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Composite-ARF YAK 55SP (3m span)
you will overheat, and damage, your valuable motor.
Depending on your motor you will definitely need to make
some sort of baffle to force the air through the cooling fins,
and this can be made from scrap 1.5mm plywood or 3mm
balsa. Cut a half-circle of 330mm diameter and glue it into
the cowling, as shown, and then a horizontal shelf of the
same material which is glued to the back of it and trimmed
to clear the cylinder fins by 6mm (1/4"). It looks neater if
you paint it matt black first, using heat-proof spray paint (as
used for car manifolds/exhausts).
Fuel Tank Base
The Fuel tank base supplied is a cnc milled balsa/compos-
ite assembly, that also provides space for mounting the
receiver and Powerbus system. It is reversible - so you can
assemble it either way around, and fit the Rx and Powerbus
on either side of the fuselage.
It is sized to fit a Dubro 1500 cc (50oz) tank (part #692), but
can be adjusted to suit your choice. Depending on the size
of your fuel tank, glue a scrap balsa block at the front of the
tank base to stop the tank moving forwards. Secure the fuel
tank to the tank base with cable-ties through the milled
slots, as shown in the R/C installation section.
Lightly sand all the parts, assemble with thin CA as shown,
and then reinforce all joints with a fillet of 30 minute epoxy
and micro-balloons. Don't forget to seal the bare edges of
the balsa sheet with a brushed-on coat of thin epoxy.
Prepare the areas well for good glue adhesion, and then
permanently glue the completed tank base in place on top
of the fibreglass sleeve for the wing tube, and
to the top of the composite side-rails at the
edges of the cockpit opening using a slow
epoxy and micro-balloon mixture.
The fuel tank is secured to the base using 3
cable-ties as shown. The small plywood dou-
blers glued underneath the tank base are for
the screws that secure the Powerbox.
techsupport@composite-arf.com
(below) Simple 1.5mm plywood
baffle to improve motor cooling.
(above & below) Top and bottom
views of assembled fuel tank base.
(above) Fuel tank base with 1500cc Dubro #692
fuel tank, Power box and Receiver.
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