A method includes providing thrust to an aircraft through a power train from a heat engine connected to the power train. The method includes controlling an electric motor connected to the power train to counter torque ripple in the power train from the heat engine. A system includes a power train for providing thrust to an aircraft. A heat engine is connected to the power train. An electric motor is operatively connected to the power train. A controller is operatively connected to control the electric motor. The controller includes machine readable instructions configured to cause the controller to control the electric motor to counter torque ripple in the power train from the heat engine.