This Piper Pawnee model has generous, fairly accurate scale air inlets in the cowl
for good cooling.
This 30cc Spitfire has no openings in the cowl, which means very little or no airflow
over the power system. In spite of that, the conservatively chosen components run
well under the manufacturer’s heat limits.
This exit vent is made by removing the covering over a cutout in the bottom plywood sheeting of a Fokker D.VII.
Simple and effective, it improved the airflow through the fuselage.
The Hangar 9 Beast 60e has a well-designed cooling airflow. A curved baffle left of the spinner directs air over
the motor. The right-side inlet directs air straight into the fuselage and over the speed control. Just forward of
the tail, a large exit vent pulls the air out of the fuselage.
and air scoops on the nose of the plane is
predetermined. A P- 40, for instance, has a fairly
large opening just below the big spinner, where
the radiator and oil cooler were located in the
original plane. A Cessna 310 has two vents in
each nacelle, one on either side of the spinner.
Models of these planes would have vents in
the same locations, making the speed-control
mounting decision easy.
Sport models are a little different in that you
can put a vent or scoop anywhere you need
to. That said, the most pleasing designs tend
to use the same locations and styles of vents
that full-scale planes do. Chin scoops, cheek
vents, and big round cowls over simulated radial
engines just look right on an airplane, while
they route air where it’s needed.
Generally speaking, electric-power
components are located fairly close to one
another when possible. One reason for that
is aircraft balance and the need to keep the
heavier bits forward of the center of gravity to
compensate for the weight of the airplane aft
of it. Another reason is to keep wire lengths
short, minimizing resistive losses and overall
weight. All of that together means that, in large
planes, it might be possible to mount the speed
control somewhere forward of the firewall—for
instance, on the underside of the motor mount.
Many smaller models require the speed control
to be mounted inside the fuselage in the battery
compartment; in this case, you’ll need to make
provisions either to get the airflow over the
speed control or to mount the speed control in
the path of the existing airflow.
Once the high-pressure air from outside the
moving plane has a way into the fuselage, it
needs to be directed to the hot spots. Well-placed holes in the firewall and other formers
inside the model can direct air fairly effectively,
resulting in a steady flow of air through the
fuselage cavity. In many models, this is all
you need. Castle Creations’ specifications for