Scott & Tanya Card RV9A build log (N4822C)

This evening I finished deburring and dimpling the elevator trailing edges and did a trial fit. This leaves things ready for some quick cleaning with MEK and then setting with proseal. That will leave the weekend free from airplane building. Maybe I should take the forced down time to go hang out on the boat (different topic) and relax for the weekend. Gotta’ love Texas for 70 degree weather in late January.

Today I received the bench dimpler that I ordered from ExperimentalAero. It is pretty cool, but I’ll have to wait for the next kit (the wings) to try it out.

 

  

 

The past couple of evenings have been spent drilling the trailing edges of the elevators. I attached some aluminum angle to the edge of the work benches to be used to achieve a “perfectly” straight edge. This involved much clamping, clecoing, and drilling. I finished the drilling and then countersunk the wedge. This isn’t fun but I think I finally have it figured out. I used the same aluminum angle on the edge of the bench as a backing plate for countersinking.

Countersinking is done. Next is to finish deburring the holes in the skins and dimple the trailing edge of the skins.

 

  

  

  

  

  

 

I completed assembly of both elevators this weekend (sort of). All that is left is to finish the trailing edges of all control surfaces and do final assembly of the trim tab. Ok, so Tanya was even quick to ask the common question of “why didn’t they design those elevator spars to face aft instead of forward?” as soon as she saw how the elevator top skin to spar rivets that had to be driven. I didn’t have a good answer for her except for an idea about the tapering angle of the pre-bent skin and a little theory about reliable bend radii in the manufacturing stamp… The top skin to spar rivets were a challenge to set. Tanya was there to help, but I found that it was easiest to drive and buck them myself so that I could feel the rivet blindly. It was slow going to do them blind, but it worked out just fine, only a few smileys were involved.

After the top and bottom spar rivets were set, we were faced with setting some of the skin rivets at the spar/counterbalance rib intersection. Others have commented about the difficulty here, but I would suggest that anybody starting this project to acquire the bucking bar pictured with this post. It has come in very handy. The rest of the elevator assembly is pretty straight forward. I did put a bit of silicone RTV at the forward and rear elevator stiffener edges as a precaution to long term stress cracks.

To finish off the evening, I did a bit of tool modification in order to install the rod end bearings for the control hinges that need to be installed. I’m quite excited about the 14mm socket modification that I did to get some leverage on these things buried in the elevator leading edge. I can’t take credit for the idea as I read about it on somebody else’s build log. I think this insertion tool will be much better than the normal PVC solution.

Oh, some may be asking what are those green things on the elevators? I bought some 25lb. bags of lead shot from the gun shop for weight. (They have come in very handy when dealing with pre-bent skins for assembly and back riveting.) The synthetic burlap bags that they are packaged in are quiet abrasive. Every time we put them on a skin they would threaten to scratch things. So, Tanya made some (green) soft cotton covers for them. A great addition to the tool set I must say.

 

  

  

  

  

  

  

  

 

We got all of the elevator parts and skins primed this evening. Next up (after putting the garage back together after priming) is the fun part of final assembly and riveting. That will be this weekend.

Just like I said, I got all of the elevator and trim tab parts alodined this evening (minus the skins). I used my dip trough for the first time. I must say that it worked quite well. It is about five feet long and eight inches wide. I used two gallons of alodine (actually PPG DX503). I have a third gallon just in case I needed it. When all was done, I was able to easily return all of the alodine to the gallon jugs that they came in. You may notice that I didn’t secure the plastic sheet in the trough, so when done, I just tipped one end off the end of the bench to a jug with a funnel in it. For the very long parts (spars), when I took them out of the dip, I just ran them out to the hose and lightly sprayed them off with water. All of the other parts I just dipped in a bucket of water on the way to the drying tray.

This evening was one of those where I had to tell myself that I really needed to just do something on the airplane each evening because it isn’t going to build itself. I’m hoping (no problem) to finish up the empennage with a few days to spare before the wing kit gets here in mid-late February.

Next up, the last primer session of the empennage!