Patent Publication Number: US-2020283160-A1

Title: Aircraft pylon fairing

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This International PCT Patent Application relies for priority on U.S. Provisional Patent Application Ser. No. 62/574,323 filed on Oct. 19, 2017, the entire content of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The application relates generally to aircraft and, more particularly, to fairings disposed around pylons used for structurally linking an engine to a wing. 
     BACKGROUND OF THE ART 
     Pylons are often disposed between a wing and an engine. To improve the aerodynamic characteristics, a pylon fairing is disposed around and/or defined by an outer layer (skin) of the pylon. The pylon fairing is typically streamlined to minimize aerodynamic losses. A plurality of different shapes of pylon fairings exist. Nevertheless, improvements are still possible. 
     SUMMARY 
     In one aspect, there is provided an assembly for an aircraft comprising: a wing having a root configured to be adjacent a fuselage of the aircraft; and a pylon fairing extending from the wing at a pylon location spaced from the root, the pylon fairing having an aerodynamic profile defining a fairing trailing edge, an upper section adjacent the wing, and a lower section configured to be adjacent an engine of the aircraft, the lower section including a shelf configured for extending through a jet generated by the engine; wherein the aerodynamic profile in the upper section of the pylon fairing is cambered toward the root of the wing; wherein the aerodynamic profile in at least part of the lower section of the pylon fairing is symmetrical; and wherein the fairing trailing edge in the upper section of the pylon protrudes rearwardly of a trailing edge of the wing at the pylon location. 
     In particular embodiments, the assembly may include any one or any combination of the following:
         the at least part of the lower section of the fairing has a chord line configured to be parallel to a central axis of the engine, the fairing trailing edge in the upper section being offset from a plane containing the chord line of the lower section and the central axis of the engine by an offset distance having a value corresponding to at least 0.3% of a local chord of the wing at the pylon location;   the value of the offset distance between the fairing trailing edge in the upper section and the plane corresponds to at most 6.5% of the local chord of the wing at the pylon location;   a value of a distance between the trailing edge of the wing and the fairing trailing edge at the pylon location corresponds to at least 3% of a local chord of the wing at the pylon location;   the value of the distance between the trailing edge of the wing and the fairing trailing edge at the pylon location corresponds to at most 13% of the local chord of the wing at the pylon location;   the pylon fairing has opposed inward and outward sides with the inward side facing the root of the wing, the outward side of the upper section of the pylon fairing being convex and the inward side of the upper section of the pylon fairing being concave;   the pylon fairing further comprises a central section between the upper and the lower sections, the central section cambered toward the root of the wing, the fairing trailing edge in the central section being forwardly offset from the fairing trailing edge in the upper section;   a height of the upper section defined from the wing to the central section has a value corresponding to at least 2.5% of a local chord of the wing at the pylon location;   the value of the height of the upper section is at most 10% of the local chord of the wing at the pylon location.       

     In another aspect, there is provided an assembly for an aircraft comprising: a wing having a root configured to be adjacent a fuselage of the aircraft; and a pylon fairing extending from the wing at a pylon location spaced from the root, the pylon fairing having an aerodynamic profile defining a fairing trailing edge, an upper section extending from the wing, and a lower section configured to be adjacent an engine of the aircraft and including a shelf configured for extending through a jet generated by the engine; wherein at least part of the lower section of the fairing has a chord line configured to extend in an engine vertical mid-plane of the engine, the fairing trailing edge in the at least part of the lower section being contained within the engine vertical mid-plane; wherein the fairing trailing edge in the upper section is offset from the engine vertical mid-plane and located between the engine vertical mid-plane and the root of the wing; and wherein a distance between the fairing trailing edge in the upper section and a trailing edge of the wing at the pylon location has a value corresponding to at most 30% of a local chord of the wing at the pylon location. 
     In particular embodiments, the assembly may include any one or any combination of the following:
         the fairing trailing edge in the upper portion is offset from the engine vertical mid-plane by an offset distance having a value corresponding to at least 0.3% of the local chord of the wing at the pylon location;   the value of the offset distance between the fairing trailing edge in the upper portion and the engine vertical mid-plane corresponds to at most 6.5% of the local chord of the wing at the pylon location;   the fairing trailing edge in the upper section is located forward of the trailing edge of the wing, or the fairing trailing edge in the upper section is axially aligned with the wing trailing edge at the pylon location;   the pylon fairing has opposed inward and outward sides with the inward side facing the root of the wing, the outward side of the upper section of the pylon fairing being convex and the inward side of the upper section of the pylon fairing being concave;   the pylon fairing further comprises a central section between the upper and the lower sections, the central section cambered toward the root of the wing, the fairing trailing edge in the central section forwardly offset from the fairing trailing edge in the upper section and from the trailing edge of the wing;   the value of the distance between the trailing edge of the wing and the fairing trailing edge at the pylon location corresponds to at least 3% of the local chord of the wing at the pylon location;   the value of the distance between the trailing edge of the wing and the fairing trailing edge at the pylon location corresponds to at most 13% of the local chord of the wing at the pylon location.       

     In another aspect, there is provided a method of directing an airflow around an aircraft between a wing of the aircraft and an engine connected to the wing, comprising: guiding the airflow toward a trailing edge of the wing between a pylon supporting the engine and a fuselage of the aircraft with a fairing of the pylon, wherein guiding the airflow includes: deviating an upper portion of the airflow adjacent the wing toward the fuselage with the fairing, the pylon fairing deviating the flow up to a trailing edge of the pylon fairing spaced rearwardly from the trailing edge of the wing, and guiding a portion of a jet generated by the engine with the fairing along a direction parallel to a central axis of the engine. 
     In a particular embodiment, a value of a distance between the trailing edge of the wing and the fairing trailing edge adjacent the wing corresponds to at least 3% of a local chord of the wing adjacent the pylon. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the present invention, as well as other aspects and further features thereof, reference is made to the following description which is to be used in conjunction with the accompanying drawings, where: 
         FIG. 1  is a schematic tridimensional view of an aircraft; 
         FIG. 2  is a schematic bottom view of an engine suspended below a wing of the aircraft of  FIG. 1  via a pylon surrounded by a fairing in accordance with a particular embodiment; 
         FIG. 3  is a schematic side view of the engine and pylon fairing of  FIG. 2 ; 
         FIG. 4  is a schematic cross-sectional bottom view of the pylon fairing of  FIG. 2 ; 
         FIG. 5  is a schematic enlarged view of area Z 5  of  FIG. 4 ; 
         FIG. 6  is a schematic enlarged view of area Z 6  of  FIG. 4 ; 
         FIG. 7  is a graph illustrating a variation of an offset of a trailing edge of the pylon fairing of  FIG. 2  relative to the engine vertical mid-plane as a function of a distance from a lower surface of the wing; 
         FIG. 8  is a graph illustrating a variation of an axial distance between a trailing edge of the wing and the trailing edge of the pylon fairing as a function of the distance from the lower surface of the wing; 
         FIG. 9  is a schematic bottom view of the engine suspended below the wing of the aircraft of  FIG. 1  via a pylon fairing in accordance with another particular embodiment; 
         FIG. 10  is a schematic side view of the engine and the pylon fairing of  FIG. 9 ; 
         FIGS. 11 a  to 11 c    are schematic cross sectional views of pylon fairings in accordance with other embodiments; and 
         FIG. 12  is a schematic cross sectional view of a pylon fairing in accordance with another embodiment. 
     
    
    
     In the drawings, embodiments of the invention are illustrated by way of example. It is to be expressly understood that the description and drawings are only for purposes of illustration and as an aid to understanding. They are not intended to be a definition of the limits of the invention. 
     DETAILED DESCRIPTION 
     Referring to the drawings and more particularly to  FIG. 1 , an aircraft is shown at  1 , and is generally described to illustrate some components for reference purposes in the present disclosure. The aircraft  1  has a fuselage  2  having a fore end at which a cockpit is located, and an aft end supporting a tail assembly, with the cabin generally located between the cockpit and the tail assembly. The tail assembly comprises a vertical stabilizer  3  with a rudder, and horizontal stabilizers  4  with elevators. The tail assembly has a fuselage-mounted tail, but other configurations may also be used for the aircraft  1 , such as cruciform, T-tail, etc. Wings  5  extend laterally from the fuselage. The aircraft  1  has engines  6  supported by the wings  5 . The aircraft  1  is shown as a jet-engine aircraft, but may also be a propeller aircraft. It is also understood that although  FIG. 1  shows a commercial aircraft, the aircraft  1  may alternately be any other type of aircraft, including, but not limited to, a business aircraft or a private aircraft. 
     Each of the wings  5  extends from a root  5   a  adjacent the fuselage  2  to a tip  5   b,  and each of the engines  6  is disposed between the root  5   a  and the tip  5   b  and below a respective one of the wings  5 . The engines  6 , which include nacelles  6   a,  are supported below the wings  5  via pylons  10  each surrounded by a pylon fairing  100  defining the surface exposed to the airflow. It is understood that the whole or a part of the fairing  100  may be an integral part of the pylon, for example defined by the pylon skin, and/or that the whole or a part of the fairing may be defined by one or more element(s) formed separately from the pylon  10  and installed around the pylon  10 . Accordingly, the term “fairing” as used herein is not intended to be limited to a structure separate from the pylon  10 . The pylon fairing  100  is typically streamlined and, in a particular embodiment, is designed to minimize friction losses that might otherwise occur if the pylon  10  were exposed to ambient air circulating around the aircraft  1 . In other words, the pylon fairing  100  is used to hide structural hard points associated with the engine attachment to the wing  5 . The pylon fairing  100  is typically designed to be wider at a wing junction compared to a remainder of the pylon fairing  100 . 
     For an under-wing mounted engine aircraft as illustrated in  FIG. 1 , there is a strong interaction between the aerodynamic flow around the wing  5 , the engines  6 , and the pylon fairing  100  that might result in lift loss (i.e., interference effect). In a particular embodiment, the pylon fairing  100  has an aerodynamic design adapted to minimize adverse flow interactions between the nacelles  6   a  and the wings  5 . As the engine fan diameter is increased, the interference effects become more pronounced. For a closely coupled engine to airframe installation, the interaction of a jet exiting the engine with the pylon fairing  100  and the wing  5  might introduce additional lift loss and an increase in aircraft drag. It may also result in appearance of flow separation at a junction between the pylon fairing  100  and the wing  5 . Such a flow separation might be an additional source of aircraft drag, which may result in a decrease in aircraft performance. 
     Referring now to  FIGS. 2 to 6 , an assembly Al in accordance with a particular embodiment is illustrated, including the wing  5  and a pylon fairing  100  defining the exposed surface of the pylon  10 . As can be best seen in  FIG. 3 , the pylon fairing  100  extends from the wing  5  and has a shelf  102  configured to be adjacent to the engine  6  and exposed to the jet J ( FIG. 3 ) generated by the engine  6 . The pylon fairing  100  extends along a pylon span-wise axis V, along which a height of the pylon fairing  100  is defined. The pylon span-wise axis V is normal to the wing chord. As can be best seen in  FIG. 4 , the pylon fairing  100  has an aerodynamic profile  104 , which may be configured for example in whole or in part by an airfoil shape. The profile  104  is defined by opposed inward and outward sides or walls  104   a,    104   b,  with the inward side  104   a  facing the root  5   a  of the wing  5  and the fuselage  2  ( FIG. 1 ). The inward and outward sides  104   a  and  104   b  meet to define a fairing trailing edge  106 . 
     Referring now to  FIG. 2 , the wing  5  has a leading edge  5   d  and a trailing edge  5   e  between which a plurality of local chord lines can be defined. It is understood that the trailing edge  5   e  may be defined by a fixed part of the wing  5 , or, when trailing edge flaps are present, by the trailing edge of the flap. In the embodiment shown, distances between the leading and trailing edges  5   d,    5   e  of the wing  5  along the chord lines vary from the root  5   a  to the tip  5   b  of the wing  5 . The pylon fairing  100  is adjacent to or abutting the wing  5  at a pylon location  5   c  located between the root  5   a  and the tip  5   b  of the wing  5 , and a local chord line  5   f  is defined at the pylon location  5   c.  In the embodiment shown, the pylon location  5   c  is located outward of but close to a flap track fairing  12  disposed around a mechanism used to deploy and retract the wing flaps, and accordingly the trailing edge  5   e  of the wing  5  at the pylon location  5   c  is determined by the flap. The interaction of the pylon fairing  100 , the wing  5 , and the flap track fairing  12  creates a flow channel  112  that might be subjected to fluidic phenomenon that impair performances. 
     Referring more particularly to  FIG. 3 , the pylon fairing  100  has an upper section  100   a,  a central section  100   b,  and a lower section  100   c,  with the central section  100   b  located between the upper and lower sections  100   a,    100   c  relative to the pylon span-wise axis V. The upper section  100   a  is located adjacent the wing  5  and extends downwardly, i.e. toward the shelf  102 . The central section  100   b  extends downwardly from the upper section  100   a.  In the embodiment shown, the transition between the upper section  100   a  and central section  100   b  is defined by an abrupt change in length of the fairing  100  as defined by an abrupt change in location of the fairing trailing edge  106 . The lower section  100   c  extends downwardly from the central section  100   b,  adjacent the engine  6 , and includes the shelf  102 . In a particular embodiment, the transition between the central section  100   b  and the lower section  100   c  is defined by a change in camber and/or lateral offset, as will be further detailed below. In a particular embodiment, the lower section  100   c  includes and is limited to the portion of the fairing  100  defining the shelf  102 , i.e. extending through the jet or flow J generated by the engine  6 . In the embodiment shown, the flow channel  112  ( FIG. 2 ) is defined more specifically between the flap track fairing  12  and the upper section  100   a  of the pylon fairing  100 . It is understood that two or all of the sections  100   a,    100   b,    100   c  may be monolithic and formed as a single piece, and that alternately the sections  100   a,    100   b,    100   c  may be formed separately and positioned adjacent one another along the height of the pylon  10 . 
     In a particular embodiment and referring to  FIG. 3 , a height H 1  of the upper section  100   a  defined between the wing  5  and the central section  100   b  along the pylon span-wise axis V has a value ranging from 2.5% to 10% of the local chord  5   f  of the wing taken at the pylon location  5   c.  A height H 2  of the central section  100   b  defined between the upper section  100   a  and the lower section  100   c  along the pylon span-wise axis V has a value ranging from 10% to 17% of the local chord  5   f  of the wing  5 . A height H 3  of the lower section  100   c  defined from the central section  100   b  has a value ranging from 17% to 23% of the local chord  5   f  of the wing  5 . Other values are also possible. 
     In a particular embodiment, the aerodynamic profile  104  defined by the inward and outward sides  104   a,    104   b  in at least part of, and in a particular embodiment a whole of, the lower section  100   c  is symmetrical. Referring to  FIGS. 2-3 , the engine has a longitudinal central axis R ( FIG. 3 ), and an engine vertical mid-plane P ( FIG. 2 ) which is defined as the plane containing the central axis R and oriented vertically when the aircraft is on the ground and the engine  6  is installed on the aircraft. Referring to  FIGS. 4-5 , at least a part of, and in a particular embodiment a whole of, the lower section  100   c  of the pylon fairing  100  has a chord line C parallel to the longitudinal central axis R of the engine  6  and extending in the engine vertical mid-plane P, and the fairing trailing edge  106   c  ( FIG. 3 ) in at least a part of, and in a particular embodiment a whole of, the lower section  100   c  is contained within the engine vertical mid-plane P. 
     Still referring to  FIGS. 4-5 , in the embodiment shown the fairing trailing edge  106   a  in the upper section  100   a  protrudes axially rearward of the trailing edge  5   e  of the wing  5  at the pylon location  5   c.  In the embodiment shown and as can be seen in  FIG. 5 , a distance D 1  is defined along the direction of the chord line C of the lower section (or engine axis R, see  FIG. 3 ) between the trailing edge  5   e  of the wing  5  and the fairing trailing edge  106   a  in the upper section  100   a  at the pylon location  5   c;  the distance D 1  is defined at the position of the flap defining the rearmost leading edge for the wing. In a particular embodiment, the distance D 1  is at least 3% and/or at most 13% of the local chord  5   f  of the wing at the pylon location  5   c,  for example at least 5% and/or at most 10% of the local chord  5   f  of the wing at the pylon location  5   c.  Other values are also possible. In the embodiment shown, the axial distance D 1  between the wing trailing edge  5   e  and the fairing trailing edge  106  remains the same along the height of the upper section  100   a.    
     In a particular embodiment, the fairing trailing edge  106   a  in the upper section  100   a  protruding axially rearwardly of the trailing edge  5   e  of the wing  5  at the pylon location  5   c  is particularly suitable for high cruise speeds, for example cruise speeds of Mach  0 . 82  and higher. Other values are also possible. 
     Still referring to  FIGS. 4-5 , in the embodiment shown, the aerodynamic profile  104  defined by the inward and outward sides  104   a,    104   b  of the upper section  100   a  of the pylon fairing  100  is cambered toward the root  5   a  of the wing  5 , and toward the adjacent flap track fairing  12 . Accordingly, the fairing trailing edge  106   a  in the upper section  100   a  is located between the engine vertical mid-plane P and the root  5   a  of the wing  5 , and is offset from the engine vertical mid-plane P by an offset distance D 2  ( FIG. 5 ) taken perpendicularly from the engine vertical mid-plane P. In a particular embodiment, the offset distance D 2  has a value of at least 0.3% and/or at most 6.5% of the local chord  5   f  of the wing at the pylon location  5   c,  for example at least 0.5% and/or at most 3% of the local chord  5   f  of the wing at the pylon location  5   c.  Other values are also possible. 
     In the embodiment shown and referring to  FIG. 3 , the fairing trailing edge  106   b  in the central section  100   b  is forwardly offset from the fairing trailing edge  106   a  in the upper section  100   a,  for example by a distance D 6 . In a particular embodiment, the distance D 6  has a value of 34% or about 34% of the local chord  5   f  of the wing at the pylon location  5   c.  Other values are also possible. The fairing trailing edge  106   b  in the central section  100   b  is located forward of the wing trailing edge  5   e.  Referring to  FIG. 6 , in a particular embodiment the aerodynamic profile  104  defined by the inward and outward sides  104   a,    104   b  in the central section  100   b  is also cambered toward the root  5   a  of the wing  5 . The fairing trailing edge  106   b  in the central section  100   b  is offset from the engine vertical mid-plane P by an offset distance D 5 . In a particular embodiment, the offset distance D 5  has a value of at least 0.3% and/or at most 3% of the local chord  5   f  of the wing  5  at the pylon location  5   c,  for example at least 0.5% and/or at most 2% of the local chord  5   f  of the wing at the pylon location  5   c.  Other values are also possible. For example, in a particular embodiment the central section  100   b  is symmetrical and/or the fairing trailing edge  106   b  in the central section  100   b  is located within the engine vertical mid-plane P. 
     Referring more particularly to  FIG. 7 , a graph illustrating a variation of the offset distance D 2  between the fairing trailing edge  106  and the engine vertical mid-plane P as a function of a distance from the wing  5  along the pylon span-wise axis V is presented. In the present graph, both the offset distance D 2  and the distance from the wing  5  are expressed as percentages of the local chord  5   f  of the wing  5  at the pylon location  5   c.  In the embodiment shown, the offset distance D 2  remains constant in the upper section  100   a,  and then decreases progressively as the distance from the wing increases until it reaches a value of  0  in the lower section  100   c,  where the fairing trailing edge  106   c  is located within the engine vertical mid-plane P. Other configurations are contemplated. 
     Referring more particularly to  FIG. 8 , a graph illustrating a variation of an absolute value of the axial distance D 1  (i.e. whether forward or aft of) between the fairing trailing edge  106  and the trailing edge  5   e  of the wing  5  as a function of a distance from the wing  5  along the pylon span-wise axis V is presented. In the present graph, both the axial distance D 1  and the distance from the wing  5  are expressed as percentages of the local chord  5   f  of the wing  5 . In the embodiment shown, the axial distance D 1  remains constant in the upper section  100   a,  and then changes abruptly between the upper section  100   a  and the central section  100   b.  The axial distance D 1  then increases progressively as the distance from the wing increases. Other configurations are contemplated. 
     Referring now to  FIGS. 9 to 11 , an assembly A 2  in accordance with another embodiment is shown, including the wing  5  and a pylon fairing  200 , where elements similar to that of the pylon fairing  100  of  FIGS. 2 to 6  are identified by the same reference numerals and will not be further described herein. 
     In this embodiment, the fairing trailing edge  206   a  in the upper section  200   a  is located axially forward of the trailing edge  5   e  of the wing  5  at the pylon location  5   c.  In a particular embodiment, the axial distance D 1  ( FIG. 10 ) between the trailing edge  5   e  of the wing  5  and the fairing trailing edge  206   a  at the pylon location  5   c  is at most 30%, and preferably at most 25%, of the local chord  5   f  of the wing  5  at the pylon location  5   c.  Other values are also possible. For example, the fairing trailing edge  206   a  at the pylon location  5   c  may overlap a flap the wing, i.e. be located rearwardly of a junction between the flap and the wing  5  and forwardly of a trailing edge of the flap. It is understood that the values for the axial distance D 1  mentioned for the upper section  100   a  can be applied to the upper section  200   a,  and that the values for the axial distance D 1  mentioned for the upper section  200   a  can be applied to the upper section  100   a.  In a particular embodiment, the fairing trailing edge  206   a  in the upper section  200   a  is axially aligned with the trailing edge  5   e  of the wing  5  at the pylon location  5   c,  i.e. the axial distance D 1  is 0 for part or a whole of the upper section  200   a.    
     As illustrated in  FIG. 10 , the fairing trailing edge  206   a  at a lowermost end of the upper section  200   a  is axially aligned with the fairing trailing edge  106   b  at an uppermost end of the central section  100   b;  for example, in a particular embodiment there is no distinct transition between the upper section  200   a  and the central section  100   b.  In a particular embodiment, the axial distance D 1  between the fairing trailing edge and the trailing edge  5   e  of the wing  5  varies at a constant rate, and/or the trailing edge  206   a  shows continuity, e.g. tangent continuity, with the fairing trailing edge  106   b.    
     In this embodiment and referring more particularly to  FIG. 9 , the aerodynamic profile  104  defined by the inward and outward sides  104   a,    104   b  in the upper section  200   a  of the pylon fairing  200  is also cambered toward the root  5   a  of the wing  5 . The offset distance D 2  may be defined similarly to that of the pylon fairing  100  as shown in  FIG. 5 , and in a particular embodiment may have the same values or ranges of values. In another embodiment, the offset distance D 2  of the upper section has a value of at least 0.3% and/or at most 3% of the local chord  5   f  of the wing at the pylon location  5   c,  for example at least 0.5% and/or at most 2% of the local chord  5   f  of the wing at the pylon location  5   c.  Other values are also possible. 
     In a particular embodiment, the aerodynamic profile  104  defined by the inward and outward sides  104   a,    104   b  in the central section  100   b  of the fairing  200  is also cambered toward the root  5   a  of the wing  5 , with the fairing trailing edge  106   b  in the central section  100   b  offset from the engine vertical mid-plane P by an offset distance which may correspond to the values of D 5  provided above. Alternately, the central section  100   b  of the fairing  200  may be symmetrical and/or the fairing trailing edge  106   b  in the central section  100   b  of the fairing  200  may be located within the engine vertical mid-plane P. 
     In a particular embodiment, the aerodynamic profile  104  defined by the inward and outward sides  104   a,    104   b  in the lower section  100   c  of the fairing  200  is symmetrical, and/or the fairing trailing edge  106   c  in the lower section  100   c  of the fairing  200  is located within the engine vertical mid-plane P. 
     In a particular embodiment, the pylon fairings  100 ,  200  allow to improve a flow quality at the fairing trailing edge  106   a,    206   a  and to reduce the drag compared to uncambered and/or shorter pylon configurations. In a particular embodiment, the pylon fairings  100 ,  200  allow to reduce a possible flow separation at the fairing trailing edge  106   a,    206   a  by accelerating the flow in the channel  112  defined between the pylon fairing  100 ,  200  and the wing  5 , more particularly between the pylon fairing  100 ,  200  and the flap track fairing  12  ( FIG. 2 ), and by modifying the wing pressure distribution in the vicinity of the pylon fairing  100 ,  200 . 
     Referring now to  FIGS. 11 a  to 11 c   , alternate aerodynamic profiles  304 ,  404 ,  504  that can be used for the pylon fairings  100 ,  200  are illustrated. The aerodynamic profiles  304 ,  404 ,  504  are each defined by an inward side  304   a,    404   a,    504   a,  and by an opposed outward side  304   b,    404   b,    504   b,  with the inward side  304   a,    404   a,    504   a  facing the fuselage  2  ( FIG. 1 ). In the embodiment of  FIG. 11 a   , the outward side  304   b  is convex and the inward side  304   a  is concave. Alternately, and as shown in  FIG. 11 b   , both the inward and outward sides  404   a,    404   b  are convex. Alternately, and as shown in  FIG. 11 c   , the outward side  504   b  is convex whereas the inward side  504   a  is flat and has no curvature. Any one of these combinations can be used to obtain the desired offset D 2  for the fairing trailing edge  106   a,    206   a  in the upper section  100   a,    200   a.    
     Referring now to  FIG. 12 , in an alternate embodiment the pylon fairing  100 ,  200  may have a trailing section  600   a  pivotally mounted to a body  600   b  via a pivot point  600   c  to be able to pivot relative to the body  600   b  about an axis V′. A flap mechanism (not shown) is provided to control movements of the trailing section  600   a  relative to the body  600   b,  and the trailing section  600   a  and body  600   b  cooperate together to define the inward and outward sides  104   a,    104   b.  Stated otherwise, the mechanism is configured to control an angle T between the trailing section  600   a  and the body  600   b  so as to obtain the desired offset D 2  for the fairing trailing edge  106   a,    206   a  in the upper section  100   a,    200   a.  In a particular embodiment, this configuration allows the optimization of an angular position of the trailing section  600   a  relative to the body  600   b  in function of the flight operating conditions. 
     In a particular embodiment and in use, directing the airflow denoted by arrow F on  FIG. 2  around the aircraft  1  between the wing  5  and the engine  6  includes guiding the airflow toward the trailing edge  5   e  of the wing  5  between the pylon and the fuselage  2  with the pylon fairing  100 ,  200 . In the embodiments shown, guiding the flow includes deviating an upper portion of the airflow F located adjacent the wing  5  and denoted by arrow F′ on  FIG. 2  toward the fuselage  2  with the pylon fairing  100 ,  200 . The pylon fairing  100 ,  200  deviates the flow up to the trailing edge  106   a,    206   a  of the pylon fairing  100 ,  200  that is distanced from the trailing edge  5   e  of the wing  5  by at most 30% of the local chord of the wing  5  at the pylon location  5   c,  for example positioned in front of the trailing edge  5   e  of the wing  5  at a distance from the trailing edge  5   e  of at most 30% or at most 25% of the local chord of the wing  5 , or positioned aft of the trailing edge  5   e  of the wing  5  at a distance from the trailing edge  5   e  of at least 3% and/or at least 5% and/or at most 13% and/or at most 10% of the local chord  5   f  of the wing at the pylon location  5   c.  The upper portion F′ ( FIG. 2 ) of the flow circulates within the channel  112 . In the embodiment of  FIGS. 2-8 , the pylon fairing  100  deviates the flow F past the trailing edge  5   e  of the wing  5 . 
     In a particular embodiment, a maximum deviation of the flow toward the fuselage  2  is achieved in a vicinity of the wing  5 , and adjacent the upper sections  100   a,    200   a  of the pylon fairings  100 ,  200 . The flow deviation decreases when a distance from the wing  5  along the pylon span-wise axis V increases. A portion of the jet J generated by the engine  6  is guided toward a direction parallel the central axis R of the engine by the pylon fairing. 
     While the methods and systems described herein have been described and shown with reference to particular steps performed in a particular order, it will be understood that these steps may be combined, subdivided or reordered to form an equivalent method without departing from the teachings of the present invention. Accordingly, the order and grouping of the steps is not a limitation of the present invention. 
     Modifications and improvements to the above-described embodiments of the present invention may become apparent to those skilled in the art. The foregoing description is intended to be exemplary rather than limiting. The scope of the present invention is therefore intended to be limited solely by the scope of the appended claims.