Wing of a vertical take-off and landing aircraft

Abstract

An aircraft wing portion comprises a shroud (1A). This shroud (1A) has a leading edge (7) and a trailing edge (9), a pressure-side surface (5) and a suction-side surface (3). The shroud (1A) also has a through-duct (11) connecting the pressure-side surface (5) to the suction-side surface (3). The through-duct (11) houses a rotor (1B). The shroud (1A) comprises a front part (27), extending from the leading edge (7) to the through-duct (11). The shroud (1A) has a profile (35) with a front section (37), corresponding to its front part (27). The through-duct (11) is closer to the trailing edge (9) than to the leading edge (7), while the profile (35) has a distance between the pressure-side surface (5) and the suction-side surface (3) that is at its maximum on its front section (37). This front section (37) has a camber of less than ten per cent.

Description

Vertical takeoff and landing aircraft wing

[0001] The invention relates to the field of vertical take-off and landing aircraft, also referred to as VTOL in the art (from the English equivalent "Vertical Take-Off and Landing"). More particularly, the invention relates to a portion of a VTOL aircraft wing, an aircraft wing comprising this portion and an aircraft comprising this wing.

[0002] A VTOL aircraft generally comprises a plurality of rotors equipped with blades which, when rotated, are capable of jointly producing an essentially vertical movement of the aircraft, particularly during takeoff and landing phases. A VTOL aircraft can take off from and land on a limited ground infrastructure, which makes its use particularly suitable in highly constrained environments, such as cities for example.

[0003] A first configuration of VTOL aircraft is known, in which the rotation of the rotors alone provides the aircraft's lift, not only in the vertical flight phases, but also in the forward flight phases. This is the case, for example, of the configuration of the aircraft known as "Velocity" from the company Volocopter. The aircraft is then generally wingless. However, aircraft in this first configuration have a fairly low forward flight speed, low energy autonomy and significant noise pollution.

[0004] This is why a second configuration is generally preferred, in which aircraft are equipped with wings. These wings produce most of the aircraft's lift in forward flight, while in vertical flight, this lift remains mainly generated by the rotors.

[0005] According to a first type of aircraft having this second configuration, the rotors are installed on the wings, in such a way that the blades of these rotors protrude from the wings. This is the case, for example, of the aircraft known as the "VX-4" from the company Vertical Aerospace. In forward flight, these rotors can either be folded so as to participate in forward flight, or left as they are. In the first case, the implementation of the folding process results in additional mechanical complexity, without necessarily being accompanied by a significant gain in performance. In the second case, significant drag is generated.

[0006] According to a second type of aircraft having this second configuration, the wings comprise a fairing provided with through ducts, each of these ducts connecting the lower surface of the wing to the upper surface of the latter. The rotors are each housed in a respective duct.

[0007] For aircraft of this type, we then seek to design wings whose fairing has ducts suitable for housing the rotors and whose ratio between lift and drag (also called "finesse" in the technique) is maximum.

[0008] It is difficult to design such wings because construction features designed to improve drag generally impair lift, and vice versa. Furthermore, these features often produce different effects depending on whether the aircraft is in forward or vertical flight.

[0009] For example, housing the rotors in through-ducts improves their efficiency in vertical flight. However, the presence of ducts passing through the fairing generates a discontinuity in lift on the wing and locally increases drag, particularly in forward flight.

[0010] VTOL aircraft are known whose wings are associated with ducted rotors mounted tilting on these wings. These rotors provide propulsion for the aircraft both in vertical flight and in forward flight. This is the case, for example, of the aircraft known as "Lilium Jet" from the Lilium company, whose propulsion is based on a single engine system, fully electrified, during all phases of flight. Contrary to the intended purpose, wings profiled in this way generally do not improve glide ratio.

[0011] Therefore, we are particularly interested here in the wings of VTOL aircraft whose fairing has through ducts, which house rotors dedicated to propulsion in the vertical flight phase only, or at least mainly.

[0012] US 11001377 Bl, EP 3431385 Al, EP 3290334 Al, CN 105711831 A and CN 104176250 A disclose wings of the type described above, the drag of which in forward flight is reduced by the addition of a rotor covering mechanism. Such a mechanism is nevertheless difficult to implement and poses a problem for obtaining a certificate of conformity with the regulatory requirements necessary for the marketing of any commercial aircraft.

[0013] EP 3532375 A1 discloses a wing of the type described above, in which the drag in forward flight is reduced by an acceleration of the airflow over this wing, acceleration resulting from the rotation of an additional propeller, arranged at the rear of the wing. The presence of this propeller, however, induces additional drag in forward flight.

[0014] EP 3470332 B1 discloses a wing of the type described above, comprising a fairing, having a leading edge and a trailing edge mutually opposed, a lower surface and an upper surface, mutually opposed and each connecting the leading edge to the trailing edge. The fairing further has a through duct which connects the lower surface to the upper surface. This through duct houses a rotor. The fairing comprises a front part, extending from the leading edge to the through duct and a profile with a front section, corresponding to its front part.

[0015] The wing of EP 3470332 B1 has improved lift in forward flight, but at the expense of drag, so that overall, this wing is not entirely satisfactory.

[0016] In this context, the Applicant sought to improve the situation.

[0017] An aircraft wing portion is provided comprising a fairing, which has a leading edge and a trailing edge mutually opposed, a lower surface and an upper surface, mutually opposed and each connecting the leading edge to the trailing edge. The fairing further has a through duct connecting the lower surface to the upper surface. The through duct is capable of housing a rotor, at least partially. The fairing comprises a forward portion, extending from the leading edge to the through duct. The fairing has a tail with a forward section, corresponding to its forward portion. The through duct is closer to the trailing edge than to the leading edge, while the tail has a distance between the lower surface and the upper surface maximum on its forward section. This forward section has a camber of less than ten percent.

[0018] The proposed wing portion configuration combines a through-duct positioned behind this portion and a particular profile of this portion. This configuration considerably reduces drag in forward flight. It also allows for the installation of a thicker spar, particularly in comparison with configurations where the spar passes through the duct, without affecting drag. This thicker spar allows for the addition of airfoil portions, without ducts, adjacent to this wing portion. This increases the wing's lift in forward flight. The result is a wing with greatly improved glide ratio.

[0019] Also provided is an aircraft wing comprising this wing portion, and an aircraft comprising one or more of these wings.

[0020] Optional, complementary or substitutive features of the invention are set out below: - the forward part houses a portion of spar, and where the portion of spar is closest to the through duct, the forward section has a chord line and the distance between the leading edge and the point on the chord line at which the depth has the distance between the intrados surface and the maximum extrados surface is between twenty-five and fifty percent of the length of the chord line; - the fairing comprises a rear portion, extending from the through duct to the trailing edge, said profd comprises a rear section, corresponding to the rear portion, and the rear section has a camber of less than ten percent; - the wing portion further comprises a rotor, at least partially housed in the through duct, the rotor comprising at least one blade capable of adopting a vertical flight position relative to the through duct, the upper surface and the lower surface are mutually opposite in a direction of the wing portion and the through duct comprises a cylindrical part opposite said blade, the cylindrical part having a height substantially equal to the size of the blade in said direction, the blade being in a vertical flight position; - the through conduit comprises a cylindrical part, an upper lip, connecting the cylindrical part to the extrados surface, and a lower lip, connecting the cylindrical part to the intrados surface, and, on the rear section, the upper lip and the lower lip each have a substantially rounded shape, while the intrados surface and the extrados surface each have a substantially rectilinear portion, respectively near the lower lip and the upper lip; - on the rear section, the distance between the intrados surface and the extrados surface is maximum near the through conduit; - on the front section of the profundus, the distance from the intrados surface to the extrados surface increases progressively from the through duct, towards the leading edge; - on the front section of the profile, the distance from the intrados surface to the extrados surface increases progressively from the leading edge, towards the trailing edge; - the maximum distance between the intrados surface and the extrados surface is around 250 millimeters.

[0021] Other characteristics and advantages of the invention will appear more clearly on reading the description which follows, taken from examples given for illustrative and non-limiting purposes, and from the drawings in which: - figure 1 represents a portion of wing according to the invention, in isometric perspective; - figure 2 is similar to figure 1; - figure 3 is similar to figure 1; - figure 4 represents a profile of the wing portion of figure 1; - figure 5 represents a detail of figure 4; - figure 6 represents a detail of figure 4; - figure 7 represents a detail of the wing portion of figure 1, in isometric perspective; - figure 8 is similar to figure 7; - figure 9 is similar to figure 7; - figure 10 represents an example of an aircraft comprising a plurality of wing portions according to the invention, in isometric perspective; - figure 11 represents the aircraft of figure 10, seen from behind; - Figure 12 represents the aircraft of Figure 10, seen from the side.

[0022] The drawings and the description below contain, for the most part, elements of a certain character. They may therefore not only serve to better understand the present invention, but also contribute to its definition, if necessary.

[0023] Reference is made to Figures 1 and 2.

[0024] These figures show a portion of wing 1 for a VTOL type aircraft.

[0025] This wing portion 1 comprises a fairing IA which partially houses a rotor IB. The wing portion 1 further comprises a stator (not shown), shaped so as to support the rotor IB on the fairing IA.

[0026] The fairing 1A has a front part shaped into a leading edge 7 and a rear part shaped into a trailing edge 9. The leading edge 7 and the trailing edge 9 are mutually opposite in a first direction of the wing portion 1, here the longitudinal direction of the wing portion 1. Here, the distance between the leading edge 7 and the trailing edge 9 in this longitudinal direction is constant over the wing portion 1.

[0027] The fairing 1A further has an upper surface shaped into an extrados 3 and a lower surface shaped into a intrados 5. The extrados 3 and the intrados 5 are mutually opposed in a second direction of the wing portion 1, here the transverse direction of the wing portion 1. The extrados 3 and the intrados 5 each connect the leading edge 7 to the trailing edge 9. Here, the distance between the extrados 3 and the intrados 5 in this transverse direction is variable on the wing portion 1. This distance can be seen as the thickness of the wing portion 1.

[0028] The wing portion 1 further comprises a through duct 11, arranged in the fairing 1A and connecting the lower surface 5 to the upper surface 3. The through duct 11 comprises a cylindrical part 31, the visible portion of which is shown here with hatching. Here, the cylindrical part 31 has a generally circular cross-section. Here, the cylindrical part 31 has a substantially constant height over its circumference.

[0029] The through conduit 11 further comprises an upper lip portion 19, connecting the cylindrical portion 31 to the extrados 3, and a lower lip portion 21, connecting the cylindrical portion 31 to the intrados 5. Here, the lip upper lip 19 has a profile of substantially rounded shape, of substantially constant curvature, over its circumference. Here, the lower lip 21 has a profile of substantially rounded shape, of substantially constant curvature, over its circumference.

[0030] Generally, the through duct 11 extends mainly in the transverse direction of the wing portion 1. The through duct 11 partially houses the rotor 1B.

[0031] The through duct 11 is closer to the trailing edge 9 than to the leading edge 7. The minimum distance which separates the leading edge 7 from the upper lip 19 (resp. the lower lip 21) is substantially greater than the minimum distance which separates the trailing edge 9 from this lip.

[0032] In the vicinity of the through duct 11, the fairing 1A further has a front portion 27, extending from the leading edge 7 to the through duct 11, and a rear portion 29, extending from the through duct 11 to the trailing edge 9. The front portion 27 and the rear portion 29 are hollow.

[0033] The forward portion 27 of the wing portion 1 houses a spar segment (not shown), or load-bearing beam, which passes through a wing from its root onto a fuselage at its end.

[0034] The rotor IB is held in the through duct 11 in such a way that its axis of rotation forms with the transverse direction of the wing portion 1 a rotor inclination angle of between approximately 0° and approximately 30°. Here, this angle is close to 0°. The inclination of the axis of rotation of the rotor IB relative to the transverse direction of the wing portion 1 improves yaw control. Any plane orthogonal to the axis of rotation of the rotor IB is called the rotor plane.

[0035] The rotor IB comprises a hub 23 and a plurality of blades 17 each mounted on the hub 23 with the possibility of pivoting. Here, each rotor IB comprises 7 blades. The blades 17 are inclined relative to the hub 23 and this inclination can be modified during flight, at least as a whole. The end of the blades 17 opposite the hub 23 is free. The end of a blade 17 forms a blade inclination angle with the planes of the rotor. Here, the blades 17 can be pivoted between a feathered position, more efficient in forward flight, corresponding to a blade inclination angle close to 0°, and an inclined position, more suited to vertical flight, corresponding to a blade inclination angle of between approximately 20° and approximately 40°.

[0036] The rotational speed of the hub 23 relative to the through duct 11 can be controlled to different values ​​during the flight.

[0037] Here, the rotor 1 B and the through duct 11 are arranged in mutual correspondence so that the blades 17 are opposite the cylindrical part 31 of the through duct 11, for the feathered position and the inclined position. There is a radial clearance between the free end of the blades 17 and the cylindrical part 31 of the duct 11. This clearance is as small as possible, for example between 0.5 and 5 millimeters.

[0038] In the prior art, the spar segment is most often placed across the through-duct housing the rotor. On the contrary, in the proposed wing portion 1, the spar segment is positioned in the front part 27, which frees the through-duct 11. Compared to the prior art, the wing portion 1 offers better performance of the rotor 1B, in particular in vertical flight, and reduces drag, particularly in forward flight. In addition, the positioning of the spar segment in the front part 27 allows a thicker spar than in the prior art. A thicker spar makes it possible in particular to support at the end of the wing portion 1 a portion of the airfoil ensuring more lift in forward flight. This positioning also makes it possible to reduce the height of the through-duct 11, which here corresponds to the size of the blades 17, and not to the thickness of the spar. This further reduces the drag that the through duct 11 tends to generate in forward flight.

[0039] Generally, the configuration described here reduces the lift discontinuity on the wing portion 1 generated by the presence of the through duct 11, and the drag induced by this discontinuity. This configuration also makes it possible to accelerate the transition between the different flight phases, by improving the suction effect in the through duct 11.

[0040] Reference is made to Figures 3 to 6.

[0041] Figure 3 shows, in dashed lines, a profile 35 of the fairing IA, according to a longitudinal section of the wing portion 1 passing through a diameter of the cylindrical part 31. The ends of the cylindrical part 31 are represented in solid lines for the visible parts and in dashed lines for the parts hidden by the fairing IA. The visible portion of the cylindrical part 31 is hatched.

[0042] The section shown in Figure 3 is a longitudinal section where the through duct 11 is closest to the leading edge 7. Here, this longitudinal section also corresponds to the section on which the through duct 11 is closest to the trailing edge 9. Figure 4 shows this profile 35 and a profile of the hub 23.

[0043] The profile 35 has a front section 37 (shown in FIG. 5), corresponding to the front part 27 of the fairing 1A, and a rear section 39 (shown in FIG. 6), corresponding to the rear part 29 thereof. The front section 37 and the rear section 39 respectively have a front chord line Co37 (of front chord value L37), and a rear chord line Co39 (of rear chord value L39). The front chord line Co37 is shown in FIGS. 4 and 5 as a dashed line. The rear chord line Co39 is shown in FIGS. 4 and 6 as a dashed line.

[0044] The front chord line Co37 corresponds to the shortest of the straight lines that connect the leading edge 7 to the rear end of the front section 37, here the cylindrical part 31 of the through duct 11. Here, the front chord value L37 corresponds to the length of the front chord line Co37, and is between 450 and 840 millimeters, for example 700 millimeters.

[0045] The rear chord line Co39 corresponds to the shortest of the straight lines which connect the front end of the rear section 39, here the cylindrical part 31 of the through duct 11, to the trailing edge 9. Here the rear chord value L39 corresponds to the length of the rear chord line Co39, and is between 200 and 336 millimeters, for example 280 millimeters.

[0046] The depth 35 of the fairing IA has a variable thickness from the leading edge 7 to the trailing edge 9. This thickness takes a maximum value E35 on the front section 37, at a distance L35 from the leading edge 7. The maximum thickness E35 corresponds to the location of the spar segment. Here, the maximum thickness E35 is between 150 and 270 millimeters, for example 244 millimeters. The distance L35 between the leading edge 7 and the point on the front chord line Co37 at which the depth 35 has the maximum thickness E35 is between twenty-five and fifty percent of the front chord value L37. In Figure 5, this distance L35 is substantially equal to fifty percent of the front chord value L37.

[0047] The front section 37 is thinned near the leading edge 7. Its thickness increases progressively from the leading edge 7 towards the trailing edge 9, until it reaches the maximum thickness value E35, then decreases progressively towards the through duct 11. The rear section 39 has a maximum thickness E39 at a distance L40 from the through duct 11, then its thickness decreases progressively towards the trailing edge 9. Here, the maximum thickness E39 of the rear section 39 is between 77 and 177 millimeters, for example 97 millimeters. The maximum thickness E39 of the rear section 39 is less than the maximum thickness E35 of the profile 35. On the Figure 6, the maximum thickness E39 of the rear section 39 is located substantially at a point located between fifteen and twenty-two percent of the rear chord line Co39, which corresponds to a distance L40 between this maximum thickness E39 and the through conduit 11 substantially equal to 44 millimeters.

[0048] On profile 35, the extrados 3 and the intrados 5 are generally symmetrical to each other. The front section 37 and the rear section 39 have a front camber Ca37 and a rear camber Ca39, respectively. The front camber Ca37 (resp. the rear camber Ca39) is equal to the ratio of the maximum deflection of the front section 37 (resp. of the rear section 39) to the front chord value L37 (resp. the rear chord value L39). The deflection of the front section 37 (resp. the rear section 39) corresponds to the distance between the front chord line Co37 (resp. the rear chord line Co39), at right angles to this chord line, and the mean line of the front section 37 (resp. the rear section 39). The average line of the front section 37, respectively of the rear section 39, is made up of all the points on this section at equal distance from the intrados 5 and the extrados 3.

[0049] Both the front camber Ca37 and the rear camber Ca39 are less than ten percent.

[0050] Figures 4 and 5 show that, on the front section 37 of the profile 35, the extrados 3 and the intrados 5 are essentially symmetrical to each other. Figures 4 and 5 show that, on the front section 37 of the profile 35, the extrados 3 is convex. Figures 4 and 5 show that, on the front section 37 of the profile 35, the intrados 5 is convex.

[0051] The cylindrical part 31 of the through conduit 11 has a diameter L31. Here, this diameter L31 is between 900 and 1350 millimeters, for example 1120 millimeters.

[0052] The profile 35 of the wing portion 1 has a size in the longitudinal direction of the wing portion 1 of value L1. The size value L1 corresponds to the sum of the front chord value L37, the diameter L31 of the cylindrical part 31 and the rear chord value L39. Here, the size value L1 is for example 2100 millimeters.

[0053] On the front section 37 and the rear section 39 of the fairing IA, the depths of the extrados 3 and the intrados 5 each follow a Bézier curve. The parameters of these curves correspond to characteristic curvature values.

[0054] On the front section 37 of the fairing IA, the curvature of the upper surface 3 is minimal near the through duct 11. There, this curvature takes a first characteristic value VL From the through duct 11, towards the leading edge 7, this curvature increases progressively until reaching, near the location of the spar, a second characteristic value V2. This value corresponds to a local maximum. The curvature of the upper surface 3 then decreases slightly before increasing again until reaching its maximum on the leading edge 7. There, the curvature takes a third characteristic value V3. Here, these characteristic values ​​VI, V2 and V3 are respectively 4.10 -3 , 1.10 -3 and 2.10 -2 per millimeter.

[0055] The curvature of the lower surface 5 on the front section 37 varies in a similar manner to that described above. This curvature takes, from the through duct 11 to the leading edge 7, characteristic values ​​VI', NT and V3', in that order. Here, these characteristic values ​​VI', NT and V3' are respectively 3.10' 4 , 1.10' 3 and 2.10 -2 per millimeter.

[0056] On the rear section 39 of the fairing 1A, the depth of the extrados 3 has a substantially rectilinear portion, which extends from the upper lip 19 to the trailing edge 9. This depth takes a first characteristic value of curvature V4, near the upper lip 19, and a second characteristic value of curvature V5, near the trailing edge 9. Here, these characteristic values ​​V4 and V5 are respectively 1.10 -3 and 2.10 -4 per millimeter.

[0057] On the rear section 39 of the fairing 1A, the depth of the intrados 5 has a substantially rectilinear portion, which extends from the lower lip 21 to the trailing edge 9. This depth takes a first characteristic value of curvature V4', near the lower lip 21, and a second characteristic value of curvature V5', near the trailing edge 9. Here, these characteristic values ​​V4' and V5' are respectively 3.10 -2 and 1.10 -4 per millimeter.

[0058] The depth of the wing portion described above contributes to reducing drag in the forward flight phase, in particular the component of this drag generated by the thickness of the spar. This depth makes it possible to guide the airflow from the leading edge 7 towards the trailing edge 9 without stalling. This depth also improves the guidance of the airflow on the lower surface 5 and the upper surface 3 at the inlet and outlet of the rotor 1B, in the vertical flight phase.

[0059] Preferably, the positioning and thickness of the spar segment are identical regardless of the longitudinal section of the fairing IA. In this case, regardless of this section, it has a maximum thickness value close to the maximum thickness value E35 of the depth 35, associated with the same distance L35 from the leading edge 7.

[0060] Here, whatever the longitudinal section of the IA fairing, it also has the same L1 value of longitudinal size.

[0061] Reference is made to Figures 7 to 9.

[0062] These figures show details of the through conduit, near the front part 27 (figure 7), between the front part 27 and the rear part 29 (figure 8) and near the rear part 29 (figure 9). The ends of the cylindrical part 31 of the through conduit are shown in solid lines for the visible parts and in dashed lines for the parts hidden by the fairing. The visible portion of the cylindrical part 31 is hatched. Figures 7 and 9 show, in dashed lines, a part of the front section 37 and the rear section 39 of the profile 35 of the fairing 1A, respectively.

[0063] The height H31 of the cylindrical part 31 corresponds to the minimum height for which the blades 17 in the inclined position do not protrude from the cylindrical part 31 in the transverse direction of the wing portion 1. The height H31 is substantially equal to the size of the blades 17 in the inclined position in this transverse direction. Here, this height H31 is substantially equal to 34 millimeters.

[0064] Reference is made to Figures 10, 11 and 12.

[0065] These figures show an example of an aircraft 101 comprising a plurality of rotor wing portions of the type of the wing portion 1 described above.

[0066] The aircraft 101 comprises a fuselage 103 provided with a pair of low wings 105 and a pair of high wings 107. The low wings 105 are positioned at the front of the fuselage 103 relative to the high wings 107. The low wings 105 and high wings 107 are generally parallel to each other, and may be equipped with a winglet at their end. The aircraft 101 further comprises a tailplane 109, positioned at the rear of the fuselage 103.

[0067] Here, each front wing 105 comprises two mutually adjacent rotor wing portions 1 and a wingtip wing portion 113. Each rear wing 107 comprises two mutually adjacent rotor wing portions 1 and a wingtip wing portion 111. The wing portions 113 and 111 are rotorless. Each wing portion 113 and 111 houses a spar segment, of substantially similar positioning and thickness to those of the spar segment housed in the adjacent rotor wing portion 1.

[0068] The wing portions 113 and 111 increase the lift of the aircraft 101 in forward flight.

[0069] According to the Applicant's tests, the configuration of the rotor wing portions 1 as described above makes it possible to obtain a drag gain of thirty to forty percent compared to a drag value for a similar wing portion, i.e. housing a rotor in a through duct, without this configuration.

[0070] The invention is not limited to the embodiments described above, but encompasses all variants conceivable by those skilled in the art. In particular: - the through duct 11 may have an increased total height, for a constant height value H31 of the cylindrical part 31, so as to increase the performance of the rotor IB in vertical flight; - the wing portion 1 may have a mechanical closing system for the through duct 11, to be activated in the forward flight phase; - the trailing edge 9 can be shaped so as to follow the shape of the through conduit 11 on the side of the rear part 29.

Claims

Claims 1. Aircraft wing portion, comprising: a fairing (IA), having a leading edge (7) and a trailing edge (9) mutually opposite, a lower surface (5) and an upper surface (3), mutually opposite and each connecting the leading edge (7) to the trailing edge (9); the fairing (IA) further having a through duct (11) connecting the lower surface (5) to the upper surface (3), the through duct (11) being capable of housing a rotor (IB), at least partially; the fairing (IA) comprising a front portion (27), extending from the leading edge (7) to the through duct (11); the fairing (IA) having a profile (35) with a front section (37), corresponding to its front portion (27);characterized in that: the through duct (11) is closer to the trailing edge (9) than to the leading edge (7), while the profile (35) has a distance between the intrados surface (5) and the extrados surface (3) which is maximum on its front section (37), this front section (37) having a camber (Ca37) of less than ten percent.; 2. Wing portion according to claim 1, in which the front part (27) houses a spar portion, and where the spar portion is closest to the through duct (11), the front section (37) has a chord line (Co37) and the distance (L35) between the leading edge (7) and the point of the chord line (Co37) at which the depth (35) has the maximum distance between the intrados surface (5) and the extrados surface (3) is between twenty-five and fifty percent of the length of the chord line (Co37).

3. Wing portion according to one of claims 1 and 2, in which the fairing (IA) comprises a rear portion (29), extending from the through duct (11) to the trailing edge (9), said depth (35) comprises a rear section (39), corresponding to the rear portion (39), and the rear section (39) has a camber (Ca39) of less than ten percent.

4. Wing portion according to one of the preceding claims further comprising a rotor (IB), at least partially housed in the through duct (11), the rotor (IB) comprising at least one blade (17) capable of adopting a vertical flight position relative to the through duct (11), in which the upper surface (3) and the lower surface (5) are mutually opposite in a direction of the wing portion and the through duct (11) comprises a cylindrical part (31) opposite said blade (17), the cylindrical part (31) having a height substantially equal to the size of the blade (17) in said direction, the blade (17) being in the vertical flight position.

5. Wing portion according to one of the preceding claims, in which the fairing (IA) comprises a rear part (29), extending from the through duct (11) to the trailing edge (9), and said depth (35) comprises a rear section (39), corresponding to the rear part (29), in which the through duct (11) comprises a cylindrical part (31), an upper lip (19), connecting the cylindrical part (31) to the extrados surface (3), and a lower lip (21), connecting the cylindrical part (31) to the intrados surface (5), and in which, on the rear section (39), the upper lip (19) and the lower lip (21) each have a substantially rounded shape, while the intrados surface (5) and the extrados surface (3) each have a substantially rectilinear portion, respectively near the lower lip (21) and the upper lip (19).

6. Wing portion according to one of the preceding claims, in which the fairing (IA) comprises a rear portion (29), extending from the through duct (11) to the trailing edge (9), and said depth (35) comprises a rear section (39), corresponding to the rear portion (29), in which, on the rear section (39), the distance between the intrados surface (5) and the extrados surface (3) is maximum near the through duct (11).

7. Wing portion according to one of the preceding claims, in which, on the front section (37) of the protruding edge (35), the distance from the intrados surface (5) to the extrados surface (3) increases progressively from the through duct (11), in the direction of the leading edge (7).

8. Wing portion according to one of the preceding claims, in which, on the front section (37) of the profundus (35), the distance from the intrados surface (5) to the extrados surface (3) increases progressively from the leading edge (7), towards the trailing edge (9).

9. Wing portion according to one of the preceding claims, in which the maximum distance between the intrados surface (5) and the extrados surface (3) is close to 250 millimeters.

10. Wing portion according to one of the preceding claims, in which, on the front section (37) of the profile (35), the upper surface (3) and the lower surface (5) are essentially symmetrical to each other.

11. Wing portion according to one of the preceding claims, in which, on the front section (37) of the profile (35), the upper surface (3) is convex and the lower surface (5) is convex.

12. Aircraft wing comprising at least one wing portion according to one of claims 1 to 11.

13. Aircraft comprising one or more wings according to claim 12.

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