The Silent Revolution — RC Electric Flight

As early as 1962, the free-flight electric glider designed by Militky was built by numerous model aircraft enthusiasts eager to experiment. The model was called SILENTIUS and was equipped with a Micromax electric motor. The gear ratio was 1:3, which allowed the motor to operate at its high RPM with maximum efficiency. The motor was mounted in the nose of the model and drove a folding propeller—designed to reduce drag during gliding flight, on the one hand, and to prevent propeller breakage upon landing, on the other. The SILENTIUS had outstanding flight characteristics. Many who chose not to activate the fuse-operated engine shut-off device for the maiden flight were in for a nasty surprise when the model vanished forever from their astonished eyes during a rapid climb.

Back then, however, carrying an RC system on board was out of the question. The engine power and battery capacity were too low, and the commercially available RC systems were too heavy. That is probably why, unfortunately, electric propulsion has since fallen into obscurity almost everywhere. Yet electric flight could have become a highly interesting free-flight category—perhaps linked to related categories such as F1B (GM), F1C (VM), or F1D (indoor flight). In any case, the EM (electric motor flight) category would have deserved at least as much attention as the VM National category, which never really took off, and the officials in charge at the time would have done more than just pay lip service to the noise problem—they would have actually taken effective action. Well, you should never expect too much from others—it’s always better to tackle the problem yourself.

The surprise was all the greater, then, when Militky demonstrated his remote-controlled electric model in 1971, showcasing truly astonishing performance and features. This time, the two motors were mounted on the wing and powered propellers designed for positive-pressure flight. While the SILENTIUS still had a wingspan of about 70 cm, the wingspan of the RC model has been increased to over 200 cm.

It didn’t take long for other designs to follow. Barely a year later, an American made a name for himself with his remote-controlled electric Fournier. The motor and battery pack (Powerpack) he used are now available for sale, including the propeller. While Militky achieves the required performance with lower RPMs and larger propellers, it appears that the American prefers high RPMs and small propellers, which almost certainly spares him the need for elaborate propeller braking devices or folding propellers. A few days ago, the improved version of the Militky model was unveiled to the public as a kit at the GRAUPNER booth in Nuremberg. However, the entire kit is expected to cost nearly 900 francs. This, however, should not prevent interested model builders from conducting their own further experiments, and it is likely that a wide range of possibilities will open up here. Here as well, various model aviators are currently working on electric flight, and it would be interesting to continue reporting on their experiences.