Consider using an ANDAIR duplex valve. It takes fuel from one tank and returns it to the same tank. Turn it and it takes and returns to the other tank. Simple in operation, but requires more plumbing.
Bill Schertz
KIS Cruiser #4045
N343BS
----- Original Message ----- From: "randy echtinaw" <rjechtinaw@toast.net>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Tuesday, December 02, 2008 6:50 PM
Subject: [FlyRotary] Re: Fuel system

Al,
   That was my first thought to just drain the smaller tank into the larger with a simple 1/4 turn on/off but I would have to run the main  at least 1/2 empty for this to work. I cannot fly ackro with less than  6 gallons in the main tank. I cannot fly ackro at all with fuel in the smaller tank so by the time the smaller tank emptied I would have  little fuel remaining in the larger tank. I even considered a small  transfer pump to fill the larger tank but I am again creating  complexity.
All input here is welcome :))
Thanks,
---------------------------------

On Dec 2, 2008, at 7:39 PM, Al Gietzen wrote:

Randy;

Is the positioning of the tanks such that you could gravity feed the small
tank into the big tank? Then you could return to the larger tank - and
eliminate the selector valve.

Al G

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]  On
Behalf Of randy echtinaw
Sent: Tuesday, December 02, 2008 3:59 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Fuel system

Gentlemen,
  Because a large majority of homebuilt problems are fuel related I
am trying to make my system as simple as possible. This is a biplane
with a 20 gal. and a 10 gal. tank in front of the inst. panel, RX-8
engine.
The only "known" problem I have at the moment is my fuel return. I
would like it to return to the main tank only. This would mean burning
off 2-3 gallons from the main tank before switching to the 2nd tank.
But, this might mean I am setting myself up for a future "pilot error"
in fuel management. If I return to both tanks I would need another
selector and cockpit control which is making the system more
complicated and, again, potential "pilot error." So, suggestions . . .
Thank you very much,
Randy