Aircraft propulsion system with selectively rotatable open propulsor rotor

A propulsion system for an aircraft, comprising:

• a propulsion section including a first open propulsor rotor and a second open propulsor rotor;
• a turbine engine configured to mechanically drive rotation of the first open propulsor rotor during a first mode and a second mode, the turbine engine including a flowpath, a compressor section, a combustor section and a turbine section, and the flowpath extending longitudinally through the compressor section, the combustor section and the turbine section from an airflow inlet to a combustion products exhaust;
• and
• a drive system comprising an electric machine, the drive system configured to drive rotation of the second open propulsor rotor during the first mode using the electric machine, wherein the second open propulsor rotor is rotationally fixed during the second mode,
• wherein, during the first mode, the drive system is configured such that a ratio of a first rotational speed of the first open propulsor rotor to a second rotational speed of the second open propulsor rotor is variable to adjust operation of the propulsion system based on at least one of an operational parameter or an environmental condition.

A propulsion system for an aircraft, comprising:

• a propulsion section including a first open propulsor rotor and a second open propulsor rotor;
• a turbine engine configured to mechanically drive rotation of the first open propulsor rotor during a first mode and a second mode, the turbine engine including a flowpath, a compressor section, a combustor section and a turbine section, the flowpath extending longitudinally though the compressor section, the combustor section and the turbine section from an airflow inlet into the flowpath to a combustion products exhaust from the flowpath;
• and
• a drive system comprising an air turbine configured to receive bleed air from the flowpath of the turbine engine, the drive system configured to drive rotation of the second open propulsor rotor during the first mode using the air turbine, wherein the second open propulsor rotor is configured as a guide vane structure for the first open propulsor rotor during the second mode.