Riveting Upper Wing Skin (1.5)

1.5 hours

 

I got the upper aft skin riveted on.  Then I spent a little time deburring the bottom side.

Deburring, part 3 (1)

1 hour

Yet more deburring!  I got the upper skin all done and cleco'd back on, so that thing is ready to rivet.

Setting Aileron Pushrod Length (0.5)

0.5 hours

The last part of setting up the aileron is to set the length of the short pushrod.  To do this, you set the bell crank at a certain angle (25°), and then put a straight edge on the top surface of the aileron and measure the distance from the straight edge to the top of the wing at the aft edge of the forward skin (74mm is what you want).

I've heard that you can do this by yourself with the wing skin on, but I think it would be pretty tricky.  I did it with the lower skin off and my wife helping, so it was easy!  I started by rigging up some precision measuring tools.

Here's a square that measures 74mm:

And this device sets the bell crank at 25°:

After a few adjustments I got it where I wanted it.

I tightened the locknut and put a blob of paint on it so I can make sure it doesn't move later.  For now, this pushrod and the aileron can go back on the shelf until later!

Aileron Balancing and Rigging (3)

3 hours

Before I got too far into setting up the ailerons, I figured I should balance them according to the plans.  This just involves hanging the ailerons by their hinge pins and drilling to the lead weights until they both sag the same amount.

I hung the ailerons from the ceiling with safety wire, and set the tops of the hinges as level with each other as I could.  As far as I could tell, they were within 1/4" of each other.  The plans say to get them within 1/2" so I think this is good enough for now.  If I paint them later I'll have to balance them again anyway.

Next I assembled the two pushrods to the RH aileron.  The short pushrod calls for a custom length bronze bushing, which you have to grind down from a longer piece.  It was pretty tedious but eventually I got a pretty good fit.

My process (mostly for my own reference when I do the LH one), was to ream the end of the pushrod to 5/16" (pretty much to remove the paint), ream the bushing to 3/16" in order to accomodate the bolt, then grind the face of the bushing down on the bench grinder.  When I got it to about 0.010" of where I wanted it, I finished it on a piece of sandpaper to make sure it was flat.

Here's the bushing about halfway through grinding.  I took it from 0.500" overall length to about 0.275".

The plans have you put the bushing through the hole in the pushrod, and then through a flat bronze thrust bearing, with a protrusion of 0.005-0.015" once the bolt is tightened down.  This is about 0.012", which I called good enough.

The other end of the short pushrod attaches to the aileron like this.  The specified bolt (AN3-10) was a little long, so I had to add two washers.  If I can remember, I'll replace this bolt with a shorter one later.

Here are the pushrods finally attached to the bell crank.  The long one goes to the left in this picture, where it would enter the fuselage.  The short one goes up to the aileron.

Here's a video of me moving the aileron with the pushrod for the first time!

Control Pushrods, Part 2 (1.5)

1.5 hours

Continuing with the pushrods.  The flap and short aileron pushrods just had to be assembled from hardware; the long aileron pushrods had to be built from tube stock.

I cut the tubing to length and drilled/riveted the machined fittings to each end.

Then I just screwed in the rod end bearings.  The drawing calls for an initial overall length, which I set, and then I tightened the lock nuts.

All three pairs done!

 

Control Pushrods (0.5)

0.5 hours

I got started on the aileron pushrods.  Most of this time was spent digging through all my parts to find the hardware!

The first step was pressing these bushings into the rod end bearings to bring the ID to 3/16".  I just used my bench vise and they went in pretty easily.

 

Deburring, part 2 (1.5)

1.5 hours

I put the upper aft skin back on and started deburring the lower skin.  I also drilled out the hole in the skin to accommodate the tiedown fitting with a unibit.  Pretty easy!

Unfortunately while I was deburring the aft ribs I ran into the back side of another rivet and exploded my deburr tool!  I was bummed becuase that thing cost $40, but I called Yard Store and they found me a used one for $10...  So I'll continue this once that thing shows up.

Flap and Aileron Mounting (1.5)

1.5 hours

I got the hinges drilled to the aft spar for both the flap and aileron.  I was kind of concerned that it was going to be hard to get everything to line up nicely, but it ended up being pretty easy.  If you plan on drilling through the hinges in the center of each lug like you normally do, then everything just about locates itself since all the holes are already there in the skin and spar channel.

Here the hinges are just clamped to the wing to make sure the lateral placement looked right.  My assistant in the background was skeptical that any of this was going to work.

Both hinges drilled!