109JB's Kitfox IV rebuild

[109JB]

I was looking through the paperwork I got with the airplane for something else and happened to see notes from the second owner who re-did the airplane back in 2007 and one of the entries read "Why doesn't right wing fold correctly? So it seems that the right wing didn't fold right way 13 years ago either. I know that guy so I'll give him a call and see if that note was referring to this issue (I think it must be) and if he ever found anything out about it.

[109JB]

Having completed my initial assessment of the airplane I decided it was time to get the shop ready and to do more disassembly. I'll have some pictures of the airplane later, but wanted to comment on a practice that just flat out puzzles me. I even went into the builders manual that came with the airplane and it is in there so it isn't a one-off builder screw up. What am I talking about? Rivets in steel tube structure. Now I'm not talking about cases where there may very well be a valid reason for doing it. I'm talking about doing it just because it is easier.

For example, the firewall on the Kitfox IV at least, is riveted to 3 different tubes at the firewall station using aluminum pop rivets. There are probably 30 rivets for that alone. That is 30 places for potential water intrusion and if water does get in it has no way to get out. Can you say "rust". Sure, the firewall needs the rivets to hold the different pieces of the firewall sheet metal together, but it doesn't need to be riveted to the tubes. It can't go anywhere because it is sandwiched between the engine mount and the fuselage and any more security it needs can be handled with a few tabs. I've now have all of those drilled off rivet tails inside of those tubes and can't get them out. At least not easily. I'm going to wind up welding all of those holes shut and putting on maybe 6 tabs for the firewall security.

Another example is a hole drilled into the top of door sill tube. What is it there for? A little wire clip that you can drop into the hole to keep the door open about 3 inches at the bottom. Ok fine, but it is also about 3/16" diameter and in the top of the tube. There is obvious rust around the hole telling me that water has had a chance to get in there and there isn't any other hole at the low point for the water to get out. I'm seriously debating whether I should just replace that whole tube or at least cut out the rear section of one to see if it is rusted inside.

I could give several more examples from my airplane from nose to tail but you get the point. I would much rather see a screw and a little sealer that a rivet. Aluminum pop rivets have a mandrel that many times falls out leaving a hole and they also work loose. Probably 1/3 of the rivets I removed were loose.

From my perspective drilling holes into steel tube structure for no good reason is an unnecessary practice. I previously built a Sonerai IIL and when I welded that fuselage it wound up with exactly 4 holes that go through into the interior of the tube structure. Those holes were put in specifically for a path to introduce preservative coating to the inside of the tubes. These holes were then plugged with sheet metal screws and a sealer (they don't leave tails inside if removed.). It can be done, and in my opinion should be done this way if possible.

OK. I'm coming down off of my soapbox now.

[109JB]

Have had other things going on but did receive my Garmin stuff and have had a chance to play with the G5. Super easy to get going in a basic sense. 2 wires and an old serial port plug got it going. I'll be putting it in with a GMC507 autopilot controller, and servos, so I want to be able to pipe in navigation data so it can fly a planned route. In that vein, I played around with a $5 bluetooth module, and a $2 TTL to RS232 module, and was able to get Avare on my Android phone talking to the G5 without any problem. You can tell that the nav is working in the picture below because the CDI needle on the G5 has appeared. Without a nav signal the CDI isn't there. There is also a pic of my current plan for the instrument panel. I may or may not mount the standard airspeed indicator. Also, to answer the inevitable questions, the green LCD below the G5 will be an engine monitor that I will build myself, and the green LCD on the right side of the panel will be a home-brew instrument that has the basics in digital format in case I want to fly from the right seat.

IMG_0806.jpg

Instrument panel.jpg

[rv9ralph]

Cool.. Congrats.

Ralph