Anderson Ed wrote:

Hi Bob,
  Bob regarding your fuel system design.  As I recall the engine for your
project sits fairly high above the wings.  If that is the case then it
would appear that you should have no problem with fuel flowing uphill
when the pumps are off and I would probably not put the 3 psi check
valve in the line to prevent fuel flow when off.  Besides with much fuel
in the wing tanks your gravity pressure head is probably greater than 3
psi depending on where your main pumps are located.  I presume they are
below the fuel level line of your wing tanks.

  I do have a question regarding the feeding of the outer tanks.  I
presume the dedicated transfer pump you mention will not permit fuel to
flow when off.  Otherwise, I can see you high wing outer tank gravity
feeding into your high wing main tank.  That still may not be a problem
except it would increase the fuel pressure in the main tank and it could
seep around your tank filler caps or tanks vents tubes. You did not
mention having tank vent tubes or a vented gas cap, but I presume you
do.

I must admit to having a bias about having one pump per tank.  The
reason is of course if a fuel pump dies it will inevitably be the pump
to the tank with the most fuel remaining in it.  So you don't won't to
be in the position where you are running out of fuel in the tank with
the good pump and can not feed from the full tank with the bad pump.  I
presume you will have some pump that will permit you to transfer fuel
from one main to the other main if need be.

Just my 0.02 worth

Ed Anderson

P.s. By the way you must measure both long pieces of the apex seal place
together.  Hold/clamp them so the their sides are parallel (beleved edge
will make the top seal want to ride over the lower seal part) when you
mic them.

 
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