1st National CO2 Competition in Frauenfeld

Organizer: MG Furttal

The idea to hold a CO2 competition came about at the first free-flight meet on May 22 at the Kantine Brunau restaurant in Zurich. CO2 model competitions have often been held following the glider-throwing competition. These competitions have long been popular abroad. Why shouldn’t we give it a try?

We decided on the following provisional rules:

One model per participant. Only single-cylinder engines in their original configuration. Three flights with no time limit.

To prevent super-thermal flights, the event didn’t start until 4:00 p.m. A modest start with seven participants shouldn’t be seen as a bad omen, since the publication of a construction plan for CO2 models didn’t appear until the June issue of Aero-Revue. Model shops rarely carry CO₂ engines, so it’s understandable that there is still a lot of work ahead for the broader model-flying community.

Model airplanes with a wingspan of 20 to 106 cm. Engines: Shark and Telco (England); Brown (USA); Modela (Czechoslovakia). Engine run times varied widely, ranging from 15 to 70 seconds. It soon became apparent that conventional fillers using small household cartridges for whipped cream dispensers were impractical and too expensive. CO₂ cylinders good for about 150 refills can be purchased at pharmacies for about 35 Swiss francs; a refill costs 4 Swiss francs.

Alternatively, you can rent large CO2 cylinders (Carba-Gas, Zurich). The former method was already presented in MFS No. 2/79. A particularly sensitive issue arose at the connection between the motor and the tank, which uses thin copper tubes. The Humbrol company recognized this problem and developed a motor with an integrated tank. However, it still has some teething problems, and I cannot recommend it at this time. The most powerful motor currently on the market is the Czech Modela, with a displacement of approximately 0.3 ccm. I designed the “Cyclon” model for this, with a wingspan of 106 cm and a weight of 90 g. The climb rate is approximately 30 meters per second

. Over 10 flights conducted that evening, the average flight time was 81.2 seconds. During a test flight at the competition, I managed a 10-minute thermal flight, which René Butty knew how to take advantage of. He took off beneath my model and achieved the best flight of the competition at 222 seconds, which was enough to secure his victory. The Gipsy models, with a wingspan of 60 cm, achieved flight times of 60–70 seconds. Overall, it was truly a competition focused on gaining experience. With this competition format, the beautiful

scale models have, of course, disappeared. Purely functional models were used.

The three pewter mugs donated by Modell-Flugsport found their recipients to applause. Maybe you’ll be there next year, too, since MG Furttal is organizing a model-building course for CO2 models later this year. The cost of materials, including the motor, is approximately 65 Swiss francs. Anyone interested should send a postcard to MG Furttal, W. Heise, Guggimoos 437, 5425 Schneisingen. W. Heise