Abstract: A suction arrangement for drawing off a boundary layer on an aircraft comprises a suction arrangement including an outer skin having suction surfaces in critical flow areas, and at least one air breathing engine providing suction. Bleed air is drawn from a comparatively high-pressure region of the engine by means of a branch line and the bleed air is used for driving a turbine of at least one turbo-supercharger assembly. A compressor of the turbo-supercharger assembly or assemblies serves as the suction source for drawing off a boundary layer at the suction surfaces in critical flow areas.

Abstract: A control system for a vehicle having plural control elements actuated at a single actuation point including a redundant electric actuator assembly including a control rod moveable linearly in two opposite directions mounting n electric motors, each motor having a controller and a feedback sensor for controlling linear movement of said rod, each motor contributing approximately 1/n of total control power required for adjusting one or more of said plural control elements, such that failure of any of said motors controllers or feedback sensors leaves sufficient predetermined minimum control power available for operating said control system.

Abstract: Fixing system for a modular leading edge (2) to the structure of an aircraft lift plane (1), in which the leading edge (2) has a covering (4) formed from a first lamina (5) and a second lamina (6) between which there is an interior airtight chamber, and the fixing system comprises a main attachment element (3) whose cross-section has a central element (13), a first arm (14) which is fixed to the first lamina (5) of the covering (4) of the leading edge (2), and a second arm (15) which is fixed to the second lamina (6) of the covering (4), and the central element (13) is in turn fixed to a covering (10) of the torsion box (8) of the structure of the lift plane (1).

Abstract: An inlet flow control system disposed within a nacelle includes a panel on an inner surface of that nacelle. The panel includes a noise attenuation layer that dissipates noise energy. A vacuum source generates a pressure differential across the noise attenuation layer for drawing airflow through the panel and away from an inner surface of the nacelle.

Abstract: A door assembly has a first door integrated with a second door. The first door has a first door cowl. The second door is pivotably mounted to the first door and has a second door cowl forming at least a portion of the first door cowl. The door assembly includes at least one actuator coupled to the first and second doors. Each one of the first and second doors is pivotable between open and closed positions and defines an opening when moved to the open position. The openings of the first and second doors face in opposite directions. The actuator is operative to pivotably move at least one of the first and second doors between the open and closed positions.

Abstract: A purging system for a laminar flow control system comprises an air scoop and a diffuser fluidly connected thereto. The air scoop is disposable into an external flow of an external atmosphere. The diffuser is configured to fluidly connect the air scoop to a suction cavity of the laminar flow control system wherein the suction cavity may be disposed adjacent a porous skin of an airfoil such as adjacent a leading edge of the airfoil. The laminar flow control system may be configured to suction boundary layer flow passing over the porous skin by drawing a portion of the boundary layer flow through a plurality of pores formed in the porous skin. The diffuser ducts high pressure flow captured by the air scoop to the suction cavity for discharge through the pores to reduce the potential of blockage thereof.

Abstract: A method for suctioning the boundary layer at the surface (1) of an aircraft having an air-conditioning system (4), at whose flow-critical points of the surface multiple suction openings (2) are provided, the air quantity suctioned via these being discharged to the atmosphere again via at least one outlet (7) placed in a way favorable for flow, the air quantity suctioned from the surface (1) being fed to the air-conditioning system (4) of the aircraft, via whose outlet (7) the air quantity suctioned is discharged to the atmosphere together with the exhaust air of the air-conditioning system (4), to reduce flow losses.

Abstract: A flow surface (16), e.g. on a swept aircraft wing, has a three-dimensional boundary-layer flow. The surface is defined by a spanwise direction (z) and a chordwise direction (x). In or on the flow surface excitation locations (22) are arranged, exciting primary disturbances. The disclosure is characterized in that the excitation locations (22) are arranged such that benign steady primary disturbances are excited and maintained on a sufficiently-high amplitude level as longitudinal vortices respectively crossflow vortices, suppressing naturally growing nocent primary disturbances by a non-linear physical mechanism. The benign primary disturbances preserve a laminar flow, such that unsteady secondary disturbances, which may initiate turbulence and which, otherwise, are excited in streamwise direction by nocent primary vortices, are suppressed or at least stabilized.

Abstract: An apparatus, method and system for combining aerodynamic design with engine power to increase synergy between the two and increase climb performance, engine-out performance, and fuel efficiency for a variety of aircraft or the like.

Abstract: Air pressure distribution for airfoil lower and upper surfaces is utilized to divert airflow using ducts formed in space-curve shapes placed inside the airfoil volume, through span-wise located inlets from high pressure areas on the airfoil lower surface near the leading edge and through chord-wise spaced inlets on the side face of the airfoil wing tip correspondingly to the side face of the airfoil wing tip through chord-wise spaced outlets on the side face of the airfoil wing tip and to span-wise located outlets to the low pressure areas on the airfoil upper surface. Triboelectric materials on the wing surfaces are employed to static charge the air in drag. Inside the ducts, the employment of either triboelectric linings and materials, or HV-supplied electrodes, or both, help to static charge the diverted air flow to and from the airfoil wing tip side face to diffuse wing tip vortex core early.

Abstract: An aerodynamic body with a plurality of nozzles for throttling a fluid flow to be removed by suction through the nozzles in a self-regulated fashion is disclosed. The aerodynamic body according to one example, includes a plurality of throttling nozzles with a throttle section that is defined by an inlet and an outlet. In one example, the interior wall of the throttle section may be designed such that an effective flow cross section is reduced in a self-regulated fashion due to the creation of turbulences on the interior wall of the throttle section as the pressure differential between the inlet and the outlet of the throttle section increases.

Abstract: Passive removal of suction air for producing a laminar flow, and associated systems and methods are disclosed. One such method includes forming a laminar flow region over an external surface of an aircraft by drawing air through the external surface and into a plenum. The method can further include passively directing the air from the plenum overboard the aircraft. For example, the air can be passively directed to a region external to the aircraft having a static pressure lower than a static pressure in the plenum, as a result of the motion of the aircraft. Flows from different sections of the external surface can be combined in a common plenum, and the corresponding massflow rates can be controlled by the local porosity of the external surface.

Abstract: A method for suctioning the boundary layer at the surface (1) of an aircraft having an air-conditioning system (4), at whose flow-critical points of the surface multiple suction openings (2) are provided, the air quantity suctioned via these being discharged to the atmosphere again via at least one outlet (7) placed in a way favorable for flow, the air quantity suctioned from the surface (1) being fed to the air-conditioning system (4) of the aircraft, via whose outlet (7) the air quantity suctioned is discharged to the atmosphere together with the exhaust air of the air-conditioning system (4), to reduce flow losses.

Abstract: A cooling system on board an aircraft includes a device for removing by suction a boundary layer, and a heat exchanger through which flows the boundary layer air that has been removed by suction. Cooling by way of a ram air channel can be reduced or entirely stopped, depending on the flight phase, such that the air drag of the aircraft and thus the fuel consumption can be reduced.

Abstract: Fixing system for a modular leading edge (2) to the structure of an aircraft lift plane (1), in which the leading edge (2) has a covering (4) formed from a first lamina (5) and a second lamina (6) between which there is an interior airtight chamber, and the fixing system comprises a main attachment element (3) whose cross-section has a central element (13), a first arm (14) which is fixed to the first lamina (5) of the covering (4) of the leading edge (2), and a second arm (15) which is fixed to the second lamina (6) of the covering (4), and the central element (13) is in turn fixed to a covering (10) of the torsion box (8) of the structure of the lift plane (1).

Abstract: A method for enhancing effectiveness of a rotor blade of a wind energy device (a wind-wheel of electric generating unit), according to which a rotor blade is implemented in the form of a thick-airfoil wing, and a vortex system for controlling the boundary layer is arranged on the rear portion of the blade, upon the leeward, which system consists of longitudinal cavities having central bodies that define annular channels; the air being sucked from the cavities and central bodies through air-intakes into receivers. The air from the receivers, under the action of centrifugal forces generated by the rotating blade, is sucked towards the blade end. Within the cavities and on the blade's outer surface are positioned the plates that restrict streaming-down of the air flow along the blade.

Abstract: The outer skin (100) of an aerodynamic body (40) has perforations (200) arranged in particular patterns in respective spanwise extending groups or bundles (250). Each perforation is preferably a micro-slot with a length of 100 to 3000 ?m and a width of 50 to 250 ?m. Air is sucked through the micro-slots from the boundary layer flowing over the outer skin, to achieve boundary layer control. In each bundle, the pattern, size, orientation, and other parameters of the micro-slots are designed to achieve mutual destructive interference of flow disturbances arising due to the suction, to minimize the excitation of flow instabilities in the boundary layer. Particularly, the spatial spectrum of the perforation pattern of a given bundle is essentially absent of significant energy at predetermined wavelengths of predetermined flow instabilities that otherwise appear in the boundary layer air flow.

Abstract: Wing tip vortices are evident from airliner vapor trails, and helicopter blade slap. Elliptically loaded high aspect ratio tapered wings have minimum induced drag but cannot eliminate it. Different methods are disclosed herein, for upper and lower surface boundary layers to cancel their opposing vorticity upon shedding from the trailing edge, thereby eliminating wake vorticty, induced drag and associated noise. This requires wing-rotor-propeller or fan blades with a platform designed for uniform bound circulation and with boundary layer control near the tip. In addition this requires special techniques to counter span-wise pressure gradients, such as tip circulation control blowing or an upwind small propeller or wind turbine on each tip. These techniques can eliminate wake vorticity with its induced drag, noise, flying on the backside of the power curve and the option for asymmetric loading by pneumatic means to eliminate need for cyclic pitch control or conventional ailerons.

Abstract: The present invention relates to a reconfigurable porous technology for fluid flow control system and more particularly to reconfigurable porosity fluid flow control system for vehicles such as aircraft, missiles, ground and water vehicles to improve the performance of such vehicles. The present invention further relates to a method of operating the reconfigurable fluid flow control system. In one embodiment, the present invention includes a reconfigurable porosity system for fluid flow control on the surface of an aircraft, missile, water-craft or ground vehicle comprising a porous outer skin comprising individual pores; individually addressable valves corresponding and connected to the individual pores for opening and closing the pores; and a pneumatic system for connecting the pores wherein fluid from a high pressure area of the porous outer skin can be directed to a low pressure area of the porous outer skin by opening and closing the individually addressable valves.

Abstract: Active flow control devices and methods are disclosed for improving the aerodynamic efficiency of airfoils. The devices and methods pertain to applying intermittent suction or intake of low-energy boundary layer fluid into airfoils in a manner delaying or eliminating boundary layer separation.

Abstract: A method to delay flow separation from a solid body in a fluid stream by coupling the region of the suction peak with the region of adverse pressure gradient. This method is particularly applicable for increasing the lift of a wing or for increasing the effectiveness of machines designed to move fluid or control fluid flow.

Abstract: Apparatus for generating vortices to control the flow of air across a airfoil of an aircraft includes a series of pressure active regions arranged along the leading edge of the airfoil. The pressure active regions include spaced apart valves connected to a source of vacuum, a controller for activating the valves, and sensors for sensing air pressure. The controller is configured to activate the valves in response to the pressure sensed by the sensors, wherein the spaced apart valves are connected to a source of pressurized air as well as to the source of vacuum.

Abstract: A system for achieving a boundary layer control by sucking at least a portion of the boundary layer air flow through perforated or porous suction areas on the outer skin of the wings or other areas of the aircraft, includes one or more jet pumps (7) arranged in the bypass engine (5) of the aircraft, and a system of suction conduits (4) connecting the jet pumps (7) to suction channels (3A) communicating with the perforated or porous suction areas (3). Each jet pump (7) includes an ejector pipe (101) that is driven by an external surrounding driving jet (8) or by an internal driving jet (8) flowing through an internal jet pipe (15). The jet pumps (7) are arranged at selected locations in the air intake upstream of the fan, in the bypass channel (18) just downstream of the fan, in the bypass channel near the outlet end thereof, in the core hot gas channel (19) upstream of a compressor assembly, and/or in the core channel downstream of a turbine assembly.

Abstract: An aircraft wing, wing assembly and method of reducing drag are provided. The wing asembly includes a main wing portion (10) and a leading edge high lift portion (12). The high lift portion is movable between a retracted position in which it generally merges with the main wing portion and a deployed position forwardly thereof. At least a substantial part of an upper surface (22) of the high lift portion is air permeable or perforated and in flow communication with a suction passage (30) in it. In flight, suction may be applied to the suction passage to reduce the chordwise extent of the turbulent boundary layer over the upper or lower wing surface.

Abstract: A vehicular boundary layer control system utilizing a series of external perforation arrays and suction sources controlled by a digital signal processor or microprocessor. Each array of perforations in the outer vehicle skin is served by a plenum chamber, which is selectively isolable from a suction manifold. The desired vacuum for each individual plenum and associated array is determined through the sampling of the turbulence associated with that array as well as other sensed environmental parameters. Vacuum is maintained at the desired level in each plenum through the arbitration of various suction sources and the selective restriction of airflow from the plenum(s) to the suction manifold. For terrestrial aerodynamic vehicles, a series of moisture separators are included in the plenums to mitigate the effects of any ingested moisture.

Abstract: A flow control device and method for eliminating flow-induced cavity resonance within a closed or nearly closed end flow passage (20) having an inlet opening (30) defined between an upstream inlet edge (32) and a downstream inlet edge (34). The passage accepts exterior fluid flow (38) therein via the opening (30). The flow control device includes a stationary inlet guide vane (44) having a leading edge (46), a trailing edge (48), and a number of support members (50) to connect the vane to the inlet. The vane (44) is positioned such that the vane leading edge intercepts the exterior fluid flow shear layer, and the vane trailing edge extends into the passage at the inlet. In a preferred embodiment, the inlet guide vane is located approximately midway between the upstream and downstream inlet edges. The inlet guide vane is cross-sectionally shaped as a cambered airfoil.

Abstract: A passive transpiration system for controlling interaction between turbulent boundary layer air and an impinging shock during supersonic airflow by application of a panel including passively activated mesoflaps that direct air circulation through a cavity in response to supersonic airflow. The mesoscopic flaps are preferably arranged in a matrix on one side of a cavity. The flaps deflect to allow air to circulate through the cavity during supersonic airflow, thus controlling the interaction between boundary layer air and air from the impinging shockwave. The flaps open to varying degrees depending on the speed of the airflow. The preferred structure includes channel sidewalls arranged parallel to one another and open on one end, creating multiple cavities. The sidewalls are connected by struts. Rows of flap support beams are connected to the sidewalls. The flaps are connected on one end to the beams, enabling them to deflect over their remainder in response to aerodynamic pressures.

Abstract: Boundary layer air on the skin structure of an aircraft is sucked off through suction holes in the aircraft skin structure by a least one ejector pump. The ejector pump is operated by at least one of several air flow sources. One source is the excess pressure in the passenger cabin at higher altitudes. The other air flow source is tap air from at least one aircraft engine. If necessary, one or the other or both air supply sources may be utilized to operate the ejector pump or pumps.

Abstract: A hybrid aircraft is taught having VTOL, R-VTOL and S-STOL capabilities. The aircraft has a lifting body hull and four wing sections arranged in tandem which are pivotally moveable about their neutral axis. Each wing section has mounted thereon a pivotal propeller-rotor assembly for providing thrust substantially in a range between horizontal and vertical. The wings and propellers are integrated to the hull by an outrigger designed to be very stiff and to distribute forces from the wings and propellers to the hull. The hull is shaped to provide aerodynamic lift in an airstream and to facilitate construction by minimizing the number of panels of differing curvature required. The hull is formed of a pressure tensioned frame covered with semi-rigid panels, a lower cladding frame and bow and stem cladding nose cones. The semi-rigid panels covering the frame are formed of gas-tight and abrasion resistant laminate material and are connected to the frame by means of an interface rib and latch system.

Abstract: A cooling device for an aircraft turboshaft engine includes a boundary layer suction device formed by a perforated external wall portion of the aircraft, a collector on the inside of the wall portion for receiving the air flowing in through the perforations, and a discharge device discharging the air from the collector. The cooling device is completed by a heat exchanger which is disposed in the path of the air flow through the collector, a pump for pumping fluid to be cooled through the heat exchanger from a circuit of the engine, and a regulator regulating the fluid flow through the exchanger to control the temperature of the fluid. The fluid which is cooled may be from the lubrication circuit, the fuel circuit, or an air circuit of the engine, and the boundary layer suction device is preferably disposed in the pod of the engine.

Abstract: The method for damping global flow oscillations (20a.x, 20b.x) in a flowing medium in the region of an unstable flow (10) separating itself from at least one boundary surface (11, 12) is comprised of detecting the global flow oscillations with a sensor system (13) and superimposing a compensatory oscillation (15, 16) controlled by the signals of the sensor system onto the flowing medium in a separation zone of the separated unstable flow. Correspondingly, the apparatus for performing the method comprises a generator (17, 18) which superimposes a compensatory oscillation on the flowing medium in a separation zone of the separated unstable flow and a control system (28, 29) which evaluates the signals of the sensor system and controls the compensatory oscillation so that the amplitude of the global flow oscillation is damped by a prespecified factor.

Abstract: An improvement to supersonic laminar flow control suction systems, including an inlet air duct (32) for providing subsonic ram engine inlet air, is provided. The inlet air duct (32) supplies air pressure power to one or more turbines of suction system compressor units alone for flight conditions at or above a particular minimum speed and minimum altitude, and in conjunction with engine compressor bleed air for flight conditions below the minimum speed and minimum altitude. The inlet air duct (32) is angled in the direction of subsonic airflow approximately 30 degrees from the horizontal off an opening in an upper wall of a subsonic diffuser of an engine inlet on a supersonic aircraft, and is connected to a power input line that feeds one or more compressor unit turbines. A check valve prevents backflow of air toward the engine inlet. The suction system further includes a short compressor output duct (38) and a short turbine output duct (40).

Abstract: An improvement to boundary layer control system, including a transpiration panel (58) for transpiring suction air in a distributed manner, is provided. The transpiration panel (58) replaces the discharge nozzle of prior art flow control systems. The transpiration panel (58) is generally a rigid panel having a plurality of small holes (62) extending from an inner panel surface (56) to a smooth outer panel surface (54). The transpiration panel (58) is positioned flush with an external aircraft surface in a region where laminar flow control is not being attempted. Exemplary subsonic and supersonic boundary layer control systems including the transpiration panel (58) are provided. A preferred location of the transpiration panel (58) for the subsonic application is the underside of a wing (80), near the leading edge. A preferred location of the transpiration panel (58) for the supersonic application including on the upper surface of a wing (114) near the fuselage (118), in a turbulent wedge region.

Abstract: A method and an apparatus are provided for optimizing the aerodynamic effect of the airfoil of an aircraft by defined changes in camber. The method includes the following steps:a. determining the flow for the flight condition caused by the change in camber,b. comparing the ascertained characteristic values with stored nominal reference values for an optimal flow,c. forming differential values between the characteristic values and the stored nominal reference values,d. deriving actuator signals from the differential values, ande. changing the camber by motor, based on the actuator signals, for minimizing the differential values.The optimum wing flow is thereby maintained more exactly. For transonic wings, the position and strength of compression shocks is also effectively controlled, which leads to a reduction of the direct shock induced separation.

Abstract: A porous material is manufactured by weaving polycarbonate fibres through a tow of carbon fibres which has been pre-impregnated with an epoxy resin. A second layer of pre-impregnated carbon fibres are superimposed on the woven layer and the epoxy resin is cured to bond the fibres together. A ceramic slurry is applied and allowed To penetrate through the second layer of fibres and part way through the woven layer of fibres to a controlled depth before being dried to form a mask. A thermoplastic powder is then applied to the unmasked region of the woven layer of fibres and sintered. Finally the mask and the polycarbonate fibres are removed chemically to produce a porous material which comprises a sintered thermoplastic layer reinforced with carbon fibres through which channels are provided.

Abstract: A perforated sheet is diffusion bonded to a thin solid sheet. Each of the perforations of the perforated sheet is tapered, having a maximum diameter at the surface that is not bonded to the thin sheet and a smaller diameter at the surface that is bonded to the thin sheet. The bonded perforated sheet and thin sheet are included with other solid metallic sheets in a forming pack to be superplastically deformed into a structure. The bonded perforated sheet and thin sheet are placed on the top of the forming pack so that the thin sheet will face outwards after the structure is formed. After the superplastic deformation process is completed, the thin sheet is removed by machining to expose the perforated sheet and provide a structure for controlling laminar flow over the perforated sheet. The exposed surface of the perforated sheet includes the smaller diameter of each tapered perforation, while the inner-facing or blind surface of the sheet includes the maximum diameter.

Abstract: A movable sheet overlying a wing is disclosed that creates laminar flow over its exposed surface. The movable sheet serves as an integral, retractable shield for protecting a suction support structure of a wing against contamination, and also serves as a movable, conductive substrate for deicing by means of electrical resistance or hot-gas heating. The invention includes a movable sheet that is mounted scroll-like on two motor-driven rollers. The sheet has a solid area without perforations that protects the suction support structure from contamination, and a porous area with perforations therethrough that allows boundary layer suction. The motor-driven rollers scroll the sheet to cover the suction support structure with either the solid area or the perforations of the sheet. Contact rollers at the edge of the sheet supply electrical current to resistively heat the sheet and melt any accumulated ice. The movable sheet can also be moved back and forth to dislodge the ice.

Abstract: Measures are disclosed for modifying the boundary layer flow over fluid dynamic surfaces using patterns of riblets which are set at a peak-to-peak spacing substantially less than 80 wall units and which are provided with boundary layer suction means comprising apertures (A) between the riblets for a combinative improvement of boundary layer flow. In a further aspect, riblets are employed in combination with wall apertures as an improved means of shock wave (W) control by permitting recirculation of boundary layer fluid from downstream to upstream of the shock wave.

Abstract: A floating speed electrically driven suction system for sucking boundary layer air flow off the external surface of an aircraft. A variable speed electrical generator drives a variable speed electrical motor which in turn drives a variable speed pneumatic compressor. Inlet guide vanes are automatically adjustable to compensate for variations in pressure. A surge control valve is operable to port in additional inlet flow as needed to avoid low volumetric surge in the suction compressor.

Abstract: Apparatus and method for airflow vectoring control for an airfoil, a two dimensional jet, and the like. An airfoil or jet with a blunt open edge and a suction system for sucking air into the open edge. A blower system for blowing air out through the open edge. A control for changing the direction of flow through the open edge. A baffling arrangement for changing the magnitude and distribution of flow across the open edge.

Abstract: Boundary layer control apparatus is provided (22). The boundary layer control apparatus (22) is for use with an aircraft propulsion nacelle (12) positioned such that the air inlet (14) of the propulsion nacelle is located proximate an aircraft surface (10), wherein a boundary layer is established on the surface when the aircraft is propelled through an atmosphere, causing air to flow over the surface. The boundary layer control apparatus (22) includes a duct having an entrance (24) positioned between the aircraft surface (10) and the inlet (14) of the propulsion nacelle (12) for capturing the boundary layer air passing over the aircraft surface and diverting the boundary layer air away from the inlet.

Abstract: A transport plane with stub tail, which is preferably propelled by two jet engines. The intake air is fed to the engines directly integrated in the fuselage tail via a diffusor, the diffusor is a short diffusor. The air obtained by boundary layer suction via a suction slot with a combination of ejectors and diffusors is fed into the rest of the intake air.

Abstract: A method and apparatus for boundary layer control by sucking air off the vortex chambers established in the trailing-edge portion of an aircraft aerodynamic surface. The rate of air bleed is controlled first by increasing it until the boundary layer is attached to the airstreamed surface, then by decreasing the rate of air bleed until the pressure in the trailing-edge aircraft portion starts decreasing. The aircraft equipped with the boundary layer control system, including a number of vortex chambers accommodating streamlined bodies and communicating, through a common passage and a receiver, with a low-pressure source.

Abstract: A system for eliminating turbulence in aerodynamic surfaces, such as engine nacelles, resulting from air passing over joints and gaps in the aerodynamic surface. Basically, this system includes a suction chamber within the nacelle and extending along the inner skin wall adjacent to gaps or joints, such as around access doors, at the interface between the nose cowl and the fan cowl door, etc. Typically, a series of apertures extend through a top portion of the suction chamber below the gap to permit air to pass from the gap to the suction chamber. At least one duct communicates with the chamber and extends to a suction pump. In operation, the pump sucks air through the duct, suction chamber, apertures and gap, to prevent the formation of a transition from low drag laminar flow to high drag turbulent flow at the gap.

Abstract: Aerodynamic boundary layer control apparatus comprising a panel assembly having one surface for immersion in an ambient fluid flow and provided with perforations, a first array of fluid transporting channels fluidly coupled with various ones of the perforations, a second array of fluid transporting channels overlapping the first array of channels, and a suction-generating apparatus fluidly coupled with the second array of channels. An opposing surface of the panel assembly has a contour congruent with that of the aircraft wing or body structure to which it is to be removably attached. The suction-generating apparatus applies a suction force to the second array of channels to draw the ambient fluid into the first array of channels to enable conformace of the fluid with the one surface.

Abstract: A supersonic aircraft having highly swept subsonic leading edge portions of the wings provided with boundary layer control suction slots. When the airplane is operating at high angles of attack under circumstances where noise is objectionable, air is drawn in through the suction strips to alleviate separated air flow and substantially eliminate (or at least alleviate) vortices that would otherwise develop over the upper wing surface. This improves the L/D ratio and permits the engines to be at a lower power setting, thus alleviating noise. There are shown a double delta planform configuration, and an arrow plan form configuration. Also, the boundary layer control suction can be used in conjunction with laminar flow control suction.

Abstract: A method and apparatus for establishing discrete zones of pressure at the surface of a perforated panel of the type typically used for laminar fluid flow control includes a first array of channel members fluidly communicating with perforations in the panel, all of the channel members in the first array extending in a first direction and being substantially parallel to one another, and a second array of channel members fluidly communicating with the fluid in the first array of channel members, all of the channel members in the second array extending in a second direction and being substantially parallel to one another, where the first and second arrays of channel members being disposed in crossing relationship with a source of pressure being applied to the second array of channel members. By this arrangement, control of fluid flow in at least one of the first and second arrays results in discrete zones of pressure at the surface of the panel.

Abstract: A laminar flow control arrangement for use in a nacelle for an aircraft turbine engine. The nacelle has a microporous outer skin in the area where air flow over the skin is to be maintained in laminar flow. A honeycomb core is bonded to the inner surface of the nacelle skin. A perforated back skin is bonded to the inner surface of the core. Several closely spaced circumferential flutes open to the back skin are fastened to the back skin. At least one collector duct is connected to the flutes and a suction pump. In operation, the suction pump pulls air through the ducts and flutes, causing air to be sucked inwardly through the microporous skin thereby maintaining laminar, rather than turbulent, flow over a large part of the nacelle during aircraft take-off and cruise operation. In addition, a chamber is preferably provided in communication with any gaps in the nacelle skin in the area where laminar flow is desired.

Abstract: The present invention involves laminar flow control for reducing drag on a body moving through a fluid. A skin is provided through which fluid in the boundary layer is drawn. The skin includes a plurality of perforations. The ratio of the effective area of the perforations to the skin area is spatially variable. The ratio is varied to compensate for expected variations in external pressure such that a substantially uniform suction results in a spatially uniform mass flow rate through the skin. Preferably, the perforations are approximately tapered to avoid inspiration of debris and unwanted outflow.

Abstract: In the present method boundary layer thickening is combined with laminar flow control to reduce drag. An aerodynamic body is accelerated enabling a ram turbine on the body to receive air at velocity V.sub.o. The discharge air is directed over an aft portion of the aerodynamic body producing boundary layer thickening. The ram turbine also drives a compressor by applying torque to a shaft connected between the ram turbine and the compressor.The compressor sucks in lower boundary layer air through inlets in the shell of the aircraft producing laminar flow control and reducing drag. The discharge from the compressor is expanded in a nozzle to produce thrust.