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Wings Closed, part 2

4 hours.

Wing skins are done! I reinstalled the flaps and got a strip of UHMW tape along the back of one, and I’ll do the other tomorrow. The other thing I have to do is find or refabricate the flap hinge pin fasteners. After that, I just have some minor wire tidying to do and the wings are done, done, done.

Wings closed, part 1

7 hours.

Yesterday, my friend Derek came by for a few hours and helped me rivet the bottom wing skins on. Derek is peripherally responsible for me being where I am today with regard to aviation: Flying leads to skydiving, skydiving leads back to flying and flying lessons, rental airplanes lead to homebuilts. Before he arrived, I did some pondering about the best way to rivet the wing skins on, and the first two things that needed to happen were the removal of the aileron push tubes and the flaps, so I did that.

Riveting the skins on the wings would have been really tough without help, especially the inboard rows near the bellcrank. As it was, I really had to stretch to get the bucking bar up in there far enough to reach the rivets closest to the aft wing spar. But it gets easier as you move outboard, and we finished off the left wing yesterday afternoon. Derek had to leave at around 3-ish: newborns really don’t care all that much about Daddy’s friends’ projects, but I kept going.

Before he left, Derek helped me get the double row of rivets on the right wing, then I got going on the rest. To say that riveting those big bastards by yourself is awkward would be like saying Stephen King sells a lot of books. Fortunately, the skins do bend quite a bit, and I wish I had a photo to show you how I did it, but the general gist of it this:

With the double row riveted, cleco the spar side and leading edge side holes together. Then climb in between the skin and the ribs, which will allow you to get a hand and a bucking bar in through the lightening holes to just about anywhere you need to go. And it should go without saying, remove the blue stuff from the inside of the skin before it gets riveted on, or you’re going to have a lot of fun later. Good thing I remembered this before we got too far along, but if you’re reading this, I hope it reminds you before you buy yourself a long night of failure-drinking.

I thought the autopilot servo was going to cause a lot of problems, but with the push tubes out of the way, it was really a non-issue. By myself, I got another row done, up to the access panel for the bellcrank, then quit for the day. I was sore and tired. Even with help, riveting wing skins on is like yoga for gearheads.

Left to do: the remaining skin rivets, and some minor wiring cleanup, since I replaced the puny 14-ga wire intended for the landing lights with a much beefier 10-ga flavor.

It’s on again.

12 hours.

That’s today and yesterday.   Shelley helped me rivet on the cover plates to patch the holes in the hull I drilled in search of better antenna locations.  There were 3, total.  One down in the tail, one under the baggage floor, and the original one just forward of the spar under the EFIS.   Since I had her in the plane, i was able to reinstall the transponder antenna properly; I’d taken it out to see if that hole might be a suitable location for the COMM antenna.   It wasn’t.   When we got that done, I went to work on putting the pax side floor back together.  Since I had access, I was able to wrap and secure all the cables going aft under the floor, and I can still access the antenna connection under the seat floor.  After that, I spent a lot of time with cable wrap, securing all the loose wiring running down the tailcone.  I took the advice of someone on VAF, who said something along the lines of “start at the tail and work your way forward, finishing everything you can possibly finish.”   Practical matters preclude me from absolutely finishing the tail section right now, but everything else got done and done.   I torqued down the autopilot pushrod bolts (been driving me crazy for a while), and secured all the wiring of the ELT and strobe pack.  The ELT wiring got secured with a length of shrink tube around the idiot DIN connection (phone cables and stereo connectors?  WTF, ACK Technologies?)  providing NMEA GPS info to the ELT.

Alphabet soup, I know.   We airplane people love our acronyms and abbreviations.

I still have one or two loose ends: I need a special platenut to completely finish the baggage floor, but that should be here tomorrow.

Today I started seeing the end of all the disassembling necessitated by having to wire the aircraft.  I got the flap actuator and flap motor put back in, but this time wired in properly with wires secured in the tunnel.  Lo and behold, I was also able to install the flap arm covers in the baggage compartment, something that hasn’t happened since the interior was painted.    I also cable-wrapped the cables running forward of the spar past the fuel lines and locked those down with cable stays, so nothing’s rubbing on anything.

I also began work on reintegrating the control system on the sticks.   A while back, before I knew what I was doing, I overstretched my trim springs and had to get new ones.   I’ve since gotten them, and was working on getting the sticks all back in order.   I had to paint the steel connectors for the springs, so that stopped while the paint is drying.  I started futzing around with the hard fuel lines on the floor, but didn’t really get anywhere.

Tomorrow I should be able to finish the sticks and see if I can’t get the fuel lines secured (they need a couple of Adel clamps to keep them from vibrating too much) and install the fuel pump permanently.

Forgot about Saturday

8 hours.

Saturday was a pretty huge day in its own right. The night before, I’d cleaned up the workshop and put all the tools away so I could start making a fresh mess. I gloated over my handiwork in drilling the wing spars for a few minutes, then got going on the flap rigging. The flaps are attached at the trailing edge of the wing with a strip of piano hinge. The right side, the inboard edge of the flap rubbed against the fuselage, which didnt allow it to travel its full range of motion. So off it came, and I filed and scotchbrited off enough metal so that it did. However, in that sentence is contained about 4 or 5 iterations of trial, error, and scratching the crap out of the flap with the file until I got smart and put some tape around where I’d be working it. Eventually, it fit fine and was able to swing up and down, and in the ‘up’ position, the skin lay flat on the belly. The left side wasn’t a problem.

After that, it was time to reinstall the flap motor and rig the flaps. This is where the first setback occurred. The flap motor was one of the first things I did on the fuselage, so maybe I screwed it up, but there are many reports of the flap motor channel interfering with the canopy latch bar. Supposedly, they fixed this in the matched-hole kit, but I have a matched-hole kit and I’m telling you now, it ain’t fixed. What I had to do was put a 3/16″ spacer between the bushing block and the F-705 bulkhead to move the canopy latch bar forward enough so that it would clear the flap motor channel. I also had to change the rivets on the upper part of the flap motor channel to flush AN426 rivets. After this, I was able to see daylight between the latch bar and the channel. Of course, this also meant that the pushrod between the latch handle and the bar was now about 1/4″ too long. Put that on the list.

Then came the weird ceremony of drilling the flap pushrod holes. I”ll post pictures of this whole mess when I get the chance.

Wing spars drilled.

2.5 hours.

I win. Sweep and incidence are set, aft wing spar bolts are in. I made a drill guide from some 5/8″x1x4 bar stock (which I’ll have to replace, I think it goes with the wheels or brakes) featuring holes of 17/64″ and 5/16″ to guide the middle and final steps of drilling.

But about that stuck drill bit. As I suspected, I was able to drill just below my ‘relief well’ and pop the broken bit out from the front. Once I drilled it with the 5/16″ bit, all traces of nastiness went away and I have a nice round hole with little to no play on the AN5 bolt that goes in there. On VAF, there are a good amount of people who recommend using a .311 reamer to obtain a close-fit, precision hole. There are also a good amount of people who say that using the plans-recommended 5/16″ bit works fine too. I don’t have a .311 reamer. I don’t want to buy a .311 reamer, or any other kind of reamer right now, and I certainly don’t have time to wait for it. I think the drill guide did the job, and as long as that bolt is torqued and cotter-pinned, I seriously doubt the wing will fall off. If it should come to pass that the wing wiggles around that bolt, I’ll go up to the next size, use a reamer and a NAS close-tolerance bolt, and that’ll be the end of that. But there are plenty of RV’s flying with 5/16″ holes in their aft spars and they don’t seem to be having much of an issue.

I’ll have to take the wings off again to deburr the holes and shoot some primer on the raw metal where it was drilled or filed, as well as do the lineup for the wing root holes, but while they’re on, I’m going to do the flap pushrods, the rudder cable links, and maybe just for giggles, put the wingtips on to make sure everything lines up along the trailing edge.