A hybrid electric propulsion (HEP) system can include a heat engine torque sensor connected between a heat engine and a combining gear box to sense a heat motor input torque input to the combining gear box, an electric motor torque sensor connected between an electric motor and the combining gear box to sense an electric motor input torque input to the combining gear box, and a combining gear box torque sensor connected to an output of the combining gearbox. The system can include a HEP controller operatively connected to each of the heat engine torque sensor, the electric motor torque sensor, and the combining gear box torque sensor to receive one or more torque signals therefrom. The controller can be configured to output one or more output signals as a function of the signals from each of the heat engine torque sensor, the electric motor torque sensor, and the combining gear box torque sensor.