Well,
After much consideration I've decided to go with my simplified fuel system configuration on my RV.
One fuel pump per tank, with the two lines going to the two inlets on my fuel filter/moisture
separator, and then on to  "T" off to the two fuel rails. The return will go to a "T" and then
back to the fuel return selector. I'll have a switch to turn either the left or right fuel pump
on, and will have to select a which tank the fuel will return to. The selector switch and valve
will be adjacent to each other and in between the fuel quantity gauges. After looking at the
failure modes/parts counts/complexity of operation/possiblity of pumping fuel overboard if I get
vapor lock of the brain, I've decided that this is the simplest setup with the least number of
connections and mechanical components to fail. Worst case -if I get a fuel pump go catty wumpuss
on me on climbout or in some critical phase of flight, I'm frightened beyond the capacity for
rational thought, I'm in brain frozen bung puckering, eye bulging fear bordering on hysteria, if I
switch pumps and forget to switch returns, the fuel will continue to be supplied to the engine
and, if the returned to tank is full, I'll pump fuel overboard. Worst I could do is pump half of
my fuel overboard. Would be noticeable a quite a while before fuel exhaustion in the tank being
used due to the weight of the fuel on the two sides being unequal. The cost of the wasted gas will
teach me to pay better attention in the future, if there is one for me at that point.

Anyway, some will find this objectionable, no doubt. Am I bold or foolish? You decide.
Brian Trubee

If one tank is empty you are down to one fuel pump. No backup.
Why don't you just get one of Bulents four way valves and use
two pumps in parallel? If one pump fails you have the other pump. 
The valve is a bargain and  cheap insurance. A quality piece.
It automatically sends the fuel back to the tank selected.
Put the pumps downstream from the selector valve.

The four positions are:

Both tanks off in case of a fire. Pointer facing aft
Left tank       Pointer facing left tank
Right tank       Pointer facing right tank
Both tanks.      Pointer facing forward

Idiot proof as can be.

Mount it down low between your legs (RV4) or in the center between the seats.

Paul Lamar


Paul Lamar
 
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