Sun Dec 9 2007

Flap work

I decided to drill out and reinstall these two rivets on the outboard left aileron bracket. That cured the gap between the two plates.

The hinge side that attaches to the flap is about an inch longer than the side that attaches to the wing...

So I cut off the extra eye.

Now that the left flap was all set, I started working on the right one. First thing was to mount the aileron. I didn't get a pic of this yesterday, but here is the spacer tube that goes at the inboard aileron bracket. It's supposed to be 17/32 inch long and it's right on the money!

Here's how I got it to be the perfect length and also have the ends nice and square. I stuck a 1/8 inch diameter wood dowel in the center (a tight fit) and used the dowel to twirl the tube around as I sanded the end on my disc sander. Once the length was close, I flipped it around and did the same with the other end until I had exactly 17/32.

Man, with the control surfaces on, the chord of the wing looks like it's almost half as much as the span. I know it's not quite that, but it really changes the look of the wing.

Uh oh...I forgot to dimple the holes in the bottom main skin where the flap brace attaches. On the good side, non-dimpled holes do a lot better job of acting as a pilot for the drill bit to drill the hinge. Now I've gotta figure out how to dimple those, though.

Actually this isn't gonna be too bad at all. I'm using the male die of my 3/32 dimple dies in combination with the female die from my pop rivet dies.

I just wedged the skinny pop rivet die between the flap brace and the skin and squeeze right through the flap brace. It made nice, crisp dimples in the skin.

I went into work and used the paint booth to prime my hinges.

After two hours of riveting hinges in place, the right flap is installed! The straps aren't really doing anything, but holding the flap from swinging to it's neutral position.

I would've been done with this flap earlier, but I got into a hurry and my brain was on hold. I got half the rivets installed to attach the hinge to the flap before I realized I hadn't checked to make sure it had no twist. So I got out my 2x4 leveling boards and leveled them up (just like the ailerons). Sure enough the flap had about 1/16 inch of twist. So out came the drill and I drilled out 32 rivets, got the flap un-twisted, and then riveted the thing back up. It's not perfect, but there's only about .010 twist, so that should be good enough.

The alignment of the flap to the aileron on the right wing is pretty much perfect. The trailing edges are lined right up.

I'd love to call this wing done, but I've got one other issue to correct. On the top of the wing, the aft edge of the main skins is flared up slightly so that it doesn't lay down on top of the flap. I think it's because the rear spar flange bend angle was slightly off. There's only about 1/8 inch of gap, but I'm gonna try to tweak it down.

I made these tools while I was at work tonight. Hopefully they'll allow me to fix that skin flare problem. I'll try this tomorrow or the next day.