I got up this morning and drilled the left flap before work.  This side didn’t end up quite as good as the right side (the flap trailing edge ended up about 1/64″ below the aileron trailing edge as it’s standing vertically like this).  I looked around at a bunch of builders websites and this is apparently a really common problem and 1/64″ is actually better than most.  I don’t think I’m going to replace the hinge since it could easily end up worse.  I may be able to tweak a few things to make it just about disappear when finally riveted together.

Van’s offers a couple of suggestions for securing the flap hinge pin.  The first is to drill a hole in the inboard aileron bracket that’s intentionally slightly out of alignment with the hinge pin.  The hinge pin is then inserted through this hole and the misalignment prevents the pin from sliding back out.  The other suggestion (which most builders including me go with) is to remove several of the hinge loops near the center of the hinge and then secure the hinge pins  against the flap brace.  Here I’ve removed one loop on the flap side and two on the wing side.  You can also see here how close the rivet holes ended up to my line drawn at 1/4″ from the lower edge.

I drilled the flap brace for the #8 nutplate and riveted it on with a couple of oops rivets.

Here you can see how the hinge pins are secured.  The bends in the hinge pins prevent the pins from migrating toward the ends of the flaps and interfering with either the ailerons or the fuselage.  The clip (which I made by cutting a couple of loops off of some extra hinge material) will keep the hinge pin from migrating inboard.  I’ll cut off the extra pin material that’s sticking out beyond the clip the next time I have the flap off of the wing.

After triple checking all of the measurements, I drilled the flap hinge to the wing.  I ended up using the P3 hinge that ships with the kit, and I’m well over the minimum 3/16″ edge clearance for AD3 rivets (I’m less than 1/32″ beyond the recommended 1/4″ edge clearance).

Here’s a shot of the whole wing.  The control surfaces add considerable area to the wings.

The first step in rigging the ailerons is to place the aileron alignment bracket over the bellcrank with a bolt through it and the rear aileron push tube’s end bearing.

Next is to adjust the length of the rear pushrod until the trailing edge of the aileron lines up with two tooling holes in the main wing rib.  I placed a couple of AN3 bolts through these holes and then put the straight edge against both sides of the bolts until the trailing edge was centered between them.  I loosened the rear aileron push tube end bearings evenly so that I will have the same amount of threads showing at each end.

Next up, I clecoed on the bottom skins and put the right flap in place.  I spent awhile adjusting the position of the end clamps to get the trailing edges in perfect alignment.

I think I said it before, but these clamps have come in super handy.  I would highly recommend getting some if you’re building.

As I was aligning the trailing edges, I noticed something funny.  The trailing edge radiuses of the flaps and ailerons are not the same.  Here is one shot looking along the edge.  The aileron is the lower trailing edge with the smaller radius and the flap is the upper trailing edge with the larger radius.

Here is a shot looking down on the trailing edges.  The problem is that with the trailing edges aligned front to back, the skin surfaces no longer align.  If I make the top skin surfaces flush, then the flap skin on the bottom of the wing will be proud of the aileron bottom skin.

I don’t think I can just squeeze the flap trailing edge either since the flap skins nicely follow the angle defined by the end ribs.  If I squeeze the trailing edge, the skin will have to bend inward as it crosses the trailing edge of the end ribs.  I’m going to see if anyone on vansairforce.net has any ideas.

Update: It turns out that the scale drawings on the flap and aileron plan pages clearly show that the flaps and ailerons have different trailing edge radii, so I’m not going to do anything about this.

After dropping the kids off the morning, I stopped back by the house and riveted on the flap braces.  I’m definitely getting the hang of riveting with the gun solo.  I slightly overdrove a couple of rivets (though not badly enough to drill out), but virtually all were perfect.

After work tonight, my wife was hosting a Bunco party at our house, so I was on kid duty.  After they went to bed, I had a little time before the ladies left, so I snuck out to the garage and mounted the other aileron.

I also safety wired the autopilot roll servo’s mounting bolts.  I’m still getting the hang of safety wiring.  It’s tricky to estimate how much extra wire to leave before twisting since the wire segment shortens as you twist it.  It only took two tries to get this properly secured.

I installed the aileron braces tonight.  All of these rivets could be squeezed, so I could do this after the kids went to bed without making too much noise.

Here is a closeup of the outboard part of the flap brace.  The relief cut on the left allows the brace to step up onto the rear spar doubler, and the complicated shape on the right allows it to follow the outboard aileron hinge bracket closely.  The brace is riveted onto the rear spar with universal rivets, but is riveted to the top skin with AN426AD3-3 rivets which are the shortest rivets I’ve had to use on the project so far (and I assume the shortest I will have to use).  I assume these rivets are so short so that there is clearance here for the aileron.

I also clecoed on the flap brace, but couldn’t rivet it on because these will have to be shot and bucked since the brace blocks access with the squeezer.

I assembled the rear pushrods.  The jam nuts are not torqued down yet since I will have to adjust these to final length once they’re installed.

I went ahead and loosely installed the left aileron on the wing.  None of the bolts are tightened down since this may have to come back off at some point.

Here is a closeup of how the pushrod comes through the rear spar.  It’s clear now why the hole is oddly shaped as the pushrod traces a curved arc as the aileron is swung through full travel.  I verified with the digital level that the aileron can exceed the maximum allowable up/down travel.  I still need to fabricate the aileron stop that will limit the travel to the recommended amount.

Here is how the pushrod attaches to the bellcrank.  Again, nothing is torqued down until I know that it’s on for good.

I think tonight will be the last priming session for the wing.  I mixed up some epoxy primer and injected a few ccs into each aileron push tube through the hole that the welder drilled to relieve pressure during welding.  I then swirled the tubes around to coat the entire inside with the primer.

I then primed the outside of the tube except for the threaded ends.

I then primed the back side of the flap and aileron braces.

And finally, I primed the parts of the rear spars and skins that will be covered up by the braces.