Carf-Models Ultra Flash, Instruction Manual

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length of the included double-sided Velcro.
Our preferred method is to have a felt clunk (Webra #1121)
fixed to the end of the brass feed tube inside the hopper
tank, in the 3-dimensional centre of the fuel tank, which is
connected to the fuel pump. Photo P9 shows the detail of
how to assemble this, using a short length of the included
clear 4mm I.D fuel tube. The very short length of Tygon tube
immediately in front of the felt clunk is to prevent the felt slid-
ing forwards off the metal clunk, and this is retained with a
small cable-tie. Connect the ‘vent’ tube of the hopper tank to
the ‘feed’ tube and clunk o the main fuselage tank.
The photo here shows the recommended position of the
hopper tank and mount, which is glued to the fuselage floor
with 30 minute epoxy and micro-balloon mixture. This posi-
tion gives nice short connections between the hopper an
main tank, which is directly above it. You can install the fuel
pump, on its milled plywood mount, on the underside of the
front fuel tank support (above the hopper), as shown in the
photos in the ‘Gear Installation’ section.
If you wish you can fit a 3rd brass tube into the hopper tank
cap for filling the fuel system. Alternatively you can install a
quick-connect Festo or Rectus (or similar) fitting between
the feed tube and the fuel pump and disconnect here to fill.
This has the added advantage that you cannot accidentally
fill the turbine with fuel if the manual shut-off valve has been
left open, or the fuel solenoid valve allows a small amount of
fuel to pass thought it. It’s your choice.
Wing Tank (Optional):
The wing tank has a capacity of about 1.3 litres, and is fitted
in the pre-cut and hinged tank bay in the centre of the wing.
It is joined and leak-tested at the factory, and is supplied
with aluminium cap hardware, kerosene stopper and brass
tubes needed.
Assemble the included aluminium tank cap hardware with
2 of the Ø 4mm brass tubes in the same way as for the
main tank. You will need to bend the ‘vent/overflow’ brass
tube inside the tank almost 90 degrees to make sure that it
reaches to top of the tank, and it can be extended with a
short length of Tygon as shown here.
To prevent kinking or flattening the tube when you bend it
you can fit a spring over the outside of the tube (eg: the
ones available at “K&S metal centres” in most good hobby
stores). Extend the brass tube as necessary with a short
length of Tygon, as shown, to reach the top surface of the
18
(above) Wing fuel tank cap assem-
bly details, with felt clunk.
(Below) A spring is used to bend
the brass tube without kinking.
(above) Assemble hopper tank
mount from the milled plywood.
(below) Hopper tank is held in
the mount with velcro band.
(bottom) Hopper tank shown in
the recommended position.