Flaps

Flaps are done!  It might be just me, but these seemed to take a long time for how simple their construction was. They are big (probably 8' each), so there was just a lot of time spent to get through all that deburring and drilling.  The day dad and I spent priming was a big one too, about a 9 hour job.

Now that the wings are mostly done, I'm sure glad I did both wings at the same time.  I couldn't imagine being at this point then having to go do it all over again.  There was definitely some economy of scale advantage to getting both knocked out at the same time.  I didn't always keep both wings in step-by-step lock though, only doing what made the most sense at the time.  For example during the leading edges, I only had enough room for 1 on the bench.  So I would get a long ways ahead on one and then catch up on the other just to save me from moving them around a lot.

The flaps were pretty easy.  No stainless pipe to deal with like the ailerons.  Lots of blind rivets.  For the trailing edge I used my trusty old door and angle iron.  Even though the flap overhung the iron by over a foot on each side, it still ended up arrow straight.

The first thing you do is create the big flap hinge brackets.  Its a little confusing as to how they go together L/R wise when you start on the Left wing, but in the end you figure out they are pretty much the same no matter what wing they are on.

The instructions have you put the bolt and associated hardware into the brackets to forcefully line them up before drilling.  I've read where others paid the price for not doing this, so I obliged.  Getting those washes in between the brackets can be a bear.  Luckily my mom gave me these left over surgical forecepts over 20 years ago.  I still have them because they are handy as heck.

Priming was a big job, because I scuff everything with scotchbrite first.  These little ribs just kill you, luckily Dad shared the pain with me.

I'm pretty sure these are the biggest rivets I've used so far.  AD470 4-10. They go through the middle flap brackets which are a big "sandwich" which consist of 6 pieces, the middle two being really fat.

My buddy John (RV-14 builder) borrowed me this trailing edge jig.  You put the extruded trailing edge piece in there and it makes it flat so you can countersink it with a drill press.  Here I'm holding it to the drill press table with a couple of clamped boards.  WHY did I not have this for the empenage?  What a no-brainer, this thing was awesome.  If your reading this and are still working on the tail, just buy it.

Here's the internal structure all riveted up.  I had to use the double offset set to get some of those rivets.  With that epoxy primer on this stuff, assemblies like this should not see the light of day for 100+ years.

Leading edge skins going on.

 

 Top skins

 

The plans have you back-rivet the two aft-most rivets in the top skin.  DONT DO THAT - its super easy to screw up.  The squeezer works perfect for this job, and its way easier.

The leading edge skins and the bottom skin is all blind-riveted.  These are the rivet tails from just 1 flap!

Ailerons

Section 21 is complete.  Now that I've done enough of these primary flight surfaces, they are getting fairly routine.  The things about this section that make it unique are:

• That goddamn stainless counterweight pipe
• The weird dimple die you use one the end ribs

 About that counterweight ... they want the aileron balanced fore/aft so in the short forward part there is a real heavy stainless steel pipe that acts as a weight.  You have to assemble a few pieces of that forward section, then mark holes on the pipe to drill.  The first set of holes then gets lined up to rib holes, so that you can then mark another set of rib holes.  This second set is real hard to get to, the plans have you wedging a long drill bit in between rib flanges to make the mark.

I thought I had a better idea - cut off a sharpie and use that since the long bit wouldn't be square to the hole anyway:

The problem I had after this was that I made a pretty accurate mark of the hole, but drilling into this stainless with my drill bits just wasn't working for crap.  Tried some boelube and a new bit, NOPE.  Finially went to Theisens and got their best quality 3/32 Dewalt bit and had much better success.  Ended up with 2 sets of holes in each pipe before I got pretty close.  The once nice thing about a pipe is that if you screw up the hole in it, just turn it and start over.

Once I got those holes as good as I could, I could still see a degree or two of twist in the assembly.  I measured it by finding two spots on my bench with the exact same reading on my digital angle finder.  See that little area under the rib?  The other side is flat.

To fix that, i just did some milling of the rib flange holes.  That allowed some wiggle room on where the pipe mounts to the ribs.  I'm not worried about any structural issues, that pipe is still wrapped very tightly by the forward skin and bolted to the ribs.  Here's what the end of the assembly looks like.

 

The dimple die I was talking about is for the end ribs.  Not that big of a deal.  Oh also be really careful which sides of the little brackets you countersink.  It would be easy to mess them up.  I thought I did for a few minutes, only to realize I had actually done it correctly.

Oh and making these skin stiffeners was a total "shut your brain off" kind of task.  Each one required final-drilling holes, laying out lines, and 3 cuts on the band saw.  Seemed like it took forever, but oddly enough I almost enjoyed it.  I'm a sick individual, folks.

Here is the trailing edge.  This was wierd to me - the extruded trailing edge wedge stick just a TINY bit past the skin, maybe 1/32 or so.  Don't remember that from any of the other surfaces.

There were quite a few pop rivets to do.  I discovered something I wish I had thought of before - using chunks of extruded trailing edge to build up the area around a pop rivet so you can get to it.  This allowed me to use my awesome $20 Harbor Freight puller on all the aileron pop rivets.

Here the top skins are going on.  You Clamp a board on to the trailing edge so you don't lock in a wavy shape to the skin.

Some of the rivets on the ends were buggers.  Had to use the double offset for the ones between brackets.  This guy got some real careful hits, no room for a full mushroom set in that little corner.

This pop rivet stem broke in the wrong place.  I emailed Vans and they said if its set, just cut it off and grind down.  So thats what I did.

Waa-laa - done!  Probably had 50 hours in these.

Wing Cradle

Now that the leading edges are on I can't lay them flat any more, so I built the wing cradle.  I reused some huge 2x6s that were part of our old ceiling, recycled 2x4s, and the casters were in a shop drawer that was Carrie's grandpa's.  They look 50 years old.

I'm duplicating instructions from Mouser here because he abandoned his build and I want them saved for posterity.  Full credit to Mouser for these, although I think he credits them to someone else also.



When you go to the lumber store, you need:

• 2x 10' 2x6
• 3x 10' 2x4
• 1 8' 2x4
• Carpet 16"x8'
• Casters

Here's how you cut the 2x4s:






The carpet should be 16" by at least 8'.

TIP: Don't try to staple the carpet to the wood before putting the wings in.  I did and it was a little crooked and the carpet side hung too low.  I measured just 1.8 degrees of downslope, but it looks like a lot more.

Instead, staple the middle of the carpet to the middle support.  Put your wing in there, and with another person holding the outboard edge, get it level.  Then pull the carpet tight and fasten.  I should have done it that way the first time .

Wing Leading Edges

The outboard wing leading edge assemblies are done and permanantly riveted to the main wing spars.  These would have been a really simple chapter if it weren't for my "quick-build" fuel tanks.  I bought my tanks from someone who had flown them hundreds of hours.  He built 4 new ones for an extreme extended range mission.  More on that in a bit...

Here's my handy tool for marking the centerline of J-channel.  Notice the notch just big enough to rest the fine tip sharpie into.




As usual the rib deburring takes a long time.  Then things initially go together pretty quickly.
 


Now back to the splice strip.

The problem with not having the uncut tank skins is that there is a "splice strip" attached to the tank skins which you normally cut off and attach to the leading edge.  This has nutplates in it lined up perfectly so that the fuel tank can be screwed to it also.  This bonds the outboard leading edge and tanks together so they are lined up properly and rigid with respect to each other.  Vans does not make that part alone, they would have to send me a whole tank skin or have me pay for a tank skin and cut that little piece off for me.  No thanks!  Not having the splice strip meant I had to fabricate my own.

I acquired a chunk of leading edge skin from the same RV-10 flyer and cut them to the right shape.  Attached them as tight as I could to the leading edge and match-drilled.



Then I put the whole leading edge on the wing spar with a bunch of clecos.  Then put the tanks on.  Using a fine tip sharpie the tank screw holes were traced onto the splice strip.

 

Getting the drill bit perfectly in the center even with my drill press wasn't easy.  Pre-punching the hole helps.  Here is the finished splice strip half riveted on.  The tanks aren't on yet, so hopefully soon I'll know if this worked.


Primed and ready to rivet.



Riveting these was no big deal, except for the front 3 or 4 which I maybe could have done by myself but instead summonsed a helper.  On the easy ones I did get some help from my mini builders:
 

I let him sign it.  Hopefully both these guys will enjoy flying it someday.





 

Before attaching to the main spar I wanted to fill the hole used for the stall warning vane.  I'll have an AoA sensor so no need for it.  I used a glob of proseal for now, hoping that will make a good backer to put in some filler later to sand out and make smooth.
 


Riveting these on the main spars was mostly easy, especially the bottom skin.  However the top skin required help.  I've seen where people online come up with contraptions to help them do it themself, to me it wasn't worth it.  So much easier grabbing a friend for 20 minutes.  I also got help with the most inboard rib to spar rivets.  They are big AD470-4 rivets and required a double-offset set.  With two people they came out perfect.

Here is the wing mounted to a bench with the outboard end hanging WAY over so you can rivet these things on.
 

Wing Skins

These skins were a pretty big job.  I guess I'd say the size of the ouboard skins and the sheer number of holes is what makes it time consuming.  I could manage moving around the big outboard skins myself, but going slow and thinking things out was a requirement.

First thing is edge debur all the skins, doublers and J-channel.  Then put the wing walk doublers on.  These add strength right next to the wing root to make an area of the wings you can walk on to get on/off the plane.

 Be careful to orient the doublers correctly.  I saw a guy online who had interference between the J-channel and the wing walk doubler because the doubler was flipped the wrong way top-to-bottom.

On one of the wings I ended up grinding a tiny amount from the ribs where it was interfering with the J-channel also.

The instructions give you an optional step "for aesthetics" to sand down the joint between the inboard and outboard skins into a taper.  I gave it a shot with some 80 grit and an electric sander.

I put the edge of the skin on the edge of a 2x4 and sanded in full even strokes.  I tried to put more pressure on the end of the skin so it would taper.  I don't think I ended up taking off much, maybe 25% of the total thickness, but that was ok with me.  If you really wanted to make that seam even, you'd probably need even more coarse sandpaper.

Commence assembly then match drilling.  Oil that air drill up, its going to get some use!

Priming these big suckers is actually not that much work compared to the ribs.  Just big flat surfaces.  Scratch 'em up, shoot 'em green.

I always wait to dimple until after the skins are primed.  The akzo epoxy is bulletproof so it sticks even during dimpling.  Also, preparing the skins for priming with scotchbrite pads is much harder when there are dimples in the skin.  It tears up the pads really fast.

It was difficult to get these monster skins dimpled myself, but between moving the tables around and some physical gymnastics, I made it happen.

Last you rivet.  There are like 2000 of these suckers to shoot, and it took Dad and I about 14 hours over three days.

You do these in a different order than usual.  Start in the middle of the skins, and rivet outwards.  The double row that joins the inboard and outboard skins is last.

I did get a new tool to help us back rivet these skins.  I know my buddy Mike J used a straight extended back rivet set to get his done.  I presume he just nudged the bottom of the rib over to get a straight shot at the shop end of the top-side rivets.  I tried out the double-offset set from Cleavland.  It was pricy, like $50, but I think it worked really good and allowed me back-rivet quite a few more than would be doable with a straight set.

The thing you MUST do with this bar though is crank the air pressure.  On my 3X gun I had it at 60 lbs to get the job done.  I would hold the end near the rivet with one hand to keep it from spinning while running the trigger with the other hand.  

 
Done.  What a marathon!
 

Unfortunately I found out in the course of this chapter that a small number of folks I thought were close to me consider my project a joke.  So be it I guess, to each his own.  Doesn't phase me though, I know that this plane is going to be awesome and its going to haul my kids and me to some awesome adventures and memories.  Maybe I even like people betting against me, its motivating as hell.  So onto the leading edges I go!