Empennage Fitting

I received the aluminum bar I needed to make the shims that go underneath the attach angles of the front spar on the horizontal stab.  The plans give measurements to get all of the layout angles for the shims right, but I just put a square piece in place under the attach angle, drilled the bolt holes through to match the existing ones, then traced around the attach angles to get the layout.  A few simple cuts and some sanding and the shims were done and in place (temporarily).

The rear of the horizontal stab has to be elevated a bit to get the incidence set to zero.  An 11/32 bit placed under the rear spar should get everything where it needs to be.  With that in place, I put a 12" long drill bit into the aft tooling holes of the ribs to get a measurement.  Then I put the same long drill bit in the forward tooling holes of the nose ribs and measured there. It was within 1/64", so I'm calling that good!  I drilled the bolt holes in the two vertical attach bars that come out of the fuselage and connect to the rear spar.  I temporarily bolted things together with the top two bolts.

The elevators have to go back on for the 100th time so the pushrod can be put in place, as well as a check for general fitment.  The right elevator looks great in terms of how it lines up with the horizontal stab.

For whatever reason, the left elevator looks less great.  I'm not sure what is causing the difference in gap between the two sides.  There's not really much wiggle room when building them, so it's hard to imagine what I could have done to create such a difference from side to side.

I slid the pushrod into position and bolted it to the bellcrank and the elevator control horns.  This is just temporary for now (I still have to prime the pushrod), but helps to get everything set to the correct length.

When I bolted the pushrod bearing to the control horns, that's when I realized I had a potential problem.  The instructions prior to this point had said to drill the control horns together by clamping the elevator counterbalance arms to the horizontal stab.  In theory, that should put the trailing edges in a neutral position, and drilling the control horns based on that should mean perfect alignment.

Once I got everything hooked up, I saw that with the counterbalance arms level to the horizontal stab, the left elevator trailing edge was 1/2" below the trailing edge of the right side.  I've emailed Van's to find out what the best way forward is.  I've looked online, and there are a suspicious number of people who have had the exact same issue, down to the same 1/2" measurement.  So there is a possibility that I either just built a twisted elevator, or something about the manufacturing of that side continues to spit out some parts that end up being a little off.  Some builders said they noticed it early and instead of lining up the counterbalance arms to drill the control horns together, they lined the trailing edges up instead.  Of course, that means that in neutral they have one counterbalance arm that is up and one that is down.  Ugly.  Others have said they left it all alone and have noticed zero negative flight characteristics (one DAR said that an RV6 he looked at had this issue.  It was already flying, and the builder decided to rebuild the elevator, only to discover it didn't change anything about how the plane flew).  I'll see what Van's has to say.  It's possible I could drill key pieces of the elevator apart and correct it, but I'm not sure.  Worse case scenario, for a few hundred bucks and a weekend of time I could have another elevator built.  Based on what I've seen online though, I wouldn't be surprised if they said that it's unlikely to have any perceivable impact.  The joy of building is that I can always fly it, and if I don't like it, I can always build a new part and replace it.

Moving on from the horizontal stab, it's time to mount the vertical stab.  I drilled and temporarily bolted a mounting plate to the front horizontal stab spar.

The front spar of the vertical stab has to be cut down a bit to fit in place.  I have no idea why they don't just ship the spar the right length or have you cut it before you build the thing.  They do weird things like that all of the time.  I set the vertical stab in place and clamped the rear spar to the aft most bulkhead in the fuselage.  There are a few measurements called out in terms of where the whole thing sets vertically.  After a lot of tapping and back and forth, I finally got it in place.  Next up, ensuring it's actually at a right angle to the horizontal stab.  100 measurements and tapping later, I think I got it.  Every time I'd tap the top portion one way or the other, that meant it slide a little vertically as well, so each tap meant remeasuring both planes.  I haven't drilled or bolted it in place yet.  I wanted to take a step back and come back to it another day to double check things.

Brake Lines & Canopy Frame

A builder who had a lot of extra plastic brake line tubing was kind enough to send me a roll of it so I could swap out the one run that I had made too short.  It didn't take much additional length to make a difference.  Now everything swings freely with no binding.  I'm still not going to attach the lines to the brake fluid reservoir or torque anything down until I get seats in and decide of where I want the whole assembly to sit.  I'll probably bite the bullet and order seats here pretty soon, even though I really won't need them for a few years.  All of the remaining costs for the plane are huge chunks (interior, engine, avionics, etc), so maybe getting a little out of the way now will take a tiny bit of the sting out of the next few years.  Staring at those big purchases, I just keep reminding myself that the plane will one day sell for at least what I have in it, if not a little more.  That's assuming gas isn't outlawed, making it a big paper weight.

I didn't get a picture, but I also got the ELT bracket drilled to the J channels behind the baggage bulkhead.  It is now sitting in the huge pile of parts to be primed in a few months.

Since I'm still waiting on a piece of bar stock to finish the empennage fitting, I moved on to the canopy frame.  The first piece to conquer is way more complicated than I would have thought.  The rollbar above the seats is made up of four U channels that get riveted together to create a rigid box.  I drilled the 1 1/2" access holes in the aft pieces to start.

The canopy frame is attached to each side of the fuselage with aluminum angle.  I didn't get far with making these, but got started at least. They're pretty fiddly to lay out, given that they have goofy angles that help set the frame in the right position.

Elevator Electric Trim

Time to make a new elevator access cover so the trim servo can be centered this time.  I had scrap sheet the right size, so making the replacement was relatively easy.

I moved the servo over about 1/8", which did the job.  I'll wait until final control setup to adjust the trim, so back in the box it goes.

Horizontal Stab, Elevator Controls & Electric Trim

I drilled the remaining holes for the horizontal stab spar attach bolts.  Since I already had the initial hole drilled, the rest were pretty easy to finish up.  A 1/8" shim has to go underneath the attach angles to set the stab incidence to zero.  Unfortunately, I used up my last bit of 1/8" bar stock a while ago when I remade a part, so I have to wait on more to arrive for the shims.  Since I have to get those shims in place before I can move on to mounting the vertical stabilizer, time to skip ahead to some other things.

I put the elevator pushrod bellcrank back in place.

A few days ago I poured boiled linseed oil into the pushrod.  It's all drained out now and has dried up into a really nice protective layer.  I cut the pushrod down to size, put the threaded rod ends on, laid out holes and put the pop rivets in.  I'll prime the outside later.

The pushrod will have to come out again (like everything - in and out, in and out...), but I put it in place for now since I'll need to tweak the length and set the elevator throw once I put the horizontal stab shims in place.

I'm setting the plane up with electric pitch trim.  It's a fairly simple setup really, with a trim "servo" (not really a true servo) that drives an internal jack screw and moves the trim tab connection.  The servo mounts to the underside of an inspection cover on the bottom side of the left elevator.

Once again, the measurements called out in the plans bit me.  The plans indicate where to mount the two brackets on the access cover, so dumb me, I laid everything out and riveted them in place.  I don't know if the size of the servo has changed over the years since the plans were drawn or what the deal is, but the part that moves in and out and drives the rod to the trim horn doesn't line up with the opening.  It's off by about 1/8".  I sent a message to Van's to verify I have the correct trim servo.  Assuming I do, I'll probably need to fabricate a new access cover so I can move the servo over.  I think I have some extra aluminum sheet to make the cover vs buy a new one.

Elevator Fitting & Mounting Horizontal Stab

I got a few things done today, but had to give up when I couldn't feel my fingers anymore.  The infrared heater works great, but only if you're in the shadow of where it radiates.  Step outside of that range and the 15 degree metal is a tad chilly to handle after a while.

First up, the elevator control horns need to be lined up and drilled for the pushrod bolt.  I clamped the elevator counterbalance arms even with the horizontal stab again (neutral position).  The first pushrod bolt hole in one control horn is drilled based on measurements, but the hole in the other control horn has to be drilled by aligning the two together.  If the holes aren't perfectly aligned, the right and left elevators won't set the same (one high, one low).  In order to get as close as possible, I stacked up some aluminum the same thickness as the space between the two control horns.  Then I drilled a hole through the material using the drill press, hopefully getting a perfectly perpendicular guide hole.  I slid the stacked aluminum  between the control horns, lining the hole up with the one already in the right control horn, clamped it all in place, and drilled the matching hole in the left side.  Then I took it all apart and drilled the final size 3/16" hole in each side for the bolt.

Now that the elevators are set up, I took them off and put the horizontal stab back on the fuselage.

The next part took forever, and all I have to show for it is a single hole (although the most important single hole I've drilled in a long time!).  The stab gets bolted to the aft deck in a number of places, but these aren't pre-drilled holes, or even measurements called out in the plans.  There are two pieces of angle on the front horizontal stab spar that set on the deck and each get two bolts that attach to the aft deck and underlying structures.  The outside bolt goes through the longeron and a piece of angle that sets below it.  The inside bolt goes through the deck and a number of spacers/angle.  All of these pieces are completely hidden, and the edge tolerances are very tight when you're talking 3/16" holes, so getting the center right is very important.  It's a spot where a lot of builders mess up and have to fabricate doublers or rip things apart and make new parts to try again.  I knew this was a trouble spot, so when I built the underlying angle pieces that nest under the longeron, I made them longer than the plans call out so they'd set as far into the longeron corner as possible.  That gives a little more wiggle room for edge distance than the measurement in the plans give.

Before any drilling happens the horizontal stab has to be set as close to perpendicular to the longitudinal center of the fuselage as possible.  You don't want it canted either direction.  I clamped the stab in place, then measured from the outside edge to the front corner of the firewall.  Since there is nothing to keep the stab centered on the aft deck (it just sets on top), this wasn't as simple as just pivoting one outside corner of the stab to get even measurements.  Every time I'd move a corner, the whole stab would also slide on the aft deck.  After 500 trips back and forth, I finally got it within about 1/32" from side to side.

After the stab was aligned properly, it was time for the dreaded first hole to be drilled through the attach angle on the front spar.  It sounds easy, until you realize that nothing is designed to have edges line up with anything else, there are no right angles to measure off of, and you can't see anything you're drilling through except the first layer.  In the end, the outside hole has to be centered on the hidden 5/8" horizontal leg of the longeron (the vertical leg is an additional 1/8") as well as centered on a second piece of angle that is under the deck and nests under the longeron.  Needless to say, it sounds fairly straight forward, but not all that easy in reality. I measured 20 times and finally got up the courage to drill a pilot hole.  I figured if I drilled a small hole and it was too far off, at least I had a chance of correcting it for the larger hole.  

I stuck my camera under the deck to see how I did. Thankfully, that pilot hole ended up exiting exactly where I wanted it to!  What a relief!  Here's hoping the right side goes just as well.  That's for another day after I thaw out though.

Elevator Fitting

Switching gears from fuselage plumbing - time to start fitting the tail feathers to the fuselage.  I pulled the horizontal stabilizer and elevators out of storage.  The garage is getting awfully full!

The elevators are connected to the horizontal stabilizer with two rod end bearings that screw into nutplates attached to the elevator spar.  Van's says the max measurement from the spar to the center of the bearing is 7/8", so I took it a little past that to start.

Getting the bolts into the rod end bearings while holding the elevator with the other hand was easier said than done.  I screwed some boards to the bench to act as a clamp for the horizontal stab to keep it from moving around.  I put both elevators on just to see how things line up before doing any drilling. The control horns don't line up well at all, but after some searching online I found that this is par for the course.  Once everything is mounted to the fuselage the control pushrod will be drilled to the control horns, so having them match up doesn't really matter as long as they are drilled together in the end.

I took one elevator off so I could get at the control horn to drill it to the center bearing (on the rear spar of the horizontal stab).  The elevator has to be in trail before any drilling is done, which is accomplished by clamping the counterbalance arm to the horizontal stab.

In order to drill the bolt hole in the control arm that connects through the center bearing, I needed a 1/4" metal bushing of some sort to help get a center hole started.  I looked through every bin at Home Depot and couldn't find anything that would work, so I ended up going the 3D printer route.  It seemed to work okay, although not as accurate as if it were metal I'm sure.

Once the pilot hole was drilled into each control horn, I final sized it to 1/4".  The next step is to put both elevators back on the stabilizer to match drill the hole that the control pushrod will connect to.  I was done for the day though, so just for fun I put the horizontal stab on the fuselage just to see if it was going to fit in the space I had.  It's going to be tight!

Fuel Pump, Almost 14 Mod, Brakes, ELT Mount

Back at the brake lines - they have to have some sort of mount to keep them from flopping around.  I glued down zip tie mounts, wrapped some self fusing silicone tape around each line just to give a little protection from the zip ties (strange stuff - not sticky at all, but as soon as it touches itself, it is almost like it's a single piece) and zip tied them in place.

The spiderweb of lines for the fuel filter and boost pump were next. Having pre-made lines that fit perfectly made this super quick and easy.

I zip tied the flexible fuel line that goes up to the firewall, but I am not going to drill the hole through the firewall for a fitting until I know for sure what firewall layout I need for the engine.

Back to the seat back brace, the modification that never seems to end.  I picked up some structural screws for mounting the brace to the outside longeron (these screws have non-threaded portions on the shank to better fit the holes and provide more strength).  I drilled out one of the existing rivet holes in the longeron to fit a screw/bolt, then put a second new hole in the longeron for another screw and bolt.  There are zero instructions for how much is necessary, so I just went off of what I've seen others do.  The two screws on each side in the longeron are probably enough, but I also wanted one a little inboard to hold the cap to the brace.  I didn't mount anything permanently for now, but figured out all of the lengths and sizes of screws I want to use once it's time to finalize it all.  Given that the brace can come out, I'll probably wait to put it in permanently until I've painted the interior next spring, just to make painting easier.

I had to tweak a number of spots on the outside aluminum caps to make them fit right (ground away places so rivets would clear and bolts would fit).  They're just aesthetic, which made it pretty easy to modify the unseen portions to make them work.  I scratched my head over the center post cap for quite a while.  The holes in it are in standard places, but are just off enough from my holes and nutplates that things don't fit quite right.  That's the downside of them trying to match hole locations that are just measured out by the builder vs prepunched.  After a lot of back and forth and enlarging some holes in the side covers, I finally got it sorted out.  The important thing I have to remember now is that it works okay as long as I screw the cap to the flap housing first and only bolt it to the cross brace after all other screws are in.

A while back I ordered an ELT mount from Van's.  I don't plan on buying the actual ELT for a while yet, but may as well figure out the bracket. It mounts to the J channels just behind the baggage bulkhead.  As is usually the case with everything, I found a standard "well that won't work" issue right off the bat - there is no way to get at the bottom J channel to drill holes into the bracket.  With the tight curve on the fuselage skin, even my angle drill is too big to drill up from the bottom side.  I think what I'll end up doing is taking a small strip of aluminum and making a template out of it with the matching holes from the bracket.  I can lay the template on the top side of the J channel and drill down vs having to drill up. Maybe tomorrow.

At this stage, I don't think there's any reason not to install the brake/rudder assembly in the fuselage.  I'm not going to tighten anything down until I have a better idea of how far forward or aft I want the assembly to set though.  It's a little hard to know for sure without seats.  The one thing I did notice once I had it all in the fuselage is that I made the plastic line that goes between the left and right side a little too short.  It's all going to depend on how much deflection the pedals need with full rudder.  If the line ends up being too short, at least it's a pretty simply swap to put a new one in.

Almost 14 Mod Center Brace

I didn't have a lot of time to work on the plane today.  I've been mulling over what to do about the center support cap of the Almost 14 mod.  It's supposed to be designed to just set in place and bolt to the seat back brace, but something about it or my setup makes the angles off so it doesn't line up with the angle of the horizontal brace or lay flat on the top.  It sets a good 1/8"+ above the horizontal brace..

I spoke to the designer of the mod and he couldn't figure out why it's not working like it should either.  Based on the discussion with him, I know which connections are important and which are aesthetic at least.  There is a small steel piece that screws directly to the vertical brace as well as the horizontal.  The holes for the vertical brace were also offset to where they wouldn't clear the front angle of the horizontal brace like it should.  I ground away a couple of areas of the horizontal brace to allow the screw access, then drilled new holes and installed new nut plates on the vertical piece.

For the 1/8" gap, I could just put a couple of washers there and call it a day, but I think it would look a lot nicer with an actual spacer.  For odd shapes like this, Fusion 360 makes it fairly easy - I imported a picture of the portion of the cap that needs the spacer, then scaled it and traced the shape for printing.  I undersized it just a little bit to make sure it wouldn't stick out anywhere.

12 cents in material later, I had that spacer, plus another one for the forward portion of the cap that also sets off of the standard parts (this spacer will be completely hidden - it's just a very awkward location that would be hard to use washers in).

Here is a trial fit of the spacer (not snugged down - everything will lay flat when tightened).  I will use screws for the final fit.