Aircraft propulsion system with hybrid-electric powerplant

A system for an aircraft, comprising:

• a propulsor rotor;
• a powerplant including a turbine engine, a first electric machine and a power coupler;
• the powerplant configured to drive rotation of the propulsor rotor using engine mechanical power generated by the turbine engine during a first mode where the engine mechanical power is transferred from the turbine engine, through the power coupler and the first electric machine, to the propulsor rotor;
• the powerplant configured to drive the rotation of the propulsor rotor using electric machine mechanical power generated by the first electric machine during a second mode where the electric machine mechanical power is transferred from the first electric machine to the propulsor rotor;
• the power coupler configured to operatively couple the turbine engine to the first electric machine during the first mode, and the power coupler configured to operatively decouple the turbine engine from the first electric machine during the second mode;
• and
• a geartrain operatively coupled between the power coupler and a rotor of the first electric machine.

A system for an aircraft, comprising:

• a propulsor rotor;
• a powerplant including a turbine engine, a first electric machine and a clutch, the powerplant configured to drive rotation of the propulsor rotor using engine mechanical power generated by the turbine engine during a first mode, and the powerplant configured to drive the rotation of the propulsor rotor using electric machine mechanical power generated by the first electric machine during a second mode;
• the turbine engine including a compressor section, a combustor section, a turbine section, a core flowpath and a first rotating structure, the core flowpath extending through the compressor section, the combustor section and the turbine section, and the first rotating structure comprising a first turbine rotor disposed along the core flowpath within the turbine section;
• the first electric machine comprising a first electric machine rotor, and the first electric machine rotor mechanically coupled to the propulsor rotor;
• the clutch configured to operatively couple the first rotating structure to the first electric machine rotor during the first mode, and the clutch configured to operatively decouple the first rotating structure from the first electric machine rotor during the second mode;
• and
• a geartrain operatively coupled between the clutch and the first electric machine rotor.