steelerscotty

Hi I was told by a fellow club member that I should run a vent line(of tubing) from the gas tank to the inside of the fuse because the pressure always stays the same inside the fuse and not changing like it would inside the cowling is this true or is he blowing smoke up my as_! any reply would be appreciate it thanks

tail strike

My Feedback: (1)

If you are running a glow motor the vent line would go to the pressuer tap on the exhost.
If you are running gas the vent line should run back behing the gas tank and then overboard.
NO vent line should be inside the fusaloge.

Charlie P.

I've heard of folks doing that (vent inside fuselage) but the pressure is the same inside or out unless you have a pressurized cabin.

When you fill the tank it's easier (IMHO) to fill with a fill line that has a klunk (and also to drain the tank) and you know it's full when the vent line starts squirting. I use a Jersey Fueler so it squirts back into the fuel can. Imagine if the vent line were inside your fuselage and you filled the tank to overflowing.

TomCrump

I assume they are referring to a carb vent line. They are sometimes necessary to equalize pressure in certain cowl designs.

aussiesteve

DO NOT vent your tank inside the fuse.
Maybe someone gave you the wrong advice or maybe the advice given was misunderstood.

The vent from the gas tank usually goes from the front of the tank, to a high point behind the tank, then out the front of the fues to below the tank with the end outside.

Some plane / Engine combos require the air pressure reference vent for the carb regulator diaphragm to be vented inside the fues to get away from the varying air pressures in side the cowl. I prefer to make that vent to a "static tube" on the outside of the fuselage.

Sorry I don't have photos of it but it is basically a tube, bent 90 degrees (I face mine backwards) with the end crushed down and a hacksaw cut half way through the tube near the end. I got the idea originally form Pe Reivers - it may even be posted on his website somewhere.

Charlie P.

Ah. Gotcha. Sometimes called a "pop-off" line, I believe. Never tried one. Somewhere I was told to cut 3X more exit gaps than intake holes to prevent back-pressure. I could see in a scale warbird or sleek model that wouldn't be possible.