Flow control systems having movable slotted plates are disclosed. A disclosed example apparatus includes a flow control plate to be placed proximate an opening of an aerodynamic body. The opening has a first slot and the flow control plate has a second slot angled relative to the opening. The apparatus also includes an actuator to move the flow control plate relative to the opening in a linear oscillatory motion to vary a flow of fluid exiting the opening over the aerodynamic body. The flow of fluid is to flow from the second slot to the first slot.

Methods and apparatus for accelerating an aircraft fuselage boundary layer via a fan powered by an APU of the aircraft are disclosed. An example aircraft includes a fuselage, an APU, and a fan. The fuselage includes an outer skin. The APU is located within the fuselage. The fan includes a plurality of fan blades arranged circumferentially about the APU and projecting radially outward from the outer skin. The fan further includes a fan drive operatively coupled to the APU. The fan drive is configured to rotate the fan blades in response to a supply of electrical energy provided to the fan drive from the APU. The rotation of the fan blades accelerates a fuselage boundary layer traveling rearward along the outer skin from a first velocity to a second velocity greater than the first velocity.

An aircraft operable to transition between thrust-borne lift in a VTOL orientation and wing-borne lift in a forward flight orientation. The aircraft has a blended wing body and includes first and second engines, a binary lift fan system, first and second forced air bypass systems and first and second exhaust systems. The engines have turboshaft and turbofan modes. The lift fan system includes ducted fans in a tandem longitudinal orientation. In the VTOL orientation of the aircraft, the engines are in the turboshaft mode coupled to the lift fan system such that the engines provide rotational energy to the ducted fans generating the thrust-borne lift. In the forward flight orientation of the aircraft, the engines are in the turbofan mode coupled to the forced air bypass systems such that the bypass air combines with the engine exhaust in the exhaust systems to provide forward thrust generating the wing-borne lift.

Methods and apparatus for accelerating an aircraft fuselage boundary layer via a fan powered by an APU of the aircraft are disclosed. An example aircraft includes a fuselage, an APU, and a fan. The fuselage includes an outer skin. The APU is located within the fuselage. The fan includes a plurality of fan blades arranged circumferentially about the APU and projecting radially outward from the outer skin. The fan further includes a fan drive operatively coupled to the APU. The fan drive is configured to rotate the fan blades in response to a supply of electrical energy provided to the fan drive from the APU. The rotation of the fan blades accelerates a fuselage boundary layer traveling rearward along the outer skin from a first velocity to a second velocity greater than the first velocity.

Variable-porosity panel systems and associated methods. A variable-porosity panel system includes a panel assembly with an exterior layer defining a plurality of exterior layer pores and a sliding layer adjacent to the exterior layer and defining a plurality of sliding layer pores. The variable-porosity panel system additionally includes a shape memory alloy (SMA) actuator configured to translate the sliding layer relative to the exterior layer to modulate a porosity of the panel assembly. The SMA actuator includes an SMA element configured to exert an actuation force on the sliding layer and at least partially received within an SMA element receiver of the sliding layer. The SMA element extends out of the sliding layer only at a sliding layer first end. A method of operating the variable-porosity panel system includes assembling the variable-porosity panel system and/or transitioning the panel assembly of the variable-porosity panel system among the plurality of panel configurations.

A cross flow fan includes a plurality of vanes arranged around a rotation axis at predetermined intervals in the circumferential direction, a tongue section arranged on the outer circumferential side of the vanes, and jetting sections that jet a fluid along the wall surfaces of a discharge path into which the fluid is discharged from each of the vanes. A facing wall section is provided to a position facing the tongue section with the vanes therebetween. The facing wall section is provided with: an upstream wall section configured so as to be equivalent to the radius of curvature in the outer circumference of a path formed when the vanes rotate; a downstream wall section that is connected to the upstream wall section and in which the radius of curvature gradually becomes larger than that of the upstream wall section; and a diffuser wall section connected to the downstream wall section.

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.

A fluid system has a lengthwise axis, a chord length, a first body portion, a second body portion, a spacer, and a fluid pressurizer. The first body portion and the second body portion cooperatively define an injection opening, a suction opening, and a channel that extends from the injection opening to the suction opening. The fluid pressurizer is disposed within the channel cooperatively defined by the first body portion and the second body portion. The first body portion defines a cavity that is sized and configured to filter debris that enters the channel during use and provide a mechanism for removing the debris from the system.

A system and a method for evaluating performance of a porous skin of an aircraft including the porous skin, and a boundary layer control system. The performance evaluation system includes a first sensor providing data related to the performance of the porous skin. The performance evaluation system is further configured to clean the porous skin based on the performance of the porous skin determined using the data received from the first sensor in order to ensure that the porous skin operates at its maximum capability.

Variably porous panels and panel assemblies incorporating shape memory alloy components along with methods for actuating the shape memory alloys are disclosed to predictably alter the porosity of a substrate surface, with the shape memory alloy maintained in an orientation relative to the panel that is in-plane with a mold-line of the panel outer surface.