N67SC: Ailerons

Section 21 is complete. Now that I've done enough of these primary flight surfaces, they are getting fairly routine. The things about this section that make it unique are:

That goddamn stainless counterweight pipe
The weird dimple die you use one the end ribs

About that counterweight ... they want the aileron balanced fore/aft so in the short forward part there is a real heavy stainless steel pipe that acts as a weight. You have to assemble a few pieces of that forward section, then mark holes on the pipe to drill. The first set of holes then gets lined up to rib holes, so that you can then mark another set of rib holes. This second set is real hard to get to, the plans have you wedging a long drill bit in between rib flanges to make the mark.

I thought I had a better idea - cut off a sharpie and use that since the long bit wouldn't be square to the hole anyway:

The problem I had after this was that I made a pretty accurate mark of the hole, but drilling into this stainless with my drill bits just wasn't working for crap. Tried some boelube and a new bit, NOPE. Finially went to Theisens and got their best quality 3/32 Dewalt bit and had much better success. Ended up with 2 sets of holes in each pipe before I got pretty close. The once nice thing about a pipe is that if you screw up the hole in it, just turn it and start over.

Once I got those holes as good as I could, I could still see a degree or two of twist in the assembly. I measured it by finding two spots on my bench with the exact same reading on my digital angle finder. See that little area under the rib? The other side is flat.

To fix that, i just did some milling of the rib flange holes. That allowed some wiggle room on where the pipe mounts to the ribs. I'm not worried about any structural issues, that pipe is still wrapped very tightly by the forward skin and bolted to the ribs. Here's what the end of the assembly looks like.

The dimple die I was talking about is for the end ribs. Not that big of a deal. Oh also be really careful which sides of the little brackets you countersink. It would be easy to mess them up. I thought I did for a few minutes, only to realize I had actually done it correctly.

Oh and making these skin stiffeners was a total "shut your brain off" kind of task. Each one required final-drilling holes, laying out lines, and 3 cuts on the band saw. Seemed like it took forever, but oddly enough I almost enjoyed it. I'm a sick individual, folks.

Here is the trailing edge. This was wierd to me - the extruded trailing edge wedge stick just a TINY bit past the skin, maybe 1/32 or so. Don't remember that from any of the other surfaces.

There were quite a few pop rivets to do. I discovered something I wish I had thought of before - using chunks of extruded trailing edge to build up the area around a pop rivet so you can get to it. This allowed me to use my awesome $20 Harbor Freight puller on all the aileron pop rivets.

Here the top skins are going on. You Clamp a board on to the trailing edge so you don't lock in a wavy shape to the skin.

Some of the rivets on the ends were buggers. Had to use the double offset for the ones between brackets. This guy got some real careful hits, no room for a full mushroom set in that little corner.