Mailing List flyrotary@lancaironline.net Message #22846
From: Greg@itmack <greg@itmack.com>
Subject: Re: [FlyRotary] Re: will EFI pumps pump air
Date: Wed, 1 Jun 2005 08:25:34 +1000
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Message
Thanks for your thoughts Bill.  I believe that 2 fuel tanks and a pump for each tank is redundancy.  If a fuel pump fails or a filter blocks up etc. just change tanks and look for a place to divert to.  Sure if I were to be doing long over water flights I would put in additional pumps in parallel or a cross flow pump. This would probably still be easier to plumb than the 6 way Andair valve.
 
Am I over estimating the reliability of these pumps?
 
Greg
RV8
 

How does this give you redundancy? If either pump fails, you end up without access to that tank's gas.
 
Bill Schertz
KIS Cruiser # 4045
----- Original Message -----
Sent: Tuesday, May 31, 2005 4:38 AM
Subject: [FlyRotary] Re: will EFI pumps pump air

I'm planning something similar for my RV8.  Left or right fuel pump is selected by change over switch so both can't be on at the same time and when the left pump is switched on the normally open solenoid for the right side is activated blocking the right return off and conversely the left solenoid is activated when the right fuel pump is switched on.
 
Perhaps some sought of change over solenoid can be used for the return instead of the 2 solenoids.  Attached is a plan of the basic layout.  Using this layout, I hope to avoid the complex plumbing for the Andair fuel selector and I may be able to place the pumps in the wing root area.
 
Greg 
 
I have separate tanks, pumps and filters on each side. Return is switched by a solenoid energized by switching the left pump on. This leads to its own set of fuel management issues, but it keeps the total redundancy I was looking for. Since we're analyzing fuel systems, I'd welcome any comments. 
 
Where does the fuel return go when both pumps are on?  Left tank I'm guessing?  Also guessing you turn that left pump off ASAP when climbing out with full tanks :-)
 
John (EM2 up and running. Checking EC2 wiring over & over) 
 
Great to year you're running again!
 
Rusty (weighing VW parts)
 
 


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