Abstract: Method and apparatus for covering a free-standing body with a uniform glow discharge plasma, particularly at atmospheric pressure. The method may be used to provide a body coated with such a plasma, and also to treat a workpiece.

Abstract: An apparatus and method of stabilizing unstable shock waves on the surface of a body induce shock waves to form prematurely at a particular location on a surface of the body and fix that location such that shock waves will form consistently and persistently at that location on the surface of the body. Boundary layer flow separates from the surface of the body at that location and can be prevented from reattaching to the surface. Shock wave oscillations due to interactions with the separated boundary layer flow are prevented, thereby minimizing vibrations induced in the body. The apparatus has a flow accelerating surface and a discontinuity in the accelerating surface. The accelerating surface causes local fluid flow over the surface of the body to accelerate and prematurely and consistently form a shock wave at the point where the discontinuity is located.

Abstract: Methods for using tip generated vortices to improve performance of foils. These methods include generating a substantially streamwise beneficial vortex (74) near the outboard end (60) of a foil (82). This beneficial vortex (74) spins in the opposite direction of an induced drag vortex (62), and is used to create an upwash field (76) which neutralizes induced drag by deflecting the flow behind the trailing edge (56) at an upward angle. Upwash field (76) causes the lift vector (118) on the foil (82) to tilt forward, thereby creating a forward directed force of induced thrust upon the foil (82). Beneficial vortex (74) is also used to contain and compress the high pressure field existing along the attacking surface of the foil (82), and displace the induced drag vortex (62) inboard from the tip of the foil (82). Numerous performance parameters are improved dramatically by using beneficial vortex (74), as well as by using a double vortex pattern (124).

Abstract: Acoustic noise resulting from the interaction of a periodic pressure and velocity fluctuation induced by a periodically passing blade wake interacting with a downstream airfoil (10)is attenuated by locating an antisymmetric pressure wave generator (30) adjacent the leading edge (18) of the vane (10).

Abstract: A low turbulence cambered surface foil, hydrofoil or airfoil, which contains indentations located on maximum camber across which a fluid can be flowed. The indentations create turbulence in the boundary layer downstream of the indentations, changing the characteristics of the flowing fluid to a turbulent boundary layer ahead of the normal point of separation of the fluid from the foil, this causing the fluid to cling close to the surface of the foil and postpone or delay trailing edge separation of the fluid stream from the foil. The noise level is reduced, the performance and efficiency of the foil is improved, or both the noise level is reduced and the performance and efficiency of the foil is improved.

Abstract: A reverse delta aerodynamic wing has a basic reverse delta wing portion bounded by a leading edge and by a pair of trailing edges extending from respective ends of said leading edge toward a trailing apex point and respective span-wise wing extensions in a natural laminar boundary layer wing region extending chordwise from said leading edge by a fraction of the chordlength of said wing and extending span-wise from opposing sides of said wing. Laminar flow control in other regions of the wing employs fuel stored in the wing as a coolant.

Abstract: A supersonic flight aircraft having a longitudinally forwardly extending axis in the direction of flight, and a wing, comprising a wing extending generally laterally relative to the axis, and having a leading edge angled forward or rearwardly relative to a normal to the axis at an angle .lambda., and the wing having a maximum thickness t; the angle .lambda. and thickness t characterized that in that in supersonic flight conditions, the forwardmost shock wave produced in association with the wing extends generally along or rearwardly of the leading edge, whereby laminar airflow conditions are maintained over the leading edge and adjacent the surface of the wing.

Abstract: A fixed seal plate for an aircraft functions to seal the gap between a movable flight control surface and its associated airfoil when the control surface is in a deflected position. The seal plate is fixed to the airfoil (typically a wing) so that it does not articulate with the airfoil movable surface, therefore having no moving parts, yet blocks airflow through the gap effectively enough to measurably improve aircraft flight performance by reducing aerodynamic drag.

Abstract: A method is described for reducing drag in airframes or airfoils. The method includes inducing cavitation in the boundary layer separating the airframe or foil skin and the air currents passing thereover to produce a reduced pressure area instead of turbulent flow. In one embodiment of this invention, a nose cone is provided for the airframe which at the juncture of its base portion provides a step between the terminal portion of the nose cone and the adjacent portion of the fuselage skin. This provides a circumferential step surrounding the fuselage which in its leeward direction induces the cavitation necessary to reduce drag. In another embodiment of this invention, steps can be provided longitudinally at mutually spaced circumferential locations extending from the front along the fuselage toward to the rear to ensure that a continuous boundary layer is provided of reduced pressure.

Abstract: A lifting body moves relative to a fluid, thereby creating a vortex field in the fluid downstream of the lifting body. The lifting body has a predetermined lift distribution along the length thereof which enhances the velocity component of the fluid flow directed outwardly from the centroid of the vortex field to reduce the strength of trailing vortices. In a preferred embodiment, the lifting body is a wing with a perturbation proximate to the tip end of the wing planform trailing 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: The boundary layer of a fluid travelling in a mean-flow direction relative to a surface of a wall of a body is controlled by generating in the fluid a magnetic field B having flux lines along the surface of the wall and an electric current density J traversing the magnetic flux lines in the fluid to form a control region. The magnetic field B and the electric current density J create in the control region a force J.times.B that can stabilize or destabilize flow in the boundary layer. A plurality of such control regions can be arranged in an two-dimensional array of control tiles that are periodically actuated in a controlled, predetermined pattern at a critical frequency that provides boundary layer control over a given area.

Abstract: A wing, or similar article of airfoil section, has a variable geometry surface for the active control of shock strength and transonic wave drag. In one embodiment, the wing has a region of distensible skin (4) aft of the line of maximum section, which extends along the span of the wing in those areas that experience drag. Pressure means (10, 20, 30) within the wing outwardly deflect the distensible region and produce a local bulge in the expansion surface. This bulge induces pre-shock compression and reduces the effect of the shock. The bulge is retracted by the natural elasticity of the skin material (which can be a conventional aluminum alloy) upon removal of the applied pressure. In another embodiment, the wing has a ramp portion (14) which is outwardly deflectable for the same purpose. The invention is applicable to supercritical and natural laminar flow wings.

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 method of detecting the onset of turbulence in connection with a body mng through a fluid medium and of reducing body drag and as well reducing the amount of drag noise radiated from the body. First, the body is supplied with sensors each for generating a signal suitable for measuring amplitude of pressure fluctuations of the medium proximate a region of said sidewall of the body in at least a region of the body in which turbulence is expected to occur. During a reference stage during which the body moves through the fluid medium when it is known that turbulence is occurring around at least a portion of said body, the sensors each generate reference temporal pressure data representing fluctuations in pressure of the fluid medium around said body.

Abstract: This invention outlines excitation means to transform the linear momentum of an underwing energized jet into rotational form in a selective manner to provide an asymmetric shear layer to increase compression wave reflection from the forward undersurface of a supersonic wing. The wing compression energy is thereby recovered into useful work as an increase in pressure on the upward reflexed wing backside. The upper surface of the shear layer is comprised of an array of vortices whose rotation is opposite to the wing circulation, providing the required angular momentum reaction. The upper wing surface is flat to avoid generation of waves and an adverse angular momentum reaction above the wing. The vortices below the wing are compressed by the underwing pressure, comprising a pressure shield to enhance the reflection.

Abstract: Controlling turbulence in a medium caused by injection of energy into the medium at relatively large scale with consequent dissipation of energy at relatively small scale, is achieved by introducing into the medium a broad spectrum stochastic external disturbance.

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: An aircraft wing having a super critical profile is equipped with a venting device extending in the direction of the span width along the upper side of the wing. The ventilating device includes a compensation chamber in the wing and the chamber is covered with a perforated wall strip on both sides of the compression shock. The forward end of the compensation chamber has a gap shaped exit for blowing out the venting medium in the flow direction of the flow across the wing tangentially to the wing.

Abstract: A supersonic flight aircraft having a longitudinally forwardly extending axis in the direction of flight, and a wing, comprising a wing extending generally laterally relative to the axis, and having a leading edge angled forward or rearwardly relative to a normal to the axis at an angle .OMEGA., and the wing having a maximum thickness t; the angle .OMEGA. and thickness t characterized that in that in supersonic flight conditions, the forwardmost shock wave produced in association with the wing extends generally along or rearwardly of the leading edge, whereby laminar airflow conditions are maintained over the leading edge and adjacent the surface of the wing.

Abstract: An aft facing step situated across the span of an airfoil. A chemical or thermal deicing or running wet anti-icing device is located in or on the airfoil upstream of the step, and causes water to run back towards the step. The step suddenly reduces the thickness of the airfoil chord section, which causes a disturbance in the boundary layer across the span of the airfoil downstream of the step. The aforementioned disturbance causes runback water to form droplets and be blown clear of the airfoil surface downstream of the step, thereby preventing ice from being formed on the airfoil surface downstream of the step.

Abstract: The boundary layer of a fluid travelling in a mean-flow direction relative to a surface of a wall of a body is controlled by generating in a near-wall region of the flow a magnetic field B having flux lines parallel to the surface of the wall and an electric current density J traversing the magnetic flux lines in the fluid. An electrolyte or other conductivity-enhancing material is introduced into the flow to provide an electrical conductivity gradient in the near-wall region. The magnetic field B and the electric current density J create in the fluid a force J.times.B having a component normal to the surface of the wall that because of the increased conductivity gradient near the surface can stabilize or destabilize flow in the boundary layer. Numerous aspects of the fluid flow and its interaction with the body can thus be controlled.

Abstract: A method of detect the onset of turbulence in connection with a body moving hrough a fluid medium. First, the body is supplied with sensors each for generating a signal suitable for measuring amplitude of pressure fluctuations of the medium proximate a region of said sidewall of the body in at least a region of the body in which turbulence is expected to occur. During a reference stage during which the body moves through the fluid medium when it is known that turbulence is occurring around at least a portion of said body , the sensors each generate reference temporal pressure data representing fluctuations in pressure of the fluid medium around said body. In response to reference temporal pressure data generated by sensors in a turbulence zone at which turbulence is occurring and sensors in a transition zone between the turbulence zone and a laminar flow zone, a method-of-delay phase portrait is generated for each of a progression of selected delay intervals.

Abstract: A swept forward wing for aircraft comprising an inner wing portion and an outer wing portion in which the upper surface curvature of the inner wing portion is designed to create three dimensional flow thereover to manipulate the sweep of the isobars and prevent desweeping thereof, the inner wing portion including a wing root section (4) having a far aft maximum thickness position (14) coupled with high camber in the region of said maximum thickness position, said wing root section (4) further including a negatively cambered leading edge portion (10) and a nose-down twist configured to suppress high leading edge velocities, the combination of thickness and camber forms aft of the leading edge region (10) causing the flow to accelerate until a maximum velocity is reached relatively far back on the wing.

Abstract: A pair of spaced slots, disposed on each side of an aircraft centerline and spaced well inboard of the wing leading edges, are provided in the wing upper surfaces and directed tangentially spanwise toward thin sharp leading wing edges of a highly swept, delta wing aircraft. The slots are individually connected through separate plenum chambers to separate compressed air tanks and serve, collectively, as a system for providing aircraft lift augmentation. A compressed air supply is tapped from the aircraft turbojet power plant. Suitable valves, under the control of the aircraft pilot, serve to selective provide jet blowing from the individual slots to provide spanwise sheets of jet air closely adjacent to the upper surfaces and across the aircraft wing span to thereby create artificial vortices whose suction generate additional lift on the aircraft. When desired, or found necessary, unequal or one-side wing blowing is employed to generate rolling moments for augmented lateral control.

Abstract: An active perturbation-producing element on the solid surface is driven to induce oscillations in the boundary layer of the fluid stream about an axis substantially perpendicular to the solid surface, to enhance the mixing of the boundary layer in the fluid stream. The method is particularly applicable for increasing the lift of a wing, but may also be used for increasing the divergence angle of a diffuser.

Abstract: A method for visualizing off-surface flows consists of releasing a gas with infrared absorbing and emitting characteristics into a fluid flow and imaging the flow with an infrared imaging system. This method allows for visualization of off-surface fluid flow in-flight.

Abstract: A porous airfoil having venting cavities with contoured barrier walls, formed by a core piece, placed beneath a porous upper and lower surface area that stretches over the nominal chord of an airfoil is employed, to provide an airfoil configuration that becomes self-adaptive to very dissimilar flow conditions to thereby improve the lift and drag characteristics of the airfoil at both subcritical and supercritical conditions.

Abstract: An aircraft is provided with an aircraft base pressure drag reduction apparatus including apparatus for ducting boundary layer air on board an aircraft wherein the air produces ram air drag, apparatus for using the air for work, and apparatus for ducting the used boundary layer air to a low pressure area of an aircraft which otherwise produces base pressure drag on the aircraft to reduce the base pressure drag that the low pressure area would otherwise produce. In a more particular embodiment of the invention the low pressure area of the aircraft is in a fan duct of an aircraft gas turbine engine. In the preferred embodiment the low pressure area in a fan duct of an aircraft gas turbine engine is on the pylon fairing and the means for using the air for work includes at least one means for bleeding boundary layer air from the surface of the aircraft for reducing aircraft boundary layer induced drag.

Abstract: An aerofoil or hydrofoil (1) has a vessel (2) for providing a high velocity jet of fluid directed from a nozzle (3) in a direction having a component of velocity in the same direction as the required direction of lift (L). The aerofoil or hydrofoil (1) also has a curved surface (5) convex on the side of the aerofoil or hydrofoil which is in the direction of the required lift, and which serves to direct the velocity of the jet in a direction which is substantially opposite to the direction of the required lift or thrust force, the primary jet being directed over the convex surface for attachment thereto; and a duct formed over a rear part of the convex surface remote from the nozzle, whereby the primary jet of fluid flowing over and attached to the convex surface causes an enhanced flow through the duct, the duct being directed at least at its exit end in a direction so that the flow therethrough has a component of velocity opposite that of the required direction of lift.

Abstract: The invention is a boundary flow control system and method which comprises heating elements 24 to trigger boundary layer transition and audio speakers 83 to provide acoustic suppression 51 of boundary layer turbulence 52. The trigger and suppression control are activated by a feedback amplifier 82 which reads boundary layer flow conditions using an anemometer probe 81. The active control of the boundary layer permits delay of flow separation and a reduction in skin friction drag as compared to natural flow conditions.

Abstract: A lift enhancing system for an aircraft having wings and a deflectable airfoil attached to the trailing edge of the wing which includes ejecting nozzles attached to and movable with each deflectable airfoil to eject gas spanwise across the surface of the deflectable airfoil and thereby enhance the lift of the wing and deflectable airfoil.

Abstract: Retarding of the point of transition from laminar flow to turbulent flow in aerodynamic boundary layers on the surfaces of aircraft is accomplished by radiating acoustic energy at frequencies greater than twice the critical Tollmein-Schlichting frequency into the boundary layer. The acoustic energy interferes with the formation of Tollmein-Schlichting waves, thereby increasing the incidence of laminar flow and reducing aerodynamic drag.

Abstract: A system is described for controlling the transition of laminar/turbulent flow at a surface which comprises a thin narrow strip heater disposed adjacent the surface and extending substantially transversely of the flow of the air stream thereacross, the heater being resiliently held in tension on or in closely spaced relationship to the surface, and a power source operatively connected to the heater for applying pulsed voltage of preselected amplitude and frequency to the heater.

Abstract: Method and apparatus for reducing aerodynamic drag and enhancing lift by using ultrasound to alter the structure of boundary layers. In one embodiment, a continuous thin sheet of ultrasound is radiated transversely into the boundary layer parallel to an aerodynamic surface, such as an aircraft wing, carrying that boundary layer.To ensure that the ultrasound sheet remains under (or over) the wing, means are provided to compensate for any downstream drift of the sheet with wing flow by transmitting it in a forward direction in proportion to the Mach number of the flow. The ultrasonic sheet may be applied as periodic strips spaced at predetermined downstream intervals.In order to decrease the amount of acoustical energy required to implement the techniques of the present invention and to operate in a more efficient manner, the ultrasound transmission is modulated with audio frequencies.Means for tuning the audio frequency to match various flight conditions are provided.

Abstract: An elongated airfoil is perforated in such a way as to cause boundary layer air at the airfoil surface to be drawn into the airfoil, and then evacuated.

Abstract: A swept wing having a leading edge flap which in its deployed position forms a slot with the forward end portion of the wing. An elongate strip is positioned on the forward portion of the wing in a manner that when the flap is deployed to form the slot, this strip protrudes into the airstream that passes upwardly through the slot. This creates a stall condition in the area of the strip to produce the desired pitch characteristics for safe recovery from stall. In the cruise configuration, where the flap is positioned against the leading edge of the wing, this strip is aerodynamically concealed.

Abstract: This invention is for a passive laminar flow airfoil which has an upper skin 12 and lower skin 14 joined at a trailing edge 16. A leading edge structure 20, such as de-icing equipment, is joined to the upper and lower skins by interface mechanisms 30 and 35. Generally, the interface mechanisms are forward facing steps, with or without adjacent gaps, shaped and dimensioned to accomplish laminar flow using standard airfoil manufacturing techniques.

Abstract: In a wing and nacelle combination, where the nacelle is positioned below and forwardly of the wing leading edge, a wake control device to control a turbulent wake which is formed at the upper forward lip portion of the nacelle. This wake control device comprises a forward vortex generating portion to create a vortex which travels over the leading edge of the wing, and also a fence located at the middle third of the nacelle to control boundary layer air and thus properly locate the wake control vortex.

Abstract: An airfoil for transonic speeds includes a porous top surface extending from a location about 50 to 60% of the chord length from a leading edge of the airfoil to a location about 80 to 90% of the chord length from the leading edge. A cavity is defined under the porous surface in the airfoil which has a depth of from 0.05 to 0.2% of the chord length. The porosity of the porous surface is chosen to be from 1 to 3% of the total airfoil surface and may be variable. The presence of the porous surface and cavity decrease airfoil drag at transonic speeds by providing a pathway between a high pressure area downstream of a shock wave formed on the airfoil at transonic speeds to a low pressure area within a bubble on the airfoil upstream of the shock wave.

Abstract: In controlling the boundary layer of flow over the surface of a body, for reducing resistance and impeding flow separation, a sensor element in the surface measures certain flow values in the boundary layer. The measured values are conveyed to an analyzer control circuit which, in turn, conveys a signal to an active vibration transmitter in the surface of the body for providing the required control.

Abstract: A method and apparatus for controlling the direction of the thrust vector of the engine exhaust stream in an upper surface blowing type aircraft includes ducts in the aircraft wings having rotary control valves for controlling the flow of air through the ducts from a source of high pressure to the low pressure upper surface of the wing. Introduction of the airflow at the upper surface rearwardly of the jet engine produces separation of Coanda effect attachment of the engine exhaust stream from the curved upper wing surface. Coanda effect attachment deflects the exhaust stream over the wing and toward the ground and results in a predominantly vertical thrust vector which augments lift of the aircraft. However, separation of the exhaust stream from the upper surface results in a predominantly horizontal thrust vector which augments forward acceleration of the aircraft. The fluidic action of the valves can rapidly change the thrust vector between basically horizontal and highly inclined orientations.

Abstract: An air lift mechanism has one or more rotating discs within wells in a top deck. Each disc has cambered convexities on its upper surface. A cylindrical wall of each well has operational ports.

Abstract: Devices to reduce the drag experienced by aircraft and other travelling bodies, comprising sail-like members mounted on the body surface. These members project into the local stream that forms close to the surface during motion, and tend to divert that local stream back into the free stream direction and in so doing to experience useful thrust. The members are cambered and the camber varies from root to tip to allow for change in the local stream direction as distance from the surface increases. Special sails for use on surfaces subject to some complex flows, adjustable sails and arrays of several sails for use especially at aircraft wing tips, are also proposed.

Abstract: A STOL aircraft having turbojet or torbofan engines mounted above and forward of the wing whereby the engine exhaust gases flow over and, by the Coanda effect, attach to the upper surfaces of the wing and a downwardly curved extendible flap to produce a downwardly turned exhaust flow having a large vertical component of thrust. Premature separation of the exhaust flow from the wing or flap due to reduced velocity in the boundary layer of the flow, which would result in decreased turning of the exhaust gases and a reduced vertical thrust component, is prevented by a boundary layer scoop extending across the exhaust flow, in an area just prior to where the exhaust flow would separate from the wing or flap, for removing the boundary layer gases and discharging them beneath the wing.

Abstract: A lightweight, segmented, easily assembled aircraft having a hollow fuselage tube, upon which the cockpit, wing, empennage, landing gear, engine, and shell segments are supported and secured, is presented. The wing construction aerodynamically extends the effective wingspan of the aircraft and stabilizes flight by including an aileron slot, which rams positive pressured air from the lower surface of the wing over the upper surface of the wing to laminarize the turbulent air near the ailerons, and including an end plate, which is toed-in and canted towards the upper surface. A fore shell segment separates from and moves fowardly of a fixed, aft shell segment along a track apparatus, secured to the hollow fuselage tube, to permit access to the cockpit of the aircraft.

Abstract: Aircraft flaps provide rearwardly convergent channels which terminate at or near the trailing edges of the flaps. The forward intakes of the channels are closed when the flaps are elevated and open when the flaps are depressed. A control is programmed to operate the flaps so as to maintain minimum drag until sufficient ground speed is attained for take-off, and to limit the velocity of air discharged from the channels to sub-sonic speeds.

Abstract: A plurality of passageways, each having its longitudinal axis substantially parallel to the flight path of an aircraft, extend through the wings, fuselage, horizontal elevators, and rudder for the purpose of permitting air to pass through these areas. The passageways diverge from front to rear on either side of the longitudinal axis. The front openings leading into the passageways are of such size and so spaced as to exhibit considerable reduction in parasite drag generated at the leading edges of the wings, elevators, and rudder, as well as at the front end of the fuselage.