The invention discloses a propeller-driven helicopter or airplane which comprises a fuselage and a propeller comprising a plurality of blades, wherein a plurality of pressure pipes are uniformly distributed between windward sides and leeward sides of the blades; a plurality of first inlets are formed in the windward sides and are communicated with outside via first channels in the blades and second outlets at tails of the blades; a high-pressure fluid of a low-speed fluid layer formed when a fluid flows through the leeward sides in a widthwise direction flows towards a low-pressure fluid of a high-speed fluid layer formed when the fluid flows through the first inlets, the first channels and the second outlets; and an upward pressure generated by the high-pressure fluid is opposite to a downward pressure generated by an external fluid above the windward sides, so that a fluid pressure above the propeller is decreased.

In an aspect, a system comprising a computing device. The computing device is configured to determine a drag minimization axis of a rotor connected to an aircraft. The rotor includes a first end and a second end. The rotor is configured to rotate about an axis. The computing device is further configured to determine a halting point of the rotor, wherein the halting point includes a drag minimization axis of the rotor. The computing device is configured to send a halting command to at least a magnetic element to halt the rotor, wherein the halting process is configured to stop a movement of the rotor and position the rotor in the halting point. The position of the rotor in the halting point includes the first end pointing in one direction of the drag minimization axis and the second end pointing in an opposite direction of the first end.

The invention relates to a nubomachine with a longitudinal axis, comprising two, respectively upstream (122) and downstream, coaxial outer propellers (122), characterised in that at least some of the blades (148) of the upstream propeller (122) comprise at least one internal air circulation chimney (150) that communicates with air-bleeding openings (152) in tire boundary layers of the blades (148), and communicates with air outflow openings (158) on the radially outer end thereof, the air-bleeding openings (152) leading to opening inlets (152a) on tire passive surfaces (156) of the blades (148), the inlets (152a) of the air-bleeding openings being radially arranged in an area (H1) contained between 10% and 45% of the radial dimension (H2) of the blades (148), measured above turd from the radial height of the blades for which the tangent of the leading edge (138) of the blades is orthogonal to the longitudinal axis, and the inlets (152a) of the air bleeding openings being arranged in an area contained between 0% and 30% of the local chord of the blades (148), measured at the level of said inlets (152a) and from the leading edges (138) of tire blades (148).

A ducted fan includes a fan and a cowl having a cylindrical shape and including an introduction port configured to introduce air from a first end portion side. The fan includes a compressor blade provided on an outer circumferential side and a thrust blade provided on an inner circumferential side of the compressor blade. The cowl includes a housing portion configured to accommodate the compressor blade in an interior thereof, an outlet configured to allow air flowing through the housing portion to be blown therethrough by the compressor blade, and an inlet configured to suck air blown out. The outlet is provided inwards in a radial direction of the cowl and near the introduction port of the cowl, and the inlet is provided inwards in the radial direction of the cowl and between the outlet and the compressor blade in an axial line direction.

Systems, methods, lift fans, and aircraft involving active flow control of a ducted fan or fan-in-wing configuration are described.

A ducted fan assembly includes a duct having an inlet, an inner surface, an expanding diffuser and an outlet. A fan disposed within the duct between the inlet and the expanding diffuser is configured to rotate about a fan axis to generate airflow. An active flow control system includes a plurality of injection zones circumferentially distributed about the inner surface. The expanding diffuser has a diffuser angle configured to create flow separation when the airflow is uninfluenced by the active flow control system such that the airflow has a thrust vector with a first direction that is substantially parallel to the fan axis. Injection of pressurized air from one of the injection zones asymmetrically reduces the flow separation between the airflow and the expanding diffuser downstream of that injection zone such that the thrust vector of the airflow has a second direction that is not parallel to the first direction.

A lift control device actively controls the lift force on a lifting surface. The device has a protuberance near a trailing edge of its lifting surface, which causes flow to separate from the lifting surface, generating regions of low pressure and high pressure which combine to increase the lift force on the lifting surface. The device further includes a means to keep the flow attached around the protuberance or to modify the position of the protuberance in response to a command from a central controller, so as to provide an active control of the lift between a maximum value and a minimum value.

In an aspect, a system comprising a computing device. The computing device is configured to determine a drag minimization axis of a rotor connected to an aircraft. The rotor includes a first end and a second end. The rotor is configured to rotate about an axis. The computing device is further configured to determine a halting point of the rotor, wherein the halting point includes a drag minimization axis of the rotor. The computing device is configured to send a halting command to at least a magnetic element to halt the rotor, wherein the halting process is configured to stop a movement of the rotor and position the rotor in the halting point. The position of the rotor in the halting point includes the first end pointing in one direction of the drag minimization axis and the second end pointing in an opposite direction of the first end.

A tracking wedge, a rotor and a method for modifying a movement of air over a tracking wedge. According to aspects of the disclosure, a tracking wedge used to correct the tracking of a helicopter rotor blade may include one or more acoustic management mechanisms. The acoustic management mechanisms may change the manner in which air moves over the surface of the tracking wedge. In some examples, changing the manner in which air moves over the surface of the tracking wedge may reduce noise generated by the use of the tracking wedge.

A rotorcraft is provided and includes a fuselage. The fuselage includes drag generating portions, a main rotor assembly and an auxiliary propulsor having an expected propulsion efficiency. The auxiliary propulsor is disposed to ingest boundary layer flows and in wake regions associated with the drag generating portions and is provided with a corresponding increase in the expected propulsion efficiency thereof.