Snorkel Work

Time: 6 Hours

I have several factors working in conjunction with the baffles that all need to work nicely together as they come together. So I have to work on all these things at the same time to make sure they all fit together. So I took some time to work on the snorkel and it’s fit. I have the brackets that tie the snorkel to the left ramp finished and just need to rivet them to the fiberglass. I don’t want to do this yet until I finish all the surface sanding/filling. I also don’t want to do that until I fixed a contact point and install the alternate air door. First was the contact point where the fuel mixture arm hits in its forward most position.

As you see in the photo the arm hits and needs to move forward another 1/4″ or so. To fix this I decided I would just redo the fiberglass in this area. I marked the spot and cut out the area. At the same time I trimmed the part that attaches to the fuel servo to make it match the servo.

After sanding and cleaning the area around the hole I mixed up some epoxy and applied three layers of cloth. Informed the fiberglass into a cup inboard to create an area for the arm to move into when it’s in its forward most position.

So I let that cure overnight and started working on the alternate air door. The way the engine gets air for the combustion process is through the air filter I have been working on. If I get into a situation where ice or snow were to get into the filter while flying it could clog and block the filter. If that happens the engine could quit running. To keep this from happening you install a alternate way of getting air. This door in the side of the snorkel can be opened in the case of filter blockage while flying. This would allow unfiltered air to enter and keep the engine running. The door consists with a ring that gets riveted to the snorkel and a circular door that will pivot on a screw at the bottom of the ring. A cable will pull the top of the door and slide the door open when needed. I used the ring to mark the spot that I needed to cut on the side of the snorkel.

After cutting the hole and tweaking so the ring sat good I match drilled the holes into the fiberglass.

I strayed away from the plans a little when I came to how to keep the air filter in place. In the last photo you see one of three angle pieces that are used to attach the top section of the snorkel to the air inlet ramp. There is one on the outboard, one on the inboard and one on the aft edges. They have a step shape to them that creates a lip for the air filters flange to rest on. I put nutplates in all three and matched the ones in the aft flange to the baffle ramp rivet holes. Those rivets will be replaced with screws. These screws will serve two functions, the first is to hold the top of the snorkel in place and the second is to hold a retention cover that will trap the air filter between it and the snorkel.

This will make for an easy removal of the filter at the same time securing it well when in place.Once I had the filter brackets fitting perfect it was time to work in the finish of the snorkel. I removed it from the air servo and removed all brackets. I put a skim layer of epoxy/fairing filler to hell with all the pin holes and flaws. After that cured it was a long standing session to smooth it all out. With a little clean up I was able to add a few coats of filler primer. There are a few small spots that require a little filler but overall I’m happy with it so far. Next up will be to rivet the brackets on and paint the final color, I’m thinking a silver metallic to match the inner cylinders of the engine.