Aircraft portion with a reduced drag

Patent metadata

Field	Value
Publication number	US-12214864-B2
Application number	US-202318373276-A
Country	US
Kind code	B2
Filing date	Sep 27, 2023
Priority date	Sep 29, 2022
Publication date	Feb 4, 2025
Grant date	Feb 4, 2025

Abstract

An aircraft portion with reduced drag includes a wing-fuselage junction fairing at the interface between the wing and the fuselage. The junction fairing has an outer surface including two lateral portions each covering the root of a respective wing, and a lower portion connecting the side portions to each other and extending under the fuselage. The flow of air around the junction fairing during the movement of the aircraft generates at least two vortices induced on both sides, respectively, of a median longitudinal plane. The aircraft portion also includes at least two vortex generating devices extending from the lower portion of the outer surface of the junction fairing on both sides, respectively, of the median longitudinal plane.

First claim

What is claimed is:

1. An aircraft portion of an aircraft comprising:
a fuselage extending along a longitudinal direction and having a median longitudinal plane;
an airfoil formed by at least one pair of wings arranged on either sides of the fuselage along a transverse direction orthogonal to the median longitudinal plane;
an airfoil-fuselage junction fairing at an interface between the airfoil and the fuselage, the airfoil-fuselage junction fairing having an outer surface comprising two lateral portions each covering a wing root of a respective one of the wings, and a lower portion connecting the two lateral portions to each other, extending under the fuselage, an air flow around the airfoil-fuselage junction fairing during a movement of the aircraft generating at least two induced vortices induced on both sides, respectively, of the median longitudinal plane; and
at least two vortex generating devices extending from the lower portion of the outer surface of the airfoil-fuselage junction fairing on both sides, respectively of the median longitudinal plane.

2. The aircraft portion according to claim 1 , wherein each lateral portion of the outer surface of the airfoil-fuselage junction fairing is separated from the lower portion of the outer surface of the airfoil-fuselage junction fairing by a separation line, the separation line corresponding to a reflection line at 45° with respect to the transverse direction on the outer surface of the airfoil-fuselage junction fairing.

3. The aircraft portion according to claim 1 , wherein each vortex generating device is arranged on a path of an induced vortex, each vortex generating device being configured for generating an attenuating vortex having a direction of rotation opposite to the direction of rotation of the corresponding induced vortex.

4. The aircraft portion according to claim 1 , wherein the airfoil-fuselage junction fairing is delimited in a vertical direction orthogonal to the longitudinal and transverse directions by an envelope surface, a projection of said envelope surface in the median longitudinal plane drawing a lower profile of the airfoil-fuselage junction fairing, and a convex side of each wing being in contact with said outer surface of the airfoil-fuselage junction fairing along a junction line a orthogonal projection of which in a projection plane orthogonal to the median longitudinal plane drawing a horizontal profile of said junction line, the horizontal profile of at least one junction line and/or the lower profile of the airfoil-fuselage junction fairing having successively, in the longitudinal direction, a convex front segment, a concave intermediate segment and a convex rear segment, the air flow around the convex front segment, the concave intermediate segment and the convex rear segment during the movement of the aircraft generating the at least two induced vortices on both sides of the median longitudinal plane and moving the at least two induced vortices away from the outer surface of the airfoil-fuselage junction fairing.

5. The aircraft portion according to claim 4 , wherein each wing has a leading edge and a trailing edge, an intersection between the leading edge and the outer surface of the airfoil-fuselage junction fairing defining a front reference point, an intersection between the trailing edge and a longitudinal plane passing through said front reference point defining a rear reference point, and a distance between the front and rear reference points making up a reference length, and the convex front segment of the horizontal profile comprises a front convexity apex, the concave intermediate segment of the horizontal profile comprising an intermediate concavity bottom, and the convex rear segment of the horizontal profile comprising a rear convexity apex, a tangent to the horizontal profile of each of the front and rear convexity apices and the intermediate concavity bottom being parallel to the longitudinal direction, the intermediate concavity bottom being withdrawn towards the median longitudinal plane with respect to each of the front and rear convexity apices.

6. The aircraft portion according to claim 5 , wherein the front reference point is situated on the convex front segment.

7. The aircraft portion according to claim 5 , wherein the front convexity apex is situated at a non-zero distance from the front reference point along the longitudinal direction.

8. The aircraft portion according to claim 5 , wherein the intermediate concavity bottom is at a first secondary longitudinal distance from the front reference point of between 35% and 50% of the reference length.

9. The aircraft portion according to claim 5 , wherein the rear convexity apex is at a first tertiary longitudinal distance from the front reference point of between 85% and 100% of the reference length.

10. The aircraft portion according to claim 1 , wherein the aircraft portion comprises a first group of vortex generating devices arranged on one side of the lower portion of the outer surface with respect to the median longitudinal plane and a second group of vortex generating devices arranged on the other side of the lower portion of the outer surface with respect to the median longitudinal plane, the vortex generating devices of a same group being arranged on a path of a same induced vortex.

11. The aircraft portion according to claim 10 , wherein each group of vortex generating devices comprises at least three vortex generating devices.

12. The aircraft portion according to claim 1 , wherein the lower portion of the outer surface of the airfoil-fuselage junction fairing comprises a front part situated at a front of the aircraft along the longitudinal direction, a rear part situated opposite the front part along the longitudinal direction and an intermediate part connecting the front and rear parts, the intermediate part extending substantially along a first plane parallel to the longitudinal and transverse directions, the rear part extending substantially along a second plane forming an angle between 0° and 15° with the first plane, each vortex generating device extending from the rear part of the lower portion of the outer surface of the airfoil-fuselage junction fairing.

13. The aircraft portion according to claim 1 , wherein each vortex generating device comprises a fin extending substantially along a fin plane substantially parallel to a vertical direction orthogonal to the longitudinal and transverse directions.

14. The aircraft portion according to claim 13 , wherein the fin plane forms an angle with the longitudinal direction, the angle being substantially between −5° and +5°.

15. The aircraft portion according to claim 14 , wherein the aircraft portion comprises a first group of vortex generating devices arranged on one side of the lower portion of the outer surface with respect to the median longitudinal plane and a second group of vortex generating devices arranged on the other side of the lower portion of the outer surface with respect to the median longitudinal plane, the vortex generating devices of a same group being arranged on a path of a same induced vortex; and
wherein each group of vortex generating devices comprises an integer number N of vortex generating devices arranged successively from upstream to downstream, the angle formed by the fin plane of the i-th vortex generating device of the first group of vortex generating devices with the longitudinal direction being equal to an opposite of the angle formed by the fin plane of the i-th vortex generating device of the second group of vortex generating devices with the longitudinal direction, where i is an intege

Assignees

• Dassault Aviat

Inventors

• Bernard Xavier
• Johan Zdenek
• Merlet Aurélien

Classifications

• B64C1/26

  Attaching the wing or tail units or stabilising surfaces · CPC title

• Y02T50/10

  Drag reduction · CPC title

• B64C23/06 Primary

  by generating vortices · CPC title

• B64C7/00 Primary

  Structures or fairings not otherwise provided for · CPC title