An aircraft propulsion unit includes a drive unit with a static part and a rotary part which rotates a fan situated downstream from the drive unit, an assembly of fixed blades situated downstream from the fan, and a nacelle in which the fan and the assembly of fixed blades are accommodated. The propulsion unit also includes an assembly of at least two coaxial shafts, wherein a fan shaft connects the fan to the rotary part, and a stator blading shaft connecting the assembly of fixed blades to the static part extends concentrically, and for at least part of its length in the interior of the fan shaft. This rigid and compact configuration limits the variations of distance between the end of the fan blades and a fan housing situated in the inner duct of the nacelle.

Methods for optimizing Boundary Layer Control (BLC) systems and related systems (e.g. a Laminar Flow Control (LFC) system or systems, a Static Pressure Thrust (SPT) system or systems, a Boundary Layer Ingestion (BLI)/Wake Immersed Propulsion (WIP) system or systems, and/or low-dissipation BLC fluid-movement system or systems) to operate in concert with each other and a bellows air-moving system are disclosed.

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.

A boundary layer suction design uses a wingtip vortex core for a lift-generating body with optimized aerodynamic performances. Holes or slots (6), connected to a core or center of a wingtip vortex of the lift generating body via a plenum (9) and pipe (7) with its outlet (8) sticking out from a surface (1) experiencing low pressure, sucked a part of the boundary layer to delay flow transition or separation. Thus, with a more stable boundary layer, the lift is increased while the drag is reduced.

A boundary layer suction design uses a wingtip vortex core for a lift-generating body with optimized aerodynamic performances. Holes or slots (6), connected to a core or center of a wingtip vortex of the lift generating body via a plenum (9) and pipe (7) with its outlet (8) sticking out from a surface (1) experiencing low pressure, sucked a part of the boundary layer to delay flow transition or separation. Thus, with a more stable boundary layer, the lift is increased while the drag is reduced.

An aircraft structure (11) for flow control including a perforated panel (13) having an inner surface (15) directed to a structure interior (17), an outer surface (19) in contact with an ambient flow (21), and a plurality of micro pores (23) connecting the inner and outer surfaces (15, 19). Elongate crack stopper elements (25) are attached to the inner surface (15) of the perforated panel (13). The crack stopper elements (25) are configured to inhibit crack propagation within the perforated panel (13).

An aircraft structure (11) for flow control including a perforated panel (13) having an inner surface (15) directed to a structure interior (17), an outer surface (19) in contact with an ambient flow (21), and a plurality of micro pores (23) connecting the inner and outer surfaces (15, 19). Elongate crack stopper elements (25) are attached to the inner surface (15) of the perforated panel (13). The crack stopper elements (25) are configured to inhibit crack propagation within the perforated panel (13).

Apparatuses and methods for controlling fluid flow over surfaces, e.g. wings, are disclosed. A system can include a surface influenced by a fluid flow moving across the surface, a vortex generator disposed proximate to the surface, the vortex generator for altering a vortex pattern within the fluid flow moving across the surface, and a controller for activating the vortex generator to alter the vortex pattern within the fluid flow moving across the surface. The vortex generator can comprise one or more fluid injectors each for injecting a fluid jet into the fluid flow driven by air pressure. The fluid injectors can be disposed along a leading edge of a strake where the strake is disposed on an engine nacelle and the surface comprises an aircraft wing surface. Activation can occur under open or closed loop control with sensors.

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.

A method of providing active flow control for an aircraft includes cooling a liquid coolant in a heat exchanger by circulating a cooling airflow through the heat exchanger, and providing fluid communication between the cooling airflow and a boundary layer flow of at least one flight control surface of the aircraft. The cooling airflow affects the boundary layer flow of the flight control surface(s) to provide active flow control. A method of cooling an engine core of an engine assembly includes circulating a cooling fluid through the engine core, and cooling the cooling fluid with a cooling airflow used to provide active flow control to a flight control surface of the aircraft. An active flow control system for an aircraft is also discussed.