The Barn Find Build

[rv9ralph]

Your pictures and descriptions show poor technique... which will require a complete inspection of everything done by the previous builder. As a suggestion, due to age replace all elastic stop nuts and inspect the rest of the AN hardware.

Good luck with it. Think of it as a restoration, you start by going backward until everything is solid, the go forward doing everything properly. In the end you will have the plane you want.

Ralph

[alexM]

Eric,
Glad you started a restoration/build thread. Maybe I could fly down to Toledo and look it over with you. That elevator push pull tube is concerning. There's supposed to be a plastic bushing in there, very similar to the rudder pedal and flaperon bushings but larger. I know because I just bought one. That dent is concerning and if it were me I would plan on replacing that tube.

I would get that covering off for sure. All of it.

[Eric Page]

Your pictures and descriptions show poor technique... which will require a complete inspection of everything done by the previous builder. As a suggestion, due to age replace all elastic stop nuts and inspect the rest of the AN hardware.

I agree. It's all coming apart. Much of the remaining hardware has surface corrosion, and the stuff that was used appears to have been universally over-torqued, so I'm planning to buy all new.

-=-=-=-=-=-

Maybe I could fly down to Toledo and look it over with you.

Yes, please do. I'll be here the rest of this week, except 11a-3p on Wed, then away Aug 1-4.

That elevator push pull tube is concerning. There's supposed to be a plastic bushing in there, very similar to the rudder pedal and flaperon bushings but larger. I know because I just bought one. That dent is concerning and if it were me I would plan on replacing that tube.

The bushing is present. I didn't think so at first because of the appearance of the tube -- it looked to me like the aluminum was wearing to powder on the steel support ring -- but it appears that the black smears are from whatever the bushing is made of. I agree on the dent, and replacing the tube.

I would get that covering off for sure. All of it.

I didn't get it done last night, but I'm definitely pulling fabric off the fuselage this afternoon.

[avidflyer]

When it comes to removing the fabric, it's just like the song that goes ' the first cut is the deepest' Hard to put the knife to the fabric, but once the first cut happens, you just keep going. Remember watching a friend who was about to rebuild his Chief aircraft. He had the hardest time making that first cut. I finally handed him the knife, and said "cut" Pretty soon after that it was naked.... JImChuk

PS, I don't think I would worry to much about the flaperons, as long as the hinges and the main tube are good, and the damage shown is the worst of it.

[Eric Page]

PS, I don't think I would worry to much about the flaperons, as long as the hinges and the main tube are good, and the damage shown is the worst of it.

Thanks, avidflyer. I was thinking about this today...

Does anyone know what alloy the flaperon skins are made from? If there were markings on mine, they've been removed. I'm guessing 2024, in which case stitch-welding isn't an option.

My initial repair idea is this: Stop-drill the cut in the skin (the hole would be barely around the leading edge, just on the opposite side). Using a wooden buck that matches the airfoil shape, fabricate a patch from 0.020 sheet just large enough to extend about an inch beyond the damage in each direction, with the slot shape pre-formed in the patch. Finally, bond and rivet the patch over the damaged area so that the patch aligns with, and reestablishes the end of, the bracket slot.

For the deep scratch in the other flaperon, stop-drill both ends of the sharp crease, use a dab of Hysol to fill the holes and crease, then use body filler and sanding to smooth out the rest of the dent.

Any other suggestions are welcome.

[109JB]

On the Kitfox IV speedster, the flaperon skin is cut all the way around making a 1/4" gap at each hinge location. At these points the trailing edge is connected with a small metal tab. The 1/4 gap is covered with fabric. Was supposedly done this way to prevent flaperon binding during high g maneuvers. If I remember I'll post the directions for this from the builder manual. Bottom line is that a little cut in the flaperon skin isn't much to be worried about.

[PapuaPilot]

My initial repair idea is this: Stop-drill the cut in the skin (the hole would be barely around the leading edge, just on the opposite side). Using a wooden buck that matches the airfoil shape, fabricate a patch from 0.020 sheet just large enough to extend about an inch beyond the damage in each direction, with the slot shape pre-formed in the patch. Finally, bond and rivet the patch over the damaged area so that the patch aligns with, and reestablishes the end of, the bracket slot.

For the deep scratch in the other flaperon, stop-drill both ends of the sharp crease, use a dab of Hysol to fill the holes and crease, then use body filler and sanding to smooth out the rest of the dent.

Your repairs for the flaperons seem good. AC43.13 would be the best guide, which has you use the same thickness of sheet metal as the original material. I am pretty sure that the flaperons are made from 2024-T3 aluminum.

[Eric Page]

Thanks, guys. I appreciate the info. I'll check 43.13 before I proceed. I'm a long way from needing the flaperons, so they can wait until I'm stuck waiting for parts on something else.

-=-=-=-=-=-

I made some progress the last couple of days. I got the fuselage and vertical stabilizer stripped of fabric, and I'm glad I did. The Poly-Tack application was pretty inconsistent, so the fabric wasn't uniformly stuck to the structure. In some places it came off easily, and in others I had to pick at it with a knife blade to get an edge up that I could get ahold of.

With the tail open I can see how the ribs were done. It looks like Hysol was applied with a kitchen spatula on the end of a broom handle (it ain't pretty!), but the ribs appear to be straight and structurally sound.

Once it was stripped, I got started on removing everything. The doors came off first, then I dove into the flight control system. In all of the controls, there was ONE nut and bolt that didn't fight me. All the rest were either torqued way too tight, or had surface corrosion that made them difficult to remove, or both. I'm REALLY glad I'm taking it apart.

The rudder torque tube assembly is a mess. The pilot's left pedal and the copilot's right pedal are very tight and hard to move. It looks like the nuts holding them to the mounting brackets are too tight, so the tubes are bound up on their bushings. Unfortunately, there doesn't appear to be any way to fix it without drilling out the rivets and separating the torque tubes. The nuts holding them in the brackets just spin their bolts and won't come loose, and the bolt heads are inside the tubes and inaccessible. At least the whole assembly is off the fuselage so I can put it on the bench.

I just need to get some cable cutters and I'll be able to finish the fuselage disassembly. The rudder pedal adjustment handles are trapped because the bolts that hold the cable ends are stuck in the handle tubes, and the cables are captive in the fuselage due to Nicopress sleeves. I have an idea how to get the bolts out using some wood blocks and the bench vise, but I've got to get them free of the fuselage first.

[PapuaPilot]

I'm REALLY glad I'm taking it apart.

That is what you want to say after wondering if total disassembly was the right thing to do.

As far as you rudder pedal issue I would search the forum on this subject. Look especially for the people who did a build log. This is a known problem and it usually takes us several days of work to align, trim, shim, and mount the rudder pedals and get them free from binding. There is a good chance this wasn't done properly at the original build. Now is the time to take care of it.