Riveting Aileron Reinforcement Plates

I didn’t get much accomplished tonight.  What has gotten me stuck is just how to deburr the inside of the A-409 counterbalance pipe for the aileron leading edge.  But I did get a little progress made, I’ll detail that below.  I started out by pulling all the parts out of the booth, and wiping any overspray off them.  Then I marked the parts and reading over the instructions and plans.  I was going to attempt to get the entire right aileron almost fully done, but after looking over the counterbalance pipe, I decided to do as much as I could on the parts. right up to needing to work with the A-409.

I grabbed the A-408 reinforcement plates for the right aileron and clecoed them in their proper spots, checking the alignments. Then I clecoe’d on the K1000-3 nutplate into position.  I also marked which holes I needed to rivet, as some of these holes need to be left open for the ribs when we assemble the skeleton.

  

I set the small -3 rivets in the nutplate first, using my squeezer and checking each rivet.  Then I followed that up with the larger -4 AN470 rivets that attach the A-408 plate to the spar.

Once I had all the rivets set for the right aileron spar plates, I decided to go ahead and do the left. These went pretty quick, and didn’t require any complex work, and they came out nice since I was using the squeezer.

I put the shop head on the A-408 plate, Conventional wisdom says to put the shop head on the side with the thickest metal.  The spar and the reinforcement plate are pretty close in thickness, but with the plate being .040″ I figured it best to put the shop head on that side.  Plus, it will make inspecting the rivets much easier since this side is the outside of the aileron.

Once I had that done, I took a look at the A-409 counterbalance pipe.  I still haven’t deburred the inside and primed, so I was going to tackle that tonight.  The priming will be the easy part:  Mix up a couple ounces of AKZO, tape up the holes in the pipe and pour some in and roll it around. The deburring is where I am challenged.  I rumaged through the shop and my garage in hopes of finding a long, thin rod that I could poke down the tube and force some scotchbrite through, but no luck. The only wooden dowel or wire I had were either too big or too small.  I think I can pick up some smaller wooden dowel rod and put some sandpaper or scotchbrite on the end and twist it through the pipe deburring and scuffing the surface at the same time. I’ll visit Ace Hardware tomorrow after work and see what I can come up with.  Here’s all the photos from tonights work:

Google Photos Link: https://photos.app.goo.gl/pi6YAmc0WJbrjQ573

Hours Worked: 1.0

Priming the Aileron Parts

I’m back in town after being gone for almost a week, and finally getting to do a little work done on he airplane. In the last session, I alodine’d some parts, so they’d be ready to prime when I got back.  I am still using the old method of scuffing and cleaning on larger parts, since I don’t want to get really messy with alumaprep and alodine, so I started out by scuffing the leading edge skins and the aileron spars and then getting them nice and clean with acetone. 

Then I mixed up 4 ounces of AKZO, and let it sit for the 30 minutes while I got everything ready for painting.  I moved all my parts into the booth, and then setup the ventilation system.

Finally, it was time to shoot a little primer.  The 4 ounces was just enough to cover all these parts very nicely, and left me a little over to touch up any missed or thin spots  I am really impressed with how well the Alodine parts absorb the primer, and how smooth of a finish it leaves.  I can really see why professional sprayers use this stuff for their exterior parts.  It makes a noobie like me come out with pretty decent primer jobs!

Since I had the ventilation setup, and everything ready for spraying, I decided to go ahead and get the galvanized pipe that’s used as the counterbalance primed as well.  Initially I was just going to leave it galvanized, since the galvanization process leaves it pretty corrosion proof.  BUT, I have been reading about corrosion between two different metals and decided to prime these as well.  I scuffed them up with some scotchbrite to get a good surface bite for the primer, and then cleaned them with acetone.  Instead of using AKZO, I decided to use some rattle can self-etching primer.  I am not sure how well a zinc-chromate epoxy primer would do on galvanized pipe, so I went with what I know works….plain old self-etching rattle can.

I haven’t gotten the inside of these things primed yet, I am still debating on how to best do that. I will probably end up using some scotchbrite on some string to scuff the inside, clean with acetone wash and then pour in some primer and roll it around to coat.  That finished up tonights work, I cleaned up all the mess and will let the parts sit overnight or longer to get a good cure before moving on to the next step. Here’s all the photos from tonights work:

Google Photos Link: https://photos.app.goo.gl/8m4XfPMInvp7JZhq2

Hours Worked: 2.0

Dimpling and Alodining the Aileron Parts

A LOT accomplished tonight.  I managed to get all the aileron parts dimpled, the counterbalance pipe countersunk, and even alodined a few of the small parts. I started off by setting up my DRDT-2 dimpler so I could make quick work of the skins.  This is pretty much what this dimpler is designed to do.  I also used it to dimple the holes in the spar, since its fairly thick metal, and fit in the DRDT-2 nicely.  I then used my squeezer to get to all the tight edges of the end ribs, and the very last little hole, I had to use my home-made hammer-and-anvil styled dimpler.  I made this a while back using some scrap metal, and a bent squeezer set.  I drilled a hole in the piece of metal, and countersunk it to fit a 3/32 dimple.  I just clamp it on my bench, and then use a 3/32 male dimple die to create the dimple in my parts.

     

   

I can get the small gap of the end ribs nicely over this hole and keep the flanges flat and straight, insert the male dimple die and the give it a good few whacks with a hammer and it forms a very nice little dimple.

After I had those end ribs done, the only thing that needing dimpling was the leading edge skins, where the counterbalance pipe is riveted on.  The instructions tell us to machine countersink the holes in the counterbalance pipe, and then when we use the bling rivets, they will form the skin into the countersunk holes enough to be flush.  I had seen other builders use different methods, but since my little hammer and anvil dimpler works so well, I figured I would give it a try.  First up was to countersink the pipe.  I ended up using an old cheap countersink I had bought from Home Depot years ago for other projects.  I didn’t want to ruin my nice one on this tough pipe, so I drug this one of the bin.

To get this done, I clamped the pipe down on to my workbench and went at it with my old electric drill and worn our countersink.  It worked good enough to get my countersinking done, but the holes were just nasty!! I had to use a #30 bit to clean up the holes and then file the outside edges down with a bastard file because of the roughness of the hole.

I ad to go back over them a few times, testing with a CS4-4 rivet as called for in the plans, to make sure I had the right depth.

  

Eventually I had them all finished up and cleaned.  Now, I decided to give something new a try.  I noticed that a 2×6 was just about the right height to hold the skin off the bench, but not quite thick enough to make it stable……HOWEVER…I realized I could use the bending brake I made with 2×6 boards to get the job done! I clecoe’d the counterbalance pipe to the skins, and then laid the skin over the bending brake and it worked great!.

Now, I could use my hammer and anvil dimpler set to create a nice dimple in the leading edge skins for the CS4-4 pulled rivet.

   

A few quick hits with the hammer and very nice little dimple was made in this rounded area!

You can see how well the rivet sits in the dimple now, and once I get it pulled, I believe I can use a small ball-peen hammer to round over the edges of the rivet to fit the countours of the leading edge on the ailerons.  I went ahead and did this to all the holes in both ailerons.  Now, all my parts were essentially ready for cleaning and primer.  I decided to go ahead and alodine my small parts since it’s easier to do that scuffing and cleaning, so I dunked them in a quick bath of alumaprep and alodine and rinsed them off.  They came out pretty decent!

  

I am headed out of town Sunday afternoon for a week, so I might be able to get these few parts primed this Saturday.  That will give them plenty of time to cure and be ready for final assembly and riveting when I get home next Friday.  That was a lot of work for one night, but I got a bunch accomplished.  Heres all the photos from tonights work:

 

Google Photos Link: https://photos.app.goo.gl/txFyiuYJP1s9RZ2u2

Hours Worked: 3.75

Deburring the Aileron Parts

Time to get down to the dirty work: Deburring, and edge finishing.  This will be a short post, but it was jam packed with work.  First I deburred all the holes in both aileron parts (skins, ribs, spar, etc).  Then, I deburred all the lightening holes in the spar, of which there are many.  I ended up using my Shaviv deburring tool to make easy work of all those lightening holes, and then touched it them up with a quick scuff of scotchbrite maroon pads. Next up was to deburr and smooth all the edges and corners of each part.  My bench grinder with a scotchbrite wheel helped this go quick. Then I had to manually work all the little tiny nooks and crannies that I couldn’t get with the wheel. The nose ribs were the worst! They are super thick metal, and have very complex curves, with some very tight spacing.  I ended up using a combination of emory cloth and maroon scotchbrite pads to get into all the tight spaces.  Eventually I had a bench like full of finished parts like this:

Lastly, it was time to do the same to the skins (leading edge and trailing edge for both ailerons). I deburred all the holes, and then used a fresh scotchbrite pad to smooth down and deburr the edges of the skins.  The last step I used a edge rolling tool to induce a very very slight bend in the last 1/4″ of the edge of the skins, downward.  This little bend will help make a very nice lap joint where the leading edge skin overlaps the trailing edge skins at the spar.  I only did this on the leading edge skin, since its the one that overlaps. This photo doesn’t do a very good job, but you can kinda see the little edge bend (Its bent slightly upward in this this pic):

And that wraps up the session for tonight.  I have all my aileron parts ready to go to the next step, which is dimpling and priming, and then final assembly/riveting.  I’ll get everything dimpled tomorrow night, and also put the small parts into alumaprep/alodine baths, and hopefully have everything ready to prime Saturday.  I have to head out of town for a week for business, so that will give the parts plenty of time for the AKZO to cure and be ready for riveting when I get home Friday. One last photo!

Google Photos Link: https://photos.app.goo.gl/KS0S5Zift06309g42

Hours Worked: 2.0

Assembling the Right Aileron

Tonight was pretty much a duplicate of last night.  I started out by assembling the leading edge and the trailing edge skins to the skeleton and match drilling everything. Making sure to drill out the holes along the bottom to a #30 hole where the skins overlap the spars. Once I had both sides match drilled, I flipped it over to finish the work.

Next up was to drill the counterbalance pipe using the leading edge skin as a template.  Learning from the work last night, I used a #40 drill to first drill the holes in the counterbalance, and the opened the holes up to a #40 size.  After drilling into this steel, I believe my drill bit is finally getting dull.  I’ll finish up the ailerons and then replace it.

( That photo doesn’t show very good, but thats a 3/32″ cleco in that hole…it looks like a giant hole from this angle heh )

Now its time to remove the trailing edge skins and re-cleco the leading edge skins to the spar so I can drill the last two holes in the counterbalance pipe.  Just like last night, I used my long drill bit, and went in through the lower mounting hole in the nose rib to back drill the counterbalance and that went well on both sides.

With all that, the right aileron is ready for deburring and edge finishing.  So far, I had only worked about an hour, and I was still ready to get some work done, so I went ahead and started deburring the holes in the parts for the right aileron.  I was able to get all of the skeleton parts holes deburred, and all I have left is the skins.  BUT, I need to remove some of the blue plastic before I do that.  So, I’ll save that for tomorrow.  Here’s all the parts I was able to get the holes deburred on.

That wraps up tonights short work session. I am still working on a few things for my job, so I don’t want to sink to much time in to each nightly build session.  Hopefully that will change soon.

Google Photos link: https://photos.app.goo.gl/RDvsOnVtc6D38a9g2

Hours Worked: 1.5

Assembling the Left Aileron

We’re getting close to having a completed aileron! I was able to fully complete the assembly and drilling of the left aileron tonight, and its parts are now ready for deburring, edge finishing, and priming. I will hold off on that until I have the right aileron done and do the all the parts in one big batch. For tonight, I started off by clecoing the A-802PP leading edge skin and the A-801-PP trailing edge skins to the spar and then clecoing the A-705-R/L end ribs into the trailing edge skin.  Once I had that done, I inserted the 1/2″ galavanized water pipe (A-409) into the leading edge skin, and then clecoed the A-704-L/R nose ribs into place to help hold the A-409 counterbalance. Once I had every thing assembled, I double checked for alignment.

    

I will admit, I have to admire the utility of using a plain old piece of galvanized 1/2″ water pipe as a counterbalance.  It’s simple, robust, and cheap, all principles that Van’s uses in their “Total Performance” moniker. Thankfully, Van’s ships this pipe in the wing kit, and its precut to length!  Once I had made sure everything was still in alignment, I went ahead and match drilled everything to their respective hole sizes.  The normal process is I cleco every other hole, and then match drill the empty holes to their correct size, then move the clecos over by one hole and drill the rest of the holes. I like to use a lot of clecos on the ends to help hold everything secure, so I have to make sure I remove them, drill and then replace them afterwards.  I am also going to use a edge roller / former to break the edge of the leading edge skins before I dimple.  This will give the skins a nice flat joint when I rivet them.

Along the bottom of the aileron, where the leading edge skin and trailing edge skins overlap one another on top of the spar, I drilled the holes for a #30, as called for in the plans to fir the CS4-4 blind rivet.  Next up was to drill the holes into the A-409 counterbalance / water pipe using the pre-punched holes in the skin as a guide.  HERE’S where I think I may have messed up.  Take a look at the photo below:

Do you see that ugly oblong hole in the skin?  This is the first time I drilled this counterbalance, and somehow my drill walked and chewed away at my skin before it made a pilot hole in the counterbalance beneath. It’s zoomed in in that photo, so it looks bad, heres a ruler for scale:

  

However, with this new found knowledge, I decided that the best course of action was to step my drill down to a #40 first, drill the holes and then move up to a #30 and enlarge the hole to its final size.  Which worked out wonderfully on all the rest of the holes in the counterbalance. BUT, I am concerned about this.  I’m going to give Van’s a call in the morning and send them the photos to get their opinion on it.  Worst case scenario is I have to buy a new leading edge skin and A-409 water pipe, best case is that they tell me to use a bigger hole and rivet (which would be super easy to do).  I’ll update this post when I find something out.

Any ways, carrying on, I decided to drill the last holes in the counterbalance just in case.  The plans has us remove the trailing edge skins, and re-cleco the leading edge back onto the spar for alignment, and then use a long 1/8″ drill bit to get to the last two holes we need to drill.  We go into one of the existing holes for the A-704 nose ribs on the bottom and then drill the hole into the counterbalance using the hole in the flange as a guide.  Like this:

That worked out really well, and the last two holes were drilled into the counterbalance via the nose ribs. For here, I disassembled everything, and put the parts on the shelf until I get time to deburr, finish the edges and clean them up for priming.  Thats it for tonights session, I will do the right aileron in the same fashion tomorrow. Hopefully after I speak with Van’s I’ll get good news that my mess-up is fixable.  I am just glad that it happened on a part thats relatively easy to replace if need be! Especially since I haven’t spent the man hours prepping and priming it yet!  Heres all the photos from tonight:

Google Photos Link: https://photos.app.goo.gl/pSLIaZ02zXNSFpKD3

Hours Worked: 1.75

Bending the Aileron Skins

Bending skins is one of those tasks that make me nervous! Van’s ships the aileron skins with the trailing edge bent only just enough to form the trailing edge.  The reason is so that you can easily attach the stiffeners via backriveting.  The task itself is not difficult, but it seems like something that could go wrong, very quickly 🙂

The above photo shoes how much bend comes from the factory, along with my homemade bending brake I built during empennage construction.  I have it clamped on to my workbench level with the surface so I can slip the trailing edge of the skin into the “jowels” and make a nice, smooth bend along the length of the aileron.  You can see more details about how I made the bending brake here: https://theskunkwerx.com/rv7/bending-the-right-elevator-trailing-edge/

I slipped the trailing edge into the brake and held it firmly as I slowly bent the skins over using very light, even pressure.  I like to use the “sneak up” method, of bending a little, and then checking the fit…..and bending a little more as needed…and repeat until i have the bend just right. 

Eventually, after several rounds in the bending brake, I wound up with the aileron where I though it was close enough to do a dry fit.  Vans has us bend the aileron just until the skins gently lay on top of the spars.  In the photo above, I am about half-way there. Once I had it to where I thought was close, I clecoed the aileron skeleton inside the skin and measure the straightness. Per the instructions, Vans tells us that the skin should be straight, form the spar all the way right up to the trailing edge radius.  The radius itself should be around 1/8″, and the profile of the aileron should match the full size drawings.  Mine were REALLY close to the profile in the drawings, so I decided to use a straight edge to check the straightness.

The process goes like this: I lay the straight edge perpendicular to the leading/trailing edge and check to see if there are any humps, bumps, or divots underneath it.  A hump/bump means I don’t have enough bend, where a divot means I have too much bend.

SOOOOO close this time! One or two more bends and it’ll be perfect!  It’s very important to get this just right because I have heard horror stories of builders having heavy wings because of an aileron that isn’t perfectly bent.  Vans actually has a procedure that calls for “squeezing” the ailerons with your hands to help get rid of a heavy wing.  Its astounding such a small little control surface can have such a big impact, even when in trail.

After a few trips back into the bending brake (which includes unclecoing and re-clecoing) I ended up with a darn near perfectly straight skin!  Once I had the top side of the skin, I also checked the same on the bottom side, using the same procedure of measuring with the straight edge at every stiffener, and at every station between the stiffeners, including the very ends at the ribs.  Things doesn’t always go great, sometimes you get a little too much bend in one section:

As you can see in the photos above, I got a little overzealous with my bending brake on this aileron (The left one). While the rest of the aileron was fine, this inboard end needed to be un-bent per-se. You can see the little divot right under the straight edge. It isn’t much , but I want to go ahead and get it corrected while its easy to do.  So, I removed the skin and use my fingers and a piece of soft scrap wood and ever so gently bent the skins back out (opening the end up a bit) until I had the straight edge sitting perfectly level across these sections.  You can see where I marked them with an “X” to keep track. Once I had one aileron bent, it went back on the shelf while I bent its sister for the opposite wing following this same procedure. Now that I have these skins bent, I can move on to fitting and drilling the skeleton to the skins and continue on.  I’ll double check the straightness of both of these before final riveting, so I can make any corrections before closing up.  Here’s all the photos:

Google Photos Link: https://photos.app.goo.gl/MmT1Pd7YN7GKmYgJ3

Hours Worked: 1.5

Riveting the Aileron Stiffeners

Since the AKZO had plenty of time to harden, I decided to go ahead and rivet the stiffeners to their skins so I can continue on with the build process.  Since these are backriveted on, this was a very quick little build session, which was nice because I have TONS of other stuff to get done tonight….not airplane related.

I started out by inspecting all the stiffeners and skins to make sure I had done a decent job priming them.  There’s a few thick spots and a few thin spots but since this is just primer on the internal parts I am not worried about it.  It’ll do its job of preventing corrosion. I setup my rivet gun with the backrivet set, dug out the backrivet plate and setup the benches.  As the drawings call for, I used AN426AD3-3.5 rivets, stuck them in the holes for the stiffeners and then used some riveters tape to help hold them in place while I back rivet.

You can see on the right side of the back rivet plate, a piece of wood.  It’s almost the same thickness as the plate, so I use it to hold the skin level to make sure the stiffeners get set squarely against the skin. Then I placed a stiffener over the rivets and held it down with my fingers as I backriveted it to the skin.  I like to set the rivet in the middle, then work my way out to the edge of the skin. Then I go back and set the rivets from the middle, working towards the bend in the skin.  This way my stiffener is well attached and won’t get mis-aligned when I push the skin back to get the rivet gun in that space near the bend.

I simply worked my way along each stiffener this way, and then worked from the inboard end of the aileron to the outboard riveting the stiffeners on.  This process went pretty quickly, so I was done with each side of the skin in about 15 minutes or less.  Eventually I had both ailerons done and it was time to call it a night for this quick session.

I’ll work on bending them to their final shape tomorrow, I’ve got to dig out my bending brake I made for the empennage kit 🙂 Here’s all the photos from tonight:

Google Photos Link: https://photos.app.goo.gl/2ExONxvwMkvCttIl2

Hours Worked: 1

Priming the Aileron Skins and Stiffeners

I was pretty happy with the way the Alodine treatment turned out last night, so I figured I would go ahead and lay down some AKZO primer on them to see how well it sticks.  This is going to be a small primer session, with only doing the stiffeners and the skins for both the left and right ailerons.  My goal is to really test the alodine procedure to see if its going to be worthwhile on these smaller parts, but I do need to get these parts done so I can move on to the next step.

I started out by preparing the edges of the skins by running a bastard file to smooth off the high points form the shearing process.  Then i rounded off the corners. Next up was scuffing the skins with scotchbrite.  I will probably do these large parts this way since I don’t want to be spraying those chemicals around, and the large parts don’t fit into a bath solution very easily.  I scuffed them as I typically do, and the cleaned the skins with Acetone.   Once the paper towel was coming up clean, I put the skins in the booth and mixed up 4 ounces of AKZO to let it do its 30 minute activation.

While the AKZO was setting up, I donned a new Tyvek suit….well a cheap copy of one from Home Depot since I blew the crotch out of my REAL Tyvek suit.

This thing was no where near the quality of the Tyvek I normally buy from Amazon, and it was actually more expensive! It will do the job though, but I am going to order a replacement Tyvek suit tonight, because this thing was hot and didn’t seal around my facemask like the Tyvek branded ones.

Finally, it was time to shoot the AKZO.  I gave the Alodined parts a couple of normal passes with the AKZO, as I like to spray a light mist instead of a heavy dose in one application.  I will note, its a bit harder to tell if you have good coverage on the parts since the Alodine is a dull, gold color, it sort of blends with the AKZO’s green color.  On natural, scuffed and clean aluminum, its easy to see your coverage even in low light, like my booth.  But, its not enough to hinder things.  I’ll probably stick a decent light in my booth anyways, as I have been meaning to do that for a long time now.  Maybe a nice LED shop light.

I did use up all 4 ounces of the primer I had mixed. I had enough to fully cover all my parts and skins, and even a little left to use on touch ups.  Here’s some shots of the parts as they are drying in the booth:

I’ll let those guys harden over a day or two and then start the next step: back riveting the stiffeners to the skins.  I still have a little work I can do on the other parts, like deburring and edge finishing in the meantime.  Thats something for tomorrow.  Thats all for this session!

Google Photos Link: https://photos.app.goo.gl/JLnZJWvuA37qWhAr2

Hours Worked: 2.25

Alodining The Aileron Stiffeners

This sort of a two-for-one post.  My Alumaprep and Alodine came in this week, and in anticipation of this new process, I installed a utility sink in the airplane factory.  I’ve been wanting a utility sink in my shop for a while now for various reasons, and this was the kicker that made me install one.  I had a nice little place picked out for it, right next to a 3″ sewer line and hot/cold supply lines.  Thankfully, the builder installed PEX lines in my house, so a couple of Sharkbite connectors is all it takes to plumb this sink in.  Whoever came up with the idea of PEX and Sharkbite push-fit connectors….I salute you!

Anyways, I am not counting the hours I spent installing the sink in the build.  So tonight I decided to try this whole Alumaprep and Alodine process.  Part of building an experimental aircraft is learning the techniques!  I mixed both of them into the proper ratios for a bath solution, and gave it a shot.  I wanted to test the lazy scenario first:  Not scuffing or cleaning the parts, and letting the alumaprep do that for me. To be safe, for my first time I figured I would just do a small batch and focus on the stiffeners (I hate scuffing those suckers).  SOOO, I put them in some tubs and poured my alumaprep bath over them until they were submerged.  At first I grabbed the stiffeners for the RIGHT aileron first to keep them sorted with the right side.

Per the instructions, I let them sit for 5 minutes in the bath solution and watched the bubbles take away all the dirt and alclad.  Once the 5 minutes was up, I pulled them out and let the Alumaprep drip back into the tub and then rinsed them off in my sink.

Now its time for the Alodine.  I done the same procedure in the alodine bath. I stuff the right stiffeners in the Alodine while I put the left stiffeners in the alumaprep.

When the Alodine bath was ready, I pulled them out and dunked them into fresh water in the sink and rinsed them off really well and left them to dry. Meanwhile, the last left side stiffeners were ready to be rinsed and then dunked into the alodine.  When their alodine bath was done, I rinsed them and set them to the side to dry.

I am not quite sure if they got “done” enough, but they have that pretty golden finish and they are a satiny feel.  I think AKZO will stick really good to these things.  I am going to let them dry overnight and then check on them in the morning.  If they look fine, I may end up shooting some primer on them.

I still think I might get some Bon-Ami cleaner and then clean my parts with it and a gentle scrubbing with a scotchbrite pad to get them more prepared for the Alumaprep bath.  Maybe this will give the primer a better surface.  I will say this….I much prefer this process over the hours of scuffing and cleaning with acetone! Here’s the photos from tonights work:

Google Photos Link: https://photos.app.goo.gl/Vf0NnRRTX0DzFGRB2

Hours Worked: 1.25