A rotary blade includes a blade tip assembly with a first bus bar segment and a main blade assembly with second bus bar segment. The first bus bar segment is connected to the blade tip assembly and the second bus bar segment is connected to the main blade assembly. The blade tip assembly is connected to the main blade assembly such that the first and second bus bar segments are longitudinally offset from one another. A low-profile interconnect spans the first and second bus bar segments for resistively generating less heat than the bus bar segments for a predetermined current flow.

A rotor, in particular for aircraft and wind turbines, includes a rotatably mounted rotor head and a rotor blade protruding from the rotatably mounted rotor head, and has a profiled cross section. A device for mechanically breaking up pieces of ice accumulated on the rotor blade is mounted to or provided on the rotor blade.

An anti-phase rotor system for an aircraft may include at least one rotor with at least two rotor blades. The aerodynamic profile of these two blades may be selected to create counteracting blade vortices to break up harmonic reinforcement due to the rotor blade passage. The aerodynamic profile may create a non-planar motion of one or more rotor blade passages, whereby the individual rotor blades are not co-planar during the rotation of said rotor. The rotor system may include a duct, which may include stationary vanes or struts configured in a manner so as to break up harmonic excitation to the rotor. The interior area of the duct at the area of the blade rotation may be designed in a manner so as to create a destructive rotor blade tip vortex interference.

A rotor blade configured to be installed on a rotary-wing aircraft includes a main blade body including an inboard end configured to be coupled to a rotor blade hub and an outboard end. The rotor blade includes a blade tip removably coupled to the outboard end of the main blade body, the blade tip including an inner cavity. The rotor blade further includes a tip block including an inboard portion coupled to the outboard end of the main blade body and a cantilevered portion extending beyond the outboard end of the rotor blade and into the inner cavity of the blade tip.

A nozzle for use with a rotor blade for a reaction drive type helicopter includes a first wall, a second wall opposing the first wall, and sidewalls extending between the first wall and the second wall enclosing a cavity having an upstream end and a downstream end. The nozzle includes an inlet section for receiving a gasflow at the upstream end. The distance between the first wall and the second wall reduces to a throat downstream of the inlet section. An expansion section extending from the throat, downstream thereof.

A blade of a rotor for a rotary wing aircraft. The blade presents a combination of relationships for variation in the sweep, the chord, and the twist of the airfoil profiles of the sections of the blade in order, firstly to improve the aerodynamic performance of the blade both in forward flight and in stationary flight, and secondly to reduce the noise given off during approach flight. The blade is double-tapered and presents three sweeps. The twist relationship is substantially constant over a first portion of the blade, and then decreases over the remainder of the blade in linear or in non-linear manner. Suitable variation in the gradient of the twist of the blade makes it possible to improve the aerodynamic performance of the blade in forward flight and in hovering flight.

A blade of a rotor for a rotary wing aircraft. The blade presents relationships for variation in the sweep and in the chord of the profiles of sections of the blade, in particular in order to improve the twisting stiffness and the bending stiffness of the blade. The blade is then double-tapered and it presents three sweeps, making it possible firstly to improve the aerodynamic performance of the blade in forward flight, and secondly to reduce the noise given off by the blade, in particular during an approach flight.

Multiple propeller blades may be joined by tip connectors to form a closed propeller apparatus. The tip connectors may create continuous structure between adjacent tips of a first propeller and a second propeller. Use of the tip connectors may reduce vortices created near the tips of the propeller blades, which cause drag and slow the rotation of the propeller blades. The tip connectors may also reduce noise caused by rotation of propeller blades. Further, the tip connectors reduce or eliminate deflection of the propeller blades by creating a support structure to counteract forces that would otherwise cause deflection of the propeller blades, thereby improving propeller blade loading. In some embodiments, the tip connectors may be formed of a malleable material and/or include one or more joints that enable at least one of the propellers to modify a pitch of blades of the propeller.

Sounds are generated by an aerial vehicle during operation. For example, the motors and propellers of an aerial vehicle generate sounds during operation. Disclosed are systems, methods, and apparatus for actively adjusting the position of one or more propeller blade treatments of a propeller blade of an aerial vehicle during operation of the aerial vehicle. For example, the propeller blade may have one or more propeller blade treatments that may be adjusted between two or more positions. Based on the position of the propeller blade treatments, the airflow over the propeller is altered, thereby altering the sound generated by the propeller when rotating. By altering the propeller blade treatments on multiple propeller blades of the aerial vehicle, the different sounds generated by the different propeller blades may effectively cancel, reduce, and/or otherwise alter the total sound generated by the aerial vehicle.

Ground effect acting on an aerial vehicle, such as an unmanned aerial vehicle, may be simulated by discharging a gas around propeller blades of the aerial vehicle while the propeller blades are rotating. For example, a gas, such as air, may be discharged at or near the tip of the propeller blades with enough velocity to disrupt the airflow around the blade tips, thereby altering the sound generated by rotation of the propeller blade.