Repaired Cowl Damage From Spinner Screws

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When I did the first taxi test, I had incorrectly installed the screws that tie the conical section of the spinner backplate halves together.  I forgot that there was a note in the installation manual that the screw heads needed to be on the aft side to provide clearance between the spinner and cowl. I installed the nut on the aft side, and the ends of the screws cut into the cowl flange a bit.  I ground all of the damaged material out of the cowl and then applied a thin layer of raw epoxy to coat the inside of the cut.  In addition to reversing the screws, I switched from AN515 to AN525 screws to further reduce the height of the head.

My flox is down at the hangar, so I cut up a small piece of fiberglass cloth into tiny pieces and mixed it into some epoxy.  I filled the gap with this and left it a little proud of the surface.  I’ll grind this flat once the epoxy cures.

While the epoxy was curing, I sanded both cowl air inlet on the top and bottom.  The cowl is very close to getting the first coat of primer.

Left Wingtip Lens and Cowl Prep

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I couldn’t go down to the hangar tonight, so I worked on some of the pieces I brought home.  I finished trimming and sanding the left wingtip lens and drilled it to the wingtip.  I’ll have to install the nutplates at the hangar where the rest of my tools are, but other than that the wingtips are ready for flight.  There is still a bunch of finish work before I’ll be happy with these, but I want to put that off until the landing lights are aimed right, then I can do all of the fiberglass finish work and put a coat of primer on the wingtip.

Speaking of fiberglass finish work, I resumed work on the cowl to get it ready for a coat of primer.  There are still a few spots that have pinholes, so I’ll be doing a little epoxy work before priming.  I spent a little time first with a file smoothing out little high spots and fixing a couple of epoxy runs.

Leak Checked Pitot System, Empennage Nutplates, Unusable Fuel and Firewall Passthroughs

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I spent some time this morning working on the left wingtip lens before heading down to the hangar.  Since I reworked the pitot and AOA tubing yesterday, I wanted to leak check it today.  I disconnected the tubing at the new fitting in the wing inspection panel and attached some 1/4″ ID latex tubing.  I could roll up the other end of the tubing to increase the pressure in the pitot system and test for leaks.  AC 43.13 recommends increasing the pressure to an indicated airspeed of 150kts and then clamping the tubing for 1 minute to check for leaks.  As long as the leaks aren’t substantial enough to cause the indicated airspeed to drop more than 10kts, then everything is fine.  After 1 minute, I had a 3 kt drop, so I’m in great shape.

Next, I tackled installing the two Click Bond nutplates in the horizontal stabilizer.  I used some hemostats to scotchbrite and solvent wipe the inside of the horizontal stabilizer around the hole and then fished some 0.025″ safety wire up through the hole and out through the nose of the inboard end of the horizontal stabilizer.  I pushed the safety wire through the end of the silicone installation plug so that I will be able to pull it back through the hole.

The Click Bond adhesive I had had dried up, so I mixed up some epoxy with West System 404 structural adhesive filler.  I applied a little bit on the flange of the nutplate and then pulled it through the hole.

Here’s a picture taken through a mirror at the installed nutplate.  Once the adhesive cures, I can just pull out the silicone plug.

With the new fuel pump installed, I decided to determine the unusable fuel.  I rigged up the hose from the spider so I could capture any fuel pumped to the engine.  I dumped 16 oz into each wing and then ran the fuel pump until nothing came out.  Finally, I drained the fuel in each tank to see how much unusable fuel there was.  I drained almost 7 oz from the left tank and 6 oz from the right tank.  I then dumped the fuel back in the tanks so that it could be included in the weight and balance.

My buddy Greg noticed that the firewall pass-throughs didn’t grip these cables very securely.  I removed the eyeballs and wrapped a couple of layers of aluminum tape around each cable and then reinstalled them.  The cables are rock solid now.

Canopy Fairing, Cowling Hinge Covers and Move Prep

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I sanded down the filler I applied yesterday.

As expected, there are some low spots, so I’ll need another coat or two, but the overall shape is getting very close.

I mixed up another coat and squeegeed it on.

The cowl has these covers over the holes to access the side hinge pins.  I decided to fasten the hinge pins to the covers, so I ground a groove in the back of the cover and mixed up some JB Weld and glued them together.  You can see the back side of the cover in the mirror above the cover.

I’ve had these vinyl letters for quite a while, but I finally took a few minutes and put them on the vertical stabilizer.  There is another one on the other side.

In preparation for my imminent move to the airport, I went through all of my tools and pulled out everything that needed to go to the hangar.  I also picked up a bunch of new tools (wrenches, socket set, screwdrivers, etc.).

I also put all of my metal working tools in a tool bag since I shouldn’t need any of them anymore.  This bag is ridiculously heavy (70-80 lbs at least).

The second coat of filler I applied this morning has cured, so I sanded it down most of the way.  The middle section is nearly perfect, but the sides still need some work.

GoPro Camera Mount, Canopy Fairing, Reversed Vacuum Valve

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I added a couple of rivnuts in the bottom of the roll bar, spaced for a RAM diamond mount (RAP-B-238).

Here’s the GoPro mounted.  It’s just to the right of the center line to clear the canopy latch.  You can also see the live preview on my phone.  I can capture the entire instrument panel, the sides of both people’s heads and a great view outside.

I mixed up some filler and applied a layer to the fairing and shaped it with a piece of aluminum that I cut to match the curve of the sanding block I’m using.

While I had some filler mixed up, I added a little more to the sides of the upper cowling to match the curve of the fuselage.

Here’s the other side.  I’ll sand this completely flush tomorrow.

One of the readers of my site noticed that I had mounted the air/oil separator’s vacuum valve backward. Fortunately, there was room to turn the valve around without interfering with anything.

I zip-tied the breather tube to the fuel line and oil line to keep it from rubbing.

The breather line nicely clears the firewall, oil filter and prop governor bracket.

I’m no longer using the nutplate on the firewall that used to secure the breather line, so I filled it with an AN525-10R6 screw to keep the firewall sealed.

Fabricated Oil Door Hinge Pin

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I have been giving some thought to how to secure the hinge pin for the oil door.  Many builders just insert the pin and bend both ends, but then you can never remove the pin without destroying it.  I decided to bend only one end and use some safety wire to prevent the pin from sliding out.  I filed a groove in the end of the pin that goes about 3/4 of the way around the circumference.

This allows me to wrap a piece of safety wire around the pin to lock it in place.

Here’s what the pin looks like installed in the cowl.  The bend is on the left and the safety wire is on the right.

Painted Inside of Upper Cowl

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I painted the inside of upper cowl with the same two-part epoxy paint I used on the lower cowl.  The finish isn’t perfect, but it’s fine for the inside of the cowl and should be sufficient to seal the surface and make it easy to clean.

I also painted the inside of the oil door.

I also painted the metal strips that hold the cowl inlet baffle seals.

Added Reflective Foil to Lower Cowl

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With the paint cured, I added the reflective foil.  The foil sticks amazingly well to the painted surface, so I’m not going to do anything else to this.  If the edges start lifting, I may add a thin coat of epoxy to seal them, but I’m going to wait and see if it is necessary.