Dave’s RV-7A Building Log

I helped Steve today with his project, removing the old refrigerator from his boat. Wasn’t too bad once we removed all the guts of the thing.

After Adele’s indoor soccer game, I stopped by the hangar. I put the rear spar bolts in, torqued, and cotter pins. I then went back to the main spar bolts. The bottom bolts are truly unpleasant on the nose draggers. The gear leg is in the way big time. I was able to get the nut on one of the bolts, but discovered I did indeed drive one bolt in too far by about 2mm. Not good. I tried various combinations of pry bar, hammer, and rivet gun, but couldn’t get it to budge outward at all. I’ll have to read up on what to do there. In any case, it’s going to take quite a while to get the bottom bolts all secured and torqued.

Steve stopped by to help me with the wings. First item of business was to remove the wings. The pins came out very easily once the wing was lifted a little bit.

With the wings off, we got the fuselage off the sawhorse, deburred the holes for the fairings, drilled for nut plates, countersunk/dimpled, and installed the nut plates. That all took quite a while.

I also flared the fuel lines, cleaned up the area I trimmed on the rear spar, and drilled a hole for the pitot tubing. I put Steve in charge of getting a pull line through the wing conduits.

Once everything was ready, we got the wings right up next to the fuselage and pulled the wires through. The only one that was tricky was the outside air temp probe because the wire was too short to reach the first wing access port. We also pulled the AOA tubing through the conduit. That all worked very well.

Time to get the wings on. I used the temporary hardware store bolts to get the wing in the proper position and then put in the larger close-tolerance wing bolts. The top ones went in pretty easily with some Boelube and some taps from a dead blow hammer. Due to the wiring, I couldn’t hammer the bottom bolts, so I used a flat set in the rivet gun turned way down low. I kept reminding myself not to drive in the bottom bolts too far so I could get the nuts on.

By this time, we’d been at it all day and it was getting late in the afternoon. I was getting to tired to even attempt starting the engine. Plus it was raining out. Still, it was very major progress to get the wings on permanently.

I did some prep work before the big day tomorrow. I drilled the fairings to the wings.

I checked the fuel line lengths again, which ended up being perfect. I cut a few strategic holes in the wing conduits to allow mid-span wiring to the autopilot servo and heated pitot.

What better place to dine than on the wing while reading over my to-do list?

I also did a few engine prep items in hopes of being able to fire up the engine tomorrow as well. I re-installed and timed the P-mags. I put the remaining screws into the spinner. And finally, I removed the top spark plugs, removed the oil pressure line from the transducer and ran the starter in 20 second bursts until oil came out the line. It was cool to see the prop spinning around like crazy. Makes quite a wind.

First order of business was to re-evaluate the wing sweep and incidence from last night. I ended up using a good ol’ fashioned analog level. I think they are actually more accurate than the digital level for surface very close to level. The digital level tends to read 0.1 in either direction kind of randomly. I tweaked the incidence on the right wing a tiny bit and then was happy. After double, triple, quadruple checking everything it was time for drilling. After dinner.

After a quick bite to eat, I drilled the rear spars. I used a thick block of aluminum that I drilled on the drill press to make sure I was drilling at a right angle. I used the marks from last night to make sure I had the required 5/8″ edge distance. I started with #30, then 1/4″, then another drill that was slightly larger, and then 19/64″, and finally a 5/16″ reamer that I borrowed from Jim. The reamer was just like butter and made a nice tight fit for the AN5 bolt.

I still had some time left in the evening, so I drilled all of the holes in the bottom flange for the #8 screws.

Julie agreed to help at the hangar tonight. I got down there earlier and finally got a picture of the wings on in the light.

While I was waiting for her, I took care of a few things. I mounted the rudder and hooked up the rudder cables. After I tightened down the rudder bolts, I was surprised to find there’s a slight drag in the swing of the rudder. To this point, I’ve never had the bolts tightened. It’s always swung really freely. It makes sense the bearings would add a little drag.

I calculated how much to trim off the fuel lines sticking out of the side of the fuselage. Before trial fitting the wings, I got them pretty close but intentionally left them 1/4″ long. I also worked on the vent line for the left wing. I got it all bent to shape and flared one end. It’s an odd shaped line.

That’s when Julie showed up. We grabbed something to eat (not a lot of good options in Renton) and then got to work. We removed the left wing. I marked 5/8″ edge distance on the rear attach bar from each side, including the amount I planned to trim. I used a drum sander in the Dremel to trim the top corner of the wing rear spar and a little bit (about 3/32″) off the front spar attach bar. Last item was to cut the calculated amount off the fuel line. We then re-installed the wing. We did a quick check of the sweep and it looked much better.

Repeat for the right wing. Julie stuck around a while and helped me set up the plumb bobs and Mason’s line. The sweep is now within 1/16″. Excellent. After she left, I messed around with the incidence a bit. I had to lift the rear spar of the right wing a tiny bit, but the left wing was right on. Using the digital level, everything was within 0.1 degree. Wing twist appeared to be absolutely zero.

I’m still not entirely sure where the level and 3″ block are supposed to be positioned on the wing. Should the level be right on the front edge of the main wing skin, or just forward of that? Should the block sit in the middle of the rear spar or at the aft edge of the spar? I think as long as I’m consistent across both wings, it doesn’t matter too much.

The rear spars are clamped and ready to drill. That was a good spot to stop and think about it overnight. I’m also going to bring down an analog level. I think they can actually be more accurate than the digital level.

Great progress tonight. Thanks Julie. Just a little drilling here and there and the wings will be ready to be permanently mounted. And then it’ll be time to fire up the windmill. Can’t wait.

I tried to get the wing sweep and incidence dialed, but the rear spar fork on the fuselage hit the wing rib flange. The wing tips need to go back about 1/2″, but can’t because of the interference. I remember running into the same issue on Jim’s wings. I’ll have to remove the wings again, file it down a bit, and re-install. Bummer. One small bright spot is that the incidence looks pretty good without any tweaking.

I tried working on other stuff, but nothing was working out very well. I went to install the rudder, but remembered I needed to secure the wire as it exits the fuselage. I put some RTV on it and clamped overnight.

Tried to install the flaps to see how those were fitting and ended up spending half an hour looking for the hinge pins. I thought I had some all made up, but now I can’t find them. And I don’t have enough hinge pin material left to make new ones. I’m about 2′ short.

The whole evening went like that unfortunately. Lots of mucking around, but nothing really got accomplished. It was also not as comfortable down at the hangar, windy, rainy, cold, and dark. Good thing there’s not much left to do.

Got a late start today as we spent last night at the Pan Pacific in downtown Seattle. It was part Valentine’s Day and part visiting with friends. It was great to have a nice dinner out and stay in a fancy hotel.

I did the same routine as yesterday on the right wing, unbolted the wing, filed the opening larger, and re-installed the mount. I then prepped the wings for trial fitting. I marked on the bottom skins where the screws should be, located my hardware store bolts, etc. I talked Julie into coming down to the hangar to help out. The enticement was removing the hard top from her car. Spring is just around the corner.

When she arrived, we got the left wing into position on saw horses. I maneuvered the spar into the slot and she supported the outboard end. The only slightly difficult part was keeping the fuselage bottom skin from hitting the wing bottom skin. The best approach is to lift the wing root up so they don’t hit. But Julie wasn’t quite heavy and tall enough to effectively push the wing in. I ended up dashing back and forth a few times, but it worked out well. With the wing all the way in, I had her lift on the outboard end until the top holes lined up. I lightly tapped a bolt in. I then had her lift more until the bottom holes lined up. Tapped in another bolt. Very easy. Repeat for the right wing. The plane looks very, very cool with wings on finally.

I’ve got a bunch of little fitting items to do and then I can remove the wings, install nut plates at the root, and install them permanently.

Way back when I fitted the gear mounts into the fuselage, I didn’t make the opening quite big enough. After I had the mounts permanently installed and the plane on the gear, I realized that the gear mounts were actually rubbing on the bottom skin. It probably would have been fine, but in the back of my mind I had a nagging worry about it. I was concerned the bottom skin (and center section flange) would fret against the gear mount and cause problems down the road.

I decided to fix the problem right before fitting the wings. I made a sawhorse to support the fuselage and then jacked the fuselage up onto it. After removing all the bolts and screws, I was able to move the gear and mount far enough forward to get a little needle file into the gap. I spent probably half an hour filing away at the area that was too close. Half an hour might seem like a long time, but it’s better than removing the gear and fuel line and brake line and wiring to get the gear mount out.

Once the filing was done, I reinstalled the gear mount. This was quite a hassle, even more so than the last time since I now had wiring and plumbing in the way. Left side is done. I’m happy I went back and did it.

I also got the elevators permanently installed, the push tube connected, and the elevator trim wiring hooked up.

Trimmed and fitted the other wing tip lens. I’m glad those are done. Also put another coat on the LED nav lights.

I spent most of the evening organizing all the papers that I’ve collected for the project over the past several months. Wiring diagrams, installation manuals, instruction sheets, etc.

I worked on one of the wing tip lens. I cut a bit more off one edge with a Dremel cut off wheel and then sanded with the belt sander until it fit perfectly. One more to go.