Inside the Lid, before the filler
neck was cut out.
Pre-fit the valve and torque tube.
Wing center section.  The hole in
front is for the radiator filler neck.
Looking up at the finished install (above
the passengers head) of the fuel valve,
fuel line, and torque tube handle.  The
valve is secured with an Adel clamp and
screwed up into the plywood doubler.  The
fuel line is secured to the forward left
cabane strut.
-----------------------------------------------------------------------------------------------------------------------------------------------------

With the Firewall Forward Retrofit in the first half of '03, I added a 10 gallon Cowling fuel tank.  
Here is the construction of that tank.
The design requirements I came up with are as follows:
1)  Devote every cubic inch of available space to fuel capacity.  A cardboard mock up was built, to transfer
the dimensions to 1/4" plywood female mould that is screwed together in order to take it apart after the
resin has cured.
2)  The bottom of the tank should NOT have anywhere that water might collect, even in the static laden
position (tail down), and give the water a path to exit the tank to be collected in the gascolator.
3)  The tank should have an inlet to accept fuel transfer from the wing tank.  
4)  The Cowl Tank compartment should be completely sealed from the cockpit area, with NO lines or
fittings in the cockpit area, in order to eliminate the possibility of a fuel leak finding it's way in the cockpit.
 The outlet faces forward, with a finger screen, 90º fitting, and cable control 3/8" ball valve.
The gascolator is located in the
lowest part of the fuel system
because that is where the water
will end up.  It Must be above the
bottom of the firewall, in case the
gear collapses, it will not become
damaged, and cause a fuel leak.
Here you can see where the Fiberglass 'Blister' protrudes through the
Firewall, 3/8" fuel outlet, blue 90º fitting, cable operated fuel shut off
valve, Throttle cable, P-Leads, Carb Heat Cable, and the white tank
was the first smoke tank, which I later replaced with a fiberglass tank
that I built, and mounted it in the lower center portion of the firewall.
The fuel line slopes slightly
back up to the carb inlet.
The Stromberg  NA-S3A1  carb on
aircraft engines, are located on
the bottom of the engine, in
order to maintain fuel pressure.
 The gascolator must be located at
the lowest part of the fuel system,
and ABOVE the bottom of the
firewall.
This turned out to be a very good
location for the smoke tank, and
filler neck.
The Fuel Cap has a Cork and Wire,
for a reliable Fuel Quantity indicator.  
It also has a ram tube, facing the
relative wind, in order to maintain a
little bit of fuel pressure in flight.
Here is the Finished Product.


Top view of the Lid, after the filler
neck was glassed in.  I should
have removed the metal in the
neck before the install - I have
trouble
Inside the lid, after 5000 L
sealer was brushed on.  
Six screws retain the aluminum
pipe thread fitting , and the #8 nuts
were glassed over on the inside of
the tank.
Side view of the completed
tank, showing the single outlet
in the bottom center.
Top view of the center section,
ready for tank install.
Bottom view of center section.
The tank had some movement
when it was installed, so I used
spray foam insulation around
the perimeter, so it would not
move.
Pilots eye view of the fuel valve handle,
located on the bottom of the wing,
above the pilot's windshield.
The Four fiberglass plies are cut and pre-fit
before the mould is waxed up.  Use gloves to
handle the plies in order to keep skin oil away
from the fiberglass.  Carefully placed in the
order they will be used, and stored on a clean
surface, the first ply down (on top) is fine
cloth, next two are medium cloth, and the last
ply down (on the bottom) is fine cloth - ready
for layup.
The inside corners have triangle strips (no 90º corners)
in order for the cloth to lay in better.
The integral mounting flanges are where the weight of the tank
and fuel is transferred to the top longerons.  The flanges are at
least 6 or 7 layers thick, and the layers are laid in a 90º raidiused
corner, to become an integral part of the side of the tank.
The mounting flanges also have two integral support flanges.  
Small square pieces of fiberglass were fitted, and ready,
before any resin was mixed.
Holes are cut in the lid, and the filler neck, and
weldable fitting inlet, is ready to be glassed in.  
The flange goes on the inside of the tank.  
Three plies of light cloth was installed on the
top & bottom.
Before applications of wax, a strip of Duct
Tape was used around the perimeter of the
lid, in order to define the line to cut the edges
to.  I used 4 applications of Turtle Wax (car
wax), and allowed it to dry between coats, but
did NOT wiped any off between coats.
Here is the area that is sealed from the cockpit, where the fuel cell will be located.  Also note: New
engine mount fittings were made, and installed, with a tab on the top mounts to secure a slanted strut
that replaces the X cables on the right side of the front cockpit.
Fuel  System
  I have a Short Fuselage, Continental engine,  9.8 gallon wing tank, and 10.7 gallon
cowling tank.  It took me a lot of time to design & build the cowling tank to use
every nook & cranny up there to put fuel in.   The bottom of the cowling tank is
sloped forward, so when the plane is in the static laden position (tail on the
ground) any drops of water will drain out of the tank, into the gascolator.  No fuel
lines or fittings are in the front cockpit, to eliminate any possible fuel leaks from
entering the cockpit.  I installed a fitting on the top, at about 10 O'Clock position
(viewed from the cockpit), to fill it from the wing tank, so there is some fuel
management with this set up.  The drawback is that several times, I've overfilled
the cowling tank, and overflow the ram air vent, and had fuel spray back across the
windshield.
  The filler necks of both tanks are from a mid 80's Ford Pickup saddle tank filler
neck, and use common gas caps.  These filler necks have a convenient flange to
fiberglass in, and seal.
  I used Polyester Resin (auto body type), but would NOT suggest this type resin
because it might be attacked by Alcohol, although I have not seen any evidence of
this.
Here is a series of construction photo's of the 9.8 gallon wing tank.  One simple
outlet in the center bottom, right above the passenger's head, with a ball valve
that is operated via a torque tube handle, located right above the rear windshield.
 It was laid up in two pieces, and glassed together around the top of the tank.
Bottom view of the center section.  
The 1/16" plywood doubler in the
center, is to support the fuel valve.
Tank is installed.  It is retained with
a strip of wood at the front, and
two screws threaded into wood
blocks that were glued to the spar
and have large washers, at the
rear.  
The reinforcements are triangle
cut foam, glassed over,  that the
polyester resin does not attack.
Moulds are waxed up, assembled,
and ready for wet lay-up.  The
outlet 'Blister' for the weldable
fitting is located at the lowest part
of the tank, front and center, and
faces forward.  This is also where a
Finger Screen will be installed.
<---- Rib Alignment Pins ---->
Holes were cut in the 1/4" plywood, before gluing
it to the ribs.  These 'Blisters' are where the filler
neck, and fuel inlet fitting is located.
The two pieces of the fuel tank is cut and trimmed to fit behind the .016" Stainless Steel Firewall.
Inside the  Lower Half.  Note :
Everything slopes to the center,
and there is nowhere that water
can collect.