Abstract:
A thermal blanket system is provided on an aircraft component to protect the component, for example, from engine heat. The component has a latch half attached thereto, which is also covered by the thermal blanket system. In some scenarios, the latch half may need to be detached from the component because the latch was stuck closed. The thermal blanket system includes a portion thereof which overlaps the latch half and breaks away from the remainder of the thermal blanket system when the latch half is detached.

Description:
FIELD 
       [0001]    The present disclosure relates to nacelles for an aircraft propulsion system, and more specifically, to thermal blankets that protect nacelles from engine heat. 
       BACKGROUND 
       [0002]    During aircraft maintenance operation, interior portions of the propulsion system may need to be accessed. Access may be gained by actuating one or more portions of the nacelle from a closed position to an open position. One or more portions of a nacelle may be held together by latches. If a latch fails to release, the latch may need to be removed so that the nacelle can be opened. Latch removal may lead to damage to portions of a thermal protection system (“TPS”), which typically comprises insulating thermal blankets fastened to nacelle components to protect them from radiating and convective heat from the engine. This may cause an aircraft to be grounded until the TPS can be replaced, which is detrimental to the availability or utilization rate of the aircraft. 
       SUMMARY 
       [0003]    In various embodiments, a system may comprise a structure, a latch system, a first portion of a TPS, a second portion of the TPS. The latch system may comprise a first latch half and a second latch half. The first latch half may be attached to the structure. The first portion of the TPS may be coupled to the structure. The second portion of the TPS may be coupled to the first latch half. The first portion of the TPS and the second portion of the TPS have a breakaway joint formed there between. The breakaway joint may be configured to separate in response to the first latch half being detached from the structure. 
         [0004]    In various embodiments, a propulsion system may comprise a gas turbine engine, a first panel, a second panel, a first latch half, a second latch half, and a thermal protection system. The first panel and the second panel may be adapted to be moveable between an open position in which maintenance access is granted to the engine and a closed position in which the first and second panel substantially surround and enclose at least a portion of the engine. The first latch half may be connected to the first panel. The second latch half may be connected to the second panel. The first and the second latch halves may be adapted to latch together when the first and second panels are in the closed position to hold the panels in the closed position. The thermal protection system may cover a substantial portion of a face of the first panel facing the engine when the first and second panels are closed. The thermal protection system may include a breakaway portion surrounding and substantially covering the first latch half. 
         [0005]    In various embodiments, a thermal protection system may comprise a first blanket portion and a second blanket portion. The second blanket portion may be coupled to the first blanket portion via a breakaway joint. The breakaway joint may be configured to provide a substantially permanent attachment of the second blanket portion to the first blanket portion during operation. The breakaway joint may also be configured to allow the second blanket portion to cleanly separate from the first blanket portion in response to a maintenance event. 
         [0006]    The forgoing features and elements may be combined in various combinations without exclusivity, unless expressly indicated herein otherwise. These features and elements as well as the operation of the disclosed embodiments will become more apparent in light of the following description and accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    The subject matter of the present disclosure is particularly pointed out and distinctly claimed in the concluding portion of the specification. A more complete understanding of the present disclosure, however, may best be obtained by referring to the detailed description and claims when considered in connection with the drawing figures, wherein like numerals denote like elements. 
           [0008]      FIG. 1A  illustrates a perspective view of an aircraft, in accordance with various embodiments. 
           [0009]      FIG. 1B  illustrates an exploded perspective view of propulsion system, in accordance with various embodiments. 
           [0010]      FIG. 2  illustrates a cross-sectional front view of a view of propulsion system, in accordance with various embodiments. 
           [0011]      FIG. 3A  illustrates an inner fixed structure including a thermal protection system, in accordance with various embodiments. 
           [0012]      FIG. 3B  illustrates a first portion of the joint and a second portion of the joint that connect the two nacelle hemispheres, in accordance with various embodiments. 
           [0013]      FIG. 4A  schematically illustrates a first portion of an inner fixed structure and a second portion of an inner fixed structure joined together by a latch assembly, in accordance with various embodiments. 
           [0014]      FIG. 4B  schematically illustrates a first portion of an inner fixed structure separated from a second portion of an inner fixed structure, in accordance with various embodiments. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    The detailed description of exemplary embodiments herein makes reference to the accompanying drawings, which show exemplary embodiments by way of illustration. While these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the inventions, it should be understood that other embodiments may be realized and that logical changes and adaptations in design and construction may be made in accordance with this invention and the teachings herein. Thus, the detailed description herein is presented for purposes of illustration only and not of limitation. The scope of the invention is defined by the appended claims. For example, the steps recited in any of the method or process descriptions may be executed in any order and are not necessarily limited to the order presented. Furthermore, any reference to singular includes plural embodiments, and any reference to more than one component or step may include a singular embodiment or step. Also, any reference to attached, fixed, connected or the like may include permanent, removable, temporary, partial, full and/or any other possible attachment option. Additionally, any reference to without contact (or similar phrases) may also include reduced contact or minimal contact. 
         [0016]    Furthermore, any reference to singular includes plural embodiments, and any reference to more than one component or step may include a singular embodiment or step. Surface shading lines may be used throughout the figures to denote different parts but not necessarily to denote the same or different materials. 
         [0017]    As used herein, “aft” refers to the direction associated with the tail (e.g., the back end) of an aircraft, or generally, to the direction of exhaust of the gas turbine. As used herein, “forward” refers to the direction associated with the nose (e.g., the front end) of an aircraft, or generally, to the direction of flight or motion. 
         [0018]    In various embodiments and with reference to  FIGS. 1A and 1B , an aircraft  100  may comprise a fuselage  102  and a pair of wings  104 . Propulsion system  110  (e.g., turbofan jet engine with a nacelle assembly) may be mounted on the underside of wing  104 . Propulsion system  110  may be configured to provide forward thrust and/or propulsion for aircraft  100 . 
         [0019]    In various embodiments, propulsion system  110  may comprise an engine  140  (e.g., a fan  142  and an engine core  144 ), a pylon  115 , and a nacelle package. The typical nacelle package, or more simply a nacelle, may comprise an inlet  120 , a fan cowl  125 , a thrust reverser  130 A and  130 B, and an exhaust system including an exhaust cone  145 , and exhaust nozzle  150 . The nacelle surrounds the engine core  144  providing smooth aerodynamic surfaces for airflow around and into engine  140 . The nacelle also helps define a bypass air duct through propulsion system  110 . 
         [0020]    In various embodiments, fan  142  may draw and direct a flow of air into and through propulsion system  110 . After fan  142 , the air is divided into two principal flow paths, one flow path through engine core  144 , and another flow path through a bypass air duct. The engine core flow path is directed into engine core  144  and initially passes through a compressor that increases the air flow pressure, and then through a combustor where the air is mixed with fuel and ignited. The combustion of the fuel and air mixture causes a series of turbine blades at the rear of engine core  144  to rotate, and to drive the engine&#39;s rotor and fan. The high-pressure exhaust gases from the combustion of the fuel and air mixture are thereafter directed through exhaust nozzle  150  at the rear of engine  140  for thrust. 
         [0021]    In various embodiments and with reference to  FIGS. 1B and 2 , the bypass air flow path includes air that is directed around engine core  144  in a duct or ducts defined by the nacelle (e.g., the area aft fan  142  and between thrust reverser  130  and inner fixed structure (“IFS”)  131 ). IFS may include an IFS panel  131 A and IFS panel  131 B The bypass air exits the bypass air ducts A 1  and A 2  at an exhaust nozzle at the aft end of the nacelle for thrust. In turbofan engines, the bypass flow typically provides a large percentage of the thrust for an aircraft. The bypass air ducts A 1  and A 2  in the nacelle in  FIG. 2  are C-shaped, and are principally defined by the exterior surface of IFS  131  and the inside surface of the thrust reverser  130 A and  130 B (shown as thrust reverser  130 A and thrust reverser  130 B in  FIG. 1B ). 
         [0022]    In various embodiments, engine  140  may be mounted to pylon  115  in two places. One of these at the aft end of the pylon  115 , over the engine turbine case, and in one of two places at the forward end of pylon  115 : the engine core (core mount) or the engine fan case (fan mount). Pylon  115  transmits structural loads (including thrust) between engine  140  and wing  104 , as shown in  FIG. 1A . 
         [0023]    In various embodiments, thrust reverser  130  may comprise two halves, thrust reverser  130 A and thrust reverser  130 B, generally configured to surround engine core  144 . Thrust reverser  130  may be hinged to the pylon  115  via one or more hinges which may provide access to an interior portion of propulsion system  110  and/or engine  140 . For example, and as shown in  FIG. 2 , thrust reverser  130 A and thrust reverser  130 B may be opened and/or rotated about an attachment point on pylon  115 . The thrust reverser  130  may comprise IFS panel  131 A and IFS panel  131 B and an outer sleeve. IFS panel  131 A and IFS panel  131 B may generally surround the engine core  144 . 
         [0024]    In various embodiments, first hemisphere of thrust reverser  130 A and second hemisphere of thrust reverser  130 B may be actuated to a closed position and retained together by a latch system. In this regards, the latch system may be configured to hold and/or retain first hemisphere of thrust reverser  130 A and second hemisphere of thrust reverser  130 B in a closed position around engine core  144 . 
         [0025]    In various embodiments and with continued reference to  FIGS. 1B and 2 , thermal protection system (“TPS”)  135  (e.g., one or more thermal blankets) may be installed on an interior surface of the IFS  131  facing the engine core  144 . TPS  135  may be configured to insulate and/or contain heat from engine core  144 . TPS  135  may be configured to act as an insulating barrier to protect IFS  131  against the heat emitted by engine core  144  and other components. Without the thermal protection of TPS  135 , the IFS  131  might overheat and lose structural integrity. TPS  135  may generally be attached to a bond panel of each of IFS panel  131 A and IFS panel  131 B. In this regard, fasteners may couple TPS  135  and/or at least portions of the TPS  135  to the bond panel. The bond panel may be the interior surface of each of IFS panel  131 A and IFS panel  131 B. 
         [0026]    In various embodiments and with reference to  FIGS. 3A-3B , IFS panel  131 A and IFS panel  131 B may be held and/or joined together by a latch system  138 . Latch system  138  may be any suitable latch system. For example, latch system  138  may be a bumper latch system. Latch system  138  may comprise a first joint portion  136  (e.g., a first latch half) and a second joint portion  137  (e.g., a second latch half). The bumper latch system may be capable of being remotely actuated. For example, the bump latch system may comprise a cable  132  that may be actuated to open latch system  138 , thus permitting IFS panel  131 A and IFS panel  131 B to separate and open. Moreover, latch system  138  may constrain and/or limit IFS panel  131 A and IFS panel  131 B from flexing outward. 
         [0027]    In various embodiments and with reference to  FIGS. 3A-3B  and  4 A- 4 B, during maintenance operations latch system  138  may be released to gain access to portions of propulsion system  110  such as, for example, engine core  144 . During operation, IFS panel  131 A and IFS panel  131 B may be operatively coupled to one another and closed when the first joint portion  136  is latched to second joint portion  137 . To unlatch latch system  138 , first joint portion  136  may be released from second joint portion  137 . 
         [0028]    In some circumstances, the latch system  138  may be stuck and it may not be possible to release first joint portion  136  from second joint portion  137 . Because first joint portion  136  is attached to IFS panel  131 A, and second joint portion  137  is attached to IFS panel  131 B, when the latch is stuck the panels  131 A and  131 B cannot be separated and opened for maintenance access. In such a scenario, it becomes necessary to disconnect first portion  136  from IFS panel  131 A. To do this, fasteners  139 - 1 ,  139 - 2  and  139 - 3  and any other fasteners attaching the first portion  136  to the IFS panel  131 A may be removed. Fasteners  139  may be accessed from the fan duct. IFS panel  131 A, when fully separated from first joint portion  136 , can now be swung away from IFS panel  131 B and opened. 
         [0029]    In a typical nacelle installation, an integral portion of the TPS 135 A that overlaps the first joint portion  136  may be trapped between first joint portion  136  and second joint portion  137 , while the remainder of TPS  135 A swings open with IFS half  131 A, which may result in the TPS  135 A tearing apart and becoming irreparably damaged. The irreparable damage required replacement of an entire portion of the TPS (e.g., TPS  135 A), which may be time consuming and expensive. 
         [0030]    In various embodiments, TPS  135  may comprise discrete pieces, portions and/or modules including for example, first portion  141  and second portion  143 . First portion  141  of TPS  135 A may surround first joint portion  136  and may be a discrete piece of TPS  135 . In this regard, the first portion  141  of TPS  135 A may be coupled to the remainder of TPS  135 A with a “breakaway” joint  133 . Breakaway joint  133  may be configured to allow a discrete portion of TPS  135  (e.g., first portion  141  of TPS  135 A and/or second portion  143  of TPS  135 B) to be separated from the remainder of TPS  135  without any irreparable and/or substantial damage, deformation and/or degradation. 
         [0031]    In various embodiments, breakaway joint  133  may be any suitable joint that is capable off allowing a clean separation (e.g., a non-destructive separation) between discrete portions of TPS  135 . In this regard, breakaway joint  133  does not cause irreparable damage deformation and/or degradation to the joined structures in response to breakaway joint  133  being separated. For example, breakaway joint  133  may be a frangible joint, a spot weld, an overlapping fold between discrete TPS  135  portions, or overlapping and interfering discrete TPS  135  portions (e.g., where first portion  141  and TPS  135 A have an interference fit with one another). 
         [0032]    In various embodiments, latch system  138  may be unfastened from IFS  131  (e.g., by removing fasteners  139 ) allowing at least one of first portion  141  and second portion  143  to separate from TPS  135  at a breakaway joint  133 . As noted herein, breakaway joint  133  may be an overlapping joint, a folded over join, and/or a frangible joint. In this regard, first portion  141  and/or second portion  143  may be removed, separated and/or detached from TPS  135  at breakaway joint  133  without damaging, cutting, and/or otherwise removing other discrete portions of TPS  135 A and/or TPS  135 B to gain access to first joint portions  136  and/or second joint portion  137 . 
         [0033]    In various embodiments, breakaway joint  133  may include a material and/or bond with adhesive properties such as, for example, room temperature vulcanizing (RTV) silicone, a spot weld, and/or the like. In this regard, breakaway joint  133  may be coupled and/or may bond discrete portions of TPS  135  in a substantially permanent manner for aircraft operation. However, during a maintenance event and in the event of a latch system  138  failure, first joint portion  136  or second joint portion  137  may be detached from the IFS panels  131 A or  131 B, respectively, and first portion  141  of TPS  135 A and/or second portion  143  of TPS  135 B may be cleanly and non-destructively separated from the remainder of the TPS  135 A or  135 B. The semi-permanent nature of breakaway joint  133  may allow a stuck latch system  138  to be opened without any significant damage to TPS  135 . In this regard, the first portion  141  of TPS  135 A and/or the second portion  143  of TPS  135 B may detach from the remaining TPS  135  structure, reducing, limiting, and/or eliminating any damage, deformation and/or degradation to TPS  135 . 
         [0034]    In various embodiments, latch system  138 , first joint portion  136  and/or second joint portion  137  may be repaired in response first portion  141  and/or second portion  143  being separated from TPS  135 . In this regard, with IFS  131  open, a technician may access latch system  138  to perform a repair. In response to a repair being complete, break joint  133  may be re-established between at TPS  135  and at least one of first portion  141  and second portion  143 . In this regard, TPS  135 , first portion  141  and/or second portion  143  may be undamaged and may be re-used. 
         [0035]    Benefits, other advantages, and solutions to problems have been described herein with regard to specific embodiments. Furthermore, the connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and/or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in a practical system. However, the benefits, advantages, solutions to problems, and any elements that may cause any benefit, advantage, or solution to occur or become more pronounced are not to be construed as critical, required, or essential features or elements of the inventions. The scope of the inventions is accordingly to be limited by nothing other than the appended claims, in which reference to an element in the singular is not intended to mean “one and only one” unless explicitly so stated, but rather “one or more.” Moreover, where a phrase similar to “at least one of A, B, or C” is used in the claims, it is intended that the phrase be interpreted to mean that A alone may be present in an embodiment, B alone may be present in an embodiment, C alone may be present in an embodiment, or that any combination of the elements A, B and C may be present in a single embodiment; for example, A and B, A and C, B and C, or A and B and C. 
         [0036]    Systems, methods and apparatus are provided herein. In the detailed description herein, references to “various embodiments”, “one embodiment”, “an embodiment”, “an example embodiment”, etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiments. 
         [0037]    Furthermore, no element, component, or method step in the present disclosure is intended to be dedicated to the public regardless of whether the element, component, or method step is explicitly recited in the claims. No claim element herein is to be construed under the provisions of 35 U.S.C. 112(f), unless the element is expressly recited using the phrase “means for.” As used herein, the terms “comprises”, “comprising”, or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.