Abstract:
An example thrust reverser of a gas turbine engine is configured to connect to an aircraft wing via a pylon via one or more thrust reverser mounts located adjacent to a top circumferential apex of the engine according to an exemplary aspect of the present disclosure includes, among other things, a first cowl moveable between a stowed position and a deployed position relative to a second cowl. The first cowl in the deployed position configured to permit thrust to be redirected from an engine to slow the engine. The first cowl forming a portion of a substantially annular encasement of the engine. The first cowl directly interfaces with second cowl of the encasement at a cowl interface position that is more than 18 degrees circumferentially offset from the top circumferential apex when the first cowl is in the stowed position.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority to U.S. Provisional Application No. 61/706820, which was filed on 28 Sep. 2012 and is incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    Turbomachines, such as gas turbine engines, typically include a fan section, a compression section, a combustion section, and a turbine section. Turbomachines may employ a geared architecture connecting portions of the compression section to the fan section. 
         [0003]    Turbomachines used to propel aircraft typically include thrust reversers. Moving components of the thrust reverser from a stowed position to a deployed position redirects thrust through the turbomachine to reduce the speed of the aircraft. In some examples, the moving components include a thrust reverser cowl that is translated axially between the stowed and deployed position. 
       SUMMARY 
       [0004]    A thrust reverser of a gas turbine engine configured to connect to an aircraft wing via a pylon via one or more thrust reverser mounts located substantially at or adjacent to a top circumferential apex of the engine according to an exemplary aspect of the present disclosure includes, among other things, a first cowl moveable between a stowed position and a deployed position relative to a second cowl. The first cowl in the deployed position configured to permit thrust to be redirected from an engine to slow the engine. The first cowl forming a portion of a substantially annular encasement of the engine. The first cowl directly interfaces with second cowl of the encasement at a cowl interface position that is more than 18 degrees circumferentially offset from the top circumferential apex when the first cowl is in the stowed position. 
         [0005]    In a non-limiting embodiment of the foregoing thrust reverser, the second cowl may extend substantially from the top circumferential apex. 
         [0006]    In a further non-limiting embodiment of either of the foregoing thrust reversers, the thrust reverser mounts may receive a pylon at the top circumferential apex of the encasement. 
         [0007]    In a further non-limiting embodiment of any of the foregoing thrust reversers, the second cowl extends in a first circumferential direction from the top circumferential apex to the cowl interface position, and the first cowl extends in the first circumferential direction from the cowl interface position to a bottom circumferential apex, which circumferentially opposes the top circumferential apex. 
         [0008]    In a further non-limiting embodiment of any of the foregoing thrust reversers, the first cowl may translate axially between the stowed position and the deployed position. 
         [0009]    In a further non-limiting embodiment of any of the foregoing thrust reversers, a fourth cowl of the encasement may move between a stowed position and a deployed position relative to a third cowl of the encasement, the third cowl directly interfacing with the fourth cowl at another position that is more than 18 degrees circumferentially offset from the top circumferential. 
         [0010]    In a further non-limiting embodiment of any of the foregoing thrust reversers, the first cowl and the second cowl of the encasement may be positioned on an inboard side of the engine, and the third cowl and the fourth cowl may be positioned on an outboard side of the engine. 
         [0011]    In a further non-limiting embodiment of any of the foregoing thrust reversers, the second cowl and fourth cowl may extend from circumferentially opposite sides of the top circumferential apex. 
         [0012]    In a further non-limiting embodiment of any of the foregoing thrust reversers, the cowl interface may be circumferentially offset from the top circumferential apex from 20 to 25 degrees. 
         [0013]    In a further non-limiting embodiment of any of the foregoing thrust reversers, the cowl interface may be circumferentially offset 32 degrees from the top circumferential apex. 
         [0014]    In a further non-limiting embodiment of any of the foregoing thrust reversers, the first cowl may move between the deployed position and the stowed position along a path that causes the first cowl to avoid contact with a slat of the aircraft wing. 
         [0015]    An engine configured to connect to an aircraft wing via a pylon located substantially at or adjacent to a top circumferential apex for the engine according to an exemplary aspect of the present disclosure includes, among other things, a first cowl and a second cowl. The second cowl extends from a thrust reverser mount located adjacent the top circumferential apex. The first cowl being translatable relative to the second cowl to selectively redirect thrust from the engine to slow the engine. The second cowl interfaces with the first cowl at a circumferential location that is more than  18  degrees circumferentially offset from the top circumferential apex. 
         [0016]    In a non-limiting embodiment of the foregoing engine, the twelve o&#39;clock position may be top circumferential apex of the engine. 
         [0017]    In a further non-limiting embodiment of any of the foregoingengines, the thrust reverser mount may be configured to receive the pylon such that the pylon extends adjacent to the top circumferential apex. 
         [0018]    In a further non-limiting embodiment of any of the foregoing engines, the first and the second cowls may be arcuate cowls. 
         [0019]    In a further non-limiting embodiment of any of the foregoing engines, the interface is an axially extending interface. 
     
    
     
       DESCRIPTION OF THE FIGURES 
         [0020]    The various features and advantages of the disclosed examples will become apparent to those skilled in the art from the detailed description. The figures that accompany the detailed description can be briefly described as follows: 
           [0021]      FIG. 1  shows a cross-section view of an example gas turbine engine. 
           [0022]      FIG. 2  shows a top view of the gas turbine engine of  FIG. 1  mounted to an aircraft wing. 
           [0023]      FIG. 3  shows a perspective view of a selected portions of  FIG. 2  with wing slats and a thrust reverser in stowed positions. 
           [0024]      FIG. 4  shows the perspective view of the selected portions of the  FIG. 2  with wing slats and a thrust reverser in deployed positions. 
           [0025]      FIG. 5  shows a highly schematic front view of the gas turbine engine of  FIG. 1 . 
           [0026]      FIG. 5A  shows a highly schematic front view of another example gas turbine engine. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]      FIG. 1  schematically illustrates an example turbomachine, which is a gas turbine engine  20  in this example. The gas turbine engine  20  is a two-spool turbofan gas turbine engine that generally includes a fan section  22 , a compression section  24 , a combustion section  26 , and a turbine section  28 . 
         [0028]    Although depicted as a two-spool turbofan gas turbine engine in the disclosed non-limiting embodiment, it should be understood that the concepts described herein are not limited to use with turbofans. That is, the teachings may be applied to other types of turbomachines and turbine engines including three-spool architectures. Further, the concepts described herein could be used in environments other than a turbomachine environment and in applications other than aerospace applications. 
         [0029]    In the example engine  20 , flow moves from the fan section  22  to a bypass flowpath. Flow from the bypass flowpath generates forward thrust. The compression section  24  drives air along a core flowpath. Compressed air from the compression section  24  communicates through the combustion section  26 . The products of combustion expand through the turbine section  28 . 
         [0030]    The example engine  20  generally includes a low-speed spool  30  and a high-speed spool  32  mounted for rotation about an engine central axis A. The low-speed spool  30  and the high-speed spool  32  are rotatably supported by several bearing systems  38 . It should be understood that various bearing systems  38  at various locations may alternatively, or additionally, be provided. 
         [0031]    The low-speed spool  30  generally includes a shaft  40  that interconnects a fan  42 , a low-pressure compressor  44 , and a low-pressure turbine  46 . The shaft  40  is connected to the fan  42  through a geared architecture  48  to drive the fan  42  at a lower speed than the low-speed spool  30 . 
         [0032]    The high-speed spool  32  includes a shaft  50  that interconnects a high-pressure compressor  52  and high-pressure turbine  54 . 
         [0033]    The shaft  40  and the shaft  50  are concentric and rotate via bearing systems  38  about the engine central longitudinal axis A, which is collinear with the longitudinal axes of the shaft  40  and the shaft  50 . 
         [0034]    The combustion section  26  includes a circumferentially distributed array of combustors  56  generally arranged axially between the high-pressure compressor  52  and the high-pressure turbine  54 . 
         [0035]    In some non-limiting examples, the engine  20  is a high-bypass geared aircraft engine. In a further example, the engine  20  bypass ratio is greater than about six (6 to 1). 
         [0036]    The geared architecture  48  of the example engine  20  includes an epicyclic gear train, such as a planetary gear system or other gear system. The example epicyclic gear train has a gear reduction ratio of greater than about 2.3 (2.3 to 1). 
         [0037]    The low-pressure turbine  46  pressure ratio is pressure measured prior to inlet of low-pressure turbine  46  as related to the pressure at the outlet of the low-pressure turbine  46  prior to an exhaust nozzle of the engine  20 . In one non-limiting embodiment, the bypass ratio of the engine  20  is greater than about ten (10 to 1), the fan diameter is significantly larger than that of the low-pressure compressor  44 , and the low-pressure turbine  46  has a pressure ratio that is greater than about 5 (5 to 1). The geared architecture  48  of this embodiment is an epicyclic gear train with a gear reduction ratio of greater than about 2.5 (2.5 to 1). It should be understood, however, that the above parameters are only exemplary of one embodiment of a geared architecture engine and that the present disclosure is applicable to other gas turbine engines including direct drive turbofans. 
         [0038]    In this embodiment of the example engine  20 , a significant amount of thrust is provided by the bypass flow B due to the high bypass ratio. The fan section  22  of the engine  20  is designed for a particular flight condition—typically cruise at about 0.8 Mach and about 35,000 feet. This flight condition, with the engine  20  at its best fuel consumption, is also known as “Bucket Cruise” Thrust Specific Fuel Consumption (TSFC). TSFC is an industry standard parameter of fuel consumption per unit of thrust. 
         [0039]    Fan Pressure Ratio is the pressure ratio across a blade of the fan section  22  without the use of a Fan Exit Guide Vane system. The low Fan Pressure Ratio according to one non-limiting embodiment of the example engine  20  is less than 1.45 (1.45 to 1). 
         [0040]    “Low Corrected Fan Tip Speed” is the actual fan tip speed in ft/sec divided by an industry standard temperature correction of [(Tram ° R)/(518.7° R)]̂0.5. The Temperature represents the ambient temperature in degrees Rankine. The Low Corrected Fan Tip Speed according to one non-limiting embodiment of the example engine  20  is less than about 1150 fps (351 m/s). 
         [0041]    Referring to  FIGS. 2 to 5 , a pylon  60  may be used to connect the engine  20  to a wing  64  of an aircraft. The pylon  60 , in this example, couples an outermost nacelle  68  of the engine  20  to the wing  64 . The nacelle  68  is an example type of annular engine encasement. Thrust reverser mounts  70  are used to couple the pylon  60  to the outermost nacelle  68 . The thrust reverser mounts  70  include hinges in some examples. 
         [0042]    The example pylon  60  engages the nacelle  68  such that the pylon extends from a top circumferential apex P, which is generally the vertically highest position of the nacelle  68 . The top circumferential apex P extends axially. The top circumferential apex P, in this example, corresponds to a twelve o&#39;clock position when viewing the front or rear of the engine  20 . As can be appreciated, the nacelle  68  also includes a bottom circumferential apex, which is the vertically lowest position, or a six o&#39;clock position, of the nacelle  68 . Vertical position, in this example, refers generally to an elevation when the aircraft is on the ground or in straight or level flight. 
         [0043]    The wing  64  includes a first slat  62  and a second slat  66 . The first slat  62  is positioned on an inboard side of the engine  20 . The second slat  66  is positioned on an outboard side of the engine  20 . The first and second slats  62  and  66  are movable between a stowed position ( FIG. 3 ) and a deployed position ( FIG. 4 ). The slats  62  and  66  are typically stowed during normal flight and deployed to slow the aircraft or during certain aircraft maneuvers. 
         [0044]    The engine  20  includes a thrust reverser  70 . In this example, the thrust reverser  70  includes at least a first cowl  74  and a second cowl  78 . The first cowl  74  is movable relative to the second cowl  78  between a stowed position ( FIG. 4 ) and a deployed position ( FIG. 5 ). The first cowl  74  is typically in the stowed position during normal flight and moved to the deployed position when reducing the speed of the aircraft is necessary. The first cowl  74  and second cowl  78  together form a transcowl. The first cowl  74  and the second cowl  78  are both arcuate cowls in this example. 
         [0045]    The example first cowl  74  moves relative to the second cowl  78  by translating aftward along an axis that is aligned with the axis A. Translating the first cowl  74  reveals an opening  82  within the nacelle  68 . The opening permits thrust T to move radially through the nacelle  68 , and perhaps reverses some of thrust. Redirecting thrust T by moving thrust T through the opening  82  slows the engine  20  and thus the aircraft. Moving the first cowl  74  to the deployed position thus redirects thrust from the engine  20  slow the engine  20 . 
         [0046]    The second cowl  78  extends circumferentially from the attachment to the pylon  60  and, more specifically, the thrust reverser mounts  70 . The second cowl  78  remains stationary relative to the first cowl  74  when the first cowl  74  moves between the stowed position and the deployed position. 
         [0047]    The first cowl  74  interfaces with the second cowl  78  at an interface  88  or “split line.” The second cowl  78  extends circumferentially in a first direction from the pylon  60  to the interface  88 . The first cowl  74  extends circumferentially in the same direction from the interface  88  to the bottom circumferential apex of the nacelle  68 . 
         [0048]    When the first cowl  74  is in the stowed position, the first cowl  74  directly interfaces with the second cowl  78  at the interface  88 . The first cowl  74  translates in the direction of the interface  88  when the first cowl  74  moves between the deployed position and the stowed position. The example interface  88  is an axially extending interface  88 . The interface  88  may extend in other directions in other examples. 
         [0049]    The interface  88 , in this example, is circumferentially offset from the top circumferential apex P of the engine  20  by more than 18°. The offset is in a counterclockwise direction when facing the engine  20  from a position in from of the engine  20 . The circumferential offset effectively moves the interface  88  to a vertically lower position than interfaces in the prior art. 
         [0050]    During assembly of the engine  20  to the wing  64 , the engine  20  can be moved vertically closer to the wing  64  without the first cowl  74  interfering with the first slat  62  when the first cowl  74  and the first slat  62  are both deployed. This is due to the interface  88 , and thus the movable first cowl  74  moving vertically lower. 
         [0051]    In one specific example, the interface  88  is circumferentially offset from the top circumferential apex from between 20 to 25 degrees. If another, more specific example, the interface  88  it is offset 32 degrees couterclockwise from the top circumferential apex P. 
         [0052]    The example engine  20  includes a third cowl  92  that extends from the pylon  60  in a direction opposite the first cowl  74 . The engine  20  also includes a fourth cowl  96  opposite the first cowl  74 . The fourth cowl  96  is movable between a stowed position and a deployed position. An interface  98  between the third cowl  92  and the fourth cowl  96  maybe circumferentially offset from the top circumferential apex P in a clockwise direction an amount that is similar to the offset of the interface  88 , such as  32  degrees. The first cowl  74 , second cowl  78 , third cowl  92 , fourth cowl  96 , and portions of the pylon  60  together form a complete annular member. 
         [0053]    Contact between the first cowl  74  and the first slat  62  is often more likely than contact between the second slat  66  and the third cowl  92  due to the first slat  62  being axially forward the second slat  66 . Thus, in some examples, only the interface  88  is moved further from the top circumferential apex P and to a lower vertical position. In some examples, the interfaces  88  and  98 , or split planes, are both moved further from the top circumferential apex P to generally the same vertical position to provide symmetry to the nacelle  68 . 
         [0054]    When viewing the engine  20  from the front, the engine  20 , as shown in  FIG. 5 , has a circular profile. In another example engine  20   a  ( FIG. 5A ), the profile may be noncircular. 
         [0055]    The preceding description is exemplary rather than limiting in nature. Variations and modifications to the disclosed examples may become apparent to those skilled in the art that do not necessarily depart from the essence of this disclosure. Thus, the scope of legal protection given to this disclosure can only be determined by studying the following claims.