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From: Dale Rogers <dale.r@cox.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Subject: [FlyRotary] Re: will EFI pumps pump air  
Date: Sun, 29 May 2005 23:15:33 -0400
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> 
> 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.