Front Deck (4)

Not much to show for a lot of effort today.  The front top skin was an absolute bear to get in place and match drill.  Finally, almost 5 hours later and after the 100th time taking it on and off, I was able to get it close enough by heating up the skin and using ratchet straps.  I still couldn't get the forward hole on each side to match up with the existing firewall flange hole though (it was off by about 1/2 hole).  I decided to just upsize those holes to a 4- rivet instead of a 3-.

I clecoed all of the subpanel pieces in place and match drilled them all.  Every last one of them fits incredibly tight.  At times I had to pull out the hammer and a block of wood to get things lined up.  I clecoed the panel back on in order to line it up on the sides and figure out where the side attach angles go.  I'll pick up there another day.  This skin issue was super frustrating, so I know if I keep going I'll probably end up making a mistake!  I only have a few pieces left on the front deck before I can pull everything apart, clean up the edges and prime.  The top skin will be the last skin put on in the entire build.  I'll wait to rivet it on until all of my avionics are installed, just to make access easier.

Front Deck (3)

I couldn't help but put some of the front deck in place to see what it looked like.  A few cushions to sit on and 10 minutes of airplane noises later, I got back to work.

I couldn't figure out how to reliably locate the two stub ribs that set just inside the two big outside ribs, so I inverted everything on the bench and clecoed the existing holes to the skin.  That let me set the stub ribs on the skin and clamp to the flanges of the center subpanel.

I didn't get pictures of the interim steps - I fluted the flanges of the outboard subpanels (it took a lot and the holes still weren't lined up very well) and clecoed those in place.  The top flange of the firewall isn't pre-drilled at all, so it has to be matched up to the skin and drilled.  I did the center portion and then attempted to get the skin sucked down to the longerons.  No luck.  I used a ratchet strap, which helped a little, but I still couldn't get the longeron holes to match up with the skin.  The photo is deceptive because it looks like most of the skin is clecoed down, but the majority of clecos are at a severe angle - definitely not good enough to finish drilling the firewall.  Skins always seem to be a fight until you figure out the perfect order of attaching everything.  I'm going to have to take it all apart and try another approach.  I might try starting at the longeron on one side and then working my way over to the other side.

Front Deck (2)

I finished up bending and match drilling the stiffener to the top of the panel.  I could rivet it on now, but I think I'll wait until I get to the point where I cut the panel for instruments.

All of the front deck parts are going to be hard to explain without referencing the drawings.  I can barely understand them when I'm staring at the drawings myself!  There is a subpanel which sets in between the instrument panel and the firewall.  I started with cutting the center channel and rib to size and match drilled them to the center subpanel.

Two stub ribs get fabricated from some channel.

The instructions say to drill these with the subpanel, but there's no indication of how they need to set vertically in relation to everything else (if I set the even with the wrong part, they won't match up with the skin - the skin is slightly curved down at this location).  I'll have to put some other parts together first and see if it becomes more clear.

The instructions don't say anything about putting these two large ribs in place yet, but I think they are the reference I need to get the stub ribs located accurately.  I may actually cleco all of this upside down on the skin since that's the ultimate reference.

I didn't get a picture of it, but I also fit the engine cable bracket to the center subpanel.  I'll hold off on doing anything beyond match drilling it though.  I don't want to locate nut plates on it (to hold the adel clamps that will hold the various cables) until I know where the engine control cables will have to come through the firewall.

Front Deck

There's still a lot of work to do in the back half of the plane, but I don't want to go crazy with riveting and final assembly until I've painted parts and run some wiring (which I need to research first).  The front deck basically includes all of the panel to firewall and is up next.  The first step is making a bunch of smaller angle parts.  As usual, laying out the various angles and holes took more time than I thought it would.

The panel itself requires a piece of 1/16" angle that follows the top contour.  In order to be able to do that, it has to have angles cut out of one leg to allow it to bend.  I measured and drilled holes for the vertex of each cutout.  The plans show that each cutout is a 15 degree wedge.  I wish they would have just listed measurements for the edge of each cutout, but no.  I took the easy way out and printed a little jig to make it easier to do the layout.

Here's half of the stiffener.  The other half mirrors this.

The stiffener will set on the back side (fore) of the panel.

More Priming

I'm a little late in uploading Sunday's work.  It was mostly more of the same - priming more parts from the pile.  I wasn't actually planning on priming on Sunday because I had a lot of things to do around the house.  While I was fixing the mower, of course I walked by the plane to get a wrench though.  I paused and thought "but it'll only take 5 minutes," so I grabbed the elevator pushrod, hung it up and hit it with Rustoleum.

Of course, then I figured that I only had a small window of nice weather left, so I'd better prime the rest of the parts!  So 5 minutes turned into an afternoon.  I finished the rest of the pile, this time using the regular Ekoprime.  I'll never go back to the epoxy primer if I have a choice.  The Ekoprime is way easier to prep and spray.  I'm mostly caught up with priming now, although I'm getting ready to start working on the front deck, which will produce more parts.  What I still have left to do is paint all of these parts that will show in the cabin though.  I'm not looking forward to having to scuff and clean everything all over again, including the inside of the fuselage itself.  I do have to wait for a longer stint of nice weather before I do that though, because ideally the paint is supposed to be kept above something like 70 degrees for 12 hours before it is allowed to cool down.

Just because I wanted to do something productive besides spray primer, I grabbed the ELT mount and attached it behind the baggage bulkhead.

Priming Session

No exciting pictures from today, but a lot of work.  The temps are in the low 70's this weekend, which means I have to suck it up and do my least favorite activity - priming.  I worked my way through the pile of parts that has been building up all winter.  I scuffed everything up and then cleaned about half of them for priming.

I had about 1/2 quart of the epoxy primer left, so I mixed all of that up and sprayed until I ran out.  It's a good, super tough primer, but I just don't like using it compared to the other Ekoprime stuff.  It just doesn't spray as evenly or easily.  I got through about half of the parts.  I'll spray the rest tomorrow (if the honey do list doesn't explode due to weather) using Ekoprime.  I can't get too excited though, the vast majority of these parts are for areas that need to be painted with my interior paint as well.  I'm not looking forward to going back through the process of scuffing up the primer and cleaning it in order to shoot the paint.  The end result is fun to see, but boy is it boring and time consuming!  To top it off, on another nice weekend it's going to be time to scuff up the cabin interior and spray it with interior paint.  A lot of the interior will be covered with interior carpets, seats, side panels, etc, but there are still areas that need paint.

Roll Bar Assembly (3)

The outside leg of the attach bracket for the roll bar has to be shaved down to fit the taper of the fuselage.  I did that, then bolted down the attach brackets so I could start to get the roll bar in the right position in order to start drilling bolt holes.  I slipped the roll bar in place and took the vertical measurement from the top (at the center) down to the level of the fuselage longerons.  Even though my roll bar was the exact height called out in the initial fabrication instructions, for some reason it was almost 1/4" too tall when put in place.  It turns out the plans just don't show or mention that the outside portion of the roll bar needs to be cut away in order to allow it to nest down into the attach bracket. Left as it was originally, the rounded inside corner of the attach bracket angle held the roll bar up into the air quite a bit.  Before I hacked away at this part that took a long time to build, I double checked a few build logs online.  Yep, the outside portion has to be ground away.

Once I had gotten the roll bar to set down to the correct 17 7/8" vertical height callout, I clamped it to the attach brackets and drilled the aft holes.  For the aft attachment, countersunk screws/nuts attach it all together and are covered up by the side skin.

The front attach holes go through the skin itself, so I used the prepunched holes in the skin to locate and drill these.  These are different than the aft screws - the skin will be dimpled and the screws will go in from the outside to hold the forward lip of the skin in place.

The aft holes get #10 screws and the front holes get #8 screws.  The difference being that the front screw holes get tapped vs using nuts.  I misread the plans and drilled the same size hole in the attach bracket as I drilled in the skin.  That works fine when you don't have to tap threads!  Duh.  So my hole was too big to tap for #8s.  I probably could have just kept with #8s and used bolts, but instead I just made the countersink a little bigger and tapped the holes for #10 screws.  Of course I don't have any #10s the right length, so I'll have to add them to my shopping list.  There's nothing keeping me from moving on at this point though.

Roll Bar Assembly (2)

The roll bar attaches to the fuselage with a Frankenstein bracket on each side.  Two pieces of angle join together, get bolted to the fuselage, then bolt to the roll bar itself.  I didn't get pictures of the process it took to just get the angles to the point below.  I clamped the smaller angle inside the roll bar, the larger angle to the outside of the roll bar, then held my tongue just right to line them up, clamp them together and drill two holes in the bases for "keeper" rivets.  The rivets are just there to make later assembly and drilling easier.

A few of the steps in attaching the roll bar structure require lining up pieces with the skin, so I put the top skin back on.

The roll bar is linked to the rear baggage bulkhead by a big U channel brace.  The aft portion has a 1/8" thick piece that stiffens up where it is riveted to the top skin.  I match drilled that, countersunk it and riveted it to the channel.  I would normally just wait and prime everything before assembly, but since there are certain parts like this that need to be riveted on before fitting, it's faster to just brush some primer on mating surfaces and continue on for now.

The first trial fit of the roll bar and upper brace.

Next up was the tricky part - getting the attach brackets located in the right place for drilling to the fuselage.  The instructions don't really provide any guidance on the best way to do this.  The problem is that there is no way to clamp everything and drill the holes through the brackets while it's clamped together.  The front surface of the roll bar needs to match up with the front edge of the skin. However, the brackets are not the same width as the roll bar, so you can't just remove the roll bar and match the brackets up with the skin.  I used a straight edge set across the fuselage to line the front of the roll bar up with the skin on each side.  With that where I wanted it, I carefully clamped each bracket in place (centered on the roll bar outside surface).  I had put tape onto the horizontal fuselage surface, so then just traced the location of the bracket.  That's never ideal since lining a part up on a line is never as accurate as drilling with all parts clamped together, but there was really no choice.  The holes that attach the vertical legs of the brackets to the roll bar aren't drilled yet, so even if I am off a little in lining up on my taped line, there will be enough wiggle room when match drilling the vertical legs later.

I pulled the roll bar off so I had access to the brackets again and lined them up to my lines.  The outside bracket does not follow the curve of the fuselage.  It has to be filed to shape.  I set the front corner just inside the skin line and clamped the bracket down.  Little by little I drilled the mounting holes until I was up to the 1/4" bolt size.

I don't want to drill the attach brackets to the roll bar itself until I'm sure the roll bar is solid and located correctly. The best way to do that is to get the top brace in place (I had just clamped it to the roll bar before).  I drilled the long piece of angle to the brace and then match drilled a smaller piece of angle for each side.  That stiffens everything up considerably.

Roll Bar Assembly

The weather is starting to warm up.  It's possible that within the next few weeks I might actually be able to prime the pile of parts stacking up on my bench.  To keep things moving, I primed some small parts (Q-tip method) so I could assemble them.  I riveted and bolted the elevator control horn stop to the aft deck.

The rudder stops are riveted with pop rivets in the front and solid rivets aft.

Since the internal side of the canopy roll bar won't see any abuse, I just primed the parts with rattle can primer.  The forward side of the u-channel and the connecting strap are riveted with solid rivets, which was an easy task with the squeezer.

The aft side also has a piece of angle that is riveted on with the middle section splice plate.  Then, the forward u-channel is riveted on with pop rivets.  Two blisters later, I had all of the pop rivets done.  That was a lot of rivets!

The roll bar has 6 tooling holes that will drive me nuts if left open, so I filled them with JB Weld.  I'll prime and paint it all later.

Rudder Fit

This week I received the missing rod end bearing for the lower rudder hinge.  I screwed it in to the suggested depth and did one of about 20 trial fits to the vertical stabilizer.  

With the forward spar of the vertical stab in front of the mounting bracket, there was about 1/16" of bow to the rear spar.  That doesn't sound like much, but because of the slight variations in holes in the rear spar hinges, this bow ended up making the center hinge hole about 1/8" too far forward.  I didn't want to back out the middle rod end bearing that much (and it would probably cause some binding being that far off of the center line), so I removed the vertical stab and attached it to the aft side of the mounting bracket.  This is a suggestion in the manual, so apparently not all that uncommon.  I had tried this once before and wasn't happy with the result, but with everything bolted down now, this actually lined the hinges up much better.  There was almost no bow to the rear spar, so I was able to play with the screwed in distance of each rod end bearing to get them lined up pretty well.

Even though the hinge line was pretty good, I still had to take the rudder off multiple times to get all of the bearings at the right distance so the rudder could swing freely from stop to stop without binding.  It was fine except for the very bottom where the rudder's control horn connects.  The way they designed that pushes the skins out on both sides, so as-is it rubs the vertical stab at full deflection.  After some fiddling I got it to clear ok.

Next up was putting the elevators back on to measure the total deflection of the rudder in relation to the elevators.  I didn't bother bolting the elevators to each other since this was all temporary.

The instructions indicate what the measurement should be from the rudder's trailing edge to the outside trailing edge of the elevator when the rudder is at full deflection.  Thankfully, it came out perfectly, so no more fiddling.

As much as I'd like to bolt everything together at this point and call it done, there's just not enough room to move around with the tail on.  I dismantled it all and moved the parts back upstairs.