To those who've been there-done that on early Lancairs -- request your comments. I want a minimum-management on-off fuel supply.

For my L235 w/ IO320, I'm now running the fuel line from each wing tank through a  filter on each Facet pump, then from each pump -- both into an open Tee, up to the header tank --

Control of the Facet wingtank pumps' is on-off with an optical level-sensor in the header,  

to break or complete the plus-circuit 12VDC to each/both tanks' power-on/off switches. 

Left and right tank Facet pumps individual switches are normally left on, and powered when a/c master is on.   A red 'pumping' light is in the wing tank pumps' power circuit, cycles on and off as sensor demands fuel for the header.   When light stays on, attention is called to the

How can power to the L and R wing tank Facet pumps automatically switch off when the wing tanks are dry?   

 

From header, fuel flows through manual on-off valve, through filter to boost pump (recirculate pressure circuit) , to engine driven pump, through fine filter to fuel servo, to spider and injectors (airflow performance.)

Would it hurt the Facets to run if one runs dry before the other? (No check valves; Flow is one-way through the pumps).

Terrence,

 

There is a device that senses the current draw change in Facet pumps when they start pumping air and then shuts off the pumps- See:

 

 

I do not use this device and have run the pumps "dry" from time to time with seemingly no problem.  I had a similar desire for simplicity when I constructed my system some 15 years ago.  I have an automatic system that keeps the header between 8 and 9 gallons (full) by pumping from both wings simultaneously.  I know the wings are "dry" when the header drops to 7 gallons and the wing fuel levels indicate zero (zero indication when wing tanks are less than 2 gallons).  The "dry" pump running condition only lasts for about 6 minutes at 10 gph.  A float valve sensor indicates when the header has dropped to 8 gallons and a timer is automatically started.  If 6 seconds passes before the float would reset the timer by going above 8 gallons, the pumps are started and are run until the float indicates full. The timer protects against falsely starting the pumps in turbulence for only a momentary run.  Each pump (located in the wheel well) runs an independent line to the header.  There are switches to run the automatic system or each pump individually.  The VM EPI 800 system provides for very accurate fuel level monitoring in all three tanks with warning lights for lo fuel in each wing and the header and a lo total as measured by flow rate.

 

The advantages of such a system are that there are at least 8 gallons in the header in case of a complete electrical failure, the wings are pumped out together thus the lateral trim remains throughout the flight unless someone jumps, there is no selector valve and the fuel in each wing is used completely since it can be pumped dry (less than 1 cup unusable) in level flight.