Right Flap (5)

I haven't heard from the shipping company itself yet, but I got word from Van's that my fuselage kit will be picked up tomorrow and head this way!  Gotta get the last flap done so I can clear a bunch of room!

With freshly primed parts, it was time to start assembling everything.  Everything had to be dimpled still, so that was first up, following by riveting the nose ribs and hinges.

After the individual hinges were put together I started riveting them to the spar. You'd think I'd remember all of the ins and outs of doing this since I just did it on the left flap not too long ago.  Enough steps have passed since then I guess, because I still had to do some trial and error to figure out the easiest way to rivet everything together.  There just isn't much room to get at a lot of these rivets, so it takes some back and forth with different squeezer yokes, rivet gun sets, bucking bar types, etc to land on the easiest way.  I guess in defense of my awful memory, each hinge assembly (and even each side of each hinge) takes a slightly different setup to get at the rivets.  I suppose shy of writing down what combination works for every single group of rivets, I shouldn't be surprised that I don't remember what I did last time.

The inboard angle kind of gave me some fits initially.  I just couldn't set the rivets nicely, no matter which method I tried.  That is, until I took a step back and realized that there must have been some longer rivets in the bin vs the size I thought they were.  They were so long that I just kept bending them over with the squeezer.  Things went better with the right length of rivet.

After the nose ribs were finished, then the main ribs were riveted to the spar, followed by clecoing on the top skin.

The top side of the nose skins were clecoed on next.  The skin/nose rib holes were up-sized to 7/64" holes and riveted with pop rivets.

Back into the cradle it all goes!  This part I definitely learned my lesson on last time, so getting the nose skins squeezed together in the cradles and clecoed was far easier this time around.

Last up for today was riveting the skin to the spar.  I also got about half of the rivets for the skin and main ribs set.  Even though I know the wave in the skin is normal, it's still disconcerting to see!  I stopped riveting the main spars when I reached about 2/3 of the way towards the tips.  I was having an awful time setting the last few without clinching them.  I have to use a narrow bucking bar, which makes it hard to keep parallel to the rivet head.  I'll try again tomorrow.  Like I did on the left flap, I'm not even going to bother to use a solid rivet in the last hole of the trailing end.  With a super tiny bucking bar (a lot of people use a wood chisel with a bucking bar taped to it for the mass), I know I could ultimately get the rivets set, but it's not worth the hassle.  I used pop rivets on the left flap, and I'm going to do the same on the right flap.  It's just not worth the frustration otherwise.  I've been told that before paint, just put a dab of epoxy/micro in each hole of the pop rivets (they're flush style) and you'll have a hard time ever telling them apart from regular solid rivets.  They are slightly raised and not perfectly flush just because that's how they squeeze, but I don't care enough to spend hours cussing trying to set rivets in this small area - rivets that in all likelihood would come out sub-par anyway.

Right Flap (4)

Not many pictures to share, but a lot of work.  I scuffed and cleaned all of the right flap parts and shot primer.  I was almost out of primer from my original gallon, so I bought one more quart of the same Ekoprime, plus one quart of the Ekopoxy.  My plan is to spray the tail cone with the Ekoprime, then I will spray the cockpit area (baggage compartment forward) with the Ekopoxy.  I think one quart of each should be enough, but time will tell.  I'm switching to Ekopoxy for the cockpit simply because it's a lot tougher than the Ekoprime - important in an area that will get a lot of wear.  It's still a waterborne primer, so not toxic like most other epoxy primers, but it's still a two part epoxy.  The downside is it means it has a pot life and the extra can't be saved once it's mixed, unlike the Ekoprime.  I decided to go one shade lighter for the cockpit area - smoke grey vs charcoal grey - since the lighter color will give the feeling of slightly more room.  That being said, I'm fairly certain I'm going to end up putting up side panels in the cockpit and probably cover most of the floor with carpet, so there won't be much of the primer to see in the end anyway.  The other option was to prime and paint the interior and leave it at that, but I think my important passenger will want the "comfy" factor of upholstered panels and floors.

There aren't a ton of parts in the flaps, but the ribs are small and awkward to scuff, so prepping and priming took about 3 hours.  At least I'm done with priming for a little while now.  Unfortunately, I think the timing will work out so that I'll have to prime the bulk of the fuselage parts during the winter, which is never easy.

Left Flat Assembly (6) & Right Flap (3)

I tackled the trailing edge riveting a little differently this time around.  The "normal" way of doing it is to tape or proseal the wedge in place, then partially set the rivets (just enough to swell and stay put) using a back rivet set, then flip everything over and use a mushroom set and the back rivet plate to finish setting the rivets.  This works fine, but it can be kind of difficult to keep the edge straight and flat, and requires some finesse with the back rivet set to keep from dinging the skin since you have to start vertical and then angle it to match the skin angle.  Instead of using the back rivet set, I decided to use the squeezer to do the initial partial set of the rivets.  Because I didn't need the back rivet plate at this first stage using this method, it meant I could leave clecos in the trailing edge to keep the wave from causing a headache.  I slid the flap off the edge of the bench just enough to allow me to get the squeezer in position.  To try to protect from a wavy edge even more, I put a board and weights on the flap to keep it all flat to the table while I riveted.

Van's calls out 3-3 rivets for the trailing edge, but those seemed short to me.  I used 3-3.5s instead, which were maybe a little on the long side, but still worked better than the 3-3s would have I think.  I set the squeezer to just squeeze the rivets to the point where the rivet set would almost touch the skin at it's widest angle, which left quite a bit of the rivet still protruding.  Because the clecos were holding everything in place and the weights were keeping it flat, I just went down the line with the squeezer.  When doing this the typical way, you have to bounce back and forth every 6-10 rivets or so to keep from creating a hook in the trailing edge by doing too many rivets in one place at once.

Once done with squeezing, I flipped everything over and finished by using the mushroom set and back rivet plate.  The shop head (that was partially set) went down against the back rivet plate, and the mushroom set hit the manufactured head.  It didn't take much to set the rivets the remainder of the way.  In the end, the edge turned out amazingly straight with no noticeable wave in it.  It's kind of hard to take a picture to show the edge.  It kind of looks like a transparent flap here.

Here's what the shop heads look like using this technique.  Very clean and flat.  I probably could have gotten away with the smaller 3-3 rivets, but I think I'll still use 3-3.5s on the other flap.

So the left flap is largely done now.  I still have a couple of rivets to set on the end ribs, but I'm waiting for a new tool to get here to do those.  It's too tight for the squeezer, and I was told that a great tool to have for awkward places is the parallel jaw Knipex pliers.  Apparently they work great for squeezing size 3 rivets in places where bucking isn't ideal and a squeezer is too big.

On to the right flap again!  Everything is fit and ready for the assembly, so that means lots and lots of deburring needs to be done.

Left Flap Assembly (5) & Right Flap (2)

I finished up match drilling everything on the right flap, including the trailing edge wedge.

I noticed that the inboard piece of angle has one hole that is just a touch too close to the edge, so doesn't meet normal edge distance rules.  This is because the instructions for putting this angle in place to match drill just say to center it on the spar.  I obviously didn't get it perfectly centered.  I emailed Van's to see if it's okay or needs to be remade.  It's not uncommon for even some of Van's predrilled parts to not have "by the book" edge distance, but they do it in places where the engineering says it doesn't matter.  We'll see what they say about this part.

Since I was done using the left flap wedge for the spacing of the right one, I put it into place in the left flap (with the VHB tape - although I'm not convinced it really helps much) and finished pop riveting the bottom skin to ribs.

Left Flap Assembly (4) & Right Flap

I clecoed the left flap bottom skin to the ribs.  I couldn't finish by inserting and clecoing the trailing edge wedge though, because I need the wedge as a spacer to set the distance of the trailing edge wedge on the right flap (I can't remember if I showed that before - the plans say to lay one wedge against the aft ends of the ribs, then slide the permanent wedge up against that.  This sets the wedge where it needs to be for drilling).  So with the left flap finished up until the point of riveting the bottom skin to the ribs and riveting the trailing wedge, I moved to the right flap.  Even though I've been told that the wave in the flap trailing edge is normal and will flatten out when the wedge is riveted, it's still a little disconcerting to see.

Now that I have the one main rib I was missing for the right flap, I can finally finish it up.  I clecoed the nose rib and hinges to the spar, the main ribs to the top and bottom skins, and match drilled everything.

I learned from the other flap and had a much easier time putting on the nose rib skins for the right flap.  I used the ratchet strap in the middle to start clecoing it to the spar, then moved the strap out towards the edges.  I was lazy and didn't feel like going out to the shed to grab a long 2x2 to hold the ribs flat while I put the nose skins on, so instead I just used shorter pieces that I weighted down.  I think this might actually work better, since they're flatter (shorter distance) and the weight just needs to span a couple of ribs at a time while working on the nose skin.

Left Flap Assembly (3)

I finished up all of the top skin to spar rivets while the flap was in the cradle.  These were relatively easy to reach and buck.  The wave that appears in the trailing edge when the nose skin is tightened up is pretty disconcerting, but it's a common occurrence, so I'm hoping it flattens out in the following steps.

The instructions say to flip the flap top side down and weigh down the skin and ribs to ensure that everything stays flat while riveting the bottom skin to the spar.  If you don't do this, it's easy to introduce a twist to the flap.  Putting the weights on the skin didn't totally flatten the wave, so I decided to just match up the trailing edge holes in the table (that I had drilled when drilling the wedge) and cleco the flap to the table.  This flattened the flap 95% of the way there.

The clecos still needed some help to really keep the ribs and skin flat.  I tried putting the weights under the skin and directly over the ribs.  That flattened the ribs, but bent the skin too much and made it hard to flatten the skin to the spar for riveting.  I finally settled on laying pieces of wood on each rib and then putting the weights on the wood. This was enough to push the ribs flat but also give me enough room to get my hand under the skin for riveting.

Left Flap Assembly (2)

Before I started on the flaps today, I did a little back tracking.  No pictures, but there were a few AN470 rivets that have been bugging me for a while.  I've since figured out that position really matters when riveting.  During my learning curve, I've destroyed some rivets, and I left them in place because I wasn't sure if I'd do a better job after drilling them out.  Fast forward, and I've got a lot more experience now - enough that I can drill out rivets without doing much damage, and enough that I can rivet with far more skill.  So today I started my garage session by drilling out about a half dozen rivets in the wings and redoing them.  Most of these were due to one thing - the manufactured head was severely dinged because I had let the rivet gun walk all over the place (the mil spec says that anything over 1/4 the depth of the manufactured head needs to be replaced due to increased risk of future cracking).  This was before I figured out that the air restriction device that goes on the gun is a terrible tool.  I don't know why it's different, but changing the air pressure at the wall makes for a completely different riveting experience.  I mean completely different.  Instead of leaving the main line at 90 psi and restricting the air using the gauge at the gun, I dial back the main line to around 40 psi for #40 rivets and 30 psi for #30 rivets.  For whatever reason, the rivet gun is much, much more controllable as compared to the 90 psi but using the valve at the gun to dial it back.  It just hits very differently.  So anyway, lessons behind me, I drilled out a number of rivets that I consider sub-par, and I redid them.  All turned out 100% better.  Once I have the flaps done and room on my table, I will bring the horizontal stabilizer back down to the shop and drill out the internal rib to spar rivets.  The exact same thing happened with them (such deep dings that I worry about cracking), partially because this was before I had purchased offset sets for the rivet gun.  I'll sleep better with those re-shot.

On to the flaps...

The next step was to rivet the top skin to the nose ribs.  While the inboard and outboard ribs have access and can be riveted using solid rivets, all of the other nose ribs have to be riveted with pop rivets.  The top skin and ribs were weighted down with about 100 lbs of weight to ensure everything stays flat while riveting.

In preparation for riveting the top skin to the spar, I put the flap back in the jig and clecoed the bottom side of the nose skin to the spar.  This is when I'm very thankful for the pneumatic cleco tool!

Originally when I had assembled the flap and drilled everything, the interface between the inboard and outboard leading edge skin was super tight - so tight that it overlapped a little bit.  I took a file to the edge to open it up until it fit correctly.  Fast forward to actually riveting the pieces together, and surprise, now there is a big gap between the skins!  Apparently I should have left it alone.  It's a complete non-issue (this area will be tucked behind the wing except for full flap deflection), but kind of irritating regardless.

I started riveting in the middle of the leading edge skins and worked my way out towards the ends.  The instructions call for 3.5 length rivets, but I ended up using -4's since I dimpled the spar instead of countersinking it.  The instructions say to countersink, but the material is  .40" thick, which is at the extreme edge of what can be dimpled, but it's also at the extreme edge of what can be countersunk.  Countersinking such thin material makes it extremely easy to make the holes too big, so I ground down one of my dimpling dies to allow it to set correctly in the angled spar flange and dimpled instead.  I honestly don't know why Van's doesn't recommend this. The dimpled spar is far stronger. 

Left Flap Assembly

Time to assemble the left flap! I started by riveting the hinge and nose rib assemblies together.  These are the nose ribs that I ended up replacing, so I will have to drill the top flange holes to the nose skin once I start putting it all together.  When you replace parts you realize just how great it is to have machine punched/drilled parts.  The holes matched up with the hinge holes perfectly.

The nose ribs and hinge then get riveted to the spar.  For the outboard and inboard hinges, that also means riveting the main ribs at the same time.  There were a few rivets that were awkward to rivet with the shop heads on the same side as the others, so I just flipped the rivets around depending on the area.  For places that will be hidden, I'm really not concerned about consistency just for aesthetics.

The main ribs were next.

I clecoed the top skin in place and then clecoed the top nose skin on to match drill the skins to the new nose ribs.  Then I pulled the nose skin off and dimpled the new holes in the nose rib flanges.

Priming Flaps

It's been a while since I really did much on the plane.  I'm finally back to a fairly normal energy level following round two of Covid, so I decided to knock out the priming of the left flap parts today.  Van's sent notice that the fuselage kit is going to crating, so my guess is it'll be ready to pick up or ship sometime in the next few weeks.  I need to try to get most of the wing related work done so I can rearrange the shop and figure out how to fit the fuselage.

The fuselage is going to have another big pile of hardware to sort through, so I finally went through the exercise of sorting the remaining hardware from my previous kits.  Up until this point I had just kept everything bagged up as sent from Van's.  That works fine, but now that I know what the more common types and sizes of hardware are, I think it'll be easier to find what I need if I just combine like sizes from the various bags.  I won't do that with everything though (for sizes where there is just one or two used, I'm just leaving those in the bags vs making a dedicated bin just for them).

I like the Husky bins/carriers that I have, but the bins are really bigger than necessary for the volume of each size of nut or bolt.  Out of boredom the other night, I drew up and 3D printed some little inserts that slide into the Husky bins, effectively giving me twice as many compartments.  I only made 4 for now, but it'll be easy enough to print more if I end up needing them.

The wiring conduit that goes through the wing ribs needed to be given some sort of protection against vibration, which over time can sometimes wear through the conduit.  Van's recommends using proseal or RTV.  I'm almost out of proseal, so I went the RTV route.  I'm not sure that this really provides a ton of protection, but once it dried it did seem to hold things more secure at least.

The left flap has been ready for primer for a while, but I just didn't have the energy to get through it.  Once it's started, it's kind of hard to stop, so it requires a good block of time to get through the prepping and priming.  I had some leftover primer from a month or so ago, so I mixed that in with a fresh batch.  This is one of the really nice things about the water based primer - much less waste compared to a catalyzed primer that has a pot life and then is no longer usable. I don't think I mixed the two batches very well though, because there was a mottled effect on most of the parts.  The coverage was still fine though.  Next up, I'll rig the left wing pushrods, set the aileron neutral point, and start riveting the left flap.  Then I get to finish building the right flap and do this priming thing all over again.  I'm assuming I'll fly this plane for many, many years, but if the day comes that I build another, my guess is I will switch methods and only do very light spray can priming on mating surfaces!  Priming isn't hard, but it definitely takes a lot of time to do.  For a plane that I'll have to keep outside for a while and want to last for many years, it's worth it.  After I gain a few more years, and assuming I can find a hangar, priming is out the window though!  Couple changing the priming picture with the new Van's kits that are punched to final size (so you just put things together and rivet vs putting together, drilling, taking apart, deburring, put together again...) and a second plane would go together very quickly relative to this one.

Wing Misc.

After being sick for the last week, I needed to get back out to the garage to keep my boredom from doing me in.  I still don't have a lot of energy, so just did a few odd jobs.  I just couldn't get up the motivation to jump back into the flaps yet.  From what I can gather, there shouldn't be any reason that I'd need to pull the fuel tanks off of the wings again, so I went ahead and put all of the Z bracket bolts in and torqued them (I still need to install the bolts on the inboard bracket, but that's too hard to do with the wings in the cradle since those go in from the front side of the spar).

I'm not going to pull wire for a while, but while the bottom skins are off I am putting conduit through the ribs.  It's ribbed, so is a real pain to pull through the holes I drilled.  

I got it pulled through the right wing, but still need to put either proseal or RTV at each hole.  Apparently vibration can chop through the conduit over time if it's not protected.

It'll still be a while before any of the aileron pushrods will get permanently installed, but they need to be put in place so the general rigging of the aileron can be done.  I think this is to just get each aileron set in a neutral position.  Once the wings are on the fuselage, I'm sure there is more to do to ensure that the right amount of deflection is there.

I just got the right aileron set in place.  Next I'll need to pull out the aileron rigging tool I made months ago as part of the wing build.  It's just a long piece of angle that has some reference holes drilled in it to align the trailing edge of the aileron (I'm assuming with the wing chord).