There is provided a vehicle (18) comprising a propulsion unit (34) configured to move the vehicle (18) and to change a characteristic of the environment of the vehicle (18). The vehicle (18) further comprises a proximity sensor (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31) configured to detect the characteristic of the environment of the vehicle. The characteristic of the environment is changed by operation of the propulsion unit (34). The vehicle (18) further comprises obstacle detection circuitry (32) configured to determine a presence of an obstacle in the vicinity of the vehicle based on a comparison between the detected characteristic of the environment and a reference value.

A flap of an aircraft includes a flap body that is provided deployably with respect to a main wing, an inclined portion that protrudes from an upper surface of a tip part on at least an outboard side in a span direction of the flap body and is inclined with respect to an aircraft axis direction, and a protruding portion that smoothly protrudes from a lower surface of the tip part on at least the outboard side. A rear end of the inclined portion is located closer to a side end edge of the tip part in the span direction of the flap body than a virtual line that passes through a front end of the inclined portion and is parallel to the aircraft axis direction.

Systems and methods according to one or more embodiments are provided for reducing noise levels in a passenger cabin of an aircraft. In one example, an aircraft includes a wing coupled to a fuselage. The wing is configured to heat air to provide a first stream of air from a central portion of a wing segment of the wing extending between the fuselage and a first engine of an aircraft. The first stream of air is at a higher temperature than an adjacent stream of air from the wing.

A device for an aircraft powerplant de-icing system making it possible to reduce or eliminate a tonal noise generated by a flow of air along a surface having an orifice opening into a cavity extending on the side opposite this surface, the orifice having a downstream edge relative to the direction of flow of the air, includes a deflector positioned next to the downstream edge, extending towards the inside of the cavity, and oriented perpendicularly to the direction of flow of the air to divert towards the outside of the orifice vortices formed in the shear layer due to the flow of the air along the surface over each orifice. The deflector at the downstream edge of each exhaust orifice of the de-icing system makes it possible to redirect the vortices outside the cavity while preventing them from being greatly deformed when they pass over the downstream edge.

An aerial vehicle is provided including rotor units connected to the aerial vehicle, and a control system configured to operate at least one of the rotor units. The rotor unit includes rotor blades, wherein each rotor blade includes a surface area, and wherein an asymmetric parameter is defined, at least in part, by the relationship between the surface areas of the rotor blades. The value of the asymmetric parameter is selected such that the operation of the rotor unit: (i) moves the rotor blades such that each rotor blade produces a respective vortex and (ii) the respective vortices cause the rotor unit to produce a sound output having an energy distribution defined, at least in part, by a set of frequencies, wherein the set of frequencies includes a fundamental frequency, one or more harmonic frequencies, and one or more non-harmonic frequencies having a respective strength greater than a threshold strength.

Sounds are generated by an aerial vehicle during operation. For example, the motors and propellers of an aerial vehicle generate sounds during operation. Systems, methods, and apparatus may actively adjust the position and/or configuration of one or more propeller blades of a propulsion mechanism to generate different sounds and/or lifting forces from the propulsion mechanism.

An end rib assembly for a high-lift device of an aircraft to reduce the noise caused by the transition between the wing and a high-lift device as well as the noise caused by the lateral side edge of the end rib assembly. An end rib assembly includes a noise-reducing portion configured to reduce noise caused by an airflow around the end rib assembly, and a guiding portion configured for guiding the end rib assembly along a pre-determined path when the high-lift device is moved between a retracted position and an extended position, wherein the guiding portion is formed such that an airflow impinging on the guiding portion is partly guided towards the noise-reducing portion.

A cavity system, comprising: a cavity (2) comprising a cavity opening; and an acoustically reflective structure (18, 20) located at least partially within the cavity (2), the acoustically reflective structure (18, 20) comprising one or more acoustically reflective surfaces (24, 26, 30, 32), each acoustically reflective surface (24, 26, 30, 32) being oblique to a plane of the cavity opening (27). The one or more acoustically reflective surfaces (24, 26, 30, 32) may be arranged to reflect incident acoustic waves out of the cavity opening while avoiding reflection into a region (48) at or proximate to a leading edge (14) of the cavity (2).

An actuator assembly is capable of manipulating a fluid flowing around a flow body, the fluid being received or able to be received in a volume of at least one cavity arranged in the flow body, and the fluid passing through at least one opening in the at least one cavity during manipulation of the fluid. In this process, the volume of the at least one cavity can be changed by moving a wall portion delimiting or defining the cavity. The actuator assembly has a drive unit with at least one actuator, which executes a periodic movement over time when actuated, causing a translational movement of the wall portion delimiting or defining the cavity and the wall portion being shaped in terms the topology thereof in such a way that it is adapted to the shape of the at least one cavity with the at least one opening thereof.

An airfoil is provided having reduced noise generation for use with an aircraft. The airfoil includes a body and a cover. The body has a leading edge spaced from a trailing edge and a side surface disposed between the leading edge and the trailing edge. The body defines an inlet proximate the leading edge and configured to receive air. The side surface defines an outlet in fluid communication with the inlet. The outlet is configured to exhaust air away from the side surface. The cover overlies the inlet and is movable between a first and a second cover position. The cover is configured to prevent movement of air through the inlet when the cover is in the first cover position and configured to permit movement of air through the inlet when the cover is in the second cover position.