AS I AM writing this column, the summer
flying season is beginning! It is a great time
for us “micro modelers,” since we can fly our
aircraft outside in the warm, calm air. The
higher temperatures improve the performance
of our Li-Poly cells and another great power
source: CO2.
CO2 motors have been
around for many years.
They have been used
in FF aircraft and
were the
pioneering
power source
for micro RC
models.
When the
single-channel
Ceto RC
system became
available more
than 10 years ago,
everyone was
looking for a
lightweight power source. Motors were
impractical at the time, because only Ni-Cd
batteries were available and they were too
heavy for most of our small model designs.
Because we could use silver oxide cells for
the receiver, we turned to CO2 motors to
power our airplanes. When I tried my first CO2
motor, I was blown away by the cool sound it
made and the power it could produce.
I recently became interested in
CO2 power again, after my cousin,
Tom Malinchak, traded his full-scale Citabria
for a Pitts S-1C. I had built an RC CO2-
powered model of the Pitts S-1 from the Herr
FF kit more than eight years ago. (Sig
manufacturing now sells the kit.)
I decided to dust off the model and upgrade
it with lighter servos and new 2-gram
Spektrum receiver. The four-channel model
has a 24-inch wingspan and weighs 7.7 ounces.
It uses a GMOT 500 CO2 motor that has a
throttle. It flies even better now than before
.I flew a few hours in the full-scale
Pitts S-2B many years ago. This summer,
Tom was gracious enough to let me fly
his S-1. The first flight in a new fullscale
aircraft is similar to piloting a new
model for the first time.
I made a few practice slow- and highspeed
taxi runs. It is a good idea to get
used to how the airplane handles on the
ground. Then I checked the “Mags” and
poured on the coals.
The S-1 is a dream to fly. I am
planning on building a 9-inch-span, fourchannel
version of Tom’s airplane using
Nick Leichty’s new 0.65-gram servos
and his new 250-milligram receiver.
Nick’s products are available via his
company, which is Micro Flier Radio.
CO2 Motor History: Bill Brown made
his first tests of CO2 motors in 1940. By
1942, he had the first one up and
running. He spent several years
developing this motor, and Herkimer
Tool and Model Works put the O.K. CO2
into production in 1947. It weighed 64.5
grams, and all parts were made from
metal.
The O.K.’s speed could be adjusted by
screwing the cylinder into the crankcase. It
worked so well that Bill used that method
on all of his CO2 motor designs. he made
many improvements to the motors and soon
had the weight down to less than 7 grams,
with his Campus A-100.
In 1965, Bill started Brown Junior
Motors and produced an upgraded version
of the Campus A-100 called the “Brown
MJ-70.” In 1973, he made a twin-cylinder
motor called the “MJ-140V.” It weighed
10.9 grams and was perfect for models such
as the J-3 Cub.
Bill designed the Campus A-23 motor in
1981. This masterpiece weighs only 6.45
grams and is perfect for peanut-scale RC
models.
In 1991, Bill flew to Europe and met
with CO2 master Stefan Gasparin to
celebrate his 80th birthday. Together they
designed the beautiful GB12, which is the
smallest one that Bill produced and is
perfect for pistachio-size micro RC models.
He also made a twin version of the GB12
called the “GB12T.”
Stefan Gasparin constructed his first
CO2 motor in 1972. He became fascinated
with that mode of power, and in 1992 he
started his company called “Gasparin CO2
Motors.” He designed and produced more
than 60 types of the power plant in many
sizes and cylinder configurations.
The nine-cylinder G24N and 18-cylinder
G24NN are works of art! His G2.6 weighs
only 1 gram and is perfect for micro RC
models that weigh roughly 5 grams.
I love the G2.6 and used it to power my
first 1/72-scale F4U and F6F. It can run for
more than two minutes on a charge and has
plenty of power. For more information
about Gasparin CO2 Motors, please visit the
Web site.
CO2 motors are easy to use. Fill the tank
with carbon dioxide using the charger, flick
the propeller, and adjust the motor rpm to
the desired speed by rotating the cylinder.
The cool thing is that after landing a
model, one can instantly refill the CO2 tank
and have it back in the air within seconds.
The only real drawback to CO2 power is
shorter run times compared with today’s
electric power systems.
The carbon dioxide motors are fairly
durable as long as you lubricate them
properly. I use Singer sewing-machine oil
that is available at craft stores. It is perfect
for these power plants, because it does not
gum up during any period of time, nor does
it affect the piston O-rings that are used in
the Gasparin motors.
Unfortunately, the Brown and Gasparin
CO2 motors are no longer produced. They
are collectibles, but you can still find
them. (I am looking for the twin version
of the Brown GB-12.)
The Black Sheep Squadron Model
Airplane Club in California is one good
source. It sells CO2 motors and support
equipment.
E-flite Blade mCX: The four-channel
Blade mCX is a great indoor helicopter. It
is available as an RTF or as the Bind-NFly
version. This model weighs only 28
grams and can fly for up to eight minutes
on the included 110 mAh Li-Poly cell.
The helicopter’s 2.4 GHz receiver is
compatible with many DSM2 transmitters.
I am using my Spektrum DX7 transmitter,
and it was easy to bind with the mCX.
The model is great for easy living
room flight. I purchased one for my wife,
Cindy, and she had no problem learning to
fly it.
I installed the glow-in-the-dark nightflying
upgrades on my Blade. I loved toys
that glowed in the dark when I was a boy,
and now I have an excuse to play with
them again! I personalized my helicopter
by coloring its blades with a red Sharpie
marker. They look cool spinning up in the
living room night air. MA
Sources:
Sig Manufacturing
(641) 623-5154
www.sigmfg.com
Micro Flier Radio
(941) 377-9808
http://microflierradio.com
Gasparin CO2 Motors
www.gasparin.cz
Black Sheep Squadron
(213) 747-7514, extension 226 (Roy
Hanson)
http://blacksheepsquadron.com
E-flite (distributed by Horizon Hobby)
(217) 352-1913
www.e-fliterc.com
