Abstract:
An aircraft includes an accessory member that constitutes an engine accessory, the accessory member being arranged between an aircraft engine pylon and an engine, in an attached state to an attachment base member that is at least one of the pylon and the engine. The accessory member includes: a surrounding portion that surrounds at least an end portion of a tubular body connected to the accessory member; and a projecting portion that projects from the end portion of the tubular body. The entire accessory member including the surrounding portion and the projecting portion is divided so as to be separable to a left side and a right side of the pylon, and the accessory member is attachable to and detachable from the attachment base member by accessing an outer periphery of the tubular body from the left side and the right side of the pylon without removing another member.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an aircraft, an engine pylon of an aircraft, a method for mounting an engine to an airframe of an aircraft, and a method for manufacturing an aircraft. 
         [0003]    2. Description of the Related Art 
         [0004]    An engine of aircraft is supported on an airframe (a main wing) via a pylon (e.g., U.S. Patent Application Publication No. 2007/0245711). 
         [0005]    When the engine is mounted to the main wing, a nacelle and a fairing that cover the engine are opened, and the engine is carried to a position below the pylon provided on the main wing by a hand truck. The engine is suspended, and fixed to the pylon by using fasteners and tools. 
         [0006]    Various accessories are collected and arranged between the pylon that is a structure on the airframe side and the engine. The accessories are attached to the engine or the pylon. 
         [0007]    Due to the existence of the accessories, when the engine is mounted to the pylon, it is not possible to ensure a work space, into which the fasteners and the tools are inserted and in which the tools are moved, between the pylon and the engine or in the vicinity thereof in some cases. 
         [0008]    In this case, a space required for the work can be formed by removing a member (for example, a duct) constituting the accessories from the pylon or the engine. However, it becomes necessary to perform a returning work of attaching the accessory member to the pylon or the engine after removing the accessory member and mounting the engine. It is not desirable that the returning work takes a great deal of time. 
         [0009]    For example, when a duct of a heat exchanger around which fuel, hydraulic, engine bleed air pipes or the like are arranged is removed and returned after mounting the engine, the returning work takes a great deal of time. In order to remove the duct of the heat exchanger, it is also necessary to remove peripheral pipes. Thus, the peripheral pipes are formed in a removable divided structure. 
         [0010]    After removing the peripheral pipes, the duct of the heat exchanger is removed, and the engine is mounted. The duct of the heat exchanger is then attached to an original position, and the peripheral pipes are also attached to original positions. Accordingly, it becomes necessary to perform a lot of returning works. 
         [0011]    Based on the above problems, an object of the present invention is to provide an aircraft in which it is possible to mount an engine to an airframe with high work efficiency while ensuring a required work space, and a method for mounting an engine to an airframe of an aircraft. 
       SUMMARY OF THE INVENTION 
       [0012]    As a result of study in view of reducing a returning work as much as possible based on a layout of accessory members between a pylon and an engine, and a handling path of tools, the present inventors found an accessory member that overlaps with the handling path of the tools with no other member or pipe arranged therearound. The accessory member is a frame-shaped member that is provided at a distal end of a duct of a heat exchanger. The member is attached to the duct while surrounding the distal end of the duct. 
         [0013]    However, there is a fan case immediately next to the distal end of the duct of the heat exchanger. There is not a sufficient space for inserting the frame-shaped member between the distal end of the duct of the heat exchanger and the fan case after completing mounting of the engine. In this case, it is not possible to surround the distal end of the duct by the frame-shaped member by inserting the distal end of the duct into an inner side of the frame-shaped member. Thus, the frame-shaped member cannot be attached to the duct. 
         [0014]    The present invention which has been accomplished in view of the above points is an aircraft including an accessory member that constitutes an engine accessory, the accessory member being arranged between a pylon that is used for supporting an engine on an airframe and the engine, in an attached state to an attachment base member that is at least one of the pylon and the engine, wherein the accessory member includes a surrounding portion that surrounds at least an end portion of a tubular body connected to the accessory member, and a projecting portion that projects from the end portion of the tubular body, the entire accessory member including the surrounding portion and the projecting portion is divided so as to be separable to a left side and a right side of the pylon, and the accessory member is attachable to and detachable from the attachment base member by accessing an outer periphery of the tubular body from the left side and the right side of the pylon without removing another member. 
         [0015]    In the present invention, the left and the right of the pylon correspond to the left and the right of the airframe of the aircraft. 
         [0016]    In the present invention, since the accessory member is attachable to and detachable from the attachment base member, an engine mounting work can be performed after previously removing the accessory member from the attachment base member. When the accessory member is removed, an extra space is left between the pylon and the engine corresponding to the projecting portion of the accessory member that does not overlap with the tubular body. It is thus possible to ensure a work space for handling tools or the like. 
         [0017]    Even if there is not a sufficient space required for inserting the end portion of the tubular body into an inner side of the surrounding portion of the accessory member when the accessory member is attached to the attachment base member after mounting the engine, the outer periphery of the tubular body can be surrounded by divided parts of the accessory member from the right and left sides of the pylon, and the accessory member can be thereby attached to the attachment base member. 
         [0018]    In the present invention, since it is possible to access the outer periphery of the tubular body from the left side and the right side of the pylon without removing another member, it is not necessary to perform a work of removing another member at the time of forming the work space by removing the accessory member from the attachment base member. 
         [0019]    Therefore, it is only necessary to reattach the accessory member removed from the attachment base member after mounting the engine, so that the man-hours of a returning work can be reduced. 
         [0020]    As a result, it is possible to mount the engine to the airframe with high work efficiency while ensuring a required work space. 
         [0021]    In the present invention, at least one portion of the tubular body is preferably formed in a bellows shape. 
         [0022]    Accordingly, the space generated by removing the accessory member is widened by contracting the bellows of the tubular body. It is thus possible to sufficiently ensure a work space required for mounting the engine. 
         [0023]    In the present invention, the engine may be a turbofan engine including an engine body and a fan, the engine accessory may be a heat exchanger that is arranged between the pylon and the engine body and uses air flowing out of the fan as a heat source, and at least the end portion of the tubular body constituting the heat exchanger may be surrounded by the surrounding portion. 
         [0024]    In the present invention, a first heat exchanger as the heat exchanger, and a second heat exchanger that uses air flowing out of the fan as a heat source may be longitudinally arranged between the pylon and the engine body, and the end portion of the tubular body constituting the first heat exchanger or the second heat exchanger may be surrounded by the surrounding portion on at least one of a front side and a rear side of the pylon. 
         [0025]    The front and the rear in the present invention mean the front and the rear of the airframe of the aircraft. 
         [0026]    In the above configuration, as compared to a case in which one heat exchanger is arranged between the pylon and the engine, a space between the pylon and the engine becomes small, and the work space for mounting the engine to the pylon tends to be insufficient on the front side or the rear side of the pylon. Therefore, the accessory member of the present invention can be preferably used. 
         [0027]    When the above heat exchanger includes the tubular body facing the fan, the end portion of the tubular body is preferably surrounded by the surrounding portion of the accessory member. 
         [0028]    When the tubular body facing the fan is located close to the fan, there is not a sufficient space required for inserting the tubular body into the inner side of the surrounding portion of the accessory member and surrounding the end portion of the tubular body by the surrounding portion. Therefore, the accessory member of the present invention can be preferably used. 
         [0029]    The present invention is also an engine pylon that is used for supporting a turbofan engine including an engine body and a fan on an airframe of an aircraft, wherein the pylon supports two heat exchangers that are longitudinally arranged between the pylon and the engine body and use air flowing out of the fan as a heat source, the accessory member of the above aircraft is attached to the pylon, the heat exchanger arranged on a front side out of the two heat exchangers has the tubular body facing the fan, and at least a front end of the tubular body is surrounded by the surrounding portion of the accessory member. 
         [0030]    The present invention can be also applied to a method for mounting an engine to an airframe of an aircraft by using the above accessory member. 
         [0031]    The method for mounting an engine to an airframe of an aircraft of the present invention includes the steps of: mounting the engine to the pylon with the above accessory member of the aircraft previously removed from the attachment base member; and surrounding the outer periphery of at least the end portion of the tubular body by the accessory member from the left side and the right side of the pylon and attaching the accessory member to the attachment base member after completing the mounting of the engine. 
         [0032]    The present invention is also applied to a method for manufacturing an aircraft through the above respective steps. 
         [0033]    In accordance with the present invention, it is possible to mount the engine to the airframe of the aircraft with high work efficiency while ensuring a required work space. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0034]      FIG. 1  is a view illustrating a turbofan engine (a left-side engine) that has not been mounted to a pylon yet; 
           [0035]      FIG. 2  is a view illustrating the turbofan engine (the left-side engine) that has not been mounted to the pylon yet (in a state in which an intake port frame is removed); 
           [0036]      FIG. 3  is a view illustrating the turbofan engine mounted to the pylon; 
           [0037]      FIGS. 4A and 4B  are schematic views illustrating the intake port frame; and 
           [0038]      FIG. 5  is a view illustrating a procedure for mounting the engine to the pylon. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0039]    In the following, an embodiment of the present invention is described by reference to the accompanying drawings. 
         [0040]    An aircraft according to the embodiment of the present invention includes a turbofan engine  10  shown in  FIG. 1 . 
         [0041]    The turbofan engine  10  is supported on a lower side of a main wing (not shown) via a pylon  15 . 
         [0042]    The turbofan engine  10  includes an engine body  12 , and a fan  13  that is arranged ahead of the engine body  12 . 
         [0043]    The turbofan engine  10  is equipped with various engine accessories such as a fuel control unit, a fuel pump, an ignition unit, and a plurality of heat exchangers although the engine accessories are not shown in the drawings. 
         [0044]    The turbofan engine  10  is also provided with a nacelle that surrounds the engine body  12  and the fan  13 , and a core cowl (not shown) that surrounds the engine body  12  on an inner side of the nacelle although the nacelle and the core cowl are not shown in the drawings. The nacelle is provided continuously to a rear side of an air inlet  14  for introducing air. A bypass flow path is formed between the nacelle and the core cowl, and air discharged from the fan  13  flows through the bypass flow path. 
         [0045]    The pylon  15  is a structural member that is provided on the main wing. The pylon  15  includes a box-shaped pylon body  151  that extends longitudinally, a plurality of struts that connect the pylon body  151  with the engine body  12 , and a fairing  152  that covers the pylon body  151  and the struts. The struts are not shown in the drawings. 
         [0046]    Various pipes such as fuel, hydraulic, and engine bleed air pipes (utility pipes), electric lines, or the like are accommodated in an inner portion of the pylon body  151 . 
         [0047]    The engine accessories of the turbofan engine  10  and pipes or the like accompanying the engine accessories (referred to as accessories below) are installed around the engine body  12  and the fan  13  on the inner side of the nacelle. Some of the accessories are provided on the pylon body  151 , and the others of the accessories are provided on the outer periphery of the engine body  12  or the fan  13 . 
         [0048]    In the present embodiment, an engine oil cooler  17  and a precooler  18  are provided on the pylon body  151 . 
         [0049]    The engine oil cooler  17  is suspended from a lower surface of the pylon body  151  and thereby supported on a front side of the pylon body  151 . 
         [0050]    The precooler  18  is suspended from the lower surface of the pylon body  151  behind the engine oil cooler  17 . 
         [0051]    The utility pipes are arranged around the engine oil cooler  17  and the precooler  18 . 
         [0052]    The engine oil cooler  17  is a heat exchanger that cools engine oil used in the engine body  12  by using air flowing out of the fan  13  as a heat source (cold source). 
         [0053]    The precooler  18  is a heat exchanger that cools extracted steam from the engine body  12  by using the air flowing out of the fan  13  as a heat source. Since it is difficult to use the high-temperature and high-pressure engine extracted steam directly as a heat source for an onboard air-conditioner or the like, the engine extracted steam is cooled by the precooler  18 , and then used for air-conditioning or the like. 
         [0054]    Each of the engine oil cooler  17  and the precooler  18  has a pipe that is connected to the engine body  12 . In order to avoid damage to the engine oil cooler  17  and the precooler  18  with large vibration transmitted thereto from the engine body  12  through the pipes, a flexible hose that damps vibration is used for the pipes, or a vibration damping mechanism is provided in the pipes. 
         [0055]    As described below, an intake duct  171  of the engine oil cooler  17  is connected to an intake port frame  21  that is provided on the engine body  12 . 
         [0056]    The intake port frame  21  formed in a rectangular annular shape is erected on an engine case  12 A that is a case of the engine body  12 . The intake port frame  21  forms an intake port for the air flowing out of the fan  13 . 
         [0057]    The intake port frame  21  and the intake duct  171  form a flow path that guides the air flowing out of the fan  13  to a plate-fin type body  170  of the engine oil cooler  17 . 
         [0058]    An exhaust duct  173  is connected to the body  170 . 
         [0059]    In order to reduce the vibration transmitted to the engine oil cooler  17  from the engine body  12  through the intake port frame  21 , the intake duct  171  has a vibration damping section  172  that is formed in a bellows shape at least partially in a length direction. The vibration damping section may have any form, and a plurality of flange pipes may be continuously provided to constitute the vibration damping section. 
         [0060]    The present embodiment relates to mounting the turbofan engine  10  to the pylon  15  that is a structural member on an airframe side. 
         [0061]    The turbofan engine  10  is mounted when a newly-designed aircraft is manufactured, when a re-engined aircraft is manufactured, or at the time of engine replacement due to an engine defect or the like. 
         [0062]    When the turbofan engine  10  is mounted, the nacelle and a fairing are opened to an outer side about a hinge that is longitudinally provided in an upper portion of each of the nacelle and the fairing. The pylon body  151  is thereby exposed. 
         [0063]    The turbofan engine  10  placed on a hand truck  19  is carried to a position below the pylon body  151 . 
         [0064]    The turbofan engine  10  is lifted a little from the hand truck  19  by suspending the turbofan engine  10  from the pylon  15 . The turbofan engine  10  is then fastened to the pylon body  151  and the struts of the pylon by fasteners. At this time, a work space is required into which the fasteners and fastening tools can be inserted, and in which the tools can be moved. 
         [0065]    The engine oil cooler  17  and the precooler  18  suspended from the pylon body  151 , and the accessories provided on the engine body  12  (referred to as engine-side accessories  20  below) exist between a lower portion of the pylon body  151  and the outer periphery of the turbofan engine  10 . 
         [0066]    In the present embodiment, since the ratio of the diameter of the turbofan engine  10  to the diameter of the nacelle is larger than that of a typical case, an interval between the inner periphery of the nacelle and the outer periphery of the engine body  12  is small. A plurality of accessories are arranged in the small interval, so that the accessories are located close to each other. The upper limit of the diameter of the nacelle is determined based on limitations on ground clearance and since it is difficult to extend a main landing gear in order to avoid an increase in weight. Thus, it is difficult to widen the interval between the nacelle and the engine body  12 . 
         [0067]    Since the interval between the nacelle and the engine body  12  is small, an interval between the pylon  15  and the engine body  12  is also small. Therefore, a work of mounting the turbofan engine  10  to the pylon body  151  is performed by inserting the fasteners and the tools into a small space left between the accessories, and moving the tools. 
         [0068]    Since the interval between the pylon  15  and the engine body  12  is small as described above, a lower portion of the engine oil cooler  17  is located close to the engine-side accessories  20 . While a predetermined clearance is set therebetween after mounting the turbofan engine  10 , a space equal to or larger than the clearance is required for handling the tools and the fasteners. Therefore, a space having a height H 1  is ensured between the engine oil cooler  17  and the engine-side accessories  20  by suppressing the truck height of the hand truck  19 . 
         [0069]    Similarly, since a space equal to or larger than the clearance is also required for handling the tools and the fasteners between the precooler  18  and the engine-side accessories  20 , a space having a height H 2  is ensured therebetween by suppressing the truck height of the hand truck  19 . 
         [0070]    On the other hand, a space is left on a rear end side of the pylon body  151 , and between the precooler  18  and the engine oil cooler  17  in an axial direction (the longitudinal direction) of the turbofan engine  10 . 
         [0071]    However, there is not a sufficient space required for the work on a front end side of the pylon body  151  since the intake duct  171  and the intake port frame  21  exist on the front end side. 
         [0072]    However, a work space for handling the tools and the fasteners is required on the front end side of the pylon body  151 . 
         [0073]    Therefore, the intake port frame  21  is configured to be attachable to and detachable from the engine body  12 . When the turbofan engine  10  is mounted to the pylon  15 , the intake port frame  21  is previously removed from the turbofan engine  10  as shown in  FIG. 2 . A space S is thereby generated, and the work of mounting the turbofan engine  10  is performed by using the space S. 
         [0074]    As shown in  FIG. 3 , when the mounting of the turbofan engine  10  is completed, the intake port frame  21  is connected to a front end of the intake duct  171 , and the intake port frame  21  is also attached to the engine case  12 A. 
         [0075]    As shown in  FIGS. 4A and 4B , the intake port frame  21  includes an annular surrounding portion  211  that surrounds the front end of the intake duct  171 , an annular projecting portion  212  that projects forward from the front end of the intake duct  171  and faces a rear end of a fan case  13 A that is a case of the fan  13 , an arm portion  215  that extends forward from the projecting portion  212 , a fixing portion  213  that is located between the surrounding portion  211  and the projecting portion  212  and is fixed to the front end of the intake duct  171 , and a fixing portion  214  that is fixed to the engine case  12 A. 
         [0076]    The dimension of the above space S corresponds to the total longitudinal dimension of the projecting portion  212  and the arm portion  215 . 
         [0077]    The intake port frame  21  is detachably fixed to the intake duct  171  by fastening the fixing portion  213  to the intake duct  171  by fasteners or the like. 
         [0078]    The intake port frame  21  is also detachably fixed to the engine case  12 A by fastening the fixing portion  214  to the engine case  12 A by fasteners or the like. 
         [0079]    When the mounting of the turbofan engine  10  is completed ( FIG. 3 ), only the space S smaller than the longitudinal dimension of the intake port frame  21  is left between the rear end of the fan case  13 A and the front end of the intake duct  171 . Therefore, when the intake port frame  21  is tried to be inserted into the space S, the intake port frame  21  interferes with the intake duct  171  and the fan case  13 A. 
         [0080]    When the intake port frame  21  is integrally configured in an annular shape, it is necessary to arrange the intake port frame  21  ahead of the intake duct  171 , and move the intake port frame  21  backward from the position in order to set the front end of the intake duct  171  on an inner side of the surrounding portion  211 . 
         [0081]    In this case, if the intake port frame  21  cannot be inserted into the space S from a lateral side, it is not possible to connect the intake port frame  21  to the intake duct  171  and attach the intake port frame  21  to the engine body  12 . 
         [0082]    Thus, the entire intake port frame  21  is divided into two parts to both sides of a center line L along a vertical direction as shown in  FIG. 4A . The intake port frame  21  includes a left-side frame part  21 L and a right-side frame part  21 R. 
         [0083]    The left-side frame part  21 L and the right-side frame part  21 R can be separated to a left side and a right side of the pylon  15  as indicated by an arrow in  FIG. 4A , and are integrally attached so as to surround the intake duct  171 . 
         [0084]    Accordingly, even if the intake port frame  21  cannot be inserted into the space S, the front end of the intake duct  171  can be set on the inner side of the surrounding portion  211  by allowing the left-side frame part  21 L and the right-side frame part  21 R to access the intake duct  171  from the right and left sides of the pylon  15  and combining together the left-side frame part  21 L and the right-side frame part  21 R. The fixing portion  213  is fixed to the front end of the intake duct  171  in the above state, so that the intake port frame  21  is connected to the intake duct  171 , and the projecting portion  212  and the arm portion  215  are arranged in the space S. 
         [0085]    The fixing portion  214  is then fixed to the engine case  12 A, so that the intake port frame  21  is attached to the engine body  12 . 
         [0086]    There exists no other accessory on the right and left sides of the intake port frame  21  connected to the intake duct  171 . Therefore, when the nacelle and the core cowl on the inner side are opened, it is possible to remove the left-side frame part  21 L and the right-side frame part  21 R from the engine case  12 A by accessing the outer periphery of the intake duct  171  without being disturbed by other accessories. 
         [0087]    Therefore, it is not necessary to perform a work of removing other accessories at the time of removing the intake port frame  21  from the engine body  12 . 
         [0088]    Next, a procedure for mounting the turbofan engine  10  to the pylon  15  is described by reference to  FIG. 5 . 
         [0089]    First, the intake port frame  21  including the left-side frame part  21 L and the right-side frame part  21 R is removed from the engine body  12  of the turbofan engine  10  that is carried into a place where an airframe is installed (step S 11 ). 
         [0090]    However, if the turbofan engine  10  is carried in a state in which the frame parts  21 L and  21 R are not mounted to the engine body  12  and are separated from the turbofan engine  10 , step S 11  is not required. 
         [0091]    Subsequently, the turbofan engine  10  is placed on the hand truck  19 , and carried to a position below the pylon  15  (step S 12 ). 
         [0092]    The turbofan engine  10  is suspended from the pylon  15 , and the mounting work is started (step S 13 ). 
         [0093]    If the intake port frame  21  has not been removed from the engine body  12  yet, the intake port frame  21  is removed before starting the engine mounting work. 
         [0094]    The suspended turbofan engine  10  is fastened to the pylon body  151  and the pylon struts by the fasteners. 
         [0095]    At this time, the space S ( FIG. 2 ) between the front end of the intake duct  171  and the rear end of the fan case  13 A is left between the pylon body  151  and the engine body  12  in addition to the space between the engine oil cooler  17  or the precooler  18  and the engine-side accessories  20 , and the space between the engine oil cooler  17  and the precooler  18 . The fastening work is performed by inserting the fasteners and the tools into the empty space, including the space S, between the pylon body  151  and the engine body  12 . 
         [0096]    Here, when the vibration damping section  172  of the intake duct  171  is formed in a bellows shape, it is possible to sufficiently ensure the space S by contracting the vibration damping section  172 . 
         [0097]    When the work of mounting the turbofan engine  10  to the pylon  15  is completed, a connection work for pipes, lines or the like to be provided in the turbofan engine  10  is performed (step S 14 ). 
         [0098]    The intake port frame  21  is connected to the intake duct  171  of the engine oil cooler  17 , and attached to the engine body  12  at around the same time as step S 14  (step S 15 ). 
         [0099]    In step S 15 , the left-side frame part  21 L and the right-side frame part  21 R surround the outer periphery of the intake duct  171  from the right and left sides, and the front end of the intake duct  171  is set on the inner side of the surrounding portion  211 . By fastening the fixing portion  213  to the intake duct  171 , the intake port frame  21  is connected to the intake duct  171 . 
         [0100]    Moreover, by fastening the fixing portion  214  to the engine case  12 A, the intake port frame  21  is attached to the engine body  12 . 
         [0101]    As described above, since there exists no other accessory on the right and left sides of the intake port frame  21 , it is not necessary to remove other accessories at the time of removing the intake port frame  21 . Therefore, after the turbofan engine  10  is mounted to the pylon  15 , it is only necessary to return only the intake port frame  21  to the engine body  12 . 
         [0102]    The mounting of the turbofan engine  10  is completed through the above steps. 
         [0103]    Note that the frame parts  21 L and  21 R of the intake port frame  21  are previously removed from the engine body  12  when the turbofan engine  10  is removed from the pylon  15 . The work of removing the turbofan engine  10  can be performed by using the generated space S ( FIG. 3 ). 
         [0104]    In accordance with the present embodiment, it is not necessary to perform the work of removing other accessories in order to form the space S by removing the intake port frame  21 . Thus, it is only necessary to return the intake port frame  21  removed from the engine body  12  to the engine body  12  after mounting the turbofan engine  10 . 
         [0105]    If the space S is formed by removing the intake duct  171 , the utility pipes arranged around the intake duct  171  need to be formed in a divided structure, and the intake duct  171  is removed after partially removing the utility pipes. In this case, it is necessary to perform a lot of returning works after mounting the turbofan engine  10 . In the present embodiment, however, a minimum returning work is required. 
         [0106]    Therefore, it is possible to mount the engine to the airframe with high work efficiency while ensuring a required work space. 
         [0107]    The constitutions described in the aforementioned embodiment may be also freely selected or changed into other constitutions without departing from the gist of the present invention. 
         [0108]    As long as the intake port frame  21  is divided into the left side and the right side of the pylon  15 , the intake port frame  21  may be divided into, for example, four parts as well as the two parts. The intake port frame  21  may have any number of parts. For example, each of the left-side frame part  21 L and the right-side frame part  21 R may be divided into upper and lower parts. In this case, the respective parts can be attached to and detached from the intake duct  171  by upwardly or downwardly escaping from other members located on the right and left sides of the intake port frame  21 . 
         [0109]    As an accessory member to be removed for mounting the engine, an appropriate accessory member according to the position and the dimension of the required work space can be employed. An accessory member attached to the pylon as well as an accessory member attached to the engine may be employed as the accessory member. 
         [0110]    In a case in which it is necessary to ensure a work space in the vertical direction, a vertically-extending accessory member connected to the duct can be removed before mounting the engine.