I couldn’t use the
fuel system for my airplane. Because
I am using a continuous flow fuel
injection system, I needed a return line all the way back into the
tanks. Stopping the
return at the selector valve
wouldn’t work. It
doesn’t provide enough
time and space for the fuel to cool and release the air bubbles.
big decision was how to run the
lines. I came up
with three options.
I could run a line
from the right tank through a transfer pump to the left tank. Then run a line from the
left tank to the
selector valve and forward. This
be pretty easy to install. I
the fact that if my transfer pump failed, I couldn’t use the fuel in my
tank. If I left the
transfer pump on too
long, I would fill the left tank, and dump the remaining fuel overboard. I really didn’t like this
either, but I
figured that was part of good piloting.
It is no worse than remembering every
half-hour to switch
I could buy one of
the $400 selector valves that switch feed and return lines at the same
time. This would be
fuel system option. It
the trapped fuel issue,
but would mean a few more lines to run.
piloting would still be needed to remember to switch tanks
I could install
two selector valves: one
for feed, and
one for return. This
would be much cheaper
($20 verses $400). It
would also solve the
trapped fuel issue, has the same lines as option two, and would still
pilot to switch tanks. This
one more benefit—it could be used as a poor man’s fuel transfer. If, for whatever reason, I
found myself with a
heavy wing, I could feed from that tank and return to the other. This would transfer fuel
through the fuel rail of
the engine to the other tank. Again,
good piloting is required to switch back to the same tank for feed and
once the imbalance is fixed.
I went for option 3.
Fuel System Installation
started by installing a second fuel
selector valve under
the left mid cabin console, exactly like the first.
Then I ran two lines from
across the F-804, and
out the right side of the fuselage, using the same route Vans
two lines to the left
much shorter, but not
any easier due to the bends required.
Last I ran the lines
the left gear box.
installed duel fuel
of the left gear box. Since
a fuel pump is a critical for flight
item, I wanted the redundancy two pumps provided.
I riveted a bracket onto the F-844-L
auxiliary longeron. Then
I used large adel
clamps to hold the pumps. A
piece of ¾ x
¾ aluminum box channel is the spacer between the upper and lower clamps.
I decided to use bulkhead
everywhere that the lines
left the fuselage. This
let me make the
wing tank to fuselage lines after the wings were hung.
This worked for all the lines except the left
wing return. I
couldn’t make the turns
tight enough to use a bulkhead fitting.
But by running the line through the fuselage
with a rubber
could make the bend work.
The last parts I
installed were the
vent lines. These
are much easier to bend and manhandle
If you have never bent
tubing, check out my
comments on each.
from Fuel System
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