Scott & Tanya Card RV9A build log (N4822C)

I decided to see if a little shim on the forward canopy frame would help the very tight skin fit on the outboard edges. It worked perfectly and improved the slightly high condition of the skin a little further up. I also needed to fabricate the mounting blocks for the tipup struts. They are mounted with #10 screws that require a dimple in the skin. Guess what, I don’t have that dimple die! Grrrrr… That one didn’t come with my Cleveland tool kit and it has annoyed me a number of times. A little quick research showed that it usually does come with the Avery kit and that is where David got his stuff. I picked up the phone and David came through with the correct die. (I finally ordered myself one too.) I decided to chop some more of the canopy skin ears off.

Separate topic: There was some conversation about people struggling with Clecos not holding skins after they were dimpled. After I dimpled the skin and was putting it back on the frame, one of the clecos didn’t hold much at all when I put it in. Hmmm… Lets see… Yeah, I have two brands of clecos. The one pictured on the left is “Wedgelock” and the one on the right is “Cleko-Lok”. The one on the right is the one that didn’t hold. I measured a good sample of different ones and found that the “Cleko-Lok” averaged about .0125″ smaller in diameter at rest. Not good.

Moving on, I stitched the skin back on the frame and checked all of my dimples and machine countersinks. Tanya helped me carefully lift it off of the fuselage and place it upside down on the bench. I got out the frame brace/stiffener kit and began fluting the holes and bending the flanges. This was about a four hour operation. I used some little delrin blocks with a slot cut in them that I borrowed from Jeff B. They worked perfectly. Thanks Jeff. The braces were a pain in the rear to edge deburr with so many flanges. I drilled the braces to the forward frame channel and stopped short of drilling to the skin. My plan is to drill at least some of the brace to skin holes with the frame in place on the fuselage to try to be sure I don’t induce some funky twist or something.

Oh, yeah, just in case you weren’t paying attention, this is the LAST skin on the whole airplane. I have edge deburred, drilled, hole deburred, and dimpled a whole skin for the last time (on this plane :). That is a pretty cool milestone.

 

  

  

  

  

  

  

  

  

  

  

  

  

  

  

 

The canopy side skins are done. All of the canopy and rear window holes are machine countersunk and drilled to final size. All plexi edges are trimmed. I still need to do the final edge smoothing all the plexi edges. Now I guess it is time to take the whole canopy frame off and hole prep, prime, paint, and rivet it together.

 

  

  

 

I machine countersunk the canopy skin in place at the aft tube. I trimmed a sacrificial CS4-4 rivet to test the countersink bit since it is a bit long and bottoms out on the tube. I am going to leave three rivets out along the aft tube on the outboard edge on each side because of a big gap that I’ll fill with something later. I’ll fill these holes with rivets to nowhere.

I got the rear canopy frame primed and riveted together and did a “final” fit of both the rear window and canopy. The canopy needs just a bit of additional trimming (sanding) along the frame split for clearance from the rear window. I am now working on laying out the side skins.

 

  

  

  

  

  

  

 

I started doing the machine countersinking for the screws on the canopy. I took a little time to ponder the situation and do a bit of experimentation. The holes are drilled in the plexiglas with a 1/8″ plexi bit. I’m going to use a countersink bit with a #30 pilot (this is a little bigger than 1/8″). No way am I going to just cram it in there as it will surely crack the plexi. There doesn’t exist (easily) a #30 plexi drill bit, and you’re not generally supposed to use standard tip drill bits on this stuff because they grab too much material too quickly, hence the deep taper angle of the plexi bits. Through experimentation in scrap, I concluded that the standard #30 bit is close enough to the existing 1/8″ holes that it can be safely used to open them up to accept the countersink bit. So that is what I did. Once the holes were a little bigger, the countersink bit was still a little tight but it worked fine. This is a tedious process as is anything with the canopy as I don’t want to produce a crack in the process.

I also spent a little time final drilling the rear canopy frame splice plate and deburring the frame channel. If you’re doing this stuff, make sure you edge deburr the canopy frame channel *before* fluting it for shape (unlike I did). It is obviously much easier to deburr without the flutes already in place as with any other part.

Next, the rear window is going to come back out for some more minor trimming and machine countersinking. I placed a small tool order this week containing the correct drill bit to open up the screw holes (5/32″ plexi) in the canopy and window. That won’t be here until Monday, so the plexi work will have to wait. Maybe I’ll look into riveting the forward top skin on the canopy frame.

One other thing I ordered is a new mini quick connect for my small air hose. The one that I’ve been using since the start of the project has failed. It is made out of a relatively soft brass or something and I guess the end of the air hose has been dropped on the floor a few too many times. I’m very eager to get this replaced.