"Ron Natalie" wrote:


For a low wing aircraft with dual wing tanks, what is the point of
having a fuel selector valve. It seems to be a source of some fuel
exhaustion caused accidents. Wouldn't it just be easier to feed off
both simultaniously?

Because there's a fuel pump involved. If one tank goes dry, the pump
sucks air. Easy experiment. Grab two straws. Stick one in a glass of
water and let the other one stay outside the glass and try to drink from
them.

There are a few low wing planes with "BOTH" positions on the selector, but
they drain to a common tank and the pump draws singly from there.
++++++++++++++++++++++++++++++++++

Not true of the Ercoupe I once owned.

Header tank was common to both wing tanks.

Fuel was pumped from BOTH wing tanks
to that common tank and then gravity fed
to the engine.

When the common tank was full, the excess
was gravity fed to the left tank. Some other
Coupes returned fuel to the right tank.

Both tanks were connected together,
so fuel would balance out... eventually.


Barnyard BOb --