I trimmed and drilled the right wingtip tonight. This went substantially faster than the left side.
Drilled Right Wingtip
Drilled Left Wingtip
In preparation for drilling the wingtip to the hinges, I cut a piece of XPS foam and inserted it between the hinges to keep them from flexing inward when drilling.
I installed the wingtip and taped it in place with some clear packing tape. I drew a line 7/8″ outboard of the row of rivets holding the hinge to the wing and marked lines even with all of those rivets.
Finally, I drilled all of the holes to lock in the wingtip’s position.
Drilled Remaining Hinges to Wings
I installed one of the hinges to the outboard end of the wings a long time ago (like two years!). Since I had practically the whole day free to work on the plane, I decided to wrap these up so that I could start fitting the wingtips. Afterward, I started fitting the left wingtip. I trimmed the flange so that it will slip into place, but had to stop before drilling it to the hinges.
Received Fuel Caps
I got my caps back from Aircraft Specialty today. They were engraved and filled with paint, then clear coated. They turned out fantastic, and I would highly recommend you contact Steve if you need your caps engraved.
Worked on Wings and Oil Cooler Plenum
I finally riveted on the flap hinge. This has been on my to do list for weeks now, but the wings are mostly stored under a tarp beside my house, so I have to pull them around to the driveway every time I want to work on them.
I also made a little more progress on the hinges that will be used to attach the wing tips. I taped a couple of the spacers to the hinge and then clamped it to the wing skin.
After drilling, deburring, dimpling, and countersinking, I riveted it on. Notice that the wing side of the hinge starts with an eyelet at the trailing edge. This is so that the hinge pin can be pre-loaded on the wing so that it’s ready to go when the wingtip is set in place.
I also pulled the oil cooler plenum out of the mold (well, mostly pulled the mold out of the oil cooler plenum) and then test fit it. It looks like it fits pretty well, but I’ll have to do a little adjustment. As I suspected, it’s also way too flimsy right now due to the lightweight cloth I had on hand. I have some 9oz cloth on order. A few more plys of that should stiffen this up nicely.
Here’s a shot down the inside. With the butterfly valve open, the air will have a nice clean shot at the oil cooler fins.
Drilled Wings for Wingtips
I’m going to be using hinges to attach my wingtips. This necessitates drilling additional holes in the end of the wing so that the hinges are attached with rivets spaced more closely together. Most of the holes already pushed in the end of the wing skins were about 2.5″ apart, so I used a rivet spacer to drill additional holes between the pre-punched holes. The hinges need to be spaced back a bit to account for the thickness of the fiberglass tips. I’m going to use 2 layers of 0.025″ alclad, so I laid out and started cutting the strips. This was brutal on my hands though, so I didn’t get through all of them tonight.
Worked on Nav/Strobe Lights
My Nav/Strobe Lights arrived from Aircraft Spruce today. I used the adaptor plate and gasket and installed them to the landing/taxi light housing. I hooked them up to the plane to verify everything works properly. Holy shit these things are bright. You can’t be looking anywhere near these things when the strobes go off; it is blinding.
Next up, I drilled the rudder bottom fairing and installed a couple of 4-40 nylock nuts.
I anchored the nuts using a couple of screws and some safety wire.
I then mixed up some 5 minute epoxy with flox and covered the nuts to anchor them inside the fairing. After the flox cured, I removed the screws and temporarily installed the tail light to ensure the nuts were secure.
Finally, I took one of the lights and installed a waterproof molex connector so that all of the connections can be made at once when installing the wingtip. I was only able to do this on one of the lights before running out of steam.
Started Working on Wingtip Lights
I started working on the wingtip lights tonight. I’m going to fabricate a reflective backing for both sides of the recess, so I was fairly generous with the cutout so that I can easily position the light. I’ll trim the backing to tightly follow the lights. I don’t want to determine the final position until the nav/strobe light is attached and the lens cover is trimmed so that I can make sure there is no interference. This is approximately where the light will end up though. The is substantially farther forward than the stock lights which should provide better lighting directly in front of the plane. The stock light position puts the bulbs a good 4″ farther aft which causes the side of the recess to shade the area directly in front of the plane.
Once I have the lens trimmed, it looks like I can probably push the light even farther forward. I’m going to try and get it within about 1/4″ of the lens. Since the light runs really cool, I don’t have to worry about overheating the lens on the ground. In flight, there’s obviously enough airflow that I wouldn’t have to worry about heat anyway.
I adjusted the lens until it looked like it would precisely follow the curvature of the outer edge of the wingtip and then taped it down. I used some masking tape to mark the cut line. The lens will pull back farther after it’s cut, so this will just be a preliminary cut line.
I played with some tin snips along the edge, and they made perfect cuts without any hint of cracking the plastic, so I used them to cut out the lens. This was far better than using the cutoff wheel since I could basically trim right to the line and then touch up the edge with some sandpaper to remove any microscopic burrs that could create stress risers and lead to cracks down the road.
With one edge of the lens aligned with the flange around the recess, it looks like I’ll need to trim about 1/8″ off of the other edge to allow it to drop behind the lip.
OAT Probe and Empennage Fairings
I drilled the bottom of the wing for the outside air temperature probe. I installed it in the wing, adjacent to one of the inspection plates (just to the upper left in this picture).
I also cut a small hole in the conduit here so that the OAT probe wires could exit. You can see the 2 conductor molex connector I used here as well. I’m honestly not sure the connector is worth the trouble since it would have to be cut off to remove the probe anyway. It’s probably better to just use a couple of butt splices to crimp the probe wires together with a service loop for future maintenance. With this done, I think I’m done with the wings until they go to the airport.
I needed a little more filler on the front of the rudder.
…as well as the aft side of the vertical stabilizer.
After that cured, I filed and sanded it down to create a uniform 0.150″ gap (the same as the lower gap under the rudder horn).
I also trimmed a little more off the bottom rudder fairing and then removed all of the gel coat around the hole in preparation for bonding a patch. For a non-structural patch like this, removing the gel coat isn’t necessary. I did it more so that the patch would be flush with the gel coat and I wouldn’t have to use as much filler to fair it in.
Finally, I added a patch made of three layers of 8.9oz/yd cloth.
To keep it tight against the fairing, I laid a piece of plastic over the patch and taped it tight. I then taped a piece of scrap aluminum over the patch to ensure it cures totally flat.
Installed Pitot Tube and Nutplates on Tank and Root Ribs
I installed the pitot tube and connected the tubing inside the wing.
I installed the remaining nutplates on the root ribs and then propped the wing up on the leading edge of the tank. This looks precarious, but it is surprisingly stable.
This allowed me to install all of the nut plates around the inboard edge of the tank skin…
…as well as install the tank attach bracket nutplates.
