<... I'd only have both "on" during takeoff, on landing, and for a brief moment each time I switched tanks in flight ...>

That would be key.  Your pumps (assuming they won't back flush) become your fuel selectors.  Turn on one or the other as you say, but not both.

Dale Rogers wrote:

From: "Russell Duffy" <13brv3@bellsouth.net>
Date: 2005/05/29 Sun PM 08:41:29 EDT
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: will EFI pumps pump air   was  Re: Fuel Tank
 Selection
 
This brings up a question that I've had before, and I'm not sure this is
exactly what anyone is doing, so it's not meant that way.
 
Say you have two tanks, with an EFI pump for each tank.   You then connect
the output of each pump together, feeding into one line running to the fuel
rail.   The question is:  What happens when one tank runs out of gas?  Will
the EFI pump move enough air through it to disturb the fuel rail pressure
that's being delivered from the other pump, or would it just stop pumping at
that point, and do no harm (other than maybe burning the pump up
eventually)?  
 
Yep, still trying to figure out how to fix my fuel transfer system. 
 
Cheers,
Rusty
    

   That's one of the situations I intend to test when I 
get my engine cell set up, but it's a situation I'd only 
expect to ever see if I ran dry during approach.  With 
separate selectors for each tank, I'd only have both "on" 
during takeoff, on landing, and for a brief moment each 
time I switched tanks in flight.

Dale R.



  

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