Micro-Flying — 2009/09
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 were used in free-flight 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 free-flight 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 a 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 full-scale aircraft is similar to piloting a new model for the first time. I made a few practice slow- and high-speed 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, four-channel 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, Micro Flier Radio.
CO2 Motor History
Bill Brown
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
Stefan Gasparin constructed his first CO2 motor in 1972. He became fascinated with that mode of power, and in 1992 he started his company, 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 the 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 company website.
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, which is available at craft stores. It is perfect for these power plants because it does not gum up over 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 GB12.)
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-N-Fly 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 night-flying 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://microflieradio.com
- Gasparin CO2 Motors
- 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
Transcribed from original scans by AI. Minor OCR errors may remain.
