Anderson Ed wrote:

Good Suggestion about fuel systems.  Will be interesting to see all the
innovative designs folks come up with on fuel systems.  I have attached
a drawing of mine, but it did not come out well. So I have provide a
description.

I use a small header tank (2x3x8)mounted on the firewall such that the
bottom half of it is below the fuel level in the wing tanks and
therefore can gravity feed.  At the bottom of the header tank are two
fittings for the high pressure fuel pumps and one for fuel input from
the wing tanks.  There is another fitting on top of the tank for fuel
returned from injectors/pressure regulator. There is a drain on the
bottom of the header tank that is flush with a hole in the bottom of the
cowl.  This permits me to drain it similar to an aircraft gasolator.  A
mechanical fuel selector switch selects which wing tank feeds the header
tank.  A low pressure boost pump is between the selector and the header
tank.

I have two high pressure fuel pumps drawing fuel from the bottom of the
header tank from seperate fittings (in case one became plugged).  One
pump is the main pump and the second is the aux pump.  Each pump has its
own fuel filter and line which come back together in a "Y" fitting and
then the fuel line goes to the injector rails.  Excess fuel is returned
from the injectors thru a pressure regulator which dumps the excess fuel
back into the header tank.

Fuel injected creates a lower pressure differential between the header
tank and the wing fuel tank.  The pressure differential is capable of
pulling fuel up at least two feet as I verified when I placed the fuel
container on the ground and it sucked the plastic marine fuel container
flat because I forgot to open the fuel container vent.

One pump is controlled by the EFI CPU and the other by a manual switch
on the instrument panel.  I take off with the boost pump and both hi
pressure fuel pumps on. System has worked fine.

Ed Anderson
RV-6A N494BW

Ed, that looks like a low res scan of a much bigger image. The file size
is fine. 
It did not come across in a readably fashion so you need to scan smaller 
parts at a higher res. Try to keep the image file sizes down to 100K or
below.

Paul Lamar
 
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