Apparatus for controlling multi-rotor vehicle vibrations and related methods are disclosed herein. An example apparatus includes a vibration level detector to determine a vibration level of a frame of a vehicle based on data received from a sensor of the vehicle, the vehicle including a rotor. The apparatus includes a rotor operation analyzer to determine an operational parameter of the rotor based on the vibration level. The apparatus includes a communicator to transmit an instruction including the operational parameter to a controller of the rotor.

A propeller control system for an aircraft propeller rotatable about a longitudinal axis and having an adjustable blade angle is provided. A blade angle feedback ring is coupled to the propeller to rotate with the propeller and to move along the longitudinal axis along with adjustment of the blade angle. The feedback ring includes position markers spaced around its circumference. A sensor is positioned adjacent the feedback ring for producing signals indicative of passage of the position markers. A controller is in communication with the sensor, and is configured for: measuring a distance between the position markers, wherein the distance is representative of a longitudinal position of the feedback ring; determining whether a value representative of the longitudinal position is within a first threshold range; and when the value is within the first threshold range, storing the value as a calibration value associated with the blade angle feedback ring.

An aerial vehicle that uses motor pulsed-induced cyclic control is provided. In example embodiments, the aerial vehicle comprises a fuselage incorporating a battery system and a payload bay for operatively receiving and holding a payload and at least one mono-blade rotor coupled to an electric motor and an electric motor control system. The electric motor control system controls the electric motor using pulse-induced cyclic control. The aerial vehicle further includes at least one wing, at least one cruise propeller, and an avionics system. The avionic system is configured to transition the aerial vehicle between a vertical take-off and landing mode in which the at least one mono-blade rotor is primarily engaged to propel the aerial vehicle vertically and a cruising mode in which the at least one cruise propeller is primarily engaged to propel the aerial vehicle horizontally.

A low-noise multi-propeller system includes at least two propellers, each propeller including at least two blades. The propellers rotate in a first direction and define an angular phase relative to one another. A drive system corotates the propellers at substantially equal rotational rates in the first direction. The propellers are substantially phase-locked at a predefined relative phase offset that reduces the overall sound power of the fundamental tone at a blade passage frequency.

An aircraft includes a first rotor assembly, a second rotor assembly, and a rotor phase angle control system. The system includes a phase adjustor operably associated with the first rotor assembly and the second rotor assembly. The method includes sensing vibrations exerted on the aircraft and offsetting a phase angle of the first rotor assembly and the second rotor assembly to minimize the vibrations.

An aircraft includes a first rotor assembly, a second rotor assembly, and a rotor phase angle control system. The system includes a phase adjustor operably associated with the first rotor assembly and the second rotor assembly. The method includes sensing vibrations exerted on the aircraft and offsetting a phase angle of the first rotor assembly and the second rotor assembly to minimize the vibrations.

An aircraft includes a first rotor assembly, a second rotor assembly, and a rotor phase angle control system. The system includes a phase adjustor operably associated with the first rotor assembly and the second rotor assembly. The method includes sensing vibrations exerted on the aircraft and offsetting a phase angle of the first rotor assembly and the second rotor assembly to minimize the vibrations.

An aircraft includes a first rotor assembly, a second rotor assembly, and a rotor phase angle control system. The system includes a phase adjustor operably associated with the first rotor assembly and the second rotor assembly. The method includes sensing vibrations exerted on the aircraft and offsetting a phase angle of the first rotor assembly and the second rotor assembly to minimize the vibrations.

Herein provided are systems and methods for synchrophasing multi-engine aircraft. A phonic wheel is coupled to a first propeller of a first engine of the aircraft. A sensor is disposed and configured for producing a signal in response to passage of first and second position markers on the phonic wheel. A control system is communicatively coupled to the sensor for obtaining the signal, and configured for: determining an expected delay between two subsequent signal pulses of the signal; identifying from within the plurality of signal pulses a particular pulse associated with the second position marker; determining, based on a particular time at which the particular pulse associated with the second position marker was produced, that a rotational position of the first propeller corresponds to a reference position at the particular time; and performing at least one synchrophasing operation for the aircraft based on the rotational position of the first propeller.

Herein provided is a phonic wheel for use in a gas turbine engine and associated systems and methods. The phonic wheel comprises a circular disk having first and second opposing faces. The circular disk defines a root surface that extends between and circumscribes the first and second faces. A first plurality of projections extend from the root surface and are oriented substantially parallel to an axis of rotation of the disk. The first plurality of projections are circumferentially spaced substantially equally from one another and each have a first physical configuration. At least one second projection extends from the root surface and is positioned between two adjacent first projections, the at least one second projection having a second physical configuration different from the first physical configuration.