SECTION 21: AILERON

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Before You Start

Special/New Tools/Supplies

• You will need fuel-tank sealant for this section (see notes at the top of the SECTION 7)
• Consider 3D-printing or buying a jig for countersinking the trailing edge wedges. There are a number of options available.
• You need a #34 drill bit for this section
• You will be match-drilling #40 and then increasing to #30 into stainless steel -- consider appropriate bits for this.

Hints

The counter balance pipe ends 2/3 down in the aileron, so critters can get inside the aileron through the counter balance pipe. Consider closing up the pipe with a plug or aluminum tape before storage.

Page 21-02

Step 2: it says to dimple all #40 holes in the flanges, but the #40 pilot holes that hold the screws for the counterbalance tube are not to be dimpled, they will be enlarged to #27 and the AN526C632R8 screws that go into them have round heads.

Page 21-03

Steps 7 and 8: Consider deferring the riveting of A-1007-1B and A-1006-1B plates to the A-1005A-1 ribs until after the top skin is attached to the spar on page 21-08. This will allow for better access to the spar attach rivets that end up being inside the hinge brackets. Just be sure to attach them before the bottom skin gets attached. If you attach the parts per manual, you most likely have to grind off one side of a straight 470 -4 rivet set as the stem is too thick to allow centering the rivet set. It's OK to rivet A-1007-1C at this time, though.

Page 21-05

Step 3: The aileron counterbalance pipe is made from stainless steel and is much harder than aluminum. When match drilling the aileron counterbalance attach holes through the nose skin it is easy for the bit to wander and significantly enlarge the pre-punched holes in the nose skin. Drill slowly, checking often that you're centered especially when starting to drill the holes. Another option would be to just mark the holes in the counterbalance and remove the skin before drilling the holes (as described for step 2).

Step 5 (left-hand side): Mark the top, sloped trim lines before cutting the stiffeners apart else you cut the reference points away. Note that you really need to pay attention here especially on the "skinny" (aft) end of these stiffeners. If you leave too much vertical flange it will interfere with the aileron skins and cause a bulge (and probably damage over time). If you leave too much material aft of the aft-most rivet hole, it will interfere with the trailing edge wedge. Consider the 10.3mm specification the maximum length and consider trimming a bit shorter than that. Consider making the vertical flange disappear flush into the bottom flange at this end so that there is nothing sticking up at the very aft end.

Step 5 (right-hand side): You can dimple all holes on all skins except for the ten #30 holes that will be riveted to the stainless steel counterweight tube. Those holes should not be dimpled. NOTE: if you are going to bend the trailing edge of the skins (as suggested on page 20-07 step 5), it's easier to do that before dimpling.

Step 7: Before you rivet each stiffener, this is your last chance to make sure that they aren't too long where they will interfere with the trailing edge ridge and/or too high where they will interfere with the opposite skin when assembled. It's a lot easier to sand these down before they are riveted to the skin.

Page 21-07

Step 2: The plans don't really specify exactly what may be causing the bowing here or what to do about it, but one thing to check at this stage is to make sure that the stiffeners' vertical flanges aren't too high and are interfering with the skins.

Step 3: The skin holes are already final drilled to #40 but the trailing edge wedge is not. However, if you are going to use a good jig for countersinking the trailing edge wedge, consider that you may not need to final-drill here. The #40 holes in the trailing edge wedge can just barely handle the countersink bit. After countersinking both sides of the wedge the #40 holes will be plenty large without having to final-drill them.

Step 4: Before disassembling the aileron, this is your last chance to make sure none of the stiffeners are too long or too high and will cause any interference. Trimming these stiffeners is still easier now than it will be after you start riveting the skins.

Page 21-09

Step 4: If you deferred the riveting on page 21-03, you will want to do that step now -- after you rivet the top skin and after you rivet the A-1005A Main Ribs, but before you Cleco and rivet the bottom skin. Note that you need to leave two #30 holes open on each side as specified on page 21-03 -- pop rivets will go into those holes on page 21-09 step 2.

Page 21-09

Step 4: Make sure the tabs of the 4 outer ribs grab the flange of the spar. Make sure the smaller bottom end ribs (A-1005B-1) go inside the larger ones from the top (A-1005A-1).
Consider using 3-3.5 rivets for all nose ribs. The manual suggests 3-3 for the A-1015-1 nose rib but they are a bit short for the task, especially if you prime.
Consider using 3-4 rivets for the 4 rivets that hold the corner tabs.