An electric propulsion system for an aircraft includes a nacelle and an electric machine. The electric machine includes a stator positioned in the nacelle, and a rotor and fan assembly positioned in a primary flow path through the nacelle. The rotor and fan assembly includes a cylindrical fan shroud, a plurality of rotor magnets positioned on an outer surface of the fan shroud, and a fan hub mounted on a central support shaft via one or more bearings. A plurality of fan blades extend between an inner surface of the fan shroud and an outer surface of the fan hub. The rotor magnets may be loaded in compression in a radial direction when the rotor and fan assembly is at rest. The fan blades may be pre-stressed in a radial direction when the rotor and fan assembly is at rest.

A thrust producing unit for producing thrust in a predetermined direction, comprising at least two rotor assemblies and a shrouding that accommodates at most one of the at least two rotor assemblies, wherein the shrouding defines a cylindrical air duct that is axially delimited by an air inlet region and an air outlet region, and wherein the air inlet region exhibits in circumferential direction of the cylindrical air duct an undulated geometry.

The invention relates to a thermoplastic molded part able to constitute a duct of an aerial vehicle or space vehicle, to a method of manufacturing same, and to this duct which comprises said part. For example, provided is a part according to the invention, which has an external surface (2) with symmetry of revolution at least in part, is such that the external surface comprises a multitude of integrally molded depressions (6) which are connected to one another in pairs by crests (7), and that: each of the depressions has a largest transverse dimension D between the adjacently paired crests of between 3 mm and 10 mm, measured in a direction d perpendicular to the crests delimiting each depression, and each of the crests has an apex of transverse width L measured in said direction d, where L<D.

An auxetic bi-stable structure that comprises an auxetic curved shell movable between a first and a second stable position, and a rigid element. At least part of the surface of the auxetic curved shell is joined to the rigid element such that the curved shell is movable with respect to the rigid element between the first and second stable positions.

One embodiment is a passive particle separation system including a plenum; an inlet for feeding outside air into the plenum, wherein the outside air has particles entrained therewith; a housing for enclosing the plenum; and a standpipe installed on the housing. The outside air enters the plenum via the inlet and plenum, housing, and standpipe interact to impact the outside air entering the plenum to cause the particles to be released from the outside air.

A rotorcraft having an aerodynamic device arranged below a rotor, which rotor participates at least in providing lift for the rotorcraft in the air, the rotor being mounted to rotate about a first axis of rotation, the aerodynamic device having a fairing provided with at least one air inlet for enabling a stream of cool air to flow from a region that is situated outside the rotorcraft to another region that is situated inside the rotorcraft; at least at a mouth of the at least one air inlet in the fairing, the aerodynamic device has at least one moving flap that is mounted to move in rotation, the at least one moving flap having at least one degree of freedom of movement in rotation about a second axis of rotation relative to the fairing, and the at least one moving flap orienting itself automatically and passively.

An apparatus for an inertial separation of air in an electric aircraft, wherein the apparatus includes an intake duct configured to intake an airflow, an inertial air separator configured to separate the airflow into a clean airflow and a dirty airflow, a propulsor configured to intake the clean airflow, wherein the propulsor includes a stator and a rotor, and a heat exchanger configured to intake the dirty airflow.

An apparatus for an inertial separation of air in an electric aircraft, wherein the apparatus includes an intake duct configured to intake an airflow, an inertial air separator configured to separate the airflow into a clean airflow and a dirty airflow, a propulsor configured to intake the clean airflow, wherein the propulsor includes a stator and a rotor, and a heat exchanger configured to intake the dirty airflow.

One embodiment is a passive particle separation system including a plenum; an inlet for feeding outside air into the plenum, wherein the outside air has particles entrained therewith; a housing for enclosing the plenum; and a standpipe installed on the housing. The outside air enters the plenum via the inlet and plenum, housing, and standpipe interact to impact the outside air entering the plenum to cause the particles to be released from the outside air.

Inter alia, an apparatus including a ramp, the ramp configured to enable variation of a cross section of a ram air passage of the apparatus. The ramp includes a first rigid member, a second rigid member and a flexible member coupled to the first rigid member and the second rigid member. The ramp is movably mounted at two ends. Moreover, a method of varying the cross section of the ram air passage of such an apparatus by moving the ramp of the apparatus is disclosed. Further, an arrangement including such an apparatus and a ram air channel communicating with the ram air passage is disclosed.