Scott & Tanya Card RV9A build log (N4822C)

Progress has continued during the past week on finishing up the baggage compartment and various other things. I went ahead and riveted on the bulkhead gussets in the aft fuselage. I didn’t see any reason to wait. I also finished up the rear baggage wall with its seat belt anchor bushing blocks. After I removed the aft top skins, I went ahead and dimpled the skins and the bulkheads. They are ready to be riveted much later, so they’re put away for now. Tanya put in the conduit that I had planned for under the baggage floors and I tied them down with some adel clamps. Oh, yeah, I am putting down 1/4″ soundproofing material on the floors. All of the baggage wall nutplates are installed as well.

Alright, one might ask what I’m doing messing with elevator pushrod and control assembly and a COM antenna! I have a confession to make. I had a little bucking bar accident a couple of weeks back where I dropped a 2lb. bucking bar with sharp ends dead center of bottom skin in the baggage compartment. It was certainly one of those very slow motion horror movie moments as the bucking bar rolled right out of my grip from a little more than two feet up. I stood there in shock for what seemed like five minutes while my brain caught up with what had just happened. As I snapped back to reality, time for analysis. Yep, dead center of the tunnel, yep, that was a sharp bucking bar, it didn’t just leave a mongo dent, it fully punctured the skin on close inspection. Holy cow, it didn’t just hit once, but twice. It didn’t take long for me to conclude that the damage area is almost exactly the size of a BNC connector on an antenna. The only problem with this location for the antenna for COM1 is the limited clearance between the skin and the elevator pushrod. The next day, I ordered the antenna and some right angle connectors to see what kind of clearance would be needed. I got out the pushrod and prepared the rod ends and roughly assembled the control assembly back to the bellcrank. This was the moment to truth (note that many days had passed at this point. Plenty of time for me to fret over the issue at hand). The verdict is that there is plenty of clearance at this location for an antenna and the connector. I will just take care to carefully secure the wire. So, I completed the antenna install and all is well. I’ll put a simple little sheet metal patch on the other dent that I drilled out.

It is the Christmas holiday now and I’m taking a week off of real work to do my favorite thing, build.

 

  

  

  

  

  

  

  

  

  

  

  

  

  

 

I spent two or three full days working on the steps on each side of the fuselage. These were certainly a design after thought. I don’t have a whole lot to say about the step fitting process except for that it wasn’t very enjoyable and I’m glad they are totally done. Don’t get me wrong, there was no “rocket science” involved and nothing particularly difficult about it. I did deviate from the instructions and added a .040″ doubler plate on the back side just to add some more metal to the setup. I’m curious if anybody has ever over stressed (bent / broken) the step attachment? I haven’t heard of any such issues. Whatever, I wanted more metal than just the side skin to hold these on. I obviously primed the steel step inside and out, as well as all of the aluminum surfaces, before assembly. Some might additionally set the rivets “wet” (dipped in primer), I didn’t. I think corrosion and failure will be easy to detect here.

Moving on to the rear baggage wall. This is a two piece thing. The only pre-punched holes are in the bottom edge of the bottom piece. So, you line up the bottom holes (I used dummy #8 screws) and drill in assembly the rest of the screw holes up the sides. Once I got the bottom section drilled, I put a #8 screw and nut in a couple of the upper holes to hold things in place. The top section starts out as a rectangular piece that must be trimmed to shape. One thing of interest is a little downward bend, only a few degrees, on one long edge. There is no mention of this in the instructions or plans. I assumed that this is kind of like edge rolling an overlapping skin, and hence, belonged at the bottom straight edge. So I marked and trimmed the curved edge of the upper section (pneumatic sheet metal shears for the flat sections, die grinder with a cutoff wheel for the rest, cleaned up on the belt sander). Once it is cut to shape, all of the attachment holes and seat belt anchor pass throughs must me measured, marked, and drilled. Then I taped the upper section to the bulkhead in alignment for drilling to the bulkhead. This worked very well. The upper holes were drilled, first to #30 so clecos could be used to hold things together, then opened up to #19.

With the baggage walls drilled, I took everything apart for deburring. I also removed the aft top skins. I deburred all of the skin and baggage wall holes that had been drilled. I also used a nutplate jig to drill all of the attachment holes for the nutplates on the baggage wall bulkhead and deburred those. I then did some small final prep on the baggage floors. I’m getting very close to putting down the baggage floors for good. The only thing left is to install the sound-proofing material that I’m going to put on the bottom skin.

 

  

  

  

  

  

  

  

  

  

 

I took a couple of days off from “real” work and got some good stuff done on the plane. I made the spacers for the elevator bellcrank which I had already built. This was easy as I had done this before on the aileron hinges. Next I moved on to riveting the side top decks. This was an adventure. The rivet tail access was minimal on most of the rivets, and nearly non-existent on some. I used a squeezer yoke on many of the rivets and my long thin bucking bar on some that were really hard to get to. I even got rivets set around the center spar uprights (no pop rivets). On those that I knew would be really tough to buck, I used a slightly short rivet to limit the pain. It took me the better part of three hours to get both sides riveted on.

Next I moved on to something really fun. Fitting and match drilling the aft top skins. I deviated from the instructions in that I installed the aft most bulkhead before putting on the skin. It just makes a lot more sense to me to do it that way. Before the skins went on, I trimmed and marked the top J-stringers. With the skins on, I drilled the bulkhead to longeron gussets to the longerons. I also fitted the top center rib and it’s little attachment clip at the rear. Access to that is a little funky but totally workable. While I was match drilling the skins, Tanya came out and made some patterns for soundproofing material for the firewall and other odd shaped interior panels. Next I’m going to attack the side steps.

 

  

  

  

  

  

  

  

  

  

  

  

  

  

  

 

It was a reasonably productive weekend. I started off making a bunch of little clips to hold the static line. It took about three tries before I had a reasonable productive fabrication method down pat. Once I had it figured out, I proceeded to make fourteen of those little suckers. That was pretty time consuming, but the static line will be well secured. I also had to figure out where to punch a hole in the bulkhead for the static line. I have spent a lot of time thinking about this one and doing a lot of research. Most people don’t say anything about it and the plans don’t either. I concluded that I would drill a 1/4″ hole in the top corner of the bulkhead, right through the bracket. I also spent way too much time trying to figure out how I was going to set the three longeron rivets on the outside skin after the bulkhead bracket was riveted in place. There is no clearance for the tail of a rivet, much less any room to buck one. I decided to grind some relief spots in the edge of the brackets (before I riveted them on) to provide enough space to use blind rivets.

Moving on to something else, I riveted the firewall upper gussets on. As always, this was more time consuming than one would think. At the back of the plane, I decided I would need a snap bushing in the second to last bulkhead to pass tail lights, so in went a bushing. Next it was finally time to rivet the aft deck. That was very easy and fun. The tail section is now solid. Moving back forward, I decided to prepare the forward side decks. Drill, countersink, deburr, dimple… Also, somewhere in there, I fit and drilled the spar side caps on the interior and put them away for installation at a much later date.

 

  

  

  

  

  

  

  

  

  

 

There are all kinds of fun little tasks to do now. Most of which have nothing to do with each other. This is a welcome change. Obviously, first I spent some quality time with the level and shims to make sure the whole fuselage was perfectly level. I came to realize that when it comes to just getting things perfectly level, the old fashioned bubble level is every bit as good as the digital level. The cool thing about the digital level is that you can measure/calculate a difference. Things being consistently level at this point is pretty important as we are getting ready to install the aft deck which will torsionally lock the fuselage with any twist (bad) that exists. Before the aft deck is installed you can very easily twist the whole aft fuselage. Once it is on, it is rock solid.

So with that, I clamped the aft deck in place, checked level, adjusted, checked, adjusted, checked, re-checked, went away for a little while, came back, re-checked again, stepped back and looked at it for a few minutes, checked again, and drilled the holes. I think Tanya was wondering why I spent so much time looking at this one part. Cool, so it is drilled, deburred, primed, and I’ll rivet it on next time I have the rivet squeezer out. On to the next little task.

Next, there is a gusset, mid fuselage, that ties the sides to the bulkhead just aft of the seat backs that needed to be fit. Piece of cake. This is also where I’m going to mount my ELT antenna. So I got it out and drilled the hole for it. While I was looking at that setup, I realized I needed to figure out how I was going to route the antenna wire down the bulkhead and through the (removable) baggage side skin. A 1/4″ ID rubber grommet trimmed and split worked beautifully. So the side skin is still removable since the grommet and antenna wire can be slid out of the side notch.

Moving forward to the firewall, guess what, another gusset to be made. This one ties the firewall to the upper longerons. You could guess its importance by the number of large rivets that go into it. This was some tedious drilling as many of the holes go through the gusset, longeron, and steel motor mount on the firewall. Once again, they were deburred, primed and are ready to rivet. I’m priming these little parts individually with the rattle can in the closed garage since it is below freezing outside.

I got out the seat belt shoulder harness tie down brackets and match drilled them to the longerons. These get bolted on later. To finish off the evening, I installed the static ports on the sides of the aft fuselage. These are just big pop rivets that get pulled and then the center nail driven out to make them hollow. A piece of tubing is then glued onto the tail of the rivet. Very simple and effective.