Dave’s RV-7A Building Log

Flipped the center fuselage over and fitted the outside seat ribs. I had already drilled the bottom skin to the outside ribs, so that part was done. I did need to trim the forward ends of the ribs about 1/4″ to get them to fit inside the flanges of the F-704 better.

I then confirmed the torque on the seat rib to F-704 bolts and dabbed them with torque seal. Next was attaching the seat belt anchors to the F-705. The only reason I did this so late was because I wanted to put a little bit of primer on them where I had to grind them down. It’s not too bad fitting them in after the ribs are in place. I got part way through attaching them.

I almost forgot that I also trimmed the aft end of the longerons and made the little cut out on each. I drilled a 1/4″ hole at the corner of the cut out and then trimmed the rest with a hack saw. A little clean up with a Vixen file, and it looks great. I normally cut everything on the band saw and clean up with the belt sander or Scotch-brite wheel, but the longerons are just too much hassle to maneuver around the garage. It’s much easier to just use hand tools for this little task.

Not only did we get the aft fuselage almost done, we also completed the center fuselage bottom skin. What can I say? Julie is a goddess.

You really have to pay attention to what doesn’t get riveted. Don’t rivet the two forward or aft rows at this point. The corner baggage ribs and outside seat ribs are also done later.

Super-duper productive riveting day. Julie was in the mood for riveting, so we knocked out most of the rest of the aft fuselage. I think the rivets between the last two bulkheads will be easier to do with the tailcone upright, so we left those for now. I was worried about the joint between the side skin at the aft-most tailskin. There was a bit of a gap there, but Julie was able to set the rivets perfectly. It pulled the skins together nicely.

I also had a heck of a time setting one of the rivets in the corner between the bottom and side skins that was right up against the J stiffener. After two attempts at bucking the rivet, I ended up back-riveting that one and it turned out great. I know some builders back-rivet the whole fuselage. We’re getting good results with bucking, so we’ll stick with it.

Julie was indeed the master riveter today. We had probably the lowest percent of bad rivets ever.

Not much progress so far this weekend. The sun was out, so I did outdoor chores like buy a Christmas tree, clean the gutters, kill the moss on the roof, fix the Christmas lights, etc. I did manage to paint a little primer on the seat belt brackets where the powder coating was taken off from grinding them down. I covered all but the very edge of the bracket.

Spent a little time taping down the rivets on the center fuselage bottom skin. It’s ready for riveting.

This picture shows the general state of the project. The wings are done, except for bottom skins and wing tips. The aft fuselage is half riveted together, still waiting for help from Julie. The center fuselage bottom skin is ready for riveting. And the longerons are done. I’m running out of things to work on while waiting for riveting help. I guess I’ll pull out the seat backs or brake pedals. I think those two things are fairly independent of the rest.

Of course putting in the downward bend and twist on the second longeron took all of 20 minutes. I bet the guy that does the longeron bending for the quickbuilds can crank out a complete set in under an hour.

I also did a little tweaking of the twist in the area of the curve. It seems that doing the curve added a twist, so I took that back out with a Crescent wrench.

I consider the longerons ready for assembly.

Drilled the aft canopy deck to the other longeron and then started the sharp downward bend. The bend isn’t too difficult, but definitely takes some serious downward pressure and hammering. I kept watching the other dimension to make sure it wasn’t bending side to side. I got out the side skin as suggested in the instructions and checked the bend against that. I ended up needing slightly more than 2-3/4″ downward deflection, at least the way I was measuring it. After getting the bend to match the side skin, I started the twist with a Crescent wrench. Again, this was not difficult, but took significant force and several iterations. Using the Smart Level, I verified that I had a 17 degree angle at the end compared to the straight section. After twisting, I ended up with a slight inward bend. I just reefed it back outward by hand, checked the other dimensions again, and decided it was a done deal.

The most time consuming part was finding enough room to lay out the side skin and position the longeron over it. I sure wish I had a 3-car garage… and no cars.

I took another look at the first longeron, and it looks good. On to the other one. I flipped the template over and traced the outline through to the back side with a pen. The second one took about 1/2 hour to get the curve looking good. I spent about 4 hours on the first one, so it’s true what they say. The second one goes much easier. I did a little more tweaking to get the curve nicely lined up with the aft canopy deck.

Adele was nice enough to take some picture (albiet blurry ones) of the process. Here I am holding the angle down and whacking it. You can see that I have the template laid out below the vise, so I can easily take it out and check my progress.

Here I am comparing it against the template.

After the curve was just right, I clamped some 0.032″ to the outside of the longeron and then clamped on the deck, getting everything lined up just perfectly. It really turned out great, within 1/32″.

I then drilled the deck to the longeron.

It feels really good to make progress on these longerons that I was so worried about.

The whimpy vise I’ve owned for almost 15 years is just not cutting it anymore. I went by Sears today and picked up a real he-man vise. I tossed aside the old vise and installed the new one in it’s place. Man was that a good move. It made the longeron bending much easier and more predictable. The new vise is 3 times bigger, and doesn’t turn when you whack on it. Despite what this picture shows, I ended up removing those cool yellow plastic cushions. They were absorbing too much of the hammer blow. I ended up just putting a rag in there to protect the soft aluminum angle from the vise teeth.

Another change I decided to make was to use the template on the plans. I cut it out and taped it to a relatively straight board. I did several iterations of tweaking on the right longeron to the point where it follows the template well within 1/16″ and lays flat in the horizontal direction. It’s looking great. There is a slight twist between the 38″ and 69″ stations, so I might work on that a little bit more.

I also discovered why I thought the aft canopy deck wasn’t matching the template. The front end of the deck should be at the 28″ mark, not the 38″ mark. I’m really glad I discovered that error before I messed anything up. Once I figured that out, everything started making more sense.

After tonight’s success on the first longeron, I’m feeling more confident about the process and actually looking forward to working on the other one.