A sleeve connecting a blade to the hub of a rotor of a rotary wing aircraft. The sleeve has a leading edge and a trailing edge, together with a protuberance arranged on the trailing edge. The dimensions of the protuberance are linked to the dimensions of the sleeve. The presence of the protuberance serves to improve the aerodynamic behavior of the sleeve and of the rotor during rotation of the rotor while the aircraft is moving forwards, both when the sleeve is advancing and when it is retreating. The presence of the protuberance also serves to reduce the vibration generated by a wake of the rotor on a tail boom or on a horizontal and/or vertical stabilizer of the aircraft.

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.

A method for the control of a vertical take-off and landing (VTOL) aircraft which reduces the acoustic profile of the rotary airfoil in hover for VTOL applications. The rotary airfoil incurs an efficiency penalty in order to improve the acoustic performance during hover. The aircraft operates the rotary airfoils of the propeller during hover in the hover angle of attack range, and the aircraft operates the rotary airfoils during forward flight in the forward angle of attack range.

A flow body for an aircraft includes a skin having a first flow surface, having a flow influencing section with at least one first layer, at least one separator layer, at least one third layer, and at least one base layer. The first layer includes lithiated carbon fibers embedded into a matrix to form a negative electrode. The third layer includes carbon fibers with an electrode active material coating to form a positive electrode. The separator layer includes a non-conductive material for electrically isolating the first layer and the third layer from each other. The flow influencing section is configured for selectively raising a region of the arrangement of first layer, separator layer and third layer from the base layer upon application of a voltage between the first and third layers to form a bump on the flow body.

A method for the control of a vertical take-off and landing (VTOL) aircraft which reduces the acoustic profile of the rotary airfoil in hover for VTOL applications. The rotary airfoil incurs an efficiency penalty in order to improve the acoustic performance during hover. The aircraft operates the rotary airfoils of the propeller during hover in the hover angle of attack range, and the aircraft operates the rotary airfoils during forward flight in the forward angle of attack range.

The ridge structure has ridge elements provided on a top face of a leading edge region directly downstream of a leading edge, which is a laminar flow region of a wing having a swept-back angle relative to a mainstream and provided with a leading edge, and extending in parallel toward downstream of the mainstream. When an angle of a ridgeline connecting vertexes of the ridge elements in an extending direction of the ridge elements relative to x direction is OR, an angle of a flow line of a boundary layer external edge of the mainstream relative to the x direction is θe, and an angle of a wavefront of stationary cross-flow instability, which is a mode in which a stationary disturbance amplifies inside a boundary layer of the surface and appears as a stationary vortex row, relative to the x direction is θcf, θR is between θe and θcf.

The invention discloses an aircraft generating a larger thrust and lift by fluid continuity. First open channels used to extend fluid paths are formed in front parts and/or middle parts of windward sides of wings of the aircraft and extend from sides, close to the fuselage, of the wings to sides, away from the fuselage, of the wings, and the first open channels are concave channels or convex channels, so that a pressure difference in a direction identical with a moving direction is generated from back to front due to different flow speeds of fluid flowing over the windward sides of the wings in a lengthwise direction and a widthwise direction to reduce fluid resistance, and a larger pressure difference and lift are generated due to different flow speeds on the windward sides and leeward sides of the wings.

The rotary airfoil 100 defines a cross section and a span, wherein the cross section is a function of the point along the span (e.g., spanwise point) and defines an upper surface and a lower surface at each spanwise point. The rotary airfoil 100 also defines, at a cross section, a lift coefficient (C.sub.L) that is a function of the angle of attack at which the airfoil is rotated through the air. The system can optionally include: a rotor hub to mount the rotary airfoil, a tilt mechanism to pivot the rotary airfoil between a forward configuration and a hover configuration, and a pitching mechanism to change the angle of attack of the rotary airfoil 100.

A flow body for an aircraft includes a skin having a first flow surface, having a flow influencing section with at least one first layer, at least one separator layer, at least one third layer, and at least one base layer. The first layer includes lithiated carbon fibers embedded into a matrix to form a negative electrode. The third layer includes carbon fibers with an electrode active material coating to form a positive electrode. The separator layer includes a non-conductive material for electrically isolating the first layer and the third layer from each other. The flow influencing section is configured for selectively raising a region of the arrangement of first layer, separator layer and third layer from the base layer upon application of a voltage between the first and third layers to form a bump on the flow body.

A system for suction of the boundary layer of a wing and protection against icing of this wing includes a wall including micro-perforations and delimiting a leading edge extended by a pressure-side wall and by a suction-side wall. The system also includes a perforated tube running along the leading edge, an exhaust duction for sucking air from this tube in order to suck the boundary layer successively via the micro-perforations of the wall and via the perforations of the tube, and a supply duct for blowing hot air into this perforated tube during a phase of protection against icing, this hot air being discharged successively via the perforations of the tube and via the micro-perforations of the wall.