Tonight I had only a few minutes, so I riveted the right air ramp into position and glued on the template for the left air ramp. I used a pop rivet in the aft-most, inboard hole, because access by squeezer was tight, and I didn’t want to use my rivet gun for fear of bending something.
Tonight I shaped the right hand air ramp.
This required sticking on a paper template, then, following a sequence of bends, shaping the piece until it conforms to relatively smooth curve. It’s a conical shape, so one end is a much tighter radius than the other. I managed to get the shape fairly close, but I ended up cracking the end with the most narrow radius. I stop drilled the crack, then filed out a relief notch to mitigate the risk of further cracks.
I then match drilled the holes into the baffling, and dimpled them. Dimpling the aft most holes was a little annoying because it was too far from the edge to use my squeezer. I used a pop-rivet dimpled instead, which doesn’t give great results, but good enough in this case.
The gasket for the fuel controller arrived today, so I went ahead and installed the fuel controller and final torqued the nuts.
Following the engine maintenance manual, I torqued the nuts to 17 foot pounds (204. Inch pounds). The manual assumes there is no adapter, which there is, but this seems like the right value for the size studs that I’m installing onto.
With that done, I worked on the alternate air installation.
The alt air is a backup air intake for emergency use if the aim air intake were to become blocked (ice, bird strike, etc). There is a door on the side of the snorkel that can be opened with a control inside the cockpit. The standard Vans design doesn’t allow the alt air to be closed once it’s opened, so you’d have to take the cowl off to reset it if it were ever pulled. That’s ok, but it means you can’t test the mechanism as part of a run-up before takeoff.
Of course someone had solved this problem and come up with an alternative door design that can open and close using the cockpit control. The only difference is the door itself, it mounts onto the standard location without any modifications. This is what I’m going to install.
I needed to buy a hole saw because I didn’t have anything big enough. The plans called for a hole that is 2 11/16 inches in diameter. The closest diameter I could find at harbor freight was 2 5/8, and when I drilled the hole, it came out slightly over-sized, which was perfect.
Some of the instructions are a bit confusing, but carefully reading and following the steps made sense eventually.
The inlet is glued into position using epoxy.
Today I worked on fitting the snorkel, completing a few more steps.
With the fuel controller covered in plastic, I placed the snorkel on the flange, and then assessed the alignment at the air filter end, where it attaches to the baffling. The instructions warn that small changes at the fuel control unit can have a large impact on the alignment at the baffling. While true, I found that I needed to take a uniform amount off the fuel control end to get the other end to line up. In total, it was about 3/8 of an inch longer than it needed to be, and after carefully sanding it down, the alignment worked out well. I had to disconnect the oil return line to complete this step, and continually bend it out of the way to avoid interference with the snorkel. I’m hoping that the replacement line I ordered will clear the snorkel, because I’m proceeding with fitting the snorkel before I have the new line in-hand.
Once everything fit, I drilled alignment holes in the air filter end of the snorkel, clecoed them, then marked out the excess snorkel to trim. Then I could take the whole assembly off the airplane and trim the snorkel. I used a hack saw to cut about half an inch off the end of the snorkel, then carefully filed it down until it was flush with the shelf on the air filter holder.
I could then install it back on the airplane, and mix up some epoxy glue to seal the gap between the snorkel and the air filter holder.
With the fuel controller in place, I was able to test fit the snorkel. Unfortunately I ran into an interference issue, but after some further investigation I found this is a known issue. I ordered a new oil return line for the #2 cylinder from Aircraft Specialty, as they have solved the problem by making a custom tube that doesn’t protrude as far forward. Kit #13 from their firewall forward hose kits: https://www.aircraftspecialty.com/rv-14.html
I also heard back from Airflow Performance, and they sent a doc that has some useful RV-14-specific install info, and confirmed I needed to order a gasket. $2 gasket, and $10 of shipping, it should be here in a couple of days.
This week I chipped away at the baffle tension rods over a series of evenings. I didn’t actually have a die for cutting the threads, so I had to order one from Aircraft Spruce. These were fairly easy to make, and came out looking good. Some more practice with cutting threads might have helped, but I got the hang of it pretty quickly. When bending the rods I used a block of wood with a slot cut in it to stop the rod rotating, which allowed me to bend both ends of the rods in the same axis.
Installing the rods was fairly easy. I cut a few lengths of 1/4 inch tubing to help prevent chaffing, although there weren’t many areas where interference is possible. Once I had the tubing slid over the rods and positioned correctly, I used some RTV to bond the tubing onto the rod.
With new crush washers in hand I also took time to install the remaining baffle hardware, and torqued everything.
Tonight I unpacked the fuel controller and installed it on the engine. This required some research, as there isn’t any documentation from the Lycoming or Airflow Performance in the box. I found some help on Vansairforce, and was able to find the Airflow Performance manual. I ended up emailing them anyway, because I don’t have a gasket in the box.
For now I installed the unit using the temporary nuts to hold it in place, so I can test fit the snorkel.
Today I spent time adjusting the front baffles to fit nicely against the engine case. The front left baffle took the most adjusting, and after several iterations I was happy with the fit.
With the baffles fitting nicely I went ahead and installed the hardware and torqued everything up. I have run out of -40 star washers, so I ordered some more and put tape on the screws that were missing washers.
Tonight I test fit the front baffles. The front right baffle was the easiest to install, and looks to be a good fit. The front left was more challenging, but after disconnecting the oil return line, I was able to get it into position. This one will need a little adjustment to properly conform to the engine casing, and a couple of corners that need some easing.
In the process of test fitting the front baffles I noticed that I had made an error with the front center bracket. Just like the aft bracket, I had misread the drawing and had it on the left side instead of the right side of the centerline. Then I noticed I had the bolt installed from left to right, instead of right to left, on both brackets. It’s probably not a big deal, but it always makes me nervous when I miss something or find an error. What else did I miss?
I fixed the errors with the bracket, installed the hardware and torqued the nuts.
Over the last few evenings I’ve made a little progress on the front baffling.
I riveted together the parts, and applied RTV where instructed. The RTV strips are to reduce chaffing on the engine cylinder cooling fins. RTV is also used to help glue the mesh in place covering the cabin hot air intake.
These are ready to be test-fit onto the engine and trimmed (if necessary).
