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.

Briefly, the disclosure relates to apparatuses and methods to form a gearbox enclosure comprising an external liner, an internal liner, and a variable porosity region disposed between the external liner and the internal liner. The variable porosity region may be configured to accommodate flow of the lubricant, thereby providing a capability to cool, for example, a lubricating fluid at an elevated temperature.

Briefly, the disclosure relates to apparatuses and methods to form a gearbox enclosure comprising an external liner, an internal liner, and a variable porosity region disposed between the external liner and the internal liner. The variable porosity region may be configured to accommodate flow of the lubricant, thereby providing a capability to cool, for example, a lubricating fluid at an elevated temperature.

A gearbox assembly comprising a plurality of component parts in torque transmission connection via gear, shaft and/or housing components; the assembly further comprising means for providing redundancy at selected locations where failure can lead to loss of torque transmission between component parts of the assembly.

A technique for generating electrical power from an engine in an aerial vehicle includes providing an alternator disk structure (ADS) between the engine and a propeller of the vehicle. The ADS is disposed concentrically with an engine drive shaft that drives the propeller and includes at least two concentric regions, a first region having a stator and a second region having a rotor. The first region is rotationally fixed relative to the engine, and the second region is coupled to a drive shaft of the engine. As the engine rotates the drive shaft, the rotor disposed in the second region spins concentrically relative to the stator disposed in the first region, thereby inducing electrical current in windings of the stator. The rotor and the stator thus work together to generate electrical power, which may be conveyed from the stator to electrical subsystems and controls of the vehicle.

A technique for generating electrical power from an engine in an aerial vehicle includes providing an alternator disk structure (ADS) between the engine and a propeller of the vehicle. The ADS is disposed concentrically with an engine drive shaft that drives the propeller and includes at least two concentric regions, a first region having a stator and a second region having a rotor. The first region is rotationally fixed relative to the engine, and the second region is coupled to a drive shaft of the engine. As the engine rotates the drive shaft, the rotor disposed in the second region spins concentrically relative to the stator disposed in the first region, thereby inducing electrical current in windings of the stator. The rotor and the stator thus work together to generate electrical power, which may be conveyed from the stator to electrical subsystems and controls of the vehicle.

A method for detecting wear before failure of a free-wheel, the free-wheel comprising a driving part integrated into an upstream mechanical power transmission system and a driven part integrated into a downstream mechanical power transmission system. The method comprises determining an oscillation measurement of a monitoring parameter within the upstream or downstream mechanical power transmission system, determining a value of at least one dynamic parameter characteristic of the oscillation measurement or of a transform of the oscillation measurement in a frequency reference frame, and generating an alarm when the value of the dynamic parameter reaches at least one wear threshold.

The disclosure describes a clutch assembly that includes a first clutch element coupled to an input shaft and including a first clutch element friction surface; a second clutch element coupled to an output shaft, and a brake clutch coupled to a stationary component. The second clutch element includes a first friction surface configured to engage the first clutch element friction surface and a second friction surface opposite the first friction surface. The second clutch element is configured to move relative to the first clutch element to engage and disengage the first friction surface and the first clutch element friction surface. The brake clutch includes a brake clutch friction surface configured to engage the second friction surface of the second clutch element when the first clutch element and the second clutch element are disengaged.

The disclosure describes a clutch assembly that includes a first clutch element coupled to an input shaft and including a first clutch element friction surface; a second clutch element coupled to an output shaft, and a brake clutch coupled to a stationary component. The second clutch element includes a first friction surface configured to engage the first clutch element friction surface and a second friction surface opposite the first friction surface. The second clutch element is configured to move relative to the first clutch element to engage and disengage the first friction surface and the first clutch element friction surface. The brake clutch includes a brake clutch friction surface configured to engage the second friction surface of the second clutch element when the first clutch element and the second clutch element are disengaged.

The present disclosure relates to a vertical takeoff and landing (VTOL) aircraft (100) and a propulsion system (600) thereof. The propulsion system (600) comprises a primary rotor (108) configured to couple to an airframe (102) and oriented to generate a vertical thrust relative to the airframe (102), a drivetrain (626) operably coupled to an engine (602) and configured to mechanically drive the primary rotor (108), and a plurality of tiltable secondary rotor assemblies (114) configured to be disposed about the primary rotor (108). The primary rotor (108) comprises a plurality of collective-only variable-pitch blades. Each of the plurality of tiltable secondary rotor assemblies (114) may have a secondary rotor (116) and an electric motor (608) to drive the secondary rotor (116). An electric generator (606) operably coupled to the engine (602) or to the drivetrain (626) may be configured generate electric power for each electric motor (608) of the plurality of tiltable secondary rotor assemblies (114). Each of the plurality of tiltable secondary rotor assemblies (114) is configured to tilt between a vertical configuration (200b) and a horizontal configuration (200a) as a function of a phase of flight of the VTOL aircraft (100).