Scott & Tanya Card RV9A build log (N4822C)

A productive weekend indeed on the forward fuselage, although not a whole lot to show for it. Tanya let me work in the garage the whole weekend. I’ve been disassembling, edge and hole deburring, dimpling, machine countersinking, and scuffing. Most of the small parts are ready for primer. All of the skins are ready for primer. I got center section and longerons removed and ready for hole prep.

Customization: I spent at least six hours planning and fabricating a bracket for the parking brake valve to replace the brake hose bracket on the firewall. I used a piece of hat channel riveted to the firewall (used the existing holes) and some .032 scrap to make the cable mount and valve arm stop. I have spent a lot of time pondering this contraption. It is all done and riveted to the firewall. I also decided to do a little reinforcement of the side arm rests. I just used a single piece of .063 3/4×3/4 angle run lengthwise. It won’t be bullet proof, but is better than nothing. As designed, the arm rests can’t take any load from a person using them to get out of the cockpit. My addition won’t accept full load, but might help. If you really wanted to be able to use the arm rest to pry yourself out of the cabin, you would need to use 1/8″ angle and tie it into the bulkheads. That would be more weight and effort than I was willing to do.

 

  

  

  

  

  

  

  

  

  

  

  

  

  

  

  

 

Still working on it. Progress has been a little slow for the last week as real work got in the way. I have completed fabricating and drilling all forward fuselage parts and am now taking it all apart for deburring, machine countersinking, dimpling, priming…

I completed the rudder pedal mount setup. I drilled for three positions at about 1-1/8″ spacing from the forward most position. The last thing before disassembly was to frame up the baggage compartment. I found that Vans had mis-labeled one of the F-724 bulkheads such that I ended up with two left parts where I need a left and a right. I immediately picked up the phone and called David (RV7A builder a few blocks away a little behind me in fuselage construction). He was kind enough to lend me his F-724-R from his kit while Vans ships a new one to me. It sure is nice that the -7 and -9 use most of the same fuselage parts. With the baggage bulkheads done, I moved on to the side skins. I didn’t notice any mention in the instructions as to the need to trim them but they clearly have to be trimmed to fit. I actually haven’t looked at the instructions in many weeks. Really all they say at this point is something like “build the airplane as shown on the plans”.

Before disassembly, I made some notes and marks for some final bend adjustments that I want to make on the lower aft of the forward side skin. How about some pictures.

 

  

  

  

  

  

  

  

  

  

  

 

Another week with much progress. I attached the forward side skins. I decided to be “bold” and bend the rear curve first. This worked out just fine, although a bit frustrating. I did end up slightly cracking the corner of the sharp bend just like they tell you not to do in the instructions. I stop-drilled the crack and removed the failed material. This is seen as a 1/4″ long notch at that corner. It is fine, just an extra stress-relieved bend. Also seen in some of the images, I needed to adjust my bend to come a little more in line with the bottom of the side skin.

I also cut the holes for the side steps AFTER doing the bend. I think that was a wise choice, as doing it before would have complicated the bend. Have you ever used a fly cutter in a cordless drill? I cut the step holes with the skin on the plane. That was exciting in a terrifying kind of way. Nah, not really, I just turned the fly cutter super slow and used it more as a low speed scribe than a high speed cutter. It worked great.

With the side skins on, I match drilled the arm rests (no brainer) and longerons. Drilling the longerons was one of those processes that requires lots of time and patience. This is also a good process to slow down and do it right the first time, yet not be petrified by the profound nature of what you are about to undertake. Ok, so this seems like an important step. I started from the aft of the fuselage and worked my way forward on both sides. I used a lot of clamps and checked to be sure I was progressing with the top of the longeron flush with the side skin after every couple of holes. I did try to leave just a bit (just a hair) of overhang on the forward skin to account for edge deburring. No big deal, but I’m at least trying to be smart about such things. Alright, so after about six hours and a whole lot of Boelube across two sessions, I completed drilling the length of both longerons. That is a lot of holes. I should note that when I got to longeron alignment at the seat back bulkhead (I forget the part number), it seemed like there should be some consideration for the fact that there is a bracket part that fits between the bulkhead and the longeron angle. It seems that you could get the longeron drilled too close to the top of the bulkhead such that the part that goes between wouldn’t fit later. So, I used a spacer to space the longeron angle off the top of the bulkhead while drilling it.

The forward sharp bends in the longerons came out surprisingly well. They matched the skin just as good as when I did a test alignment against the skin when I was bending them (shouldn’t be any big surprise). I did find that I needed to put some extra twist in the longeron to make it match up to the firewall engine mount angles partly because the side skin wants to take the twist out of the longeron. No big deal, a little extra twist and things came out fine. (picture shown is before extra twist).

Next up was to put on the firewall. Whew, another critical operation. I followed the instructions, used some more Boelube, and the firewall and bottom forward skin are attached.