An aircraft propeller control system for an aircraft propeller with adjustable blade angle has a blade angle feedback ring and a sensor, one of which is mounted for rotation with the propeller. The blade angle feedback ring moves longitudinally along with adjustment of the blade angle and has position markers circumferentially spaced apart at distances that vary along a longitudinal axis. The sensor is positioned adjacent the feedback ring for producing signals indicative of passage of the position markers. Intervals between signals are indicative of circumferential distances between position markers. A controller measures longitudinal position of the feedback ring based on the intervals and is configured to produce a warning signal if the longitudinal position is outside a first threshold range.

This disclosure describes aerial vehicles and systems for altering the noise generated by the rotation of a propeller during flight of the aerial vehicle. In some implementations, propellers of the aerial vehicle are paired in a coaxially aligned configuration in which the pair of propellers both rotate in the same direction, are rotationally phase aligned, and separated a defined distance so that the noise from high pressure pulse of the induced flow from the lower propeller is at least partially canceled out by the noise of the high pressure pulse of the induced flow from the upper propeller.

This disclosure describes aerial vehicles and systems for altering the noise generated by the rotation of a propeller during flight of the aerial vehicle. In some implementations, propellers of the aerial vehicle are paired in a coaxially aligned configuration in which the pair of propellers both rotate in the same direction, are rotationally phase aligned, and separated a defined distance so that the noise from high pressure pulse of the induced flow from the lower propeller is at least partially canceled out by the noise of the high pressure pulse of the induced flow from the upper propeller.

A system and method for blade angle position feedback. The system comprises an feedback device and a sensor mounted adjacent the feedback device and configured for detecting a passage of position markers on the feedback device during propeller rotation. The position markers are spaced apart from one another around the circumference of the feedback device and are oriented at an angle to one another and to a longitudinal axis. The feedback device and sensor are configured for relative axial displacement. A detection unit is connected to the sensor for receiving the sensor signal therefrom, determining on the basis of the sensor signal a time interval elapsed between the passage of successive position markers, and computing from the time interval blade angle position.

Sounds are generated by an aerial vehicle during operation. For example, the motors and propellers of an aerial vehicle generate sounds during operation. Systems, methods, and apparatus may actively adjust the position and/or configuration of one or more propeller blades of a propulsion mechanism to generate different sounds and/or lifting forces from the propulsion mechanism.

Sounds are generated by an aerial vehicle during operation. For example, the motors and propellers of an aerial vehicle generate sounds during operation. Systems, methods, and apparatus may actively adjust the position and/or configuration of one or more propeller blades of a propulsion mechanism to generate different sounds and/or lifting forces from the propulsion mechanism.

An interconnect drive system for an aircraft has a driveline and clutch control system. The driveline comprises a shaft for each propulsion assembly, each shaft for transferring torque to and from the associated propulsion assembly, and a clutch operably coupling the shafts and configured for selective engagement. The clutch is capable of transferring a first amount of torque between the shafts while engaged and a second amount of torque between the shafts while disengaged. The system also has a clutch control system, comprising a computer operably connected to the clutch for controlling operation of the clutch and sensors for sensing torque applied to the driveline, output from the sensors being communicated to the computer. The computer commands operation of the clutch in response to the output from the sensors, the clutch being commanded to disengage to relieve a transient torque imbalance in the driveline.

An interconnect drive system for an aircraft has a driveline and clutch control system. The driveline comprises a shaft for each propulsion assembly, each shaft for transferring torque to and from the associated propulsion assembly, and a clutch operably coupling the shafts and configured for selective engagement. The clutch is capable of transferring a first amount of torque between the shafts while engaged and a second amount of torque between the shafts while disengaged. The system also has a clutch control system, comprising a computer operably connected to the clutch for controlling operation of the clutch and sensors for sensing torque applied to the driveline, output from the sensors being communicated to the computer. The computer commands operation of the clutch in response to the output from the sensors, the clutch being commanded to disengage to relieve a transient torque imbalance in the driveline.

A multi-rotor aircraft includes a fuselage, a propulsion engine coupled to the fuselage that generates thrust to propel the aircraft along a first vector during forward flight, and rotors coupled to the fuselage, each rotor comprising blades, each rotor coupled to a motor, and each motor configured to supply power to and draw power from the coupled rotor. The aircraft includes a flight control system configured to control the motors coupled to the rotors in a power managed regime in which a net electrical power, consisting of a sum of the power being supplied to or drawn from each rotor by its motor, is maintained within a range determined by a feedback control system of the flight control system. The flight control system can also be leveraged to adjust rotor control inputs to modify at least one of thrust, roll, pitch, or yaw of the multi-rotor aircraft.

A multi-rotor aircraft includes a fuselage, a propulsion engine coupled to the fuselage that generates thrust to propel the aircraft along a first vector during forward flight, and rotors coupled to the fuselage, each rotor comprising blades, each rotor coupled to a motor, and each motor configured to supply power to and draw power from the coupled rotor. The aircraft includes a flight control system configured to control the motors coupled to the rotors in a power managed regime in which a net electrical power, consisting of a sum of the power being supplied to or drawn from each rotor by its motor, is maintained within a range determined by a feedback control system of the flight control system. The flight control system can also be leveraged to adjust rotor control inputs to modify at least one of thrust, roll, pitch, or yaw of the multi-rotor aircraft.