Fuel selector question

es330td wrote:
Sorry if this is dumb (I am only at 8.3 hours toward my PPL)...

In the email I got from AOPA ePilot training tips today there is a
discussion of fuel starvation that makes regular mention of the fuel
selector switch. All my flying is done in a CE172 and the first and
last time I worry about the switch is during pre-flight when I confirm
that it is on both. I fly on both and never fly any other way and to
be honest, outside of gravity flow issues when parked on an incline I
cannot think of why one would want to select one tank at a time vs
both.

All aircraft fuel systems aren't as simple as they are in the 172. All
Aircraft can't use gravity feed either.

Let's take for example the little 601XL I'm building. It is low wing and the
fuel pumps move the fuel from the wing tanks to the engine. No as an
experiment to see what would happen if there were a both setting on the fuel
selector take a glass of water and two drinking straws. Put on of the straws
in the glass and hold the other out side the glass. Put both straws in your
mouth and suck.