The disclosure relates to an electric aircraft propulsion assembly for an electric vertical takeoff and landing, eVTOL, aircraft, the assembly comprising: an electric storage unit; a first electric motor connected to power a first propulsor; a first converter configured as a DC:AC converter for driving the first electric motor and a second electric motor connected to power a second propulsor, a second converter. A controller is connected to control operation of the first and second converters and is configured to operate in a first mode in which the first and second converters are operated as DC:AC converters to drive the first and second electric motors and a second mode in which the first converter is operated to drive the first electric motor to power the first propulsor and the second converter is operated to drive the second electric motor to provide a braking torque on the second propulsor.

The disclosure relates to an electric aircraft propulsion assembly for an electric vertical takeoff and landing, eVTOL, aircraft, the assembly comprising: an electric storage unit; a first electric motor connected to power a first propulsor; a first converter configured as a DC:AC converter for driving the first electric motor and a second electric motor connected to power a second propulsor, a second converter. A controller is connected to control operation of the first and second converters and is configured to operate in a first mode in which the first and second converters are operated as DC:AC converters to drive the first and second electric motors and a second mode in which the first converter is operated to drive the first electric motor to power the first propulsor and the second converter is operated to drive the second electric motor to provide a braking torque on the second propulsor.

A hybrid electric aircraft propulsion system and method of operation are described. The system comprises a thermal engine, a generator coupled to the thermal engine, a first electric propulsor operatively connected to the generator to receive alternating current (AC) electric power therefrom, a second electric propulsor, a generator inverter operatively connected to the generator to convert AC electric power to direct current (DC) electric power, and a first motor inverter operatively connected to the generator inverter and selectively connected to one of the first electric propulsor and the second electric propulsor and configured to receive the DC electric power and provide the first electric propulsor and the second electric propulsor with AC electric power, respectively.

A hybrid electric aircraft propulsion system and method of operation are described. The system comprises a thermal engine, a generator coupled to the thermal engine, a first electric propulsor operatively connected to the generator to receive alternating current (AC) electric power therefrom, a second electric propulsor, a generator inverter operatively connected to the generator to convert AC electric power to direct current (DC) electric power, and a first motor inverter operatively connected to the generator inverter and selectively connected to one of the first electric propulsor and the second electric propulsor and configured to receive the DC electric power and provide the first electric propulsor and the second electric propulsor with AC electric power, respectively.

A shaft system includes an outer shaft including an inner surface defining a conduit and an inner shaft extending within the conduit. The inner shaft includes a radially extending passage having a first end and a second end. A centrifugal force activated damper extends between the outer shaft and the inner shaft. The centrifugal force activated damper includes a first member arranged between the inner shaft and the inner surface at the first end of the radially extending passage, a second member arranged between the inner shaft and the inner surface at the second end of the radially extending passage, and a connecting member extending through the radially extending passage. Rotation of the shaft system causes the first member and the connecting member to shift away from the second member into the inner surface of the outer shaft.

A shaft system includes an outer shaft including an inner surface defining a conduit and an inner shaft extending within the conduit. The inner shaft includes a radially extending passage having a first end and a second end. A centrifugal force activated damper extends between the outer shaft and the inner shaft. The centrifugal force activated damper includes a first member arranged between the inner shaft and the inner surface at the first end of the radially extending passage, a second member arranged between the inner shaft and the inner surface at the second end of the radially extending passage, and a connecting member extending through the radially extending passage. Rotation of the shaft system causes the first member and the connecting member to shift away from the second member into the inner surface of the outer shaft.

A propulsion unit having a propeller for an aircraft including a nacelle; a propeller mounted in the nacelle so as to be capable of rotating about a longitudinal axis of rotation, the propeller having blades mounted by a root so as to be capable of pivoting between a deployed position, in which they extend radially relative to the axis of rotation, and a folded position, in which they are longitudinally received against the nacelle; drive means that rotate the propeller; indexing means for stopping the propeller in at least one indexed angular position relative to the nacelle; the propulsion unit wherein the indexing means consist of a stepping electric motor including a rotor that is coupled to the propeller.

A propulsion unit having a propeller for an aircraft including a nacelle; a propeller mounted in the nacelle so as to be capable of rotating about a longitudinal axis of rotation, the propeller having blades mounted by a root so as to be capable of pivoting between a deployed position, in which they extend radially relative to the axis of rotation, and a folded position, in which they are longitudinally received against the nacelle; drive means that rotate the propeller; indexing means for stopping the propeller in at least one indexed angular position relative to the nacelle; the propulsion unit wherein the indexing means consist of a stepping electric motor including a rotor that is coupled to the propeller.

The invention relates to a hybrid electric drive system (10) for multi-motor aircraft (20). The hybrid electric drive system comprises at least a first and a second hybrid electric drive unit (31, 32), each of which comprises: an internal combustion engine (41, 42), a motor-generator unit (71, 72) and a gear box (51, 52) for transmitting drive power to a propeller (61, 62). In order to supply the motor-generator units (71, 72) with electrical energy, the drive system (10) has a fuel cell (73), which in turn is supplied with hydrogen by means of a fuel tank (74). In the fuel cell (73), hydrogen is converted into electricity, which then supplies the motor-generator unit (71, 72) with electrical power by means of the transmission device (80) and power converters (81) and (82), in order to drive the propellers (61, 62). Advantages: On the basis of a turboprop aircraft (20) with approximately 40 to 90 passengers, approximately 40% of the energy during a 1-hour mission can be provided emission-free by means of hydrogen and fuel cell. This means no CO2 emissions at all during the cruising flight and also no climate-damaging exhaust-gas and contrail effects at cruising altitude (FL250), which are a significant share of aviation emissions.

The invention relates to a hybrid electric drive system (10) for multi-motor aircraft (20). The hybrid electric drive system comprises at least a first and a second hybrid electric drive unit (31, 32), each of which comprises: an internal combustion engine (41, 42), a motor-generator unit (71, 72) and a gear box (51, 52) for transmitting drive power to a propeller (61, 62). In order to supply the motor-generator units (71, 72) with electrical energy, the drive system (10) has a fuel cell (73), which in turn is supplied with hydrogen by means of a fuel tank (74). In the fuel cell (73), hydrogen is converted into electricity, which then supplies the motor-generator unit (71, 72) with electrical power by means of the transmission device (80) and power converters (81) and (82), in order to drive the propellers (61, 62). Advantages: On the basis of a turboprop aircraft (20) with approximately 40 to 90 passengers, approximately 40% of the energy during a 1-hour mission can be provided emission-free by means of hydrogen and fuel cell. This means no CO2 emissions at all during the cruising flight and also no climate-damaging exhaust-gas and contrail effects at cruising altitude (FL250), which are a significant share of aviation emissions.