A vertical take-off and landing aircraft includes a ducted rotary wing. The ducted rotary wing includes a duct and a rotary wing. The duct runs through a body from an upper surface to a lower surface thereof. The rotary wing is provided inside the duct and includes a hub and a blade configured to rotate about the hub. The blade includes a tip inlet, a trailing-edge outlet, and a trailing-edge flow path. The tip inlet is provided on a tip surface of the blade. The trailing-edge outlet is provided at a trailing edge that is an edge on a rear side in a rotation direction of the blade. The trailing-edge flow path allows the tip inlet and the trailing-edge outlet to be in communication with each other.

A rotor blade spar for use in a rotor blade is provided comprising a housing defining an interior and having an open end. An end cap is affixed to and sealed on the open end to seal the interior from an exterior outside of the housing. The end cap includes a first port and a second port fluidly coupling the interior to the exterior. A port sealing system closes the first and second ports. The first port is connectable to an external device configured to generate a pressure differential between the interior and the exterior sufficient to create an airflow through the first and second ports which removes a liquid disposed in the housing through one of the first and second ports.

This invention is directed toward a propeller with one of more propeller blades. The propeller blades have some combination of a sharpened leading edge, one or more steps on the upper or lower surface of the propeller blade, and an S shape. The combination of these radical changes from traditional propeller design creates a quieter, more efficient propeller that has applications on any device that uses propellers: from quadcopters and airplanes to boats and fans. Propellers with one, two, three, four, five and more propeller blades are contemplated depending upon the substance the propeller is intended for use in.

The new wing or blade design for wingtip device, rotor, propeller, turbine, and compressor blades with energy regeneration can be used to generate lift, propel vehicles more efficiently, compress fluids more efficiently, harness energy more efficiently. This system can be used as a wing, as a wingtip device, as a propeller for aircraft or boats or any vehicle moving through a fluid, in a compressor, as a rotor for wind turbine or helicopter, in a gas turbine. The new wing or blade design for wingtip device, rotor, propeller, turbine, and compressor blades with energy regeneration is a series of low aspect ratio wings placed in parallel with gaps between them connected by smaller wings that are placed in the gaps to harness the energy and produce forces; the gaps are shaped to decelerate the fluid and/or accelerate the fluid by varying the cross-sectional area of the gaps. Even if the small aspect ratio makes those wings inefficient, the strength of the vortices is smaller in the gaps.

According to one embodiment, a noise reduction device includes speakers, microphones, and a processing circuit. The speakers are arranged around a rotor and emit control sound based on control signals. The microphones are arranged around the rotor and convert the control sound and noise emitted by the rotor into microphone signals. The processing circuit generates the control signals for reducing acoustic power in positions of the microphones, based on the microphone signals, rotation speed of the rotor, and a phase of noise that reaches the microphones from the rotor.

A wing tip designed for attachment to a winglet of an aircraft, the winglet coupled to a wing of the aircraft and having a leading edge and a trailing edge continuously transitioning from a leading edge and trailing edge of the wing. 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.

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.

A rotorcraft with a fuselage and a tail boom, comprising: a horizontal stabilizer mounted to the tail boom; rotor blades with rotor blade tips which form a virtual blade tip circle upon rotation around a rotor head; luminescent components provided on the rotor blade tips; and a blade tip illumination device comprising at least one light source integrated into the horizontal stabilizer and configured to emit a light beam toward the virtual blade tip circle for excitation of the luminescent components; wherein the luminescent components emit light in response to excitation via the emitted light beam, and wherein the emitted light forms during rotation of the rotor blade tips around the rotor head on the virtual blade tip circle a luminous ring.

A replacement tip section for a rotor blade, from which a legacy tip section was removed, includes a blade tip portion configured to be attached to an intermediate section of the rotor blade after removal of the legacy section. The intermediate section has a connection feature at an end of the intermediate section to which the blade tip portion is attachable. The replacement tip section includes a transition region configured to be attached to a forward end of the connection feature. The transition region is configured to form a leading edge of the rotor blade and extends from the blade tip portion to form an opening into which the intermediate section is attached. The transition region includes a first end having a first airfoil that conforms to the intermediate section airfoil at the connection feature, and a second end having a second airfoil that conforms to the blade tip portion.

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.