The invention relates to a profiled structure, elongated in a direction in which the structure has a length exposed to an airflow, and transversely to which the structure has a leading edge (164) and/or a trailing edge, at least one of which is profiled and has, in said direction of elongation, serrations (28a) defined by successive teeth (30) and depressions (32).

Along the profiled leading edge and/or profiled trailing edge, the successive teeth (30) and depressions (32) extend only over a part of said length exposed to the flow over which the amplitude and/or spacing of the teeth varies monotonically except for the few teeth nearest each end of said part, a remaining part (280) of said length being smooth.

An aircraft is disclosed having a structure at least part of which is capable of generating aerodynamic lift. A body having a mass is movably mounted to a portion of the structure by an active support. The active support includes an actuator to move the body relative to the portion of the structure, and a controller for controlling movement of the actuator in response to a dynamic input. The active support provides a range of movement for the body in at least one degree of freedom. The actuator moves the body across the entire range of movement in that one degree of freedom in a time period of less than 3 seconds. The actuator moves the body sufficiently rapidly to generate an inertial force that is equal to or greater than any aerodynamic force generated by the body during that movement of the body. The active support may be used to reduce loads on the aircraft structure.

An aircraft is disclosed having a structure at least part of which is capable of generating aerodynamic lift. A body having a mass is movably mounted to a portion of the structure by an active support. The active support includes an actuator to move the body relative to the portion of the structure, and a controller for controlling movement of the actuator in response to a dynamic input. The active support provides a range of movement for the body in at least one degree of freedom. The actuator moves the body across the entire range of movement in that one degree of freedom in a time period of less than 3 seconds. The actuator moves the body sufficiently rapidly to generate an inertial force that is equal to or greater than any aerodynamic force generated by the body during that movement of the body. The active support may be used to reduce loads on the aircraft structure.

A boundary layer control (BLC) system for embedment in a flight surface having a top surface, a bottom surface, a leading edge, and a trailing edge. The BLC system may comprises an actuator having a crossflow fan and an electric motor to drive the crossflow fan about an axis of rotation. The actuator may be embedded within the flight surface and adjacent the leading edge. In operation, the actuator is configured to output local airflow via an outlet channel through an outlet aperture adjacent the top surface to energize a boundary layer of air adjacent the top surface of the flight surface.

The invention relates to an air system for an aircraft, that includes air consumers; air sources and a network of ducts and associated control valves controlled by a control unit. The air system is characterized in that: the network of ducts and associated valves includes at least one isolation valve, arranged between an air bleed device and an air duct connecting an air conditioning pack and an auxiliary power unit; the control unit is configured to be able to determine an ideal configuration of the control valves according to the identified requirements of each consumer and a degraded configuration that makes it possible to supply air to predetermined air consumers from the available air sources when the ideal configuration is not attainable.

The invention relates to an air system for an aircraft, that includes air consumers; air sources and a network of ducts and associated control valves controlled by a control unit. The air system is characterized in that: the network of ducts and associated valves includes at least one isolation valve, arranged between an air bleed device and an air duct connecting an air conditioning pack and an auxiliary power unit; the control unit is configured to be able to determine an ideal configuration of the control valves according to the identified requirements of each consumer and a degraded configuration that makes it possible to supply air to predetermined air consumers from the available air sources when the ideal configuration is not attainable.

A boundary layer ingestion fan system for location aft of the fuselage of an aircraft is shown. It comprises a nacelle (501) defining a duct, and a fan located therewithin. The fan comprises a hub arranged to rotate around a rotational axis (A-A) and a plurality of blades attached thereto. Each blade has a span (r) from a root at the hub defining a 0 percent span position (r=0) to a tip defining a 100 percent span position (r=1) and a plurality of span positions therebetween (r ∈ [0, 1]), and leading and trailing edges defining, for each span position, a chord therebetween to having a chord length (c). For each of said plurality of blades, the ratio of chord length at the 0 percent span position (c.sub.hub) to chord length at the 100 percent span position (c.sub.tip) is 1 or greater.

A boundary layer ingestion fan system for location aft of the fuselage of an aircraft includes a nacelle (501) defining a duct (502), and a fan (503) located therewithin. The fan comprises a hub which rotates around a rotational axis (A-A) and a plurality of blades attached thereto. Each blade has a span (r) from a root at the hub defining a 0 percent span position (r=0) to a tip defining a 100 percent span position (r=1) and a plurality of span positions therebetween (r∈[0, 1]), a leading edge and a trailing edge defining, for each span position, a chord therebetween having a chord length (c), and a blade thickness (t) defined for each span position thereof. For each blade, a ratio of thickness at the 0 percent span position (t.sub.hub) to chord length is 0.1 or greater.

A boundary layer ingestion fan system for location aft of the fuselage of an aircraft is shown. It comprises a nacelle defining a duct, and a fan located within the duct. The fan comprises a hub arranged to rotate around a rotational axis (A-A) and a plurality of blades attached to the hub, each of which has a span from a root at the hub defining a 0 percent span position (r.sub.hub) to a tip defining a 100 percent span position (r.sub.tip) and a plurality of span positions therebetween (r∈[r.sub.hub, r.sub.tip]). A hub-tip ratio of the fan, defined as the ratio of the diameter of the hub to the diameter of the fan measured at the leading edge of the blades, is from 0.45 to 0.55.

A raised structure for reducing frictional drag due to viscosity of a flow toward an object in a direction forming an acute angle with an end portion of the object. The raised structure includes a plurality of raised bodies provided on a surface of the leading edge of the object at a downstream side of a stagnation point of the main flow, wherein a height of each raised body changes along a smooth convex curve, and the raised bodies are arranged in an array to form a first uneven shape changing periodically in a first cross section having a constant distance from the stagnation point and orthogonal to the surface, and a second uneven shape changing in a second cross section that is orthogonal to a line composed of the stagnation point and the first cross section, the second uneven shape having concave portions and convex portions that change periodically.