Aero Telemetry designed, integrated, and tested several different engine systems for an unmanned helicopter project. The initial design called for a power plant that could produce about 125 lbs of lift from a custom 4-bladed rotor system. Several different air cooled 2-stroke engines were installed and tested. Most problematic was keeping the air-cooled engines operating within acceptable temperatures during hover and flight. This proved to be a considerable problem with larger displacement, high horsepower 2-stroke engines.
Finally, a water cooled 2-stroke engine was installed. It produced more horsepower than the air-cooled engines and did so at much lower operating temperatures. However, it operated at a much different RPM band that required we come up with different gearing for the main rotor. Once the new pulleys were made the new combination was tested with excellent results.
