Pneumatic deicer assembly having a self connecting shell

Abstract: A pneumatic deicing system for deicing an airfoil includes a flexible deicing member having inflatable tube-like passages provided therein for being inflated with a pressurized fluid, wherein the deicing member is bonded to a shell having a snap type connector for mating with another connector either on the airfoil or integrated into another part of the shell. An air connector extends through the shell and is utilized for putting the deicing member in fluid connection with the fluid source. Radar absorptive material may be disposed between the shell and the deicing member for reducing the radar cross section of the airfoil.

Description: The present invention relates to deicing systems and more particularly, a pneumatic deicing system adaptable to small cross-section airfoils. Under certain operating conditions aircraft are vulnerable to accumulation of ice on component surfaces. It is well known that such accumulation of ice can lead to disastrous results. A wide variety of systems have been developed for removing ice from aircraft during flight and can he placed into three general categories: thermal, chemical, and mechanical. The mechanical category of deicing systems operate by distorting the airfoil surface of the aircraft to he deiced. Distortion of the airfoil surface causes cracking in the ice accumulated thereon, and subsequent dispersal of that ice into the air stream passing over the aircraft component. The principal commercial mechanical deicing means is commonly referred to as pneumatic deicing wherein a component (e.g. the leading edge of a wing) of an aircraft is covered with a plurality of expandable, generally tube-like structures inflatable by employing a pressurized fluid, typically air. Upon inflation, the tubular structures tend to expand substantially the leading edge profile of the wing or strut and crack ice accumulating thereon for dispersal into the air stream passing over the aircraft component. Typically, such tube-like structures have been configured to extend substantially parallel to the leading edge of the aircraft component. Fig. 1 illustrates a prior pneumatic deicer 12 formed from an elastomeric composite having rubbery or substantially elastic properties. The deicer 12 is disposed on an airfoil 14. A plurality of tubes 16 are formed in the composite and are provided pressurized fluid, such as air, from a manifold 18. The manifold 18 is supplied fluid via a connector 20, which transfers fluid from a pressurized source (not shown). Connector 20 is integrated into the deicer 12 during manufacturing. Tubes 16 expand or stretch under pressure by 40% or more during inflation cycles, thereby causing a substantial change in the profile of the deicer (as well as the leading edge) to cause cracking of ice accumulating thereon. Referring now to Fig. 2, a prior pneumatic deicing system 10 is comprised of a deicer 12 having a plurality of tubes 16 and a manifold 18 provided therein. The deicer 12 is bonded or attached to an airfoil 14. Pressurized fluid is provided to manifold 18 via a connector 20, which is integrated into deicer 12. A large hole 22 must be provided in airfoil 14 in order to accommodate connector 20. One drawback to the system illustrated in Figs. 1 and 2 is that hole 22 provides a significant source of radar reflection when so exposed. Another drawback to this deicing system is that connector 20 represents a size limitation in that the thickness of the airfoil 14 cannot be smaller than the smallest manufacturable height of connector 20. In other words, connector 20 imposes a size restriction on the airfoil because the connector can be reduced in size only so much. The deicer system cannot be utilized therefore, for very thin airfoils, such as propellers of an airplane or the rotor of a helicopter. US-A-2 539 576 discloses a pneumatic deicing system for attachment to an airfoil comprising a flexible deicing member with an inflatable tube-like passage provided therein, said flexible deicing member having a top side exposed to the air and a bottom side attached to the airfoil. Fluid connection means for placing said deicing member in fluid communication with a fluid source are formed integrally with the flexible deicing member. US-A-2 539 576 is silent concerning the connection between the flexible deicing member and the airfoil. US-A-2 363 592 describes a pneumatic deicing system having a flexible deicing member with an inflatable tube-like passage provided therein similar to the flexible deicing member disclosed in US-A-2 539 576. Fluid connection means for placing said deicing member in fluid communication with a fluid source are provided, the fluid connection means being effectively joined in a quick-detachable manner. US-A-2 363 592 is silent concerning the connection between the flexible deicing member and the airfoil. US-A-5 112 011, which forms the basis for the precharacterizing part of claim 1, describes a pneumatic deicing system being comprised of a flexible deicing member having an inner ply and an outer ply, the inner and outer plies being covered by an outer sheet member and an inner sheet member, respectively, the sheet members being made of resilient rubber-like material. The flexible deicing member comprises a plurality of inflatable tube-like passages provided therein. The sheet member of the flexible deicing member is adhered to an airfoil by a suitable adhesive. WO91/12173 describes a combined pneumatic deicing and electro-magnetic wave attenuation system. The combined system comprises a flexible deicing member having a plurality of inflatable tube-like passages provided therein. The flexible deicing member is bonded to an electro-magnetic wave-absorber which itself is bonded to an airfoil by known cements or other bonding agents. It is the object of the present invention to provide a pneumatic deicing system which allows to be used in hard to get places. This object is solved, according to the invention, with the features of claim 1. The deicing system according to the present invention provides a pneumatic deicer assembly which is attached to a shell that fits over the airfoil surface to be deiced and is secured to the airfoil with positively engaging airfoil connection means attached to the shell or to the shell and the foil. Preferrably, the pneumatic deicer is formed or bonded to a shell that fits over and is secured mechanically to the airfoil surface to be protected and includes a fluid connective fitting protruding from the pneumatic deicer assembly area. According to a preferred embodiment of the present invention a deicing system is comprised substantially of a flexible material or composite, which includes a plurality of tube-like members formed therein and arranged substantially parallel to one another, which expand or inflate when provided a pressurized fluid. The flexible material is formed or bonded to a hardened shell that fits over and is secured mechanically to the airfoil surface to he protected. In accordance with a second preferred embodiment of the invention, a pneumatic deicing system is comprised substantially of a flexible material composite, which includes a plurality of tube-like members formed therein and arranged substantially parallel to one another, which expand or inflate when provided a pressurized fluid. The flexible material is formed or bonded to a shell that fits over and is secured mechanically to the airfoil surface to be protected. A fluid connective fitting is provided in the shell to be mated with a connector in the airfoil in order to provide fluid communication between a fluid source and the inflatable tube-like members. The present invention allows for installation of pneumatic deicers where limited physical access prevents or limits use of prior pneumatic deicing systems. The present invention is easy to manufacture and is also easy to replace during regular maintenance overhauls. These and other features and advantages of the present invention will become more apparent in light of the detailed description of exemplary embodiments thereof, as illustrated by the drawings, in which: Fig. 1 is a top view of a prior art deicing system. Fig. 2 is a fragmentary cross-sectional view taken along line 2-2 of Fig. 1. Fig. 3 is a cross-sectional view of a pneumatic deicing system in accordance with a first embodiment of the present invention. Fig. 4 is a fragmentary cross-sectional view of a deicing system in accordance with a second embodiment of the present invention. Fig. 5 is a cross-sectional view of a connection means for a deicing system in accordance with the present invention. Fig. 6 is a fragmentary cross-sectional view of a pneumatic deicing assembly in accordance with a third embodiment of the present invention. Fig. 7 is a cross-sectional view of a connector for a pneumatic deicing assembly in accordance with the present invention taken along line 7-7 of Fig. 5. Fig. 8 is a cross-sectional view of a pneumatic deicing system in accordance with a fourth embodiment of the present invention. Referring now to Fig. 3, a first embodiment of a pneumatic deicing system 110 includes a pneumatic deicing assembly 112, comprised substantially of a flexible elastomeric or composite material having inflatable tube-like members which are inflated by a pressurized fluid source (not shown). Deicing system 110 is illustrated in Fig. 3 in a noninflated state. Flexible elastomeric pneumatic deicing assemblies are well known in the art, examples of which are disclosed in US-A-4,779,823, US-A-4,561,613, US-A-5,112,011 and US-A-4,687,159. The deicer assembly 112 is bonded to a shell 114, which is attached to the airfoil (not shown) to be deiced. Shell 114 must be a resilient yet flexible material, such as a composite, and preferably a plastic composite. Composites, and plastic composites are well known in the art. A suitable composite material for shell is fiberglass. Under these conditions, a cement, such as an epoxy cement may be used to bond the deicer assembly 112 to the shell 114. A connector 116 is disposed within a hole 118 in the shell 114 for placing the deicer assembly 112 in fluid communication with a fluid source (not shown). Connector 116 has an output flange 120 which is bonded to the shell 114 utilizing a cement, such as an epoxy cement. Connector 116 also has an input flange or barb 122 which is utilized to provide a snap type connection which will be described in greater detail hereinafter. Connector 116 represents the male part of a snap type connection means. An O-ring 124 is disposed within an annular groove 126 for providing a sealing means when connector 116 is mated with its female counterpart. It is evident from Fig. 3 that the airfoil to be deiced must have a receptacle for receiving connector 116 and also a pathway or passage for putting the deicer assembly 112 in fluid communication with a fluid source (not shown). For communicating fluid, connector 116 has a cylindrical input orifice 128 which merges into a frustoconical opening 130 which merges into a cylindrical passageway 132. A plurality of slots 129 extending axially through connector 116 to orifice 128 and frustoconical opening 130 allows the shell to flex inward when the connector 116 is being mated with its connective counterpart, not shown in Fig. 3 but described in greater detail hereinafter. Referring now to Fig. 4, a second embodiment of a deicing system 140 in accordance with the present invention includes a deicer assembly 142 and a shell 144 similar to deicer assembly 112 and shell 114 illustrated in Fig. 3. A jacket 146 of radar absorptive material, such as carbonyl iron, is provided over the leading edge 148 of the shell 144 between the shell 144 and the deicer assembly 142. Jacket 146 is preferably bonded to the shell 144 utilizing a cement, such as an epoxy cement and is bonded to deicer assembly 142 utilizing a cement, such as an epoxy cement. Jacket 146 of radar absorptive material reduces the radar signature of the airfoil to he deiced. Referring now to Fig. 5, a receptacle 150 or female connector for mating with male connector 116 includes a cylindrical opehing 152 for receiving the connector 116. Cylindrical opening 152 merges into a frustoconical seat face 154 for engaging with frustoconical surface 123 of male connector 116. Frustoconical seat face 154 merges into cylindrical aperture 156 which merges into a duct 158. Connector 116 is preferably made of a formed, resilient non-metal such as hardened rubber. The female connector 150 is preferably made of a suitable composite, such as fiberglass. O-ring 124 seals the connector 116 in the receptacle 150 and thereby prevents blow- by of fluid. Referring now to Fig. 6, a third embodiment of a deicing system 170 includes a deicing assembly 172, similar to deicing assembly 112 described and illustrated herein before in Fig. 3 which is formed or bonded to a shell 174, which is similar to shell 114 described herein before in Fig. 3. The ends of shell 174 opposite the leading edge end are configured in a manner so as to have a snap together function. In this manner one side of shell 174 has a connection means 176 in the form of a nipple shaped protrusion while the other side of shell 174 is configured to have a corresponding connection means 178 in the form of female receptacle to receive the nipple 176. Deicing system 170 may therefore be held in place on the airfoil structure by positioning the assembly around the airfoil structure and then "snapping" it together. This function makes both installation and removal of the deicing system easy, and allows use of deicing systems in hard to get places not previously deicable. Of course, the connection means may have other configurations then that specifically shown, the important point being that the shell is adapted to have an attachment scheme such that the shell positively engages with, or snaps onto the airfoil to he deiced. Alternatively, deicing system 170 may be constructed with a male connection means 176, such as a nipple shaped protrusion which is mated with a female connector portion provided in the airfoil. In this attachment scheme, deicing system 170 doesn't necessarily fully enclose the airfoil, yet it has the similar advantage of being adapted to be snapped into place. Referring now to Fig. 7, wherein connector 116 is illustrated as having four slots 129 provided therein to facilitate flexing of the nipple shaped connector 116 inward when it is inserted into the female connector 150. Of course other slot quantities and configurations may be utilized to accomplish the same objective. It is also to be understood that if the deicing system of the present invention is configured such that it doesn't fully enclose the airfoil, the fluid connector, such as connector 116 illustrated and described hereinbefore, may also be utilized to perform the attachment function in addition to the fluid connection function. That is, the fluid connector would perform two distinct functions, attachment and fluid connection. Referring now to Fig. 8, wherein a pneumatic deicing system in accordance with a fourth embodiment of the present invention is generally similar to the pneumatic deicing assemblies illustrated hereinbefore in the previous figures and is thus indicated by references numerals corresponding to those discussed above, except that a 300 "prefix" is utilized. A pneumatic deicing system 310 thus includes a pneumatic deicing assembly 312, comprised substantially of a flexible elastomeric or composite material having inflatable tube-like members which are inflated by a pressurized fluid source (not shown). Deicing system 310 is illustrated in Fig. 8 in a noninflated state. The deicer assembly 312 is bonded to a shell 314, which is attached to the airfoil 300 to be deiced. A connector 316 is integrated into shell 314 for placing the deicer assembly 312 in fluid communication with a fluid source (not shown). Connector 316 represents the male part of a snap type connection means. A receptacle 350 or female connector for mating with male connector 316 is provided in the airfoil 300. It can be seen that deicer assembly 312 has a "T" shape and does not encompass the entire airfoil to be deiced, but can still be snapped into place for easy installation and removal. A deicing assembly having the features illustrated in Figs. 3-8 provides an assembly which allows fluid to be routed through a very thin airfoil, thereby eliminating the need for external fluid lines. In addition, the present invention provides deicing for tightly fitted airfoils, such as those found on turbine engine inlets.

Claims: A pneumatic deicing system for attachment to an air-foil utilizing pressurized fluid from a fluid source comprising: a flexible deicing member (112;142;172;312) having a plurality of inflatable tube-like passages provided therein, said flexible deicing member (112;142;172; 312) having a top side exposed to the air and a bottom side, fluid connection means (116;316) for placing said deicing member (112;142;172;312) in fluid communication with the fluid source, and a shell (114;144;174;314) attached to the bottom side of said deicing member (112;142;172;312) and being connected with the airfoil (300) to be deiced, characterized in that said airfoil connection comprises positively engaging airfoil connection means (116,150;176,178; 316,350) mechanically securing said shell (114;174; 314) to said airfoil (300) and being comprised of at least one first connector means (116;176;316) associated to said shell (114;174; 314), and wherein the airfoil (300) or the shell (174) includes at least one second connector means (150;178;350) for engaging with said first connector means (116;176;316). A pneumatic deicing system in accordance with claim 1, wherein said first connector means (116;176;316) is a male connector means and said second connector means (156;178;350) is a female connector means. A pneumatic deicing system in accordance with claim 2, wherein said male connector means (316) is/are nipple-shaped. A pneumatic deicing system in accordance with one of claims 1-3, wherein said fluid connection means and said airfoil connection means are an integral assembly. A pneumatic deicing system in accordance with one of claims 1-4, wherein said fluid connection means (116) is/are comprised of a generally cylindrical protrusion having an annular grove (126) disposed therein for receiving an O-ring (124) and a substantially frustoconically shaped barb (122) formed on the end for disposal within a female shaped connector (150) adapted for receiving and engaging with said fluid connection means (116). A pneumatic deicing system in accordance with one of claims 1-5, wherein said shell (114;144;174;314) is comprised of a plastic composite. A pneumatic deicing system in accordance with one of claims 1-5, wherein said shell (114;144;174;314) is comprised of fiberglass. A pneumatic deicing system in accordance with one of claims 1-7, wherein said deicing member (112;142; 172;312) is comprised of an elastomer. A pneumatic deicing system in accordance with one of claims 1-8, further comprising an intermediate layer (146) of radar absorptive material disposed between at least part of said shell (144) and said deicing member (142). A pneumatic deicing system in accordance with claim 9, wherein said radar absorbent material is carbonyl iron. A pneumatic deicing system in accordance with claim 1, wherein said shell (174) surrounds the airfoil to be deiced and wherein said airfoil connection means is comprised of at least one male connector means (176) on said shell (174) and a corresponding female connector means (178) for receiving and engaging with each one of said at least one male connector means (176), said connector means being located such that said deicing system (170) is held onto the air-foil by engaging said male connector means (176) with said female connector means (178). A pneumatic deicing system in accordance with claim 11, wherein said male connector means (176) is nipple-shaped.

Inventors: FAHRNER ALAN JOHN, WEISEND NORBERT ADRIAN JR, FAHRNER, ALAN JOHN, WEISEND, NORBERT ADRIAN, JR.
Applicants: GOODRICH CO B F, THE B.F. GOODRICH COMPANY
Application year: 1993
Main classification: B64D15
IPC codes: B64D15