Dave’s RV-7A Building Log

Primed the tank attach Z brackets for the left wing.

Since they need to dry overnight, I moved on to the tank stiffeners. Might as well do them all, left and right. I did the rough cuts with the band saw, cleaned them up with the belt sander, and did a final smoothing on all sides with the Scotch-brite wheel. A little deburring and they are set to go.

I started to put the tank ribs in place. Those things are going to be tough. You really have to push on them to get the holes to line up. I’m going to leave that for tomorrow.

I wasn’t happy with the way the first Z-bracket turned out after back-drilling it through the spar. One of the holes in the spar ended up slightly elongated. Instead I went a different route. For each bracket, I lined it up with a bolt through the middle hole and squared it to the spar. I then marked the location of the other two holes with a marker. I then drilled them on the drill press. With the center line already marked, it was pretty easy. For me, it was easier then back-drilling through the spar. I checked each one and they are lined up perfectly.

I then deburred all of the holes. Next was doing the nut plate drilling: bolt on the nut plate, make it straight drill one side hole to #40, cleco, and then drill the other hole. Nut plates are so much fun. After that, I countersunk all of the side holes.

I think I’m going to prime the brackets before putting on the nut plates, but not tonight. Instead, I pulled out the tank ribs. I had already squared up the flanges to 90 degrees, but never fluted them. Now’s the time. Grab a beer, crank up the tunes, and dive in. I fluted all the tank ribs for left and right. And just to finish up the fluting for good, I did the funky inboard rib for the right leading edge. All ribs are now fluted!!! I’m glad that’s behind me. One big priming session on the right wing ribs and the right wing will be ready to put together. I’m glad I did all of the prep work for both wings together.

The last thing I did was to pull out the right tank skin and put in the cradle. All ready for assembly.

Didn’t do too much tonight. I drilled the center hole in each Z bracket. I bolted one on the spar and drilled the two side holes. Decided to call it a night after that.

After Steve left, I started the first steps on the fuel tanks. I cleaned up the Z brackets on the Scotch-brite wheel.

I decided to follow the DanC method of fuel tank placement. It seems much more accurate to me. It might be more work to take the leading edge and tank on and off, but I don’t think it will be easy to use Van’s instructions either. Elongating the holes in the brackets in order to make the fuel tank sit right next to the leading edge will require some on and off of the tank as well.

I think I’m following Dan’s instructions correctly. I marked a line on one side of each bracket that is 1/16″ toward the bracket web from the center line. It makes sense. That will move the bracket over slightly, so that the pop rivets on the other side of the bracket will have more clearance. My pop riveter from Cleaveland has a huge head on it. I’ll have to find a riveter with a smaller head on it.

I also set aside one of the Z brackets as the inboard bracket. That one is different from all of the others. On that one, I put the line 1/16″ away from the web. In this picture, you can see how the centerline is slightly offset up or down.

This little edge marker tool is very handy. I got it from Avery or Cleaveland.