Abstract: The invention relates to heatable wind energy turbine blades and to a method of heating and deicing the turbine blades using conductive fabrics to displace and/or cease the buildup of ice on the turbine blades by electrothermal fabric heater disposed or integrated on the turbines for effectively deicing the blades. Multiple turbine blade design methods are explored as well as heater materials and the application of such materials.

Abstract: A deicer comprises a skin heating device immediately subjacent an outer skin overlying an apex of a leading edge, and a skin deflection device immediately subjacent the outer skin chordwise aft of the apex. The skin heating device prevents the formation of ice over the apex and the skin deflection device deflects the outer skin to expulse ice formed chordwise aft of the apex. A controller controls the heating and deflection cycles to minimize power consumption of the deicer.

Abstract: The present invention is a de-icing system that uses electro-magnetic actuators mounted within the airfoil of an aircraft to effect de-icing. Advantageously, the actuators have low-energy requirements. Each actuator includes conductive strips fabricated on a flexible dielectric sheet. The conductive strips are wound into coils with the actuators shaped into a flattened elongated tube. The axis of the winding coils is coincident with the longitudinal axis of the elongated tube. Low adhesive coatings may be used to enhance the efficiency of the electro-magnetic coils in expulsing the ice accretion.

Abstract: The heating device comprises electrically conducting longitudinal fibers extending substantially parallel to a leading edge of the aerofoil close to said leading edge, and means for electrically connecting the ends of the longitudinal conducting fibers to an electric power supply. The conducting fibers are grouped together in conducting rovings forming part of a hybrid fabric which furthermore includes a weft of electrically insulating fibers woven together and woven with the conducting rovings.

Abstract: The invention includes system for modifying ice adhesion strength of ice adhered to an object. The system includes an electrode that is electrically insulated from the object and a DC source, e.g., a battery, coupled to the object and the electrode. The source generates a DC bias to an interface between the ice and the object when the ice completes the circuit. The object is conductive or is doped as a semiconductor so that the DC bias applies a voltage to the interface which modifies the ice adhesion strength selectively as compared to the ice adhesion strength with substantially zero bias voltage at the interface. The strength can be increased or decreased relative to its static state (i.e., the state without applied voltage). In this manner, ice such as ice on an aircraft wing can be removed with less work. The system preferably includes an electrically insulating material disposed between the object and the electrode; the insulating material is substantially conformal to the object and the electrode.

Abstract: To combat the formation of ice on an aerofoil, several resistive elements each consisting of electrically conducting fibers parallel to the leading edge and through which an electric current is made to flow to dissipate heat by a Joule effect are incorporated into this aerofoil close to its leading edge. In order to obtain a thermal power which can vary along the leading edge, the resistive elements are produced by superposing several layers of conducting fibers, at least one of which layers has a constant width, and at least one other of which has a width which varies continuously along the leading edge, but remains smaller than said constant width.

Abstract: A number of resistive elements are incorporated into the aerofoil in the vicinity of its leading edge. Each of the resistive elements is electrically connected to the other resistive elements at its distal end and is fitted at its proximal end with means of connection to an electrical power supply. The resistive elements are split between a first set that includes at least two resistive elements and a second set that includes at least one resistive element. In service, the resistive of the first set are powered in turn, while each resistive element of the second set acts as a return path for the electricity and is powered continuously or almost continuously.

Abstract: A thermal de-ice and anti-ice system for aircraft surfaces employs a laminate in which flexible expanded graphite foil is an electrical and heat conducting layer that is disposed below an outer heat conducting layer, with an electrically insulating layer below the graphite layer. The flexible expanded graphite layer requires about three times less wattage than known resistance heating pad thermal systems to achieve de-ice and/or anti-ice temperatures. The temperature of the surface is controlled by varying the power supplied to the flexible expanded graphite layer of the laminate in response to a real time temperature value transmitted to a power control.

Abstract: A deicer comprises a skin heating means immediately subjacent an outer skin overlying an apex of a leading edge, and a skin deflection means immediately subjacent the outer skin chordwise aft of the apex. The skin heating means prevents the formation of ice over the apex and the skin deflection means deflects the outer skin to expulse ice formed chordwise aft of the apex.

Abstract: A busbar supplies current to an electrically resistant area heating device, such as an array of fine closely-spaced wires, which extends over a window, e.g. a laminated vehicle windscreen. The busbar is arranged to turn a corner, e.g. a corner of the window, by providing a separate corner piece of busbar strip which is electrically connected to adjacent lengths of straight busbar strip. This facilitates concealment of the busbar, as is desirable for vehicle windscreens, especially when the corner piece is shaped to suit the corner of the window. Electrical connection of the corner piece to the adjacent lengths of busbar strip is achieved by use of a solder of low melting point, which melts on autoclaving of the window.

Abstract: An apparatus for detecting ice forming conditions includes a substrate having a first surface and a second surface; a sensor disposed on the first surface, the sensor being made of a material having a characteristic which varies in a known manner with respect to temperature; and a unit for monitoring the characteristic and for detecting ice forming conditions from the characteristic. A method for positioning the apparatus to detect ice forming conditions, to detect the presence of ice, and to determine an ice accretion rate is also provided.

Abstract: The present invention is de-icing system that uses electromagnetic actuators mounted within the airfoil of an aircraft to effect de-icing. Advantageously, the actuators have low voltage and current requirements. Each actuator includes conductive strips fabricated on a flexible dielectric sheet. The conductive strips are wound into coils with the actuator shaped into a flattened elongated tube. The axis of the winding coils is coincident with the longitudinal axis of the elongated tube.

Abstract: The installation links a supply conductor to an electrical device for de-icing a blade using at least one cable with a first stretch linked to the supply conductor by a connector and to a second stretch with an overhead hook in the form of flattened half loop, itself linked to the device for de-icing the blade by a second connector fitted on the blade, possibly via a straight and flat third stretch and a second overhead hook. The first hook is of nonscreened structure, with an elongate part of substantially flattened rectangular transverse section and with a concavity pointing towards a device for retaining and articulating the blade on a hub.

Abstract: An ice protection device for an airfoil comprises a plurality of discrete mat sections which are individually secured to the structural member by an adhesive.

Abstract: An improved ice protection apparatus 8 includes a top polyurethane layer 10, an active layer 12, and a base layer 14 cured together into a unitary matrix, wherein the base layer is either polyurethane or chloroprene. The active layer may be either a thermal ice protector, a pneumatic ice protector, or an electro magnetic protection apparatus.

Abstract: A blade de-icer for rotary wing aircraft comprises magnets placed around rotor mast and coils with laminated plates installed at the blade cuff of each rotor blade, in sufficient proximity to produce a high voltage, high current pulse every time a magnet and a coil pass each other while the rotor is turning. Electrically conductive cable or wire carries the current down each rotor blade to heating elements which melt any accreted ice on the blade. In one embodiment, magnetic metals are used. In another embodiment, electromagnets are used. In each embodiment, difficult switches for turning the de-icer on and off are provided.

Abstract: A new deicing technology is described which utilizes the actuating properties of shape memory alloys (SMAs) to debond ice accretion formed on a surface. A thin sheet of SMA material is mounted to the icing prone surface to perform the force and displacement combination that can debond the ice. The SMA sheet is activated to expand or contract causing shearing and peeling of the ice. An SMA actuator portion located aft of the icing area can be used to pull the sheet over a ribbed underlay and grooved bands which generates a strain field that severs the ice's adhesive bond. Two-way shape memory action and natural ice latent heat powering are used in different modes of operation to reduce the power requirements and the structural complexity of the deicing system.

Abstract: A de-icing system is provided including a de-icer attached to an aircraft structural member subjected to an impinging airstream during flight, the airstream passing over the structural member in a fore to aft direction. The deicer has a primary heater element disposed beneath a primary shedding zone upon which ice accumulates during flight, the primary heater element being configured to heat the primary shedding zone upon application of an electrical potential across the primary heater element, and a secondary heater element disposed beneath a secondary shedding zone upon which ice accumulates during flight, the secondary heater element being configured to heat the secondary shedding zone upon application of an electrical potential across the secondary heater element, the secondary heater element being disposed immediately aft of the primary heater element.

Abstract: A de-icing blanket and method of ice-removal from a moving object such as an airfoil comprises a center portion including a heater, and side portions flanking the center portion, each side portion including an electro-expulsive de-icing system (EEDS). The center portion is placed on the leading edge of the airfoil forwardly with respect to the side longitudinal portions such that when the airfoil is in motion, an airflow impinging on the airfoil forces water contacting an exposed surface of the center portion to flow rearwardly and to freeze on accreting surfaces of the side portions where the ice is subsequently removed by energizing the EEDS. The blanket may include a leading edge cap made of a highly polished impervious material to protect the blanket from atmospheric weathering.

Abstract: A laminated window includes at least one rigid external substrate (5) and a sheet made of flexible plastic material (6) which is adjacent to the substrate (5). The window is equipped with an electrostatic protection circuit which is capable of dissipating the charges which have accumulated on the external sheet (7). This circuit includes conducting elements (2) which cross through at least the substrate and at least one part of the sheet made of plastic material (6). The conducting elements (2) are connected to a collector element (3) which is connected to the ground (4) and embedded in the sheet made of flexible plastic material (6).

Abstract: An improved sliding contact for use with a propeller ice protection system is provided. According to an aspect of the invention, a silver graphite brush forms a sliding contact with a hardened copper alloy slip ring. A sliding contact according to the invention demonstrates improved performance in an oil contaminated environment.

Abstract: A turbojet having an air intake case including radial arms between an outer annular structure and an inner central structure, and a deicing unit configured to deice the radial arms by microwaves and located in the central structure. The deicing unit has a microwave generator and a transmitting element configured to transmit energy and including an inside annular waveguide located inside of the central structure. An energy distributing element configured to eliminate ice is coupled with the transmitting element by a coupling element. The radial arms are made from a dielectric composite material.

Abstract: A microwave deicing and anti-icing system for aircraft wings, rotors, and airfoils. Microwave energy is absorbed in a propagation tube inside the leading edge of the aircraft wing and turned into thermal energy. An highly absorptive coating on the interior surface of the tube and a mirror/insulator are used to insure the most efficient transforming of the microwave energy into thermal energy. The thermal energy is then conducted to the skin of the wing, rotor, or airfoil by thermal transfer vanes to the skin of the leading edge of the wing, rotor, or airfoil, so that the temperature in that part of the wing, rotor, or airfoil can be raised and maintained well above the freezing temperature to break and prevent ice.

Abstract: An apparatus for deicing an aircraft is defined by an insulated shelter being a size capable of enclosing an aircraft. The shelter is positioned on a deicing surface that absorbs heat from means such as electrical filaments or heated pipes within the deicing surface or through the application of infrared radiation onto the deicing surface. In turn, the deicing surface radiates heat into the air within the shelter. Once an aircraft is enclosed within the shelter, infrared radiation is applied to a portion of the exterior surface of the aircraft. The combination of the infrared radiation and the heat radiating from the deicing surface rapidly deices and substantially dries the exterior surface of the aircraft. The exterior of the aircraft is subsequently heated to a sufficiently high temperature that ice will not reform on the aircraft prior to take off.

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: An electro-expulsive deicing system 114 for attachment to an airfoil 110 is comprised of a plurality of electro-expulsive elements 120 separated by a dielectric filler regions 122 all of which are disposed between a top dielectric layer 124 and a bottom dielectric layer 128. A contiguous top skin layer 116 covers the entire deicing apparatus 114.

Abstract: A method and apparatus for determining the severity of icing conditions for an aircraft in flight. A mobile probe projecting from a surface of the aircraft is heated to a predetermined range of temperatures, and the total power required for the heating is measured. The measured total power is divided into a basic power corresponding to the thermal exchange in dry air having the same flow parameters as those measured and a complimentary power corresponding to the evaporating of drops of water contained in the actual air. A parameter representative of the speed at which the thickness of ice increases at the surface of the aircraft is computed from the complementary power.

Abstract: An active noise control subassembly for an aircraft engine. An aircraft engine noise radiating panel is bendably vibratable to generate a canceling noise generally opposite in phase to at least a portion of the discrete tonal noise produced by the engine. A piezoceramic actuator plate is vibratable by an applied electric AC signal. The plate is connected to the panel such that vibrations in the plate cause bending vibrations in the panel and such that the plate is compressively prestressed along the panel when the panel is free of bending vibrations. The compressive prestressing increases the amplitude of the canceling noise before the critical tensile stress level of the plate is reached. Preferably, a positive electric DC bias is also applied to the plate in its poling direction to increase the amplitude of the canceling noise before the sum of the AC signal and DC bias exceeds the depolarization voltage in a direction opposite to the poling direction.

Abstract: Apparatus is provided for creating heat by electromagnetic induction between relatively rotating components. In RAT applications, part of the nose cone (34) is formed from electrically conductive material (106) which is in thermally conductive relation to the nose cone exterior. A magnetic field is created by components (60) that are spaced apart from the electrically conductive material and relatively rotatable with respect to that material. The electrically conductive material intersects the magnetic field, at least in part, such that eddy currents are created in the electrically conductive material by relative rotation with respect to the magnetic field. These eddy currents create heat which is conducted to the exterior surface of the RAT nose cone. Preferably, the magnetic field is created by a pair of spaced-apart permanent magnets (60) mounted on a support plate (62) inside the RAT hub (28) and immediately behind the nose cone.

Abstract: An improved ice protection apparatus 8 includes a top polyurethane layer 10, an active layer 12, and a base layer 14 cured together into a unitary matrix, wherein the base layer is either polyurethane or chloroprene. The active layer may be either a thermal ice protector, a pneumatic ice protector, or an electro magnetic protection apparatus.

Abstract: A monitoring system is disclosed to automatically indicate excessive wear of electrical brushes in deicer assemblies for aircraft. In the preferred embodiment, the indicator system includes an electrical brush with an initially insulated wire embedded in it; and an electrical detection circuit, connected to the brush, with a warning device such as a light. When the brush becomes worn, through excessive "end wear" and/or "flank wear", the insulated wire becomes exposed and eventually stripped at the point of wear. This creates a conductive path from the electrical brush, through the bare wire spot, to the detection circuit. This turns on the warning device to indicate that the brush has become worn and needs replacement.

Abstract: An improved brush assembly is provided for conducting electrical power from a fixed power system to a rotating ice protection system. The invention is especially adapted for use with an aircraft propeller ice protection system. According to an aspect of the invention, the brush assembly has a housing with a brush enclosure and an attachment leg that attaches the brush assembly to a mounting bracket with the brush enclosure spaced to one side of the mounting bracket. According to another aspect of the invention, an internally mounted transient voltage suppressor is provided with minimized impedance between the transient voltage suppressor and the power system connection thereby providing improved lightning protection. These and other features are provided which are described in detail and represent further improvements over prior brush assemblies.

Abstract: A de-icer for a structural member of an aircraft is provided. The de-icer includes first and second heaters having first and second electrically conductive strips, respectively. The first and second conductive strips are configured to form first and second marginal portions, respectively. The first and second heaters are positioned relative to each other such that the marginal portions are overlapped.

Abstract: An electro-impulse de-icer for de-icing an aircraft structural member having an opening in the leading edge and including an inductor coil. The inductor coil is disposed either at least partially within the opening or adjacent to the opening. The de-icer further includes a movable metal target disposed in proximity with the coil. The target is supported by a flexible, ice-accumulating support member that permits the target to move relative to the coil and to the structural member. The support member is rapidly, and forcefully, displaced away from the coil and the structural member upon passing a short-duration, high-current pulse through the coil. The current flow creates an electromagnetic field that induces eddy currents in the target and the support member (if made of metal). Upon collapse of the electromagnetic field in the coil, the target and support member are pulled rapidly to their rest position.

Abstract: A modular ice protection system for an airfoil includes a deflection assembly attached to the airfoil and a removable outer shell having a modulus of elasticity of at least 40,000 kPa impermanently disposed over the deflection assembly, wherein the deflection assembly causes distortion of the separable outer shell during de-icing. The deflection assembly may likewise be removable from an underlying substructure which is attached to the airfoil.

Abstract: A de-icer for a structural member of an aircraft is provided. The de-icer includes first and second heaters having first and second electrically conductive strips, respectively. The first and second conductive strips are configured to form first and second marginal portions, respectively. The first and second heaters are positioned relative to each other such that the marginal portions are overlapped.

Abstract: A laminate coating comprising a durable outer ply which is resistant to abrasion and impermeable to water, bonded to and through a conductive layer of fibers and an integrally enveloping adhesive layer which is disposed on a vehicle component surface, such that the laminate coating upon curing is bonded to the vehicle component surface such as the surface of an aircraft part especially the fuselage, wing parts or tail section. The conductive layer is connected to a source of electrical energy and control means adapted to control the temperature of the coated surface of the aircraft part.

Abstract: An electroexpulsive deicing system 18 in accordance with the present invention includes a plurality of expulsive elements 18, 22 comprised of printed circuit boards 12 having a plurality of parallel metal lines 14 formed thereon in a predetermined pattern. Adjacent expulsive elements have current flowing in opposite directions for creating expulsive electromagnetic forces between elements.

Abstract: In a thin-walled structure being cleaned, there are generated converging waves of elastic deformation by virtue of synchronous excitation of single equal pulses along the contour of the surface being cleaned in the points opposite to one another. To effect this method use is made of an electromagnetic source (1) of mechanical pulses in combination with a waveguide (2) transmitting mechanical pulses to the structure (4) being cleaned and representing a ring (8) with a disk (9) designed to accommodate the source (1) and connected to this ring by jumpers (10).

Abstract: An aircraft icing detection system detects accumulation of ice on an upper surface (12) of a wing (10) of an aircraft. The system includes an air pump (18) that delivers air through first and second conduits (24, 26). The first conduit delivers air through a first air knife (32) to openings (34) in the upper surface of the wing. The second conduit delivers air through a lower wing surface (14) through openings in a second air knife (42). When ice accumulates on the upper surface, flow from the first air knife is restricted. A differential pressure sensor (46) senses a pressure difference between the conduits and warns the pilot of possible ice accumulation by illuminating a warning light (50).

Abstract: A structural member having integral surface de-icing capability and method of manufacture are described. The structural member includes a non-metallic high tensile modulus fiber-reinforced matrix structural backing, thin force and displacement generation means, and a thin high tensile modulus outer skin bonded to said backing and said force and displacement generation means which is postioned between the backing and the skin. The force and displacement generation means may include one or more inflatable tubular members and/or electromagnetic apparatus. The structural member may be substituted for the aluminum alloy leading edge structural skin typically employed on modern aircraft.

Abstract: An electrical an (10) for the icing-susceptible stator vane stage (16) located in an air inlet section (12) of a turbomachine (not shown). A plurality of stator vanes (20) which are electrically isolated from a plurality of structural shrouds (30, 32) are grouped in one continuous, or a plurality of contiguous arcs about a fanshaft which is generally coincidental with the turbomachine's longitudinal axis (X--X). Low voltage alternating current is provided by an alternator (not shown). This current is directed through a plurality of electrical conductors (26) and is further distributed through each stator vane (20) which is either electrically conductive or employs an electrically conductive medium disposed proximate to an icing susceptible surface of an airfoil contour (21). The electrical current flow, which is generally directed in a radial orientation through each stator vane (20) causes a direct electrically-resistive heating effect to the airfoil contour surfaces (21) of the stator vanes (20).

Abstract: A wiring harness is provided with connectors which are electrically and physically attached to terminal wires extending from the electrical resistance deicer heater and cables extending from a power supply so that the connectors when assembled, establish the desired electrical connection, the assembled connectors being secured to a bracket fastened to the hub of a propeller, blade with a portion of the bracket being engageable with the assembled connector bodies to hold the connectors in assembled position on the hub.

Abstract: A protection element containing a spring steel strip is bent to have a greater curvature than the curvature at the leading edge of a fan blade. This protection element is then fixed to the leading edge of the fan blade over an area of maximum erosion. Rubber or another elastomer can be extruded over the strip before or after it is fixed to the fan blade or the strip can incorporate an outer hardened layer to resist erosion. Attachment of the strip to the blade is advantageously accomplished using rivets or screws at spaced locations along the blade and at the leading edge of the blade.

Abstract: A planar coil construction, especially adapted for use in a force-producing device such as a de-icer, includes first and second sheet-like members, each defined by a continuous electrical conductor having a plurality of turns and first and second ends. The first end of the first conductor defines an electrical input to the coil, while the second end of the second conductor defines an electrical output from the coil. The second end of the first conductor and the first end of the second conductor are electrically connected. The sheet-like members are superimposed such that current flow through adjacent turns of the conductors is in the same direction. Within each sheet-like member, adjacent conductors also have current flow in the same direction. The invention includes a technique for spacing the conductors by means of a dielectric layer, and a technique for encapsulating the sheet-like members.

Abstract: The deicing system includes a plurality of relatively thin, flat coils positioned between an aircraft surface and an outer sheet. If the aircraft surface is electrically conducting such as aluminum, such that eddy currents may be established therein, then the outer sheet is resistant to eddy currents being established therein. An electrically conducting layer may be positioned between the coil and the aircraft surface to improve efficiency. If the aircraft surface is resistant to eddy currents being established therein, then outer sheet is electrically conducting. However, if an electrically conducting layer is positioned between coil and outer sheet, the outer sheet may be made from non-conducting material. A rapidly rising current through the coil will result in a rapid repulsion between the coil and the particular member which is electrically conducting, causing ice to be removed (shattered) from the outer sheet.

Abstract: A blade heater (10) for an aircraft engine propulsor blade (14) has a foil pattern (18) which is comprised of a plurality of elements (25-56). The resistance of the elements (25-56) varies according to the distance between the elements (25-56) and the leading edge (12) of the blade (14).

Abstract: An attachable electro-impulse de-icer for de-icing an aircraft structural member includes an inductor coil disposed in proximity with the outer surface of the structural member. The coil is supported by a flexible, ice-accumulating support member (surface ply) that permits the coil to move relative to the structural member. Preferably the coil and support member are formed in an integral construction that can be attached to the leading edge of the structural member. The coil and support member are rapidly, and forcefully, displaced away from the structural member upon passing a short-duration, high-current pulse through the coil. The current flow creates an electromagnetic field that induces eddy currents in the support member (if made of metal), and the structural member (if made of metal). Upon collapse of the electromagnetic field in the coil, the support member is pulled rapidly to its rest position adjacent the structural member.

Abstract: A structural member having integral surface de-icing capability and method of manufacture are described. The structural member includes a non-metallic high tensile modulus fiber-reinforced matrix structural backing, thin force and displacement generation means, and a thin high tensile modulus outer skin bonded to said backing and said force and displacement generation means which is positioned between the backing and the skin. The force and displacement generation means may include one or more inflatable tubular members and/or electromagnetic apparatus. The structural member may be substituted for the aluminum alloy leading edge structural skin typically employed on modern aircraft.

Abstract: A deicer pad for use on the airfoil of an aircraft wherein the pad has an elastomeric flexible covering with metallic spaced strips embedded therein in side by side relationship. An electromagnetic field pulse generator is mounted within the airfoil adjacent to the strips for imparting successive pulses to the strip for movement thereof to effect de-icing.