securely enough, while still being flexible enough to prevent
them breaking under normal vibrations. If using internal
mini-pipes, C-ARF recommend that you protect the top sur-
face of the moulded carbon-fibre main landing gear legs by
covering them with a thin sheet of 1mm plywood, attached
with silicone adhesive. No other heat protection is neces-
sary to the fuel tank base, when using the DA-150 and mini-
pipes as shown.
The last job to do, an important one, is to cut out the 2 slots
in the bottom of the fuselage to let the warm air from the
exhaust system escape from the fuselage. These slots
should be 50mm (2”) wide and 150mm (6”) long, and it is
best if you make nice rounded corners to reduce any
chance of tearing in the composite skin.
Depending on your motor, you may need to make a simple
3mm thick balsa baffle plate inside the cowling to make
sure that enough cooling air is directed around the engine
cylinder heads, instead of just going directly out of the
opening in the bottom of the cowling. See photo here for an
example of the baffle, which improves the cooling consider-
ably. In any case, check that your motor is not overheating
when you make the “engine-running” R/C range checks
before flying.
Make up a wire lever so that you can operate the ‘Choke’
for starting thru’ the cut-out in the front of the cowling.
Fuel proofing:
We highly recommend that you protect all
the bare wood parts inside the front of the plane with one
thin coat of 24 hr laminating epoxy, or similar, brushed on.
Be careful not to add excess weight here - it only needs
about 30 grams (1 oz) of epoxy to fuel proof all the wood in
the whole area inside the front of the plane.
Note:
Please call your Composite-ARF Rep. or email us at:
[email protected], if you need any addition-
al help with the motor and mini-pipe installation.
Composite-ARF SuperXtra 330L
(3.1m span)
28
Don’t forget the all-important
engine test-run, with both ‘engine
running’, and ‘engine-off’ range
checks before the first flights.
Here you see the preparation and
range checking before the 1st flight
of the 3.1m SuperXtra 330L built for
these instructions, made on our
runway in front of the factory.
(above) Don’t forget to cut the 2
slots, 50 x 150mm, in the bottom
of the fuselage to allow the warm
air from the mufflers to exit.
(above and below) A simple balsa
sheet baffle will improve motor
cooling considerably by making
sure the air is directed through the
cylinder cooling fins.
