Fuel system woes

Hi Roger,

"There are Mfg's that run a return line into the gascolator and into fuel supply hose  way back before it gets to the engine compartment into cooler fuel. It doesn't have to go directly into the fuel tank."

The only way, that I can see, that this version of the fuel return, can hope to approach the same level of effectiveness, that the Rotax recommended method delivers, is if the fuel return is sufficient long, so that the fuel/vapour has time to cool.

I have seen fuel return cooling systems on cars, that involve a similar design as oil cooler ie convoluted line (length) with cooling fins (surface area), delivering time for vapour to transition to liquid & liquid to shead heat. 

Just because some "Mfg's" take the cheap option, does not mean it's the most effective. I wonder has such a system been tested in the summer  heat of the US south or that of Australia??😈

Problems with copying images of potential fuel cooling systems.

Hi Sean,

It doesn't necessarily need a long line to cool, but returned into a cool fuel line like the one that comes from the tank to maybe the gascolator. Once any partial vapor and liquid fuel hit cool fuel the vapor should no longer be an issue. If it was thousands of aircraft would be in trouble, but they're good to go.

All Just Aircraft models are set up with a small header tank fed from both wing tanks. The fuel return line is connected to this header tank. I’ve never had a single issue with restarts.

Kitfox does exactly the same thing.  As, I suspect, do all of the other Avid-derived airplanes.