Step 7.0 Ailerons

It turns out that the ailerons are a lot like the flaps in construction and size.  For those not familiar, the ailerons are located just outboard of the flaps and occupy about half of the trailing edge of the wing.  The purpose of the aileron is to provide a banking action to the aircraft which is helpful when it comes time to turn.  Although it is possible to turn an aircraft with the aileron or rudder alone, it really takes the combined action of the rudder and the ailerons to maintain coordinated flight through a turn.

The big difference in the construction of the ailerons vs. the flaps is that the ailerons use stiffeners internally rather than the rib construction that the flaps used.  Each aileron uses 16 stiffeners which is quite a lot considering that each one is individually cut from the Van's supplied angle stock.  Each stiffener has two tapered sides and two straight ends to cut.  That all means a lot of time in front of the band saw.  As always, the first step is to get the blue plastic off.

Match drilling the stiffeners to the skin.

Then deburred and dimpled, the stiffeners are ready for primer.

Then the rest of the aileron frame is assembled and match drilled.

Here's a tool I made to dimple the leading edge.  The standard dimple die is too large in diameter to fit inside the curved leading edge.  I drilled and counter sunk a 1/2" piece of bar stock to make a female die that can fit inside the leading edge.  A larger diameter bar would have been better, but 1/2" is what I had on hand.  

With the female die inside the leading edge, a nail fits through the back of the die then through the leading edge where it meets the the male half of a pull rivet based dimpler.

And the dimpled leading edge.

 

Here's the first 16 stiffeners in the paint booth. Lots of steps were performed, but not pictured, to get to this point. They are mostly omitted here so as not to induce a reader coma this early in the posting. You can thank me later.

After the primed stiffeners are riveted to the skin it's time to bend the skin down.  When the skin reaches the correct angle, the top and bottom just fit over the spar.  The last time we saw this homemade bending brake was for bending the elevator skins.  I'm sure glad I didn't throw it away.

So here is the counter balance weight that will be riveted to the inside of the leading edge.  This thing is heavy!   It is basically just a big pipe similar to galvanized water pipe.  The purpose of a counter balance is to dampen the tendency of a control surface to flutter.  Aerodynamic flutter can, in an extreme case, rip the control surface right off the airplane in a matter of seconds.  Midair disintegration of an aircraft is very rare, but when it does happen flutter is often suspected.

Let's take a break from building to watch Carol using the iPad to fix the Dish satellite reception.  Isn't technology great!  Notice the coat though.  She's arctic ready.

Now take a look at the actual temperature in the shop taken at the time of the photo above:

Out of the paint booth and the parts are ready for riveting.

And here is the right aileron finished.  Well almost finished.  I still had the hinge brackets to bolt on after this photo was taken.