A blade angle feedback assembly for an aircraft-bladed rotor, the rotor rotatable about a longitudinal axis and having an adjustable blade pitch angle, is provided. The assembly comprises a feedback device coupled to rotate with the rotor and to move along the longitudinal axis with adjustment of the blade pitch angle, the feedback device comprising a plurality of position markers circumferentially spaced around the feedback device, a plurality of sensors positioned adjacent the feedback device and each configured for producing a sensor signal in response to detecting passage of the position markers as the feedback device rotates about the longitudinal axis, the sensors circumferentially spaced around the feedback device and axially offset along the longitudinal axis, and a control unit communicatively coupled to the sensors and configured to generate a feedback signal indicative of the blade pitch angle in response to the sensor signals received from the sensors.

There is described herein the automation of propeller feather testing functions, whereby the test is automatically performed and a pass/fail signal is issued upon completion.

There is described herein the automation of propeller feather testing functions, whereby the test is automatically performed and a pass/fail signal is issued upon completion.

An aircraft capable of carrying at least 400 pounds of payload, has four rotors systems, each of the rotor systems being independently driven by an electric motor or other torque-producing source. Each of the rotor systems provide sufficient thrust such that the aircraft is capable of controlled vertical takeoff and landing, even if one of the variable pitch rotor is inoperable. An electronic control system is configured to control the rotational speed and pitch of at least one of the rotor systems in each of the first and second rotor pairs. The rotors may be arranged in coaxial stacks or maybe otherwise configured.

A method of reducing the noise generated in-flight by a vortex wake caused by each first blade of a main rotor of a hybrid helicopter. The hybrid helicopter includes a main rotor, at least two wings and at least one propeller. The method enables a stabilized flight phase on the level or with a non-zero aerodynamic slope to be implemented by determining a first value of the pitch of the second blades of each propeller and an angle of incidence of the main rotor as function of the flight conditions, then by applying the first pitch value to each propeller and by applying the angle of incidence to the main rotor so as to direct the vortex wake to limit the noisy interactions between the vortex wake and the other first blades and/or the second blades.

Provided is a system for controlling an RPM of a propeller and a rotor of a flight vehicle having multiple power units including: a collective pitch angle command generating unit generating a collective pitch angle command upon receiving a thrust control command from a pilot or an automatic controller; a disturbance factor compensating unit for generating an RPM compensation electronic speed control (ESC) command for compensating for an RPM error, and an electronic speed adjustment command generating unit generating a final ESC command upon receiving a collective command input or derived in the process of generating the collective pitch angle command by the collective pitch angle command generating unit and the RPM compensation ESC command generated by the disturbance factor compensating unit. RPMs of motors of a flight vehicle having a plurality of propellers and rotors may be maintained to be the same.

Provided is a system for controlling an RPM of a propeller and a rotor of a flight vehicle having multiple power units including: a collective pitch angle command generating unit generating a collective pitch angle command upon receiving a thrust control command from a pilot or an automatic controller; a disturbance factor compensating unit for generating an RPM compensation electronic speed control (ESC) command for compensating for an RPM error, and an electronic speed adjustment command generating unit generating a final ESC command upon receiving a collective command input or derived in the process of generating the collective pitch angle command by the collective pitch angle command generating unit and the RPM compensation ESC command generated by the disturbance factor compensating unit. RPMs of motors of a flight vehicle having a plurality of propellers and rotors may be maintained to be the same.

A propulsion system for an aircraft comprises at least first and second propulsors, each propulsor being independently driven by a respective electric motor. The first and second propulsors each comprise respective rotors comprising a plurality of blades. The rotor of the first propulsor (30a) comprises a different number of blades to the rotor of the second propulsor, and the rotors of the first and second propulsors each have a blade pitch varying mechanism.

Methods and systems for validating a propeller control unit associated with a propeller having blades are provided. Actuation of a control valve of the propeller control unit is commanded to alter a pitch angle of the blades. One of an actual pitch angle of the blades and an actual rotational speed of the propeller is determined after a predetermined time delay has elapsed. The one of the actual pitch angle of the blades and the actual rotational speed of the propeller is compared to a corresponding one of a pitch angle threshold and a rotational speed threshold, the pitch angle threshold and the rotational speed threshold based on a commanded pitch angle. A warning signal is issued in response to determining one of the actual pitch angle failing to meet the pitch angle threshold and the actual rotational speed failing to meet the rotational speed threshold.

A blade-pitch change mechanism includes a motor comprising a rotating motor shaft and a housing, a solenoid coupled to a first end of the rotating motor shaft and to the housing, and a hub coupled with a second end of the rotating motor shaft. The hub includes a cylindrical puck having formed therein a gated castellated groove and connected to the second end of the rotating motor shaft and a cylindrical blade-pitch hub selectively couplable with the cylindrical puck via a plurality of drive pins and having formed therein a blade-pitch adjustment groove.