A sensor simultaneously determines a maximum rub depth and running clearance of a plurality of blade tips in a jet engine. The sensor includes an inductive component (e.g. inductor) and a resistive component comprising resistor portions each indicative of a depth into a layer of abradable material near the blade tips. When the blade tips move in proximity to the inductor, eddy currents in the blades generates a magnetic field that interact with the magnetic field generated by the inductor, which appears as an AC component in the current. When the blade tips abrade the abradable material, the resistor portions are severed and the DC current changes due to a change in resistance at the resistive component. An amplitude of the AC component indicates a running clearance as the blades move in proximity to the inductor. The frequency of the AC component indicates the rotational speed of the blades.

Rotary-winged vehicle systems and devices are disclosed. In one aspect, one or more engine components are mounted within rotor blades of the rotary-winged system. In one embodiment, engines are mounted within the rotor blades, with exhaust ports positioned at the rotor blade tips. In another embodiment, the engine of a rotary-winged vehicle includes a centrifugal compressor co-axially mounted with a spindle of the rotor blades. In one aspect, the compressor of one or more engines is decoupled from the engine turbine and electrically driven. In one aspect, the rotary-winged vehicle may be operated autonomously.

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.

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.

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 rotor blade is provided. The rotor blade includes a blade portion, a tip cap formed to define a dimple, a fastener and a doubler. The fastener includes a flat-headed shaft and is disposable such that the flat-headed shaft extends through the blade portion and the tip cap at the dimple. The fastener is configured to urge the blade portion toward the tip cap. The doubler includes a dimpled portion disposable between the tip cap and a portion of the flat-headed shaft at the dimple and an exterior portion. The exterior portion is disposable flush with respective exterior surfaces of the blade portion and the flat-headed shaft.

A method for improving performance in an aircraft having a winglet coupled to a wing, the winglet having a leading edge and a trailing edge continuously transitioning from a leading edge and trailing edge of the wing. The method includes coupling a wing tip to the winglet. The wing tip may include a curved leading edge from the winglet leading edge to a leading end point, a curved trailing edge from a winglet trailing edge to a trailing end point, and an end segment connecting the leading end point and the trailing end point. The end segment may be swept back from the trailing end point to the leading end point at an end segment angle.

An arrangement of lifting surfaces including a primary lifting surface having a flexural axis extending in the spanwise direction of the lifting surface, a root, and a tip. A first tip device is attached to the tip and has a first lifting surface. A second tip device is attached to the tip and has a second lifting surface. A control system is coupled to the first and second tip devices for moving the first and second lifting surfaces relative to the tip or for actively controlling circulation of the first and second lifting surfaces. The control system is operable to change a value of torque effective at the primary lifting surface about the flexural axis.

A rotor for a hover-capable aircraft is described that comprises: a hub rotatable about a first axis and at least two blades hinged to the hub; each blade comprises a main portion hinged to the hub and a tip portion, which is arranged radially outermost with respect to first axis with respect to the corresponding main portion; the tip portion of each blade is movable with respect to the corresponding main portion of that blade; the tip portion of each blade is selectively movable with respect to the corresponding main portion of that blade between a first position, in which it defines a dihedral or anhedral angle with respect to the corresponding main portion; and a second position, in which it defines a positive or negative sweep angle with respect to the corresponding main portion.

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.