I want to reiterate the only correct way to do a

canard fuel

system is follow the Ruttan plans. To do other

wise is risking

your life. Reproduced here in gif form.

If you have a EFI high pressure fuel system with

return

flow use a high quality dual level selector valve

and return the flow

to the tank you are sucking fuel from. Not the

sumps tanks. (there

are two in the stock canard system.) There are a

lot of factors and

scenarios to be taken into consideration when

designing a fuel system.

Some of these factors are:

Vent configuration. Air pressure in the tanks

under all conditions.

Heat of the return fuel. Position of the HP fuel

pumps. Height of

the fuel tanks
affecting the gravity flow. Size of the lines.

Quality of the fuel

selector valve if used. Shape and location of the

sump tank.  Etc.,

Etc.
The only difference in my 3D below is the depth of

the sump tanks

which should lengthen the time the engine will

still run during

slips or uncoordinated turns. In the stock system

they are integrated

into the main left and right tanks. Make the

connecting lines between

tank and sump as large as possible. Keep the high

pressure

pumps as low as possible and as close to the

selector valve

as possible. Don't use a both selector valve. It

has no place

here. Tall and skinny sump tanks are essential.

Don't make

them wide.

The vent lines to the main tanks are facing forward to
enhance the flow from the main tanks to the sump

tanks.

The sump tank vent lines are not facing forward to

insure

the air pressure in the sump tanks is not the same

as the air pressure

in the main tanks. At real high speeds it is

possible that

the air pressure in the main tanks could force

fuel out of the

sump tank vent lines if they are less than about

28 inch high.

If that happens face sump tank the vent tank lines

forward as well

to equalize the air pressure. Do not route the

vent lines

any other why as a siphon situation could be set up.

Don't fool around with it unless you are a highly

qualified mechanical

or aerospace engineer.

There are some unmoderated list out there in

Internet land where

every poorly thought out half baked scheme is

given equal weight.

Paul Lamar

Do these concepts all apply to a high-wing system?
In previous posts, I believe Paul recommended using
BOTH upper tanks draining into a central sump tank
for a plane like the Glass Goose.  These rec's
included two, in-tank fuel pumps, with appropriate
filters, gauges, valves,etc.  I also think the FI
return was to the sump.  There are no existing plans
for a FI return system on this plane, so they must
be created.

The Glass Goose has plenty of room for a large sump
tank (3 or more gal).  Is there a certain volume of
fuel that would disspate the heat from returned fuel
to a sump?  If a sump return is not consistent with
the present concepts, it is OK to return the fuel to
both upper wing tanks, where gravity will help
equilibrate flow to the sump, or must it always
return to one tank?


Scott Gettings


Are the tanks in the upper wings? If so sounds OK
Make sure you put the high pressure fuel pumps
in the 3 gallon sump tank and vent it to the
highest part of the fuselage. Do not point the vent
forward. Shield the vent from any airflow. You can point the
main tanks vents forward as the glass goose will never go fast
enough to pump all the fuel overboard through the 3 gallon sump
tank. Keep the sump tank tall. As tall and as  skinny
as you can while still getting the high pressure pumps
in the bottom of the sump tank.

Paul Lamar