Wings: Flaps. Trailing edge wedges.

The plans call for the (AEX?) trailing edge wedge to be countersunk on both sides to accept the skin dimples.  Not an easy task given the wedge angle.  So, I fashioned a jig to present the wedge straight to the countersink cage.  Thanks to Ed and Bill for the idea.

The jig uses a scrap section of the wedge with a couple of countersunk screws driven into wood to hold the wedge down.  When the wedge you want countersink is placed on top of jig, the face of the wedge remains parallel to the face of the wood and cage (i.e., when properly stacked, the wedge that's mounted on the wood offers a -12 degree angle to "cancel" out the 12 degree angle of the wedge you want to work on).  Just be sure to drill a few holes deep enough to accept some clecos to hold everything down.

An example of  how to align the wedge you wish to work on.

Here is the tool illustrating usage.  Drill press makes things go quickly.  Ultimately, I always cleco'd to the wood since it offered more stabilization of the part.  This was a trial run.

Here are all of the flap wedges countersunk on both sides.  Because the opposite countersinks meet in the middle due to the material thickness, one side of the wedge doesn't look as pretty as the other if you look real close.  Probably should have slowed the drill press down.

We'll see if this was a good technique when it comes to completing the flap.

Wings: Flaps. Spar-nose-rib rivets.

First, Van's reordered the section numbers in the plans as of 25-Sep-13, so I'll cease using the numbers to avoid confusion. (I've updated page references in the blog prior to the above date to reflect the new ordering.  Hopefully I got them all.  13-Jul-14.)

Now, the AN426AD3-4.5 rivets that hold the flap skin, nose skin and main ribs together are nestled in there pretty good.  I couldn't find a good way to buck them (other than the squeezable inboard- and outboard-most ones).  The challenge is to get a bar in there that doesn't damage the factory head of the AN470AD4-4 spar-rib rivets and provides a good angle to make a nice shop head.

So, I..."buckled" and...bought a tungsten (wolfram) bucking bar that was narrow enough to fit in the space near the spar flange.  I decided to splurge on this bar since I wanted something small and heavy.  More weight means less control of the bar is necessary on the part of the holder.  Very important, especially when going solo.  I was surprised at the density of this material.  Don't think I've held something this dense before.  Denser than lead.

Placing some properly sized Popsicle sticks (thank you band saw) that are just slightly higher than the factory heads on the AN470AD4-4 spar-rib rivets, the bar can hit the AN426AD3-4.5 rivet that I want to buck and float above those AN470AD4-4 guys without damaging them.

And here's a nicely bucked rivet in the space of concern.  No part of the flap body or other rivets have been touched.

I think I'll be able to use this bar when bucking the few buckable rivets on the bottom skins.

Wings: Flaps. Top skins on.

Left and right flaps have their top skins on, save just a few rivets each.

Below are the left rod end subassemblies.  Yes, on the inboard one I foolishly match-drilled and countersunk for a non-existent nutplate.  Consider them lightening holes.

 

It's not easy to squeeze some of the ribs onto the spar since other immediately adjacent ribs impede access.  Below is my suggested sequence and method of setting the rivets on those ribs that are crowded out a bit.

Left inboard hinge pair subassemblies.  The main rib's rivets were bucked.

Unfortunately, I initially tried to squeeze the outboard rib's rivets.  The middle rivet was easy, but the flanges separated slightly around the rivet shaft.  In order to access the upper and lower rivets I had to bend the main rib quit a bit.  Though the plans mention that such an approach is acceptable, you have to consider that the flange will be pulled from being flush against the spar.  This means a potential space between the spar and rib flange opens up and becomes an actual space for your rivet shank to have a party in and fill.  The left image is how that comes out.  Look at the left and right rivets - no narrative necessary.  The right side is what it looks like after I pulled out the rivet on the left (which is the bottom of the spar) and instead bucked it.  You can see that the removal process (a challenging affair given the limited access) elongated the hole so the replacement rivet doesn't sit in there nicely:  The shop end is short and now the spar is slightly deformed. 

I deemed that unacceptable.  Now, removing those left and right rivets wasn't going to be easy a second time.  The holes got even worse.  Here are the holes with a AN470AD4-5 (plans call for a -4) rivet placed in them.

An AN470AD5 nearly fit in them.  I didn't want to put that large of a rivet in there since I only have a 2x gun, don't have a rivet set for it and the flanges didn't need the additional stress from trying to buck such a rivet.  So for each side, I took an AN470AD4-5 (again, the plans call for a -4) and pre-squeezed to fit just snug in the hole.  Below are two pics showing, right-to-left, an AN470AD5-5, my pre-squeezed AN470AD4-5 and an AN470AD4-4.  This gives a good indication of how large I made that hole.

Here is the left side with the pre-squeezed rivet place in the hole.  It's a better fit, but isn't perfect.

I could then bend the spar back and get a better fit with all the flanges together.  The left image is from the left flap after (the now second) replacement with the pre-squeezed rivets.  The right image is the right flap in same place showing what things look like when you get it correct the first time.  Given the three layers coming together, looks like I should just have bucked them all on the right side.  That middle squeezed rivet separates out the flanges.

I'm pretty sure I'll be removing the two left flap rivets and just drilling up to an AD5.  I don't like how it all sits.  The right looks okay, save for that middle rivet which I can straighten up.

The hinge pair subassemblies call for the rivets along the joggled end to be riveted double flush.  I initially tried to buck these double flush rivets but because it's very hard to keep the subassembly flush against the backing plate, they didn't sit nice and it was too easy to injure the part with the rivet set.  So, after sanding out the damage I caused, I decided to squeeze all of the double flush rivets on the joggles.  Having never done that before, I was pleased with the outcome.  Unless you look really close, you might have a hard time distinguishing the factory (left) and shop (right) heads.  Tip:  If you screwed up a machine countersink on one side of the joggle, just put the shop end in that countersink.  Problem solved! 

 

Left and right flap skeletons ready for skins.

Here the left flap sits with the top skin cleco'd, ready for riveting.

Right flap with most of top skin riveted.  The inner AN426AD3-4.5 rivets have yet to be bucked.  I decided I wanted a bucking partner for those.  Too easy to damage the factory heads on the main rib rivets when going solo.  Also the aft two-most rib rivets need to be back-riveted.

Left flap in same state parked in the (nearly empty!) wing crate next to a bottom flap skin and aileron skins.

And just to be complete, here are the backsides of the right and left flaps.

Wings: Fuel tanks. Left tank capacitance probes and baffle install.

I decided to redo my fuel tanks.  See here for why.  The entries specific to the redone tanks are here.

Capacitive probes on left tank are installed.  I had to replace a screw from last week since it got stripped going into the nutplate.  Thankfully the nutplate wasn't damaged.  The work for the left tank was identical to the right tank, so I won't go into as much detail here.

I put the masking tape just over the skin's baffle rivet holes this time.  Turns out it wasn't as useful as I had anticipated:  When the tape is removed, it just takes the sealant bead with it since the bead just fell aft onto the tape.  Here is the sealant on the skin ready for baffle install.  You can see the capacitive probe wire in the image.

As with the right tank I put a very thin layer of sealant on the baffle flanges (shown below) and aft rib flanges.

Here is an image looking aft through the filler flange to see the sealant along the baffle-skin joint.

And here are the "shop heads" of the AD-42H blind rivets along the rib flanges as seen through the filler flange.

I had to remove a AN470AD4-4 rivet I put on the outboard attach zee (it needs a -5).  With all the wet sealant, I realized a "chip catcher" was necessary.

And here is the left tank, inverted for curing.

 

I also countersunk for and placed the final baffle rivets on the right tank.  After it cures, it will be test time.  Once the left cures I will go through the same process.

Wings: Flaps. Parts primed.

Nothing too exciting today.  Just primed up the flap constituents and some other extraneous parts (e.g., replacements and modifications).

General update:  Right fuel tank continues to cure after baffle install.  Waiting on a screw for the capacitive plate on the left tank (original got stripped) prior to its baffle install.  Still need to machine countersink the AEX wedges for the flaps.  I did get some of the connectors I need to finish up the wiring for the heated AOA/pitot.

And today is the 400 hours mark.