CARF-Models Extra 330SC (3.1m)
www.carf-models.com
18
Canisters
You have a choice of canisters. We use the ones of MTW or
Krumscheid KS.
To fit the canisters at the fuselage we used the KS-
ComfortMount mounting-system together with two aluminium
profiles as shown at the photos. It’s very important to install
the mounting rings at the strengthened part of the canisters.
Alternatively you can use milled plywood bulkheads with
hard silicon tube to isolate the canisters. If the position of the
bulkheads is outside the strengthened part, it’s advisable to
reinforce the canisters at the particular position with some
carbon fiber. Otherwise the canisters may get damaged by
the vibrations.
Tuned pipes
A 170cc engine on tuned pipes is a really great drive for our
Extra SC because power is then comparable to a 200cc 4zyl
engine.
Fitting the pipes at the fuselage is almost the same as fitting
the canisters as described before. Note that you’ll need more
weight at the front of the fuselage, if tuned pipes are
installed. Consider that during the RC-installation. Lay the
cables carefully so that there is no chance for any cable to
contact the hot pipes. That will kill the isolation and may end
in the damage of a servo or your Extra!
The cutouts at the bottom of the fuselage for the exhausts
should always be reinforced by some carbon roving or the
like.
Cooling
Whatever type of exhaust system you chose, it is very
important to have enough cooling for both the engine and
exhaust, and make sure that the warm air can exit the
fuselage.
We highly recommend that you cut large enough holes in the
front of the motor dome so that the canisters and headers
can be installed from the front, rather than having to squeeze
them under the tank base, or remove the fuel tank for
access. This also makes sure that plenty of cooling air can
enter and flow around the headers and canisters. Leave at
least a 30mm wide strip of fibreglass in between the cutouts,
as this area has the carbon joining tape on the inside of the
motor dome.
That may happen to your
canisters, if you don’t reinforce
the bearing position
The tuned pipes installed at the
fuselage
The exhausts made of VA
tubes and the reinforced
cutouts
The holes in the front of the
motor dome
