Abstract:
A nacelle for housing an aircraft jet engine. The jet engine has a fan case and a portion disposed downstream of the fan case relative to a direction of airflow through the jet engine. The nacelle comprises an inlet for receiving airflow, a fan cowl panel for covering a forward portion of the fan case, and a thrust reverser having a longitudinal length sufficient to cover the downstream portion of the jet engine in addition to a rearward portion of the fan case. Opening the thrust reverser enables access to an entire area formed by the downstream portion as well as the rearward portion of the fan case.

Description:
FIELD OF THE INVENTION  
       [0001]     The present invention relates to aircraft engine nacelles. In particular, the present invention relates to an aircraft engine nacelle having a thrust reverser that overlaps a portion of an aircraft engine fan case.  
       BACKGROUND OF THE INVENTION  
       [0002]     With reference to  FIG. 1 , a conventional aircraft engine nacelle is illustrated at  10 . The nacelle  10  houses a conventional aircraft engine  12 . The nacelle  10  generally includes an inlet cowl  14 , a fan cowl panel  16 , and a thrust reverser  18 . The engine  12  generally includes a fan case  20  and various components aft of the fan case, such as an engine core  22  including a nozzle  24 . The inlet cowl  14  surrounds an area forward of the fan case  20 . The fan cowl  16  surrounds and covers the fan case  20 . The thrust reverser  18  surrounds and covers the engine core  22 . The thrust reverser  18  does not cover the fan case  20 .  
         [0003]     Mounted to the fan case  20  are various components and devices of the engine  12 , such as an oil tank  26 , an engine control unit (ECU)  27 , and often a gear box  28 . To gain access to the fan case  20  and the components mounted to the fan case  20 , such as the oil tank  26 , ECU  27 , and the gear box  28 , the fan cowl panel  16  is opened. To gain access to the components of the engine core  22 , both the fan cowl panel  16  and the thrust reverser  18  are opened. Both the fan cowl  16  and the thrust reverser  18  open in a “clam-like” fashion using a sophisticated hydraulic lift system. Both the fan cowl  16  and the thrust reverser  18  cover important components of the engine  12  and need to be opened to permit access to these components. The fan cowl panel  16  and the thrust reverser  18  each include a separate hydraulic lift system (not shown) that opens the panel  16  and the thrust reverser  18  and supports them in the open position. These lift systems add to the overall weight of the aircraft.  
         [0004]     While conventional aircraft engine nacelles are suitable for their intended uses, they are subject to improvement. In particular, there is a need for an aircraft engine nacelle having a reduced weight and reduced complexity, as compared to conventional nacelles, but which still provides easy access to those areas normally covered by the thrust reverser and the fan cowl panel.  
       SUMMARY OF THE INVENTION  
       [0005]     The present invention provides for a nacelle for housing an aircraft jet engine. The jet engine has a fan case and a portion disposed downstream of the fan case relative to a direction of airflow through the jet engine. The nacelle comprises an inlet for receiving airflow, a fan cowl panel for covering a forward portion of the fan case, and a thrust reverser having a longitudinal length sufficient to cover the downstream portion of the jet engine in addition to a rearward portion of the fan case. Opening the thrust reverser enables access to an entire area formed by the downstream portion as well as the rearward portion of the fan case. Because the thrust reverser overlaps the fan case, opening the thrust reverser permits access to the fan case and engine components associated with the fan case. There is seldom a need to open the fan cowl panel to access the forward fan case and the conventional fan cowl can be eliminated in some embodiments. Therefore, the conventional mechanism used to automatically open and close the fan cowl can be eliminated and some structural weight elements reduced to reduce the weight of the nacelle and realize enhanced fuel efficiency.  
         [0006]     The present invention further provides for a nacelle for housing an aircraft jet engine. The jet engine has a fan case and a portion disposed downstream of the fan case relative to a direction of air flowing through the jet engine. The nacelle comprises an inlet for receiving airflow, a fan cowl panel for covering about a forward half of the fan case, and a thrust reverser. The thrust reverser includes a main body having a longitudinal length sufficient to cover the downstream portion of the jet engine and an extended portion mounted to the main body having a longitudinal length sufficient to cover approximately an aft half of the fan case. Opening the thrust reverser enables access to an entire area formed by the downstream portion as well as approximately the aft half of the fan case.  
         [0007]     The present invention still further provides for a nacelle for housing an aircraft jet engine. The jet engine has a fan case and a portion disposed downstream of the fan case relative to a direction of air flowing through the jet engine. The nacelle includes an inlet for receiving airflow and a thrust reverser having a longitudinal length sufficient to cover the downstream portion of the jet engine and the entire fan case. Opening the thrust reverser enables access to an entire area formed by the downstream portion as well as the entire fan case.  
         [0008]     The features, functions, and advantages can be achieved independently in various embodiments of the present inventions or may be combined in yet other embodiments. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The present invention will become more fully understood from the detailed description and the accompanying drawings, wherein:  
         [0010]      FIG. 1  is a side view of a prior art aircraft engine nacelle;  
         [0011]      FIG. 2  is a side view of an aircraft engine nacelle according to an embodiment of the present invention;  
         [0012]      FIG. 3  is a top view of the nacelle of  FIG. 2 ;  
         [0013]      FIG. 4  is a bottom view of the nacelle of  FIG. 2 ;  
         [0014]      FIG. 5  is a cross-sectional view along line  5 - 5  of  FIG. 2 ;  
         [0015]      FIG. 5A  is a close-up view of area  5 A of  FIG. 5 ;  
         [0016]      FIG. 5B  is a close-up view of area  5 B of  FIG. 5 ;  
         [0017]      FIG. 5C  is a close-up view of area  5 C of  FIG. 5 ;  
         [0018]      FIG. 5D  is a close-up view of area  5 D of  FIG. 5 ;  
         [0019]      FIG. 6A  is a perspective view of the nacelle of  FIG. 2 ;  
         [0020]      FIG. 6B  is a close-up view of the nacelle of  FIG. 6A ;  
         [0021]      FIG. 7  is a perspective view of the nacelle of  FIG. 2 ;  
         [0022]      FIG. 8  is a perspective view of the nacelle of  FIG. 2 ;  
         [0023]      FIG. 9  is a cross-sectional view taken along line  9 - 9  of  FIG. 8 ;  
         [0024]      FIG. 10  is a side view of an aircraft engine nacelle according to another embodiment of the present invention; and  
         [0025]      FIG. 11  is a cross-sectional view taken along line  11 - 11  of  FIG. 10 .  
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0026]     The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses.  
         [0027]     With initial reference to  FIGS. 2 through 4 , an aircraft engine nacelle  100  is shown. The nacelle  100  houses an aircraft engine  102 . The nacelle  100  and the engine  102  are mounted to an aircraft (not shown) by a pylon or strut  104 .  
         [0028]     The engine  102  can be any conventional engine such as, for example, a high-bypass ratio aircraft engine. Typically, the engine  102  includes a fan case  106  and various components aft of the fan case  106 , such as an engine core  108  including, for example, a nozzle  110 . As described herein, “aft” is the right side of the engine  102  as viewed in the figures and “forward” is the left side. Further, the components aft of the fan case  106 , such as the core  108 , are downstream of the fan case  106  relative to a direction of airflow, which enters the engine  102  through the inlet  128  and flows through the remainder of the engine  102 .  
         [0029]     The fan case  106  houses the engine fan  112  and is cylindrical. Various components and devices of the engine  102  are mounted to the fan case  106 , such as an oil tank  114 , an engine control unit (ECU)  115 , and often the gear box  116 . The engine  102  is mounted to the pylon  104  by one or more mounts  118  of the pylon  104 . The mounts  118  can secure the engine  102  at a variety of different locations. As illustrated, a mount  118 A is located at the fan case  106  and a mount  118 B is located at the engine core  108 .  
         [0030]     As illustrated in  FIG. 5 , also mounted at or near an exterior surface of the fan case  106  is an inlet aft bulkhead  120  and a support ring  122 . Both the bulkhead  120  and the support ring  122  extend around the outer diameter of the fan case  106 . The bulkhead  120  and the support ring  122  are mounted at or near the fan case  106 . The support ring  122  is mounted by a series of trusses that are generally “V” shaped.  FIG. 6  illustrates a truss  124  of the support ring  122 . The bulkhead  120  and the support ring  122  can also be mounted at or near the fan case  106  in any other suitable manner. The bulkhead  120  is mounted generally at or near the forward portion of the fan case  106  and the support ring  122  is generally mounted at the aft portion of the fan case  106 . As illustrated, the support ring  122  is mounted near the oil tank  114 .  
         [0031]     The nacelle  100  is generally cylindrical and includes an inlet cowl  128 , a fan cowl  130 , and a thrust reverser  132 . The position of these components of the nacelle  100  is first set forth below and a description of how these components are mounted follows.  
         [0032]     The inlet cowl  128  includes an inner barrel  134 B, an outer barrel  134 A, a nose lip  136 , and a forward bulkhead  137 . The outer and inner barrels  134  are aft of the nose lip  136  and the forward bulkhead  137 . The inlet cowl  128  surrounds an area forward of the fan case  106 , which is left of the fan case  106  as illustrated. The inlet cowl  128  receives airflow to the engine  102 .  
         [0033]     The fan cowl  130  surrounds and/or covers the fan case  106 . The fan cowl  130  covers approximately the forward half of the fan case  106  and does not cover approximately the aft half of the fan case  106 . With reference to  FIGS. 3 and 4 , the fan cowl  130  includes a first fan cowl panel  130 A and a second fan cowl panel  130 B.  
         [0034]     The thrust reverser  132  also surrounds and/or covers a portion of the fan case  106 . In particular, the thrust reverser  132  includes a main body  138  and an extended portion  140 . The extended portion  140  has a longitudinal length sufficient to cover approximately the aft half of the fan case  106 . The extended portion  140  includes one or more openings or doors  142  to permit access to the fan case  106  itself and various other components, such as the oil tank  114 , the gear box  116 , the ECU  115 , and thrust reverser actuators  144 . The main body  138  has a longitudinal length sufficient to cover the portions of the engine  102  aft of, or downstream of, the fan case  106 , such as the engine core  108 . The thrust reverser  132  includes a first thrust reverser portion  132 A and a second thrust reverser portion  132 B. The bottom of the main body  138  includes an opening or door  146  ( FIG. 4 ) to provide access to the aft portion of the fan case  106 .  
         [0035]     The extended portion  140  can be integral with the main body  138  or the extended portion  140  can be a separate portion that is secured to the main body  138  in any suitable manner. For example and as illustrated in  FIGS. 5 and 5 A, the extended portion  140  can be secured to the main body  138  by a bracket  148  that generally takes the shape of an “L.” One end of the “L” bracket  148  is fixedly mounted to a torque box  150  of the main body  138 . The other end of the “L” bracket is fixedly mounted to the extended portion  140 . The torque box  150  is a support structure. The torque box  150  extends around the circumference of the forward portion of the main body  138  to provide support to the main body  138  and the extended portion  140 .  
         [0036]     The inlet cowl  128  is mounted to the inlet aft bulkhead  120  to support the inlet cowl  128  at the forward end of the fan case  106 . Specifically, the nose lip  136  is fixedly mounted to the forward bulkhead  137  and/or the outer/inner barrel  134  in any suitable manner and the outer/inner barrel  134  is fixedly mounted to the inlet bulkhead  120 . With reference to  FIG. 5B , the outer barrel  134 A is mounted to the bulkhead  120  by a bracket  152 . The bracket  152  is generally “T” shaped. The outer barrel  134 A is mounted to one end of the bracket  152  in any suitable manner, such as with a fastener  154 . The opposite end of the bracket  152  is mounted to the bulkhead  120  with a fastener  156 . The bracket  152  also abuts the fan cowl  130  and provides support to the fan cowl  130 . With reference to  FIG. 5C , the inner barrel  134 B is mounted to the fan case  106  by a ring bearing  157 . The bearing  157  extends around the inner barrel  134 B and is secured to the inner barrel  134 B in any suitable manner, such as by any conventional fastener. The bearing  157  includes knobs  157 A and  157 B. The knob  157 A is mounted to the inlet bulkhead  120  using any conventional fastening system or device to secure the inner barrel  134 B to the inlet bulkhead  120 . The knob  157 B is secured to the fan case  106  using any suitable fastening device or system to secure the inlet cowl  128  to the fan case  106 .  
         [0037]     With additional reference to  FIG. 6 , the fan cowl  130  is mounted about the fan case  106  by a hinge assembly  158 . The hinge assembly  158  includes a plurality of hinges  160  on each side of the hinge assembly  158 . The hinge assembly  158  can be fixedly secured to the fan case  106  in any suitable manner using any suitable fastening device or fastening means. In some embodiments, the hinge assembly  158  can be attached to the pylon  104 . The first fan cowl panel  130 A is mounted to the hinges  160  of one side of the hinge assembly  158  and the second fan cowl panel  130 B is mounted to the hinges  160  of the opposite side of the hinge assembly  158  to allow the portions  130 A and  130 B to pivot about the hinges  160 . The first and second portions  130 A and  130 B are secured together at the under surface of the nacelle  100  by a series of latches  162  ( FIG. 4 ). With reference to  FIG. 5B , the fan cowl  130  is supported about the engine  102  not only by the bracket  152 , but also by a “T” shaped bracket  163  that is secured to the support ring  122  by fasteners.  
         [0038]     As illustrated in  FIGS. 6A and 6B , the hinge assembly  158  is covered by an upper fixed fairing  164 . The upper fixed fairing  164  is secured over the hinge assembly  158  in any suitable manner, such as by being fastened to the pylon  104 . The fairing  164  includes a raised portion  165  to accommodate the pylon  104 .  
         [0039]     The thrust reverser  132  is mounted about the aft portion of the fan case  106  and the engine core  108  by a series of hinges  166 . The hinges  166  are fixedly mounted to the pylon  104  in any suitable manner. The thrust reverser  132  includes a first thrust reverser portion  132 A and a second thrust reverser portion  132 B. The first and second portions  132 A and  132 B are secured to opposite sides of the hinges  166  to allow the first and second portions  132 A and  132 B to pivot about the hinges  166 . The first and second portions  132 A and  132 B include a latch beam or a series of latches near the undersurface of the thrust reverser  132  to secure the portions  132 A and  132 B together. The latch beam is on the interior of the thrust reverser  132  and is not shown. The extended portion  140  of the thrust reverser  132  is supported about the fan case  106  by the bracket  163  of the support ring  122  ( FIG. 5C ).  
         [0040]     With reference to  FIG. 6A , access to the forward portion of the fan case  106  is provided by opening the fan cowl  130  in a “clamshell” type manner. The majority of the components of the fan case  106  are located on, and can be accessed at, the aft portion of the fan case  106 , which is covered by the extended portion  140  of the thrust reverser  132 , making it seldom necessary to open the fan cowl  130 . Therefore, the fan cowl  130  need not include equipment for automatically opening the fan cowl  130  and supporting the fan cowl  130  in the open position of  FIG. 6A . However, in some applications the fan cowl  130  may include equipment, such as conventional hydraulic equipment and “hold open” rods, to open and support the fan cowl  130  in the open position.  
         [0041]     With reference to  FIG. 7 , access to the aft portion of the fan case  106  and the portions of the engine  102  aft of the fan case  106 , such as the engine core  108 , is provided by opening the thrust reverser  132  in a “clamshell” type manner such that the first portion  132 A and the second portion  132 B pivot about the hinges  166 . The majority of the components of the fan case  106  are located on the aft portion of the fan case  106 , or can be accessed at the aft portion of the fan case  106 , and numerous important components of the engine  102 , such as the engine core  108 , are aft of the fan case  106 . Therefore, it is often necessary to open the thrust reverser  132  to gain access to such components for servicing.  
         [0042]     To facilitate opening of the thrust reverser  132  the thrust reverser  132  includes an opening mechanism. The opening mechanism may be any suitable thrust reverser opening and support mechanism as is commonly known in the art. The opening mechanism comprises one or more hydraulic actuators  168  and hold open rods (not shown). Both the first and the second thrust reverser portions  132 A and  132 B are opened and closed, and supported in the open position, by one of the actuators  168  (only one of which is illustrated). The actuators  168  are connected to a different one of the portions  132 A and  132 B at one end and a portion of the engine  102  or the pylon  104  at the opposite end. Use of the actuators  168  to open, hold open, and close the thrust reverser  132  is particularly helpful because the majority of the components of the engine  102  that require access for servicing are concealed by, or can be accessed beneath, the thrust reverser  132 .  
         [0043]     With additional reference to  FIGS. 8 and 9 , the thrust reverser  132  further includes a translating panel  170  and a grating  172  in the form of turning vanes for re-directing air flow. The panel  170  and the grating  172  are located at the forward portion of the main body  138  just aft of the extended portion  140 . The panel  170  includes an outer panel  174  and an inner panel  176 . The inner panel  176  is closer to the engine than the outer panel  174 . The grating  172  is between the outer panel  174  and the inner panel  176 . The panel  170  includes blocker doors  180  and support rods  182  that cooperate with guide tracks  184  to guide the panel  170  between a closed position ( FIG. 2 ), in which the panel  170  abuts the torque box  150 , and an open position ( FIGS. 8 and 9 ). When the panel  170  is in the closed position the engine  102  operates to produce forward thrust to propel the aircraft forward. When the panel  170  is in the open position air flow of the engine is redirected through the grating  172  by the blocker door  180  to produce reverse thrust to slow the aircraft or propel the aircraft in reverse.  
         [0044]     With additional reference to  FIGS. 10 and 11 , an aircraft engine nacelle according to an additional embodiment of the present invention is illustrated at  100 ′. Elements of the nacelle  100 ′ that are similar to elements of the nacelle  100  are designated with like reference numbers, but include the prime (′) designation. The description of the like elements provided in connection with the description of the nacelle  100  equally applies to the nacelle  100 ′.  
         [0045]     The nacelle  100 ′ does not include the fan cowl  130  of the nacelle  100 . Instead, the thrust reverser  132 ′ of the nacelle  100 ′ extends across substantially the entire fan case  106 ′ to take the place of the fan cowl  130 . Specifically, the extended portion  140 ′ of the thrust reverser  132 ′ takes the place of the fan cowl  130  and extends to the inlet cowl  128  where the extended portion  140 ′ is supported by the inlet aft bulkhead  120 . Eliminating the fan cowl  130  and replacing it with the extended portion  140 ′ decreases the weight of the nacelle  100 ′ because it eliminates the need for the support ring  122  and the need for a device to open and close the fan cowl  130 , as well as support the fan cowl  130  in the open position. Elimination of the fan cowl  130  also can provide longer runs of laminar flow of air over the nacelle  100 ′, thus increasing fuel efficiency.  
         [0046]     The present invention provides numerous advantages over the prior art. For example, the thrust reverser  132  of the present invention is extended to cover at least a portion of the fan case  106  to take to permit access to the fan case  106  and numerous components mounted to the fan case  106  without having to open the fan cowl  130 , making it rarely necessary to open the fan cowl  130 . In some embodiments the fan cowl  130  can be eliminated entirely. Because the fan cowl  130  rarely needs to be opened or can be eliminated entirely, the conventional mechanisms used to open and close the fan cowl  130  and support the fan cowl  130  in the open position can be eliminated. Elimination of such mechanisms reduces the weight of the nacelle  100  and the weight of the associated aircraft, thereby providing enhanced fuel economy. Also, elimination of the fan cowl  130  increases the laminar flow of air over the nacelle  100 ′ by eliminating the joint between the fan cowl  130  and the thrust reverser  132 , thus increasing fuel efficiency.  
         [0047]     While various preferred embodiments have been described, those skilled in the art will recognize modifications or variations which might be made without departing from the inventive concept. The examples illustrate the invention and are not intended to limit it. Therefore, the description and claims should be interpreted liberally with only such limitation as is necessary in view of the pertinent prior art.