Aircraft portion with reduced wave drag

Patent metadata

Field	Value
Publication number	US-11745849-B2
Application number	US-202117560625-A
Country	US
Kind code	B2
Filing date	Dec 23, 2021
Priority date	Feb 14, 2018
Publication date	Sep 5, 2023
Grant date	Sep 5, 2023

Abstract

An aircraft portion includes a fuselage oriented in a longitudinal direction, an airfoil made up of at least one pair of wings arranged on either side of the fuselage in a transverse direction orthogonal to the longitudinal direction, and an airfoil-fuselage junction fairing at the interface between the airfoil and the fuselage. The junction fairing has, in a vertical plane, a lower profile and, in a horizontal plane, a horizontal profile at the junction of the outer surface of the junction fairing with the convex side of each wing. The horizontal profile and/or the lower profile successively has, in the longitudinal direction, a convex front segment, a concave intermediate segment, and a convex rear segment.

First claim

What is claimed is:

1. An aircraft portion, comprising:
a fuselage oriented in a longitudinal direction and having a median longitudinal plane;
an airfoil formed by at least one pair of wings positioned on either side of the fuselage in a transverse direction orthogonal to the median longitudinal plane; and
an airfoil-fuselage junction fairing at an interface between the airfoil and the fuselage, the junction fairing having an outer surface and being delimited in a vertical direction orthogonal to the longitudinal and transverse directions by an envelope surface, a projection of the envelope surface in the median longitudinal plane drawing a lower profile of the junction fairing, and a convex side of each wing being in contact with the outer surface of the junction fairing along a junction line, an orthogonal projection of which in a projection plane orthogonal to the median longitudinal plane draws a horizontal profile of the junction line, wherein the horizontal profile of at least one of the junction lines has, in the longitudinal direction, a convex front segment, a concave intermediate segment, and a convex rear segment and/or the lower profile of the junction fairing successively has, in the longitudinal direction, a convex front segment, a concave intermediate segment, and a convex rear segment,
wherein at least one of the wings has a leading edge and a trailing edge, an intersection between the leading edge and the outer surface of the junction fairing defining a front reference point, the intersection between the trailing edge and the longitudinal plane passing through the front reference point defining a rear reference point, and a distance between the front and rear reference points making up a reference length,
the front reference point being located on the convex front segment,
wherein the convex front segment of the horizontal profile comprises a front convexity apex, the concave intermediate segment of the horizontal profile comprises an intermediate concavity bottom, and the convex rear segment of the horizontal profile comprises a rear convexity apex, a tangent to the horizontal profile of each of the front convexity apex, the rear convexity apex and the concavity bottom being parallel to the longitudinal direction, the intermediate concavity bottom being withdrawn toward the median longitudinal plane relative to each of the front convexity apex and the rear convexity apex,
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.

2. The aircraft portion according to claim 1 , wherein the intermediate concavity bottom has a first primary longitudinal deviation relative to the front convexity apex, the first primary longitudinal deviation being between 15 and 45% of the reference length.

3. The aircraft portion according to claim 1 , wherein the intermediate concavity bottom has a first secondary longitudinal deviation relative to the rear convexity apex, the first secondary longitudinal deviation being between 35 and 65% of the reference length.

4. The aircraft portion according to claim 1 , wherein the intermediate concavity bottom has a primary transverse deviation relative to the front convexity apex, the primary transverse deviation being between 0.5 and 2.5% of the reference length.

5. The aircraft portion according to claim 1 , wherein the intermediate concavity bottom has a secondary transverse deviation relative to the rear convexity apex, the secondary transverse deviation being between 2.0 and 4.5% of the reference length.

6. The aircraft portion according to claim 1 , wherein the front convexity apex is at a first primary longitudinal distance from the front reference point of between 5 and 20% of the reference length.

7. The aircraft portion according to claim 1 , 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.

8. The aircraft portion according to claim 1 , wherein the front convexity apex is at a primary transverse distance from the front reference point of between 0.0 and 1.0% of the reference length.

9. The aircraft portion according to claim 1 , wherein the intermediate concavity bottom is at a secondary transverse distance from the front reference point of between 0.5 and 2.0% of the reference length.

10. The aircraft portion according to claim 1 , wherein the rear convexity apex is at a tertiary transverse distance from the front reference point of between 1.5 and 3.0% of the reference length.

11. The aircraft portion according to claim 1 , wherein each point of the junction line has a single orthogonal projection, specific to the point, over a segment connecting the front and rear reference points.

12. The aircraft portion according to claim 1 , wherein the junction line is at least of class C 2 .

13. The aircraft portion according to claim 1 , wherein the convex front segment of the lower profile comprises a front curve apex and the lower profile has, at an interface between an intermediate region and a rear region, an inflection point, a tangent to the lower profile at the front curve apex and the inflection point being parallel to the longitudinal direction, the inflection point being withdrawn toward the fuselage relative to the front curve apex.

14. An aircraft portion, according to claim 1 , wherein the intermediate concavity bottom has a primary transverse deviation relative to the front convexity apex, the intermediate concavity bottom has a secondary transverse deviation relative to the rear convexity apex, the secondary transverse deviation being smaller than the primary transverse deviation.

15. An airplane comprising:
the aircraft portion according to claim 1 ; and
a powertrain arranged at a rear end of the fuselage.

16. The airplane according to claim 15 , wherein the airplane is a subsonic airplane in which the airflow around the wings moves close enough to the speed of sound to enter a transonic state.

17. An aircraft portion, comprising:
a fuselage oriented in a longitudinal direction and having a median longitudinal plane;
an airfoil formed by at least one pair of wings positioned on either side of the fuselage in a transverse direction orthogonal to the median longitudinal plane; and
an airfoil-fuselage junction fairing at an interface between the airfoil and the fuselage, the junction fairing having an outer surface and being delimited in a vertical direction orthogonal to the longitudinal and transverse directions by an envelope surface, a projection of the envelope surface in the median longitudinal plane drawing a lower profile of the junction fairing, and a convex side of each wing being in contact with the outer surface of the junction fairing along a junction line, an orthogonal projection of which in a projection plane orthogonal to the median longitudinal plane draws a horizontal profile of the junction line, wherein the horizontal profile of at least one of the junction lines has, in the longitudinal direction, a convex front segment, a concave intermediate segment, and a convex rear segment and/or the lower profile of the junction fairing successively has, in the longitudinal direction, a convex front segment, a concave intermediate segment, and a convex rear segment,
wherein at least one of the wings has a leading edge and a trailing edge, an intersection between the leading edge and the outer surface of the junction fairing defining a front reference point, the intersection between the trailing edge an

Assignees

• Dassault Aviat

Inventors

• Merlet Aurélien
• Johan Zdenek
• Loyatho Ximun
• Roge Gilbert

Classifications

• B64C1/26

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

• B64C3/14 Primary

  Aerofoil profile · CPC title

• B64C3/32

  specially adapted for mounting power plant · CPC title

• B64C7/00

  Structures or fairings not otherwise provided for · CPC title

• B64C23/04

  by generating shock waves · CPC title