FR2536037A1 - WING DEGIVER - Google Patents

Abstract

WING DEFROST. THIS DEFROSTING AND DESINSECTIZATION SYSTEM INCLUDES AN ELEMENT 26 IN THE FORM OF A LOADING SURFACE ATTACK EDGE. THIS ELEMENT IS IN THE FORM OF A NON-METALLIC, POROUS, SELF-SUPPORTING AND RIGID COMPOSITE STYLING MATERIAL, CONSISTING OF AN EXTERNAL ENVELOPE 36 AND AN INTERNAL ENCLOSURE 38 FORMING A CAVITY 32 BETWEEN THEM. THE CAVITY FOR ADJUSTING THE FLOW OF ANTIFREEZE FLUID TO THE EXTERNAL SURFACE OF THE ELEMENT 26. APPLICATIONS IN PARTICULAR TO AIRCRAFT WINGS.

Description

De-icer of wings.

  The present invention relates to a de-icing system

  and disinsection for aircraft and it concerns more specifically

  the use of lightweight, non-metallic, rigid composite

  and self-supporting constituting on the one hand the leading edge of an over-

  side, and on the other hand one of the elements of a new system of

  de-icing and disinsection of aircraft wings.

  De-icing the leading edges of airfoils, or wings, of aircraft to prevent or eliminate the accumulation of frost on the leading edge of a wing by watering its surface by means of glycol and other deicing chemicals in liquid form,

  is a well-known practice Deicing systems of this type

  normally carry a glycol storage means, a subsystem ensuring the distribution of glycol on the leading edge of the wing of the aircraft, and a means for regulating the flow and distribution of glycol on the edge of the aircraft; A disadvantage of some de-icing systems according to the prior art, of the type described, lies in the fact that these may not be suitable for modern aircraft Another disadvantage of some systems according to the prior art is due to

  their weight, which may be excessive when added to the surfaces

  your, so that their use is to be avoided on small planes.

  This disadvantage usually stems from the use of

  Another disadvantage of some de-icing systems of this type according to the prior art lies in the inability of the glycol distribution subsystem to ensure a uniform distribution of the glycol on all parts of the de-icing system. 'attack,

  in order to prevent frost formation. This results in the need for

  to use excessive amounts of deicing fluid to ensure

  For example, several of the de-icing systems

  according to the prior art use a non-rigidified fabric for constituting

  to kill the leading edge of the wing and to regulate the flow of glycol to it. See, for example, US Pat. Nos. 2,200,838 and 2,075,659. It would appear that such non-rigidified constructions are unsuitable for modern aircraft. Particularly to jet aircraft US Pat. No. 2,249,940 represents a tightly woven fabric compound made from metal or alloy wire and fiber and applied to the surface of an aircraft wing. patent states that the metal or alloy wires prevent the fabric from becoming elongated, while the fibers provide the necessary permeability to the deicing liquid. It is believed, however, that efficient regulation of the flow thereof would be difficult with In addition, a canvas of this type is likely to add excessive weight, so that its use on small aircraft would be undesirable or to be avoided. defrosting according to the prior art, described in US Pat. Nos. 2,843,341 and 3,423,052,

  used a rigid bearing surface, but the deicing fluid is distributed

  fired by networks of separate holes that can cause a

  unequal system of this system. One of the systems described in the

  No. 3,423,052 includes the use of stainless steel cladding.

  and porous structure, to form the leading edge of the wing.

  However, this stainless steel cladding is of a high weight and does not

  not necessarily the regular distribution of the desired fluid, because of the impossibility of controlling the poor dimensions and density of the

sheathing.

  Another disadvantage of some of these de-icing systems according to the prior art lies in the absence of satisfactory means for regulating the flow of glycol from the storage medium to the

leading edge of the aircraft.

  Despite the fact that an accumulation of insects on the leading edge of a natural laminar flow bearing surface can destroy the laminar flow on this surface, thus causing an increase in profile drag, it does not appear that It has been found in the prior art that such a bearing surface can be

  disinfected by watering with a liquid flowing through an over-

porous face.

  The main object of the present invention is to provide a system

  improved de-icing and disinsection system that would eliminate or

  would greatly reduce the disadvantages mentioned above.

  The present invention has the specific object of providing a sys-

  defrosting system ensuring uniform distribution of the deicing fluid

  on the leading edge of the bearing surface, while minimizing the

  the amount of deicing fluid required to prevent icing.

  Another object of the present invention is to provide a system

  effective regulation of the flow of deicing fluid, or disinsectant, de

  then the storage device to the leading edge of the wing.

  One of the objects of the present invention is also to provide a de-icing and disinsection system, using elements

  particularly suitable for small modern aircraft.

  Finally, the object of the present invention is to provide a de-icing system (which term will be used hereinafter to designate also a disinsectisation system) of a relatively simple design and which

  overcomes the aforementioned difficulties for a relatively low cost.

  The above objects, among others, are realized by the creation

  of an improved aircraft wing de-icing system,

  system comprising means for storing an antifreeze liquid, or degassing

  a fiber-based interlining, non-metallic, porous, self-

  wearing, rigid and lightweight, shaped in the shape of surface leading edge

  bearing, and means for regulating the flow of antifreeze liquid, or

  from the storage means to the outer surface of said

  compounding The building of the leading edge from

  non-metallic compound, gives structural compatibility and

  with the wing which consists of a similar composite material

  In order to maintain the laminar flow over the entire surface of the wing, the section of the airfoil must not vary significantly

  with the wing load The composite linings allow the construction

  a very rigid wing that does not deform under the aerodynamic load.

  namic. In the preferred embodiment, the control means of the

  flow of the deicing fluid comprises a microporous plastic membrane

  located between the storage medium and the composite interlining

  the last is preferably made of a fiberglass fabric with 3 di-

  Partially impregnated with resin Preferably, a distribution means consisting of a layer of aramid fiber fabric is laminated on the outer surface of the compound interlining, so as to ensure a more uniform distribution of the antifreeze solution on the surface. outer surface of the wing.

  The present invention will be well understood on reading the

  following description made in conjunction with the attached drawings, in which:

  FIG. 1 represents a plan view of a small aircraft characterized by

  showing the locations where it is proposed to use the porous elements of the leading edge of the de-icing system according to the

present invention.

  Figure 2 shows a partial sectional view, along the section plane 2-Z of Figure 1, a porous leading edge element;

  FIG. 3 represents an isometric rear view of the interior of

  with a porous leading edge element; FIG. 4 represents a partial plan view of a single

  layer of the preferred 3-way compound used in the present invention.

  tion; and FIG. 5 represents a partial sectional view according to the

sectional plane 5-5 of Figure 4.

  The deicing system according to the present invention comprises a tank mounted in a convenient place inside the aircraft for storing a deicing fluid such as glycol. A pump is used to pump this fluid from the tank to the elements. porous leading edge Metering assemblies are typically used to provide a more even distribution to all elements

  Porous leading edge As has been described so far, the system

  It is well known to those skilled in the art. In accordance with the present invention, an improved, non-metallic, porous, self-supporting, rigid and lightweight composite interliner is used to form the leading edge elements of an aircraft. and to provide a porous surface allowing

  the deicing fluid supply.

  As shown in Figure 1, locations are indicated

  on a small airplane 12, showing where the elements of the

  leading edge of the deicing system according to the present invention.

  Designed primarily to be installed along the edges of 20

  wings 14 of the aircraft, the leading edge elements of the degassing system

  can also find their use as leading edges of other bearing surfaces such as on the empennage, for example, the

  edge 22 of each horizontal stabilizer 16 and the front edge 24 of the horizontal

  vertical benchmark 18 In order to simplify the description of the system

  me defrosting according to the present invention, will be described only

  the element forming the leading edge 20 of the wings 14 of the aircraft The structure

  ture and operation of each of the leading edge elements of the

  installed as leading edges on other surfaces

  aunts, are substantially the same as those installed on the wings 14.

  However, the dimensions and shape of each edge element

that can vary.

  As shown in FIG. 2, the leading edge element 26 of the de-icing system comprises, firstly, a non-metallic, porous and self-supporting compound fabric, fairly rigid but relatively light, so as to be particularly useful for aerodynamic needs

  modern aircraft and, secondly, a means of regulating

O

  bit of antifreeze solution flowing through the pores of the element towards the

  In the preferred embodiment, the outer surface thereof

  26 of the leading edge comprises an outer envelope 36 and an inner envelope 38, these two envelopes 36 and 38 being fixed to each other so as to form between them a cavity 32 They provide the required self-supporting rigidity to form the bearing surface of the leading edge of the wing The cavity 32 is provided to contain a fluid which, on the one hand, is subjected to a positive pressure with respect to the surface

  outer casing 36 and which, on the other hand, is pumped from

  then the reservoir (not shown) of the system through a

  supply connector 44 The preferred leading edge member 26 comprises

  also takes a microporous plastic membrane 28 laminated in the cavity 32, between the outer casing and the inner casing, for

  regulate the flow of fluid in the driver.

  The outer and inner preferred envelopes are

  killed from one or more layers of cloth, each of which is woven as

  3-way canvas 3-way linings are well known.

6 2536037

  In addition to these, multi-directional liners such as seven-direction (7-D) or eleven-direction (11-D) liners described in US Pat. No. 3,949,126 could be used.

  4 and 5, such 3-D interlining 48 comprises four separate groups.

  Two groups of wires 50 and 52 are arranged in the Y direction (see the indications of the coordinate systems accompanying FIGS. 4 and 5) and form two parallel layers of wires as shown in FIGS. group are arranged

  in the X direction and form a third layer of wires enclosed in

  The yarns 56 of a fourth group are interwoven with the yarns 50 and 52 in a Z direction, so as to grip the yarns 50 and 52 (see FIG. Thus, the four groups of yarns together The weaving, the size of the yarns and their distribution in the interlining 48 may be varied in order to obtain a stabilizer having the desired mesh and porosity distribution. The preferred material for the yarns 50, 52, 54 and 56 is the glass fiber The interlining forming the outer casing 36 is impregnated with a resinous material so as to form a compound and stiffened material 40, but without filling all the pores of the stabilizer so that this material 40 remains porous Further, the outer shell comprises,

  preferably at least one additional layer 30A of a fabric

  only on the outer surface of the envelope to form an outer skin; this fabric will be made of a material (such as any one of the many aramid fibers of the type manufactured by EI du Pont de Nemours and Co. Wilmington, Delaware under the brand KEVLAR) which will add to the bearing surface a resistance to wear and fatigue as well as aerodynamic flatness It will be, in addition, a weave fine enough to ensure a more even distribution of the antifreeze solution on the outer surface Similarly, the inner surface of the outer casing 36 can be coated with a layer of fabric 30 B, similar to layer A, to provide greater rigidity The inner shell 38 is sufficiently impregnated with resin to be rendered completely non-porous

  so that no fluid can pass through it.

  The microporous membrane 28 intended to regulate the flow of the

2536 03 T

  Antifreeze solution through outer casing 36 preferably comprises at least a thin film or sheet of polyvinylidene fluoride of substantially uniform microporosity, of the type manufactured by Millipore Corporation of Bedford, Mass., under the trade designation HVLPOOO 1 O, although it is understood that other microporous films

  made from the same material or another material, may be used.

  The membrane 28 will preferably be affixed to the inner surface of the outer casing 36 by adhering the outer edges of the membrane 28 to the casing

  36 using a suitable adhesive.

  Referring to FIG. 3, each leading edge element 26 is preferably composed of several sections 42 each forming a

  cavity 32 separated, the contiguous cavities being limited by a recess 46.

  A supply connector 44 for each cavity 32 is attached to the inner casing 38; it is intended to be coupled to a fluid line (not shown) and will ensure the passage thereof between this pipe

and the cavity 32.

  The following example describes a method of manufacturing a leading edge member 26, it being understood that this is an illustrative example and

non-limiting.

  The outer casing 36 is vacuum bag molded into a female mold. A cloth layer made of dry, finely woven aramid fibers (purchased from EI at the Pont de Nemours in Wilmington, Delaware under the trade designation NO. 120 KEVLAR 49) is first placed in the mold to form the outer skin layer 30 A 1.016 mm thick pre-impregnated textile glass web is then placed

  (40 mils), in the mold over layer 30 A This pre-printed textile glass

  Three-way gel is obtained by dipping the ribbon in a DER 331 epoxy resin bath manufactured by Schell Chemical Company of Houston, Texas (with NMA and BDMA hardeners), diluted with 50% Mek, curing the resin. being obtained in stages or continuously in a furnace heated to a temperature of about 1210 C (2500 F) for a period of about sixteen (16) minutes Finally, another layer of aramid fiber fabric identical to layer A, is placed on the layer of preimpregnated textile glass thus constituting the inner layer of the outer casing 36. This results in the mold a sandwich structure partially impregnated with resin and composed of a layer of glass fibers between two layers of fiber fabric aramides The inner casing 38 is molded to the vacuum bag in the same female mold with a modification which consists in placing a layer of cork with a thickness of 1.498 mm (0.059 mm). ") in the mold to simulate the outer casing 36 during the molding of the inner casing 38 Rectangular cork plates of the same material are attached to the aforementioned cork layer and are spaced apart from each other

  to simulate cavities 32 separated by troughs The composite laminate

  killing the inner casing comprises three layers of 7500-38 prepreg boat-type fiberglass, finish NO 1-62A, manufactured by Northern Reinforcements, Exeter, New Hampshire, impregnated with 100% epoxy solids in particular each of the three layers of glass fibers was formed by dipping a three-directional, 40 mil (1.016 mm), three-directional prepreg textile glass strip into

  100% DER 331 epoxy resin with NMA and BDMA hardeners.

  The baking of the resin is then carried out in stages or continuously in

  an oven heated to 1210 C (2500 F) for sixteen (16) minutes.

  After molding and baking the inner laminate, a small hole has been drilled in the corner of each cavity 32 to allow the deicing fluid to enter. A polyethylene connector 44 is adhered to each hole by means of a structural adhesive, such as EA 934 adhesive manufactured by

  Dexter Hysol Corporation of Pittsburg, California.

  The inner 38 and outer 36 laminate shells are then welded together, two layers of the polyvinylidene fluoride membrane being sandwiched between these envelopes. The outer edges and the boundaries between the cavities are bonded with the EA 934 adhesive and tightened during curing the adhesive After curing, the edges can be sandblasted and any leaks sealed with a suitable sealant, such as the Hysol R 9-2039 epoxy resin

hardens at room temperature.

  We will now give a description of how the system works

  According to the present invention, an antifreeze fluid, such as glycol, is discharged under a certain positive pressure, for example by a pump, from a central storage container (not shown) through a pipe (not shown) to each The inner casing 38 is non-porous, so that the pressurized glycol passes through the microporous plastic membrane 28 at a rate that is determined by the pressure of the fluid. and the nature of the membrane 28, and from there it passes through the outer casing 36 of the element 26 After passing through the porous composite material 40 of the outer casing, it meets the layer

  Thin mesh 30A (Figure 2), which ensures-a distribution

  very uniform glycol on the outer surface of the element 26 The pressure of the glycol is adjusted so that it oozes through

  the surface layer 30A at a suitable rate to prevent any

  Frost formation on the leading edge 20 of the wing 14 In order to minimize the amount of glycol required to prevent frost formation as mentioned above, the glycol seepage rate is

  kept as low as it is practically possible.

  Although the preferred embodiment of the present invention has been described, it is obvious that the leading edge element 26

  may be modified while remaining within the scope of the present invention.

  For example, the present invention can be modified by removing the porous plastic membrane 28 from the leading edge member 26 and adjusting the flow rate of the fluid by means of the composite material 40 of the outer shell 36 of the element. The content of the resin, the composition thereof, as well as the construction of the fabrics making up the interlining 40 can be varied,

  in order to control the porosity and pore configuration of the enven-

  outer envelope 36, thereby regulating the glycol flow rate through this

last.

  Other possible methods for controlling the flow rate of the fluid through the composite material 40 of the outer casing 36 include:

  1) the use of a fugitive filler in the base resin; and 2) the use

  Fugitive fibers in material 48, as described in more detail above. 1) The composition of the resin used for the manufacture of material 40 could be modified by introducing soluble or volatilizable fillers which would be removed from the material. the resin by leaching or by evaporation after molding of the composite material 40 The particle size distribution of such a fugitive filler could be modified so as to obtain

253603?

  a composite material 40 with a porosity capable of controlling the flow rate of the

fluid in a desired manner.

  2) Fugitive fibers such as alcohol could be introduced

  polyvinyl, in weaving the material 48 according to a predetermined pattern.

  When the fugitive fibers have been leached out of the material 48, there remains a composite material 40 having the porous structure required to effect proper control of the flow of fluid through the envelope

36 of the element 26.

  In addition to its use in particular in a deicing system for leading edges of airfoils, the present invention, as noted above, has other uses. One of these is to permanently allow a larger laminar flow of air on all dynamic surfaces, keeping the leading edge of the bearing surface in a smooth state Constant and uniform seepage of a fluid (which is not necessarily glycol) on the outer surface the leading edge of the airfoil would also tend to prevent particles of matter, including insects, from adhering to the leading edge and, therefore, to maximize the laminar flow of air over the the

  bearing surface, while minimizing turbulent flow.

  The invention illustrated and described above has many advantages. First, it allows the leading edge of a bearing surface to also function as a part of the deicing device, while minimizing the weight added to the aircraft. compared to

  similar de-icing systems which employ a metal interlining.

  The leading edge element 26 of the deicing system according to the present invention enables a weight reduction of up to 50%. The use of the non-metallic, rigid and light composite material 48 could also make it possible to manufacture de-icing systems. at a lower cost than the current possibilities. In addition, the use of the composite material 40, non-metallic

  and rigid, gives the leading edge member 26 a structural strength.

  adequate structure and porosity structure to facilitate the distribution of

  The surface layer 30 also provides the element 26 with a smooth aerodynamic surface so as to maximize the laminar flow of air on the flange 14 while minimizing turbulent flow. preferred embodiment of the present invention, the surface layer 30 consists of a fabric of aramid fibers, finely woven, providing at the same time to the element 26 an increased resistance to wear The fineness of the mesh of the fabric Finally, the aramid fiber fiber provides a very uniform distribution of the antifreeze fluid on the outer surface of the element 26, thus minimizing the opportunities for ice accumulation at any point in the

surface of the element 26.

  The present invention is not limited to the embodiment examples la which have just been described, it is on the contrary susceptible of variants

  and modifications that will occur to those skilled in the art.

Claims (16)

R E V E N D I C A T IO N S   An article having an outer surface shaped like a leading edge of a bearing surface and adapted to be used with a reservoir comprising a fluid and means for pressurizing said fluid so that it flows on said outer surface to a predetermined flow rate, this article being characterized in that it comprises a composite, non-metallic, porous, self-supporting and rigid interlining material, as well as a means for regulating the flow of this fluid under pressure through the material up to the outer surface of it.   Article according to Claim 1, characterized in that the   material has a structure along at least three directions.   Article according to claim 1, characterized in that the   Flow control means comprises a microporous membrane.   4 Article according to claim 1, characterized in that the non-metallic, porous, self-supporting and rigid composite material constitutes an outer envelope forming the outer surface, this article further comprising an inner envelope cooperating with the outer casing for   form a cavity between this outer envelope and this envelope   upper, intended to retain the fluid under pressure; An article according to claim 4, characterized in that the flow control means comprises a microporous membrane disposed at   the interior of said cavity, between the outer and inner shells.   Article according to claim 5, characterized in that the   Microporous membrane is attached to the outer shell.   Article according to claim 6, characterized in that the   membrane contains polyvinylidene flower.   8 Article according to claim 1, characterized in that the   Composite material is a fiberglass material, impregnated with resin.   Article according to claim 8, characterized in that it further comprises a layer of aramid fiber cloth disposed on the   composite material to form the outer surface.   An article according to claim 9, characterized in that the fabric layer is formed of a fine weave so as to provide a wear-resistant surface and a more uniform flow of the fluid on that surface external.   An article according to claim 10, characterized in that it further comprises a second layer of aramid fiber web arranged by   above the composite on the surface opposite to the outer surface.   12 Article according to claim 11, characterized in that the composite comprises a layer of fabric of a structure following at least three directions.   A system for wetting the bearing surface, characterized in that it comprises, in combination, a hollow bearing surface leading edge member formed of a porous composite material and a foraminous, non-metallic, self-supporting and rigid structure, this element being fixed to a non-porous support and having in front of the support an empty space for receiving a fluid under pressure; means for adjusting the flow of fluid from the empty space through the member; a means for transporting the fluid   even in this space; and means for pressurizing the fluid.   System according to Claim 13, characterized in that the composite material, which is porous and of a foraminous structure, is a resin-impregnated fabric formed of glass fibers woven in three directions, this composite material having a mesh and characteristics predetermined porosity.   System according to claim 14, characterized in that the porosity of the composite material is determined by the amount of resin contained in the material.   System according to Claim 14, characterized in that the porosity of the composite material is a function of the fugitive material removed from the resin contained in the canvas.   System according to claim 14, characterized in that the porosity of the composite material is a function of the fugitive fibers eliminated some cobweb.   System according to Claim 14, characterized in that the   porosity is a function of the viscosity of an antifreeze type of the fluid.