never have made it as FF fliers, a CL
aircraft didn’t have to be bricks kept in
the air by brute power and centrifugal
force. It took modelers such as George
Aldrich, Davey Slagle, and others to
show the rest of us that larger, lighter
models could execute smoother, more
realistic maneuvers while being more fun
and easier to fly.
Our local CL club members slowly
began flying RC, and only when I was
one of the few left standing in the circle,
did I move over to RC.
Today there is little, if any, CL flying
in my town, partly because of a lack of a
flying field. I miss CL because life seemed
much simpler then. You simply hand-started an engine and flew. Using a good
fuel filter, the only adjustment needed
was one click of the needle valve in the
spring and another in the fall. Mechanical
failures were rare and unless you flew
Combat, an airplane lasted forever.
Contest modelers want to build
lightweight models. Because construction
consists mainly of wood and glue,
those are two of the chief items that
the builder can control. One piece of
advice frequently given to novices is to
concentrate on minimizing glue weight.
Make closely fitted joints and only use
the necessary amount of glue.
Your control of balsa weight is limited
to what you can purchase. Balsa density
is usually expressed as pounds per cubic
foot. It’s a term familiar to FF modelers
and anyone else who is concerned with
keeping weight to a minimum. Another
common term is contest-grade balsa,
with “gold standard” wood being as light
as 5 pounds per cubic foot. Most balsa is
roughly double that density.
There’s an old formula for quickly
calculating the weight of balsa into
pounds per cubic foot. Using standard
3 x 36-inch balsa sheets, make a stack
of them that is 1 inch high. Weigh the
stack on an accurate scale. The weight in
ounces is also the weight in pounds per
This trick works because a volume
of 1 x 3 x 36 inches happens to be 1/16
of a cubic foot, and an ounce is 1/16
of a pound. You can tinker with the
arithmetic for final proof.
HobbyKing altimeter instruction sheet
1001 Patterson Rd.
Santa Maria CA 93455
SAM rule book
Walter Angus, SAM secretary
Phoenix AZ 85050
89 Model Aviation APRIL 2015 www.ModelAviation.com