Dave’s RV-7A Building Log

I ended up spending more time on the project than I was planning on. I managed to catch a cold over the weekend, so I didn’t have the energy to do anything else active today.

Started off by priming some parts from the flap actuator and tunnel cover.

Since it’s best to let the parts cure overnight, I pulled out the gear mounts. The instructions say to first line up the gear leg in the mount and drill out the hole at the top to .311 or 5/16″. Since they are only .0015 different, I went with what was on hand, 5/16″. I used the slow speed on my cordless drill with lots of Boelube and drilled them out.

I spent the rest of the day fitting the left gear mount. I drilled out two nut plates on the F-704 flange on each side to make it easier to get the mount in and out. That was a good suggestion from Matthew’s site.

In total I probably put that stupid gear mount in and pulled it out 20 times. It took several iterations to get the hole in the bottom skin correct. I used the template from the drawing when I originally cut the hole. Turns out it is undersized by about 1/16″ all the way around. The hole needs to be larger in order to get the mount through it. I used a sanding drum in the Dremel and bit by bit enlarged it. There is now a small gap around the mount, but I’ll fill that in with some Proseal or something.

After the hole was the correct size, I discovered the interface problem with the rivet at the bottom of the forward F-704 flange (yellow arrow in picture). A few people mention this on their site. I used the grinder and Dremel with grinding stone to provide some clearance for that rivet.

With the clearance issues all worked out, I put in one bolt at each corner of the mount. I actually didn’t bother with nuts on the inner two bolts, but did crank down the bolts for the wing spar using the wood spacer I made a while back. The instructions say it’s OK to use the bolts to pull tight a 1/16″ gap or less. That’s what I did, and it wasn’t working. Of course the problem rivet was hitting the mount again and the mount was pulled close against the edge of the bottom skin hole. I pulled everything apart again and took care of those two problems. Bolt it all together again, and it was finally a nice fit.

I drilled the aft 5 holes through the side skin, lower longeron, and gear mount in stages. I started with #30, then #19, and finally #12. (Tip: Use a drill stop. I ended up nicking the gear mount with the drill bit.) The front two holes are a little tricky. One is drilled from the inside and then the other has to be drilled from the outside because of interface with the F-902 bulkhead. It’s straightforward to measure 1″ forward of the other hole and drill away. Worked perfect. Also note that the forward two holes take a #8 screw versus the AN3 bolt for the back 5. I almost messed that up.

I pulled everything apart one last time and deburred. The hole that I drilled previously in the bottom skin for the brake line didn’t line up perfectly with the hole in the gear mount. Matthew mentioned that problem as well. I’ll have to see what fitting goes there to see if I need to enlarge the hole or not.

Overall, fitting the gear mount was more difficult than I expected. It was a pain in the rear end (or actually a pain in the back), leaning over the side of the plane for hours fiddling with the thing. It fit OK, but wasn’t perfect. It took a fair amount of tweaking, especially for the bottom skin hole. At least it’s now done. I’m not going to permanently install it quite yet. I’ve heard it’s easier to bend the fuel lines if the mount is still loose. Hopefully the right gear mount goes more quickly now that I know what to expect.

I went to the Mariners game yesterday, so I didn’t get anything accomplished on the project.

I did the rest of the flap actuator fitting and drilling. There’s nothing difficult to it. Just follow the instructions. I found that it was easiest to mess with the flap actuator from inside the plane rather than leaning over the side.

I also used the two tips from Matthew Brandes’ site. The channel gets drilled larger for the bolt head and the bottom of the “back rest” should be 1/8″ above the vertex of the angle. Both things are called out in the plans, but are not immediately obvious. To wrap it up, I put the side covers on and drilled them to the back channel. I used a 12 volt battery from the cordless drill to run it up and down a few times. That was pretty fun.

I’ve been lazy about snapping pictures lately. These two show the motor half installed, but I didn’t get a picture of everything put together.

I did a little bit more deburring on the cabin covers followed by some work on the flap actuator.

I drilled the little hole for the safety wire in the end of the motor arm. I also finished fabricating the various parts, including the center plastic block and the brackets at the top and bottom of the channel. There are a lot of little parts to the flap actuator.

It took me a while to find the end blocks. Turns out I already made those as part of the F-705 bulkhead and put them in a different place.

Like the rudder pedal tubes and the steps, the fit of the plastic blocks is pretty tight. Setting the block on the floor and pushing the tube into works really well. I then put the tube into the plane, loosely bolted it in place, and marked the location of the center block.

I did a little more deburring on the cabin covers and washed a few parts to prep them for priming.

After that, I decided it was time for something more fun. I pulled out the parts and drawing for the flap actuator. The electric flap actuator is a standard part on the RV-7, but was an option on the RV-6. As shipped it’s an add-on kit for the RV-6, so it has a few extra parts in it that are not needed on the RV-7. It was a little confusing trying to figure out what was where and what needed to be fabricated. Luckily, there aren’t many fuselage parts left. After studying the drawings a bit, I started to fabricate the necessary parts.

Adele had a piano recital, so I just spent a little time deburring the forward covers.

I fitted and drilled the heat baffle and then fitted and drilled the forward covers. The instructions are pretty good in this area, taking you step by step on how to fit the covers in place. I used the cover under the fuel valve to locate everything. However, I’ll eventually use the cover in the Airflow Performance fuel pump/filter kit from Vans.

Julie was willing to help today, so it was time to take care of the miscellaneous riveting on the fuselage that I’ve put off now for quite a while. First up was the baggage ribs to F-706 bulkhead. I was able to squeeze some of the rivets a while ago, but some required bucking because of access issues. Even bucking these rivets proved challenging. The rib flange was half supported by the reinforcement for the bellcrank rib and half not. That made the rivet turn and the buck tail leaned over. No matter what we tried, they all leaned over. It was also a very difficult area to drill out. After drilling out 5 rivets, I decided to bail on bucking them and just used blind rivets.

Next up was to finish the half dozen or so fuselage skin rivets. We knocked those out pretty quickly and easily. Since those were finally complete, I was able to install the bolts and spacers in the outer-most seat rib to F-705 junction. I had to spread the forks a little bit with a wood wedge, but eventually got the spacers located just right. I installed the bolts, torqued them, and marked them with torque seal. I then solo riveted the two rivets on each side in that same rib flange.

I moved on to the bellcrank support. I installed that and was able to buck or squeeze all the rivets solo, except for the ones through the skin. I installed the bellcrank and spacers I made a while back and confirmed that everything fit perfectly. Per the instructions, I removed it and stored it away.

Keeping on with the pick-up work, I solo riveted one rivet on each side in the arm rest. I thought I was going to need help with them, but I ended up bucking it solo just fine. And finally, I squeezed the rivets at the top of the F-724 aft fuse bulkheads. The plans called for universal head rivets, but I decided flush rivets would look better and weren’t that much additional hassle.

This is a shot of all the stuff I needed today. We only set maybe 3-4 dozen rivets, but they were all challenging in their own special way.

To cap off the day, I set the seat skins in place and threw in a couple of cushions from the couch. It’s really bizarre to think that this thing is actually going to fly some day.

I went back out to the garage after dinner to work on a little something. I didn’t feel like deburring the seat skins on the Scotchbrite wheel (too noisy and dusty). I pulled out the forward covers, but didn’t want to jump that far ahead. I pulled out the crotch strap attach point kit, but I think I need to verify the thickness of the seat belts before I install that.

I ended up deburring and dimpling the top halves of the bulkheads and the gusset and rib that go under the top skin. A worthwhile task that doesn’t take too much thinking.

I looked ahead in the instructions and there is a fair amount to do, but not too much. I need to install the forward covers, flap actuator, and gear mounts, attach the empennage, work on the rollbar/cabin frame, brake, fuel, and vent lines, and then the forward top structure and skin. I’m going to wait until I’m in the hangar to fit the wings, so I think that’s about all that’s left on the fuselage. Cool.

Looking at the tunnel cover on other web sites, I thought it was a big thing. It’s actually rather small, but very sturdy. I guess the purpose of the thing is to let the elevator push rod rise up.

The instructions for the tunnel cover are a little tricky, but work well. I first drilled the holes in the cover to #40. I then drilled the holes in the bottom part of the supports to #21 and clecoed them in the cabin with the seat skins.

Next put the cover in place and push it up until it sits nicely against the seat skins.

Drill out the front hole and then the side holes making sure everything looks even. I made sure I had the drill stop set for the forward two holes in the support, otherwise it would have gone right into the seat skin.

Decided to make some room in the garage for the convertible. Now that we have the hard top off, it’s better to keep it inside. With the finish kit arriving in a month, I’m not sure how long there will be enough room in the garage. For now, we moved the wings into the spare bedroom. We had to temporarily place the wings on the lawn while moving the cradle, which made for an odd picture.