in the fuselage. First, I put in the screened vent fittings on the bottom. That was easy. Then, here's a picture of the side of the fuselage where the other fitting goes. A big round aluminum washer goes on here, so both the washer and the side of the skin were prepped and primed.

Below, the primer is dry and the masking is removed. Ready to install the washer and the fitting.

The fitting is installed and torqued down. Yes, there's a big washer here alright. In this picture, it looks like the spot on the skin, but the spot on the skin is actually all covered up by this big washer. Anyway, this will all be underneath the fairing for the wing and not seen.

With the fittings installed, the vent tube can be put in. This is the left side. The air comes in on the right through the screened vent fitting in the floor, goes up through the loop, and out through the fitting on the left. A short tube will connect this to the vent line on the fuel tank in the wing. Why the big loop? The top of the loop is higher than the highest level of fuel in the tanks, so it prevents any possibility of siphoning. Nice safety feature. There may be other reasons I'm not even aware of.

The hardest part of the vent lines is this end. I started on this end and worked my way to the front end. All these curves and bends are necessary to make the tube go around the stiffener, and avoid the rudder cable. It takes a lot of careful, patient work to get this right. That's why it took me so long. You don't want it touching or rubbing anywhere. It took me several tries and I cut the end off and redid it several times. Trying to get a good flare on an end that short (before the curve) isn't easy. Fortunately, I was able to get it done without ruining any significant amount of the tubing. One trick I learned is to use a piece of wire to bend into shape the way you want the tubing to go. Then the wire can be used as sort of a pattern to duplicate when you start bending the tubing. It was also helpful to help me figure out how much tubing I was going to need for this side, so you don't cut it too short on the other end. I was able to measure just the right amount with a few inches to spare, so I got this right the first time and I don't have to go buy more tubing. I think the next one on the other side will go much faster.

Yeah, I know this is over the top. Even for me. But I just had to paint the washer on this fitting with my JetFlex topcoat paint, so it matches the rest of the interior. It's inside the plane and it's visible, and that big gray primed washer was just bugging me.

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Contact me: swayze "at" europa.com (replace "at" with the @ sign... no spaces... you know the deal)