Glossary
What is a rotor tachometer?
The gauge showing rotor RPM, a reading with no equivalent on a fixed-wing aircraft and one a gyroplane pilot watches as closely as airspeed. It is often combined with the engine tachometer in a single dual-needle instrument, fed by a Hall-effect sensor at the rotor head, not the engine.
Also called RRPM gauge
That is the whole entry for now. The longer version, with the mechanics and worked examples, is still to be written. See autorotation for how those read once they exist.
