I hot-glued the form down to a couple of spacer blocks and then glassed the plenum. I used about four layers of glass, but I only have 3oz glass on hand. I’ll probably need to add quite a few more layers (or step up to some 9oz cloth) to make this stiff enough. The outside is covered with peel-ply which should leave a surface ready to bond to additional layers.
I trimmed the edges of the large aluminum area washers that surround the vent tube ports on the side of the fuselage. I then primed and installed them
Finally, I covered the oil cooler plenum and butterfly valve with packing tape so that I can layup some fiberglass over it. Because of the compound curves of the mold, I had to use a number of narrow strips to avoid wrinkles.
I riveted the additional bracket onto the oil cooler and reattached it to the engine mount.
There will be one more adel clamp and bolt when the oil cooler is installed for good. This is just installed temporarily so that I can fabricate the plenum.
I cut down the foam block a bit more and then determined where the butterfly valve would need to be positioned.
Afterward, I did some further shaping of the foam to define the final shape of the plenum.
Here’s a better shot. The bevel cut on the left edge allows the plenum to clear the engine mount tube. I’ll probably tuck a small foam wedge there so that the plenum extends under the engine mount tube to allow air to flow through the entire oil cooler.
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.
I installed the fittings in the oil cooler tonight. The top fitting is a standard AN822-8 elbow, but the bottom fitting is an AN826-8 tee with the pipe thread on the run. You can also see that I trimmed part of the oil cooler flange to provide a little more clearance with the firewall.
Here’s a better shot of the tee fitting. The blue tape covers the flare port that will connect to one of the oil cooler lines to the engine. The other flare port has an AN929-8D cap that can be removed during oil changes to drain the oil from the cooler and lines. Without this, at least a quart of oil would remain in the cooler and lines during an oil change.
I fabricated three spacers that will used when installing the oil cooler.
They will fit between the flanges (along with some washers) to allow the mounting bolts to support both the front and back sides of the oil cooler.
I fabricated a small oil cooler support plate and painted it (I’ll show a picture tomorrow). While waiting for the paint to dry, I decided to install the fuel overflow tubing. I used a piece of 1/4″ ID Tygon tubing to run from the AN842-4D fitting on the fuel pump down to a piece of 1/4″ tubing on the firewall.
The tubing is held on to the fitting with a piece of safety wire that is double wrapped around the tubing.
At the bottom end, I bent a short piece of 1/4″ soft aluminum tubing so that it cleared the engine mount tube and poked through a 1/4″ hole I drilled through the firewall flange and hinge. I slipped a short piece of Tygon tubing over the aluminum tubing and zip-tied it to the engine mount. I then used some safety wire to attach the Tygon tubing from the fuel pump to the other end of the aluminum tubing.
I took off the peel-ply and cleaned up the fiberglass a bit. I’ll need to do a bit more work to clean this up, but it made a big difference in the door stiffness already.
I picked up some two-part expanding polyurethane foam at TAP Plastics and poured some in a box that looked about the right size to form the oil cooler plenum. This needs 24 hours to cure before I can start shaping it. I fully expect that this first piece will be practice, and I’ll have to make another plug before I can layup the fiberglass over it.
I mixed up some epoxy/flox and riveted on the oil door latches. I then placed a couple of layers of 8 oz cloth with a 1/8″ fiber core for stiffness. This will substantially stiffen the oil door to prevent it from bowing out in flight. To ensure an even tighter seal, I’ve slightly flattened the oil door (that’s what the blue tape is doing). This will ensure that when the bottom is latched, the middle of the door will be tightly pressed against the cowl.
I also put a couple of layers of fiberglass over the side of the hinge bonded to the cowl. The top layer you see in both layups is peel-ply to wick away excess resin.
I installed a connector on the tail light along with a piece of heat shrink over the wires. Once the rudder is installed permanently, I’ll install this on the bottom fairing and hook it up.
I drilled some extra holes in the hinges and then mixed up some epoxy and flox. I glued and then riveted the hinge on with some soft rivets.
Next, I cut holes for a couple of Hartwell latches. These are perfectly flush with the surface of the oil door and hold it really tight. These needed to be mounted in this orientation because of the curvature of the oil door.
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.
