stoya789

And if so then why? Helicopters and airplanes don't have a one-way valve and they are far more aerobatic then an r/c car will ever be...

378

My Feedback: (4)

Negative. Such a valve would be pointless anyways. Cars are only designed to run one way up. They can get away with a rigid pickup because of this. Aircraft need to be able to run in any orientation so their pickup is free to move about in the tank quite a bit.


Also, quickly filling up is a high priority for cars. We demand the ability, even in cars that never see a track, to fill the tank in two seconds while the engine runs. Aircraft do not need this functionality.

stoya789

Yeah, did some research and they are called check valves (one-way valve) to let air into the tank (pressure) but stop fuel from getting out.

For some reason I though they were built into some r/c car fuel tank lids.

I know they are built into gasoline tanks like lawnmower and chainsaw to let air in the tank when fuel is being consumed. They allow the tank to breath.

378

My Feedback: (4)

They don't need one. During normal operation they aren't in a situation where one would be needed, and when you do roll it, a combination of exhaust pressure and the positioning of the pressure line relative to the tank means they won't leak.

stoya789

Yeah, I guess its not needed when you get fuel pressure from an exhaust pipe. But if you were to use, say, a perry pump, you would then use the pump to move fuel to the carb and replace the exhaust pressure line with a check valve.

378

My Feedback: (4)

Perhaps, but it's quite rare that someone does that. AFAIK no cars come that way from the factory.

stoya789

Yeah its done mostly in airplanes to regulate the fuel pressure so that it is consistent when doing stunts. An exhaust pressurized tank typically has a richer fuel mixture when you have a full tank which progressively gets leaner as the tank empties. This can turn out to be a problem when doing precise aerobatics.