Hybrid turbofan engine with a planetary gearset for blending power between an electric output and variable-thrust bypass fan

An aircraft powerplant comprising:

• an engine having an output power shaft;
• a power transmission coupled to the output power shaft of the engine, wherein;
• the power transmission is configured to divide power output of the engine between a mechanical power output and an electrical power output;
• a majority of the power output from the engine is adjustable to output to either of the mechanical power output or the electrical power output;
• and
• the power transmission comprises a planetary gearset and an electric machine, the electric machine configured to control a gear of the planetary gearset and thereby control division of the power output between the mechanical power output and the electrical power output;
• a propulsion mechanism coupled to the mechanical power output;
• and
• a control system configured to cause the power transmission to:
• deliver the majority of the power output of the engine to the propulsion mechanism to generate thrust or
• deliver the majority of the power output of the engine as electrical power output via the electrical power output.