ESTIMATING SYSTEM AND ESTIMATION METHOD AND AIRCRAFT

A state of charge estimating system includes: a power generator for supplying power to rotors and ; a battery for accumulating power supplied from the power generator and also supplying the accumulated power to the rotors; an ECU for detecting a voltage between terminals of the rotors (an inverter ); and a flight controller for determining if a detection result of the voltage between terminals detected by the ECU is stable over time, and estimating, when it is determined as being stable, state of charge of the battery based on the detection result of the voltage between terminals and a corresponding relation between an open-circuit voltage and state of charge of the battery . The state of charge of the battery can be estimated from the corresponding relation between the open-circuit voltage and the state of charge of the battery.