Carf-Models Extra 330SC Instructions Manual page 19

CARF-Models Extra 330SC (3.1m)
You will also need to make a rectangular cutout in the lower
back edge of the cowling, as shown at the photos. Radius
the corners of all the slots and cut-outs to reduce any chance
of tearing of the composite skin. Furthermore we advice to
make some cutouts in the bottom cowling for fresh airflow to
the canisters or tuned pipes.
It is also just as important to make sure that all the warm air
can exit the fuselage. You need to cut two slots in the bottom
of the fuselage, about 100mm behind the wing tube, each of
about 200mm long and 50mm wide. Best is to build up a little
scoop in front of the slots as shown at the photos in order to
increase airflow. Don't forget to reinforce the slots by some
carbon roving.
Hood in front of the slots
Depending on your motor, you will almost certainly need to
make a simple 3mm thick balsa baffle plate inside the
cowling to make sure that enough cooling air is directed
through the engine cylinder fins, instead of just going directly
out of the opening in the bottom of the cowling. See the
photos for an example, which improves the cooling
considerably, and is strongly recommended. A full-size
template for this baffle is included at the end of these
instructions. In any case, check that your motor is not
overheating when you make the "engine-running" R/C range
checks before flying.
It's important that the baffle plate for DA200 encloses the
whole engine as you can see above. It consists of three
parts which are fitted by M3 screws.
Hoods towards in- and outside
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T he canister exhausts and the
cutouts in the cowling (DA200)
The cutouts in the cowling
(DA170 on tuned pipes)
The baffle plate inside the
cowling (DA170)
The aluminium profile to fit the
side parts of the baffle plate for
DA200