Oil Separator

My kit came with an oil separator, the black cylinder attached to the firewall. It’s possible I added it to my order as an extra because many other builders don’t seem to have one. As I understand, it minimizes loss of oil, especially when flying inverted. Any oil, or vapor, that comes out of the top of the engine get routed through a tube to the separator. There a ball bearing in the top that prevents oil from flowing back to the top of the engine when inverted. Oil collects at the bottom of the separator where it can flow back into the bottom of the engine (steel braided tube). Vapor escapes through the black vent tube out the bottom of the plane.

Oil Separator

Fuel System Water Test

The picture below shows the final part of the fuel system; the transducer (to measure flow) and line from the tank. My choice of location for the gascolator was both good and bad. On the front of the firewall it fits great with the drain easily accessible between the exhaust pipes, smooth run to the aeroinjector, and it’s mounted firmly to the vertical angle strut. Unfortunately, I didn’t foresee that the angle strut would prevent me from attaching anything but straight fitting on the inside of the fuselage. I had to order some AN parts to extend the line far enough that I could attach the transducer. Since it ended up right between the pedals, I added a guard plate to hold it secure should my feet kick it accidentally. Later I added a vertical angle to protect the line to the tank too.

With all the fuel system components in place, it was time to take it apart and add fuel lube/sealant to the threads of all the AN unions, bends, reducers, etc. Once that was done, I filled the tank with water to check for leaks. There were a couple in the burp elimination lines that were easily fixed by tightening the caps.

A couple things surprised me. First was the aeroinjector dripping continuously. When I opened the throttle a stream came out of it. Pulling the mixture closed stopped it. The idea of fuel flowing out of the injector is a bit scary, even if only right before engine start when the mixture has to be open. I asked Denny Myrick about it and he pointed me to the flight manual that warns about this situation and advises “Do Not delay engine start”. Interesting.

Second, when I filled the tank to the brim, water started flowing out of the burp elimination drain, and it didn’t stop even when the water level dropped beneath the vent on top of the tank. The drain that goes out the bottom of the plane is the lowest point in the fuel lines. So when the fuel level reaches the vent on the top of the tank, a negative pressure can start pulling the fuel out the drain and there’s nothing to stop it, except some positive air pressure. I put my mouth in the fill hole, sealing it with my cheeks and blew. Water shot out the drain and the flow stopped. Luckily it was just water. I don’t fancy doing that with a tank full of 100LL.

Interior Fuel Connection

Firewall Electronics

To the firewall I mounted the battery, grounding block, and electrical pass-through. It’s hard to know what’s the best layout for the firewall. I’m trying to be strategic. The electrical pass-through is right next to a engine mount arm to which I can easily run wires with zip-ties. The negative lead of the battery is an inch or two away from the grounding block which is also right next to the engine mount arm. It’s like an electrical wire highway and parking lot.

What remains to be mounted:

  • master contactor/solenoid
  • voltage protection contactor/solenoid
  • voltage regulator
  • oil pressure sensor (still waiting for line and connecting hardware to arrive)

There’s plenty of room for all this but I’m stalling to see if any inspiration helps me find a good location for it all.


I’ve been hesitating to start installing avionics and running electrical wires, but I’m running out of other things to do.

135 Pilot Training

I started training to be a 135 charter pilot with Elite Flight Jets today. I continue training tomorrow so work on the OneX is taking a back seat.