From what source does the rotor tachometer in the Schweizer 300c operate?

The rotor tachometer in the Schweizer 300C operates via a cable drive system. This type of tachometer relies on a mechanical connection, where a flexible cable is connected to the rotor system. As the rotor spins, it turns the cable, which in turn drives the tachometer, providing an accurate reading of the rotor's RPM (revolutions per minute). This method of operation is beneficial for ensuring real-time performance data without relying on electrical systems or battery power, which can be affected by electrical failures.

In contrast, other systems mentioned, such as electrical or battery-powered devices, would depend on the functioning of electrical components that could potentially lead to inaccuracies if there is a malfunction. The magneto system does not play a role in this specific application, as it is primarily used for ignition in engines rather than measuring rotor speed.