Dave’s RV-7A Building Log

Used a Scotch-brite pad to smooth the lightening holes in the wing ribs. The drum sander yesterday left them kind of rough. I’m sure there must be a better way to debur these things. Now that I’m almost finished with them, I’m sure I’ll figure it out. All that is left on the ribs is to do some touch up deburring in the flange corners, make the flange angle 90 degrees, and fluting. At that point I can cleco them to the spars for drilling. And then of course the routine of deburring, cleaning, etching, and priming. I’m going to end up going through that pile of ribs about 50 times before they’re done.

I also drilled the registration hole in the tie downs.

I didn’t spend too much time on the project tonight. The dog seems lonely since the family is still out of town, so I spent some quality time with him.

I mostly cleaned up the garage to make way for the wing stand. I put the empennage parts in the garage attic, except for the HS which is too big. I suspended that from the ceiling with two big utility hooks from Home Depot.

I screwed together two sets of 2 x 4’s, and put them up for the wing stand. Feels solid enough.

I also did some wing rib prep work. I spent about an hour with a drum sander smoothing the edges of the lightening holes. Some of the holes, mainly the larger ones, were really rough.

I also marked the position of the one hole on each tie down. You drill one hole as a registration point and then back drill the other holes through the spar web. The drawing says to use a 3/16″ drill bit, but the chart I have says a #10 is the right size for AN3 bolts. I’ll do the drilling later.

Installed the nut plates on the front of the spars at the root. These are some sort of attachment point for later.

I dimpled the holes on the access covers and verified they fit will on the spars.

Trimmed the tie down brackets. They didn’t require much trimming. I cleaned up the ends with the Scotch-brite wheel, and they were the right length. I also rounded the corners, eventhough the instructions don’t mention it. There are fewer and fewer details as you go along, so you need to fill in between the lines, e.g. radius corners.

Fabricated the spacers that go behind the tie down brackets. They came out pretty good. I cut the 1″ holes with a fly cutter. That thing is scary. If the stock got loose, it would really whip around. I clamp it down extra good. Following a suggestion on somebody’s web site, I cut all of the holes first and then cut the 4 pieces with the band saw. That’s much easier than trying to cut 1″ holes in tiny 2″ pieces of bar stock. The band saw is well worth $100, by the way. I radiused the corners and deburred the edges. I cleaned up the inside of the holes with a Dremel and what looks like a mini Scotch-brite wheel. It worked pretty well, although I’m not sure how long the wheel is going to last.

I also deburred the long edges of the main wing ribs–the daily wing rib prep. My mind really wanders when I’m working on those things. I start imagining all sorts of ways to automate the deburring process–none of them practical, of course.

Started off with an hour of smoothing edges with the Scotch-brite wheel on the rest of the wing ribs.

And then started the “fun” stuff. I discovered that plate nuts are not that fun. I started off by countersinking for the nut plate rivets at the root of the spar. There are 4 of those total. Next was countersinking for all of the fuel tank and access panel screws. I then primed all of the countersink holes with a Q-tip.

I discovered this about countersinking: speed and a light touch is not your friend. Things sped up considerably when I figured out that moderate pressure and a low speed cuts much faster. Otherwise, the cutter just skips over the surface. And one more thing, it makes a huge mess:

Spent half an hour deburring the edges of the tank and leading edge ribs.

Riveted all 164 plate nuts for the tanks and access panels to the front spars. It’s tough to get the squeezer in a few of the spots. The thin nose, no hole yoke worked well.

I spent an hour smoothing the edges of the tank and leading edge ribs with the Scotch-brite wheel. I’m going to spend about an hour a day working on the ribs to spread out the boredom.

And then I finally got to do some fun stuff. I drilled out all of the nut plate attach holes on both front spars. And then countersunk them all for the AD3 rivets. For now, I’m going to work on both spars at the same time, so I don’t have to set up everything twice. It took 10-15 minutes to get the countersink set up perfectly for the AD3 rivets. I then deburred the backs of the holes. The final step was to use a cotton swap to dab some primer in all of the freshly cut countersinks.

I put blue tape over the crack between the spar and reinforcement, because I’ve seen lots of people do this. I had to move the tape once, so the countersink cage would sit flush on the spar flange, and noticed that the tape is leaving a lot of gunk behind. And this is blue tape. Either the anodizing is affecting the tape, or it’s just old tape. Shouldn’t be too hard to clean off the gunk. Not sure the tape is really necessary, though.

It’s amazing how your eye can start to discern a countersink that’s just barely too shallow. After doing a hundred of them, you get to know what they should look like. I still double-checked them all with a rivet.

Sorted all of the little parts, counted most of them, and put them into little bins, so I can find them later. There sure are a lot of little parts. I’m actually short a few minor things, but I’m not going to worry about. All of the expensive stuff (bearings, fuel fittings) are there.

I also pulled out the left front spar and checked it out. It’s very cool looking. Figured out the orientation and marked top/bottom, front/rear. All ready to do some real work tomorrow night.

My friend Steve dropped by after work and we did the inventory of the wing parts. It truly is like Christmas, unwrapping tons of pieces and parts. The fuel caps are cool. The front wing spars look awesome. The amount of ribs is daunting. There’s about 50 of them.

It took a while to identify everything, but it’s all there. It also took a while to find a place for things. I found a safe, out-of-the-way place for the fuselage longerons. Won’t need those for a while. (Van’s ships all of the long stuff with the wings, so they don’t have to ship another long box for the fuselage. Smart, huh?)

I checked each part bag against the list, but haven’t looked inside them yet.

I can’t wait to get started!!

The wing kit has arrived!!

Julie wouldn’t let me do much tonight, since she leaves for Paris in the morning. The kit couldn’t have arrived at a better time. I have a week and a half without wife or kid. My only obligations this week are work and dog. The rest of the time will be drillin’ and deburrin’! I can even work all day on Valentine’s Day!!!

Here’s how the air plumbing turned out. The compressor connects via a flexible hose to several feet of copper running back and forth. That will help cool the air down before it hits the separator. It all has a slight slope down to the drain at the bottom. The air then goes through a separator and regulator. I’ve made it so I can take out the separator/regulator combo and hook it direclty to the tank, if needed. The other picture shows what the drops look like. I have several of these up on the ceiling. The pipe goes up and over so that the water (if any) stays in the pipe and runs down to the drain.

Worked on a few things around the shop to help organize things before the wing kit gets here. I’m in the process of plumbing some copper for the air, and made a cool frame to hold the empennage parts.

My daughter said the garage looks like I’m making another home out there.