Currently having an issue with fuel coming out of the fuel cap vent line on my homebuilt airplane. The fuel tanks are in the wings, and the fuel cap that we use is a standard Usher UD-3 (Usher Flush Fuel Caps | Aircraft Spruce). The kit manufacturer has you drill a hole in the top of the cap and epoxy an aluminum tube with a right angle bend that is oriented into the wind for ram air. Another smaller hole is drilled in the bottom half of the fuel cap to allow air in and out of the fuel tank. When the fuel cap is re-assembled the two hole are offset to help keep fuel from splashing out.
The problem is that we can't fill the tanks over 3/4 full or ground movement or "sloshing" of fuel in the tanks will cause fuel to come out the vent line dumping fuel and staining our fabric wings. The two wings tanks are connected together through a header tank so even a good sustained slip may cause fuel to exit the vent line.
I need a check valve that allows air in and out of the tank but prevents fuel from exiting. I've seen some for ATV's but they need a vertical orientation. Has anyone come across something that might work?
The problem is that we can't fill the tanks over 3/4 full or ground movement or "sloshing" of fuel in the tanks will cause fuel to come out the vent line dumping fuel and staining our fabric wings. The two wings tanks are connected together through a header tank so even a good sustained slip may cause fuel to exit the vent line.
I need a check valve that allows air in and out of the tank but prevents fuel from exiting. I've seen some for ATV's but they need a vertical orientation. Has anyone come across something that might work?
