Dave’s RV-7A Building Log

Bending soft aluminum tubing is an art form. You tweak it a little in one spot and the shape of the whole thing completely changes.

I got the vent on the right side pretty close to the final form. There was one whole jog I left out yesterday in the upper right corner. I still haven’t cut it to length yet. I kept trying to make small tweaks, but it would completely change shape. At some point, I’m going to have to just call it finished.

Rather than continue with the right side to the point of frustration, I bent and cut the left side to the rough shape. It’s amazing how the first one will take 2 hours and the second one takes 20 minutes.

I’ve learned a few tricks:

• Start at one end of the tubing and work your way to the other end. It might take several passes to get it right.
• Use the spring bender for the first pass to make the sharp bends. You can then make small tweaks without the spring.
• The sleeves for the flares will not slide over a tight bend. Plan around that. And make sure to put them on before flaring!!

I also received my order from Spruce. I ordered some 960-4L washers to replace the one I borrowed from the electric elevator trim kit, a few Nylo-seal fittings for the static system, and 12′ of extra 3/8″ soft aluminum tubing to practice with. The Nylo-seal fittings (on the right) don’t look nearly as nice as the plastic tube fittings that Van’s put in the static kit (on the left). I think they’ll work fine, though.

I took advantage of the sunny weather and painted a bunch of parts for the cockpit.

Later I decided to work on the fuel vents. I figured it would be best to learn on this tubing before playing with the fuel supply tubing, especially since the 1/4″ tubing is much easier to bend.

I uncoiled the 1/4″ tubing and started working on the right fuel vent. The vent is snaked up through the cabin in order to get enough height to keep fuel from seeping out and I think to keep water from coming in. I got the basic form of the tubing worked out. The only tricky part was getting the flare on the forward end of the tube along with the tight bends needed to avoid the rudder pedals. I did the flare and then bent the tubing with the spring bender. The spring works really well to keep the tubing from collapsing while bending. It’s just a little difficult to slide it over the 90 degree bends.

I started to work on the fuel vents. The hardest part was drilling the hole for the fuel vent in the side skin. I can understand why Vans doesn’t pre-punch the hole. They use the same side skin for the RV-7 and RV-9, which have the vent in different places. But why can’t they call out dimensions on the drawings? Using the 1/8 scale on the plans, I calculated that the hole was 1.12 inches in front of the rivet line for the F-902 and 1.84 inches above the rivet line for the lower longeron. I eyeballed these measurements against the wing root, and it seems like they’ll work out ok. After much measuring and double-checking, I drilled the holes out to 7/16″ per the plans.

I also prepped the spacers needed for the fittings that will go through the skins along with some other parts. I’ll paint them tomorrow.

Adele and I spent the weekend at Camp Orkila for a Y Princesses camp out. Since this is our last year in the program, I decided to make it special and fly up in a rented Cessna. Lots of other dads flew up in sea planes as you can see here:

Adele took some pictures on the flight “home”. The first is a look back at Eastsound on Orcas Island. The second picture is us landing at Skagit Regional on the way home.

The “Volt” annunciator illuminated on the way home. The ammeter and voltmeter confirmed that there was something wrong with the electrical system. I flipped the alternator main off and on a few times with no affect. At that point, I turned off the second radio and the ADF and found a place to land. Once on the ground, I consulted the owners manual, which suggested checking the alternator circuit breaker. It was not tripped. The battery may have lasted long enough to get to Boeing Field, but I decided I did not want the possibility of flying in there without a radio and transponder. Galvin (where I rented the plane) was nice enough to send someone up to fetch us, eventually.