Baffle Bending (2)

2 hours

Another job I haven't been looking forward to is the cooling baffles, but it's finally time to get them over with!  The kit comes with a bunch of laser cut parts, a plan for bending the parts, and some extremely vague instructions and photos.

I figured I'd start by bending all the parts and then seeing if I could figure out how they went together.

I don't have a bending brake, but clamping this piece of bar stock over each part and tapping it with a rubber hammer worked fine.

I got all of the parts bent according to the instructions, so we'll see how they fit!

Turbo/Intake/Exhaust (1.5)

1.5 hours

With the firewall sealed up I can finally install some of these large parts that will block access to a lot of it.  Since the turbo sits pretty close to the firewall, I slapped a sheet of this self-adhesive heat shielding on behind it to protect the cabin and fuel tank from some of the heat.

Next I installed the turbo with its gasket and finally tightened it down all the way.  The only minor issue I ran into was the little tab on the wastegate actuator was a tiny bit too thick to allow its retaining snap ring to fit into place.  I filed it slightly thinner and then it fit fine.  Then I installed the exhaust and the turbo heat shield.

Next I installed the intake tubes.  Oddly, even though they go on either end of the same tube, the straight silicone hoses are somewhat larger than the reducers that connect to the intake manifolds.  I checked with Sonex and they're the right parts.  They don't fit as tightly on the intake tubes but they tighten up fine with a hose clamp.

Next thing was the big intake elbow to connect the AeroInjector carb to the turbo.  I will have to mess with the orientation of the carb later to make the throttle and mixture cables line up correctly.

Out of the box my turbo exhaust exit caused the lower part of the exhaust to significantly run into the engine mount.  I took it to an exhaust shop and they straightened the 90-degree bend slightly for a case of beer, and now it fits.

Firewall Prep (3)

3 hours

Before I get too much further along with the engine, there were a few more things I wanted to do to the firewall.

First, when I installed the fuel tank and then riveted the top of the firewall to the glareshield flange, I found that the tank was very close to the back side of the upper firewall.  So close to one spot, in fact, that I couldn't even insert a couple of rivets all the way!

I decided that I really should pull the tank back out and redo those rivets, and make sure there weren't any real serious interference issues between the tank and the firewall.

Removing the tank was actually easier than I expected, EXCEPT I totally mangled the bulkhead fitting on the top forward end of the tank that connectd the vent line.  I'll have to replace that fitting.  Besides removing the vent fitting, I had to pull the panel off and remove the two throttle mount plates and the brake lever, and then I was able to wrangle the tank out.  I found a few little marks on the front corner but nothing too extreme thankfully.

I drilled out and replaced those two problem rivets with the shortest rivets I had.

Next, there were some decent size gaps between the firewall and the upper engine mount blocks.  Too big for caulk at least, in my opinion.  I found some fireproof putty on Amazon, and used that to fill the gaps.

I did not have to use very much.

Next, in order to alleviate any concerns about the top edge of the tank chafing against the back of the firewall, I used some spray adhesive to attach some felt strips to the inside flange for padding.

When I re-install the tank, I plan to put some teflon anti-chafe tape along the top edge of the tank to further protect it!

Finally, I used some fireproof caulk to seal up all the seams and rivets on the front of the firewall.

Cowl Side Vents (2.5)

2.5 hours

While the cowl was still nicely attached to the plane I went ahead and got the side vents mostly fit.  The vents aren't mentioned in my version of the plans at all, but Sonex published a revision with the required info on the website: https://www.sonexaircraft.com/documents/plan_sheets/SNB-WXB-P13_Detail_P.jpg

Installation is pretty straightforward; I just cut the top and aft edge of the holes first, then cleco'd the vents in place.  Then I cut the bottom and forward edges to fit the vents.  The plans say to just glue the vents in place.  I think I will glue them and use the clecos to clamp them in place white the glue sets.  If it seems sturdy I'll just patch the little holes, and if I decide I don't fully trust the glue I'll put rivets through those holes as backup.

Luckily it doesn't interfere with where I plan to install the battery!

Cowl Fasteners (6)

6 hours

Now that all the cowl pieces physically fit together and I have all the holes drilled and cleco'd, it's time to figure out what actual fasteners I'm going to use to attach the upper cowl.

The plans call for simple nutplates but also recommend Southco fasteners as an option.  I did not want to use nutplates and screws because I didn't like the idea of having loose hardware that I could potentially drop somewhere in the engine bay and lose.  Plus they would take forever to remove or install every time I needed to take the cowl off/on.  I'm also not super impressed with Southco after messing around with one on the fuel door.  After some research I decided to go with Skybolt Camloc fasteners.  These things are more expensive than Soutchco but they're super nice and easy to install.

Skybolt has a LOT of options for fasteners, so it took me some research to figure out what I actually needed.  Their PDF catalog is a lot easier to browse than their website, so I found that to be helpful: http://skybolt.com/wp-content/uploads/2019/04/Skybolt-Catalog-v5.1_Print-aerospace-fasteners-1.pdf

Pages 10 and 11 of the PDF pretty much gave me all the info I needed.  I ended up going with SK26S51-SET1 for all the cowl fasteners.  This one has adjustable depth receptacles so you can use them on a wide range of panel thicknesses.  I also bought some extra SK2600-SW washers.  Those washers allow the stud part of the fastener to retract when open, which makes the parts easier to disassemble.  The washers that come in the fastener set hold the studs in place which only works if you can pull the parts you're fastening straight apart from each other.

Anyway, for each fastener I bought one of each of these parts:

https://store.skybolt.com/sk26s51-set1-p2697.aspx

https://store.skybolt.com/sk2600-sw-p3582.aspx

I also bought a couple of drilling templates which turned out to be super handy:

https://store.skybolt.com/template-213-p691.aspx

I bought everything directly from Skybolt.  Here's the heap of parts I got in the mail:

The rivet pattern for the receptacles is exactly the same as for regular nutplates.  The little drilling jig made it real easy to drill the rivet holes in the correct places relative to the fastener holes I already had drilled.

Here's what the recaptacle looks like riveted in place.  I used CCC-32 rivets.

The stud part gets inserted into the other part to be fastened.  They sell special pliers to compress the spring inside the stud to make it easier to install, but I found I could just use a small open-end wrench and my thumb to install them without any special tools.

Once both parts are installed they go together really nicely.  You just line everything up and give them each a quarter turn to lock them in place.

I did several iterations of installing the upper cowl, checking the fit, installing a few fasteners, and repeating, in order to make sure everything was still lining up nicely.  Eventually I got them all installed.  Due to all the bonus fasteners I had to use along the upper edge, I ended up using a total of 24 fasteners, versus the 15 called for in the plans.  So that was pretty expensive!  But it turned out really nice so whatever.

Anyway moving on.  I also bought one more extra fastener for the fuel door.  Way back when I installed the Soutchco fastener for the door, I installed the receptacle 90 degrees off because the windshield blocked me from installing it the correct way.  It didn't occur to me that when I did that, it made it so the flat part of the wingnut stud stuck out perpendicular to the airflow.  It really bugged me, but I could not find a stud with the wingnut part rotated 90 degrees!  However, Skybolt sells one with a wingnut that folds down.  So I replaced the Southco with one of these: https://store.skybolt.com/sk2600fw-set1-p3644.aspx

It's way nicer than the Southco anyway, and now it folds down and looks like I meant to do it that way all along.

Oh yeah, I also riveted the three piano hinges on the lower cowl during this time as well.

Upper Cowl Fix (0.5)

0.5 hours

After scratching my head for a couple days about how to address the huge bulge at the center of the windshield skirt, I finally figured it out.

First I added another fastener on each side of center to constrain everything a little more in the middle.  I'm already using way more fasteners than the plans called for, so I figured what's a couple more.

Then I just cut the little strip of material in front of the fuel door, right in the center.

Then all I had to do was file a tiny bit of material off each side until the two halves sat flat next to each other, and then drilled them to both the firewall flange, and the cowl.

All fixed!  The little tiny seam is not perfect, but it's way better than that bulge was.  I can live with it.

Upper Cowl (4)

4 hours

Moving on to the upper cowl!  This piece will pretty much serve as the hood of the plane, ideally being easy to remove and install for minor maintenance things like adding oil, etc.

I found it initially real tricky to weasel the upper cowl into place.  Pretty much all of the trimming and sanding I had to do was around the prop hub and air inlet areas, but once I got those forward sections to fit together the whole upper cowl fit into place.

One small interference I found once the cowl finally dropped all the way in was the flange on the top forward edge of the oil cooler.  You can see in the picture above how the seam between the upper and lower halves isn't quite closed at the front; it's because the cowl was resting on that flange.  I cut it off with a dremel tool and then it fit nicely.

Next I began drilling all the holes for the fasteners.  The sides were easy.

The top, where the cowl slides under the windshield skirt, was less easy.  There's not really a good way to hold the cowl tight against the flange to drill them together.  I found I could use my big jack handle to press the cowl up in some areas, but not all of it.

Eventually I got it all drilled together, except the center.  The windshield skirt is just slightly larger than the cowl, so all the extra material is bunched up in the center.  The cowl itself is also sagging there since there's nothing to hold it up yet, so the flange and cowl really need to meet in the middle.  I'll have to figure out a way to fix this!

There are also a couple other much smaller bulges at the corners but I'm less concerned about those and I think I can tighten them up a bit before I call it done.