Scott & Tanya Card RV9A build log (N4822C)

Yee Haw! On to the next assembly. This building thing is seriously addictive. I’m having a ball. The best days are when I come in from the garage in the evening with my feet hurting from standing all day.

This is the start of the 705 bulkhead that is just aft of the seats. It actually provides an number of structural needs: This is where the top of the seat backs are supported, this is where the seatbelt anchors are attached, and the bottom of this bulkhead is were the rear wing spars attach. I started by spending about 20min. in the parts room finding all of the pieces for this assembly. Much of it was just raw material stock that had to be identified. With all the materials spread out, I started marking the materials that needed to be cut for part fabrication (spacers, blocks, brackets, etc.). Measure twice, mark the part, and measure again before going to the bandsaw. Then I spend some quality time at the bandsaw, belt sander, and scotchbrite wheel (oh, there was also plenty of filing by hand too) to fabricate all the needed parts from sheet, angle, and bar stock. How many times have I said this before: The instructions are now very brief, like “Assemble parts A, B, C, D, E, and F per drawing 20.” Well, you first have to make those parts from the correct stock…

With most of the parts made, I back drilled the lower aluminum bar on the drill press. This worked out very well. Getting all of these parts to come together in alignment is kind of tricky. I sure have a lot of respect for those that built these things before pre-punched kits were available. With the lower bar drilled (a couple of hours of work), I moved on to the seat belt brackets. The sequence on these is to measure, mark, and drill all of the left brackets, then jig things up to match drill the right brackets. This is where I left off.

 

  

  

  

 

I got back to work on the center bulkhead by installing all of the nutplates on the top flange. I installed all of these with NAS1097AD3 rivets which are 3/32 rivets with a small head (like what Vans calls an oops rivet in AD4 sizes). The deal is that the machine countersink doesn’t have to be nearly as deep and can be done with just a few turns of a deburring bit. This is the deal for nutplate installation in thin material where the surface has to be flush (nearly always). I used the same method for the nutplates in the cover brackets too.

I then started riveting the uprights to the bulkhead ends. I have seen that many people do all kinds of gyrations for driving these rivets with the C-frame. I tried it, yes it worked quite well, but was a very slow and unnecessary operation. I quickly abandoned the C-frame and jigged the bulkhead upright on the end of the bench (clamped rigid) and shot all of the rivets normally. This was much easier for me. After all of the rivets were in, I popped in the snap bushings and did some preliminary control stick assembly fitting.

I had been fretting about how I was going to make the spar blocks that are required to be exactly 1 and 7/16″ thick. I couldn’t think of anybody that I knew that had a planer. I ended up going around the garage measuring every piece of ply wood that I had (it takes an awful lot of wood to build a metal airplane). The key was finding the thinnest piece of 3/4″ ply that I could find. I found a piece that was almost exactly 1/32″ short of 3/4″. Two of these laminated together with a very thin layer of glue came out perfect with very little effort. After the glue dried, I match drilled blocks for the spar bolts and this assembly is done.

 

  

  

  

  

  

  

  

  

 

I have had some recent general conversations about Tape and clamps of various types. It is amazing the opinions you can form about the details of a particular type, brand, and configuration of a product with a project like this. Yes, I have an entire toolbox drawer full of different types of tape. The pictured clamps are only representative of type, not quantity (multiples of most). Some of the clamps are better than others… Yeah, that was the conversation.

 

  

  

 

Next up is the center section bulkhead. I spent a little time digging out parts that came with the wing kit for the center spar section that makes up the backbone of the airplane. These parts are match drilled at the factory with the spars in the wings. I started out with opening up some pre-punched holes for snap bushings with a unibit. It is a bit of a scary operation to go after this beautifully anodized assembly that is matched to the wing spars (no easy replacement) with a unibit to 5/8″. Don’t just measure twice and cut once, but think three times and drill once here.

Then I assembled the uprights (fore and aft) using the close tolerance bolts to line things up. I measured the bolts and found one that was .0005 smaller than the rest. I used that one and one other to line up the parts. Match drill after everything is lined up. Next up was the shear blocks. I aligned these with close tolerance bolts and back drilled them by hand. Looking back, I probably would have just marked them with the back drilling process and then transferred the drilling process to the drill press. i.e. my by-hand drilling wasn’t perfectly square, but will be just fine.

I also match drilled the control pivot brackets (pictured) via the above concept. Then the brackets were trimmed per the plans on the band saw. Oh, yeah, don’t forget deburring both sides of any holes that are drilled. Next is to prepare and assemble nutplates on the top edges of the center section…

 

  

  

 

With everything ready to go, I setup to rivet the firewall stiffeners and brackets. I squeezed most of the rivets along the bottom and side stiffeners, then back riveted the rest. This was kind of a slow process as I back riveted just a few (4-6) rivets at a time. It also took some jigging with 4×4 blocks. Two to support the firewall and one with the back rivet plate on it. I didn’t put any rivets in that will eventually secure the recess hole in the middle. There are certainly a bunch of little thinking parts inbetween. We’re now definately building from drawings and not so much from instructions. Firewall is done.