Hello All,

I also have interest in this problem as relates to a new LSA design...

The main tanks are in stub wings (part of the fuselage) which were going
to be connected with 1" tubing to allow filling from one side
only. Tanks are also connected by a 1/2" "equalizer" tube at the top for
air . The 1' tube is to be "U" shaped and attached to a sump tank.
There is about 24" from bottom of main tanks to sump, 3/8 lines from the
lowest point during climb to the sump (sump still lowest point unless
you can climp @ 60degrees :D ), and no other transfere hardware.  I was
intending to have a vent only near the fill fitting/cap unless heat
expansion creates problems with only one vent.

From the sump to on/off valve, to final filter then external fuel
pumps.  For carb systems no return.  For EFI systems, check valves at
each pump and return to the sump which will be 2 to 10 gallons depending
on total fuel wanted by the customer. Low fuel warning light in the sump
@ 2-4 gallons reserve.  At rest pressure at the sump pickup is the head
of about 36 to 44" of fuel column.  Will have to review LSA regs about
requirement for a gascolator in addition to existing sump drain.

Does anyone see problems??  Are the pressure/vent caps used on autos
verbotten for a good reason?

Fly safe,

Dan F

If you make a sketch of this system Dan I'll do a 3D. I assume it is a high wing.
Is this a new design?

I can see why you would not want to pressurize an aircraft fuel tank as they
are flat and lightly built compared to an automobile fuel tank. One or two psi could convert
many aircraft fuel tanks to ballons.

Paul Lamar ...No rotor no motor.

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