Compound aircraft having an additional anti-torque device

Patent metadata

Field	Value
Publication number	US-10005550-B2
Application number	US-201615207771-A
Country	US
Kind code	B2
Filing date	Jul 12, 2016
Priority date	Jul 16, 2015
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

A compound aircraft having a fuselage, a main rotor, a main anti-torque device and two wings positioned on either side of the fuselage. Each wing has at least one movable flap situated at its trailing edge. The flaps can be deflected asymmetrically relative to an air stream generated in reaction to the lift of the main rotor on either side of the fuselage so as to create longitudinal aerodynamic forces in opposite directions on either side of the fuselage and consequently create an additional torque that is added to the main torque from the main anti-torque device.

First claim

What is claimed is:

1. A compound aircraft situated in a reference frame constituted by a longitudinal direction X extending from the front of the aircraft towards the rear of the aircraft, an elevation direction Z extending upwards perpendicularly to the longitudinal direction X, and a transverse direction Y extending from left to right perpendicularly to the longitudinal and elevation directions X and Z, the aircraft comprising:
a fuselage;
a main rotor situated above the fuselage, being provided with a plurality of blades and driven in rotation about an axis that is substantially parallel to the elevation direction Z and that serves to provide the aircraft with lift as a result of the aerodynamic lift of the blades;
a main anti-torque device generating a main torque opposing the rotor torque C R generated as a result of rotating the main rotor;
at least one wing situated beneath the main rotor and extending substantially in the transverse direction Y; and
at least two flaps situated beneath the main rotor, at least one flap being situated on a first side of the fuselage relative to the longitudinal direction X, at least one flap being situated on a second side of the fuselage relative to the longitudinal direction X, each flap extending substantially in the transverse direction Y, each flap being connected to a wing and being movable relative to the wing, each wing co-operating with the flap(s) connected thereto to form a wing-and-flap assembly on each side of the fuselage; and
the wing-and-flap assemblies generating longitudinal aerodynamic forces directed in the longitudinal direction X on either side of the fuselage under the effect of the air stream generated in reaction to the aerodynamic lift of the main rotor and, consequently, generating an additional torque that adds to the main torque in order to oppose the rotor torque C R , the wing-and-flap assemblies having identical aerodynamic profiles and the flaps being oriented asymmetrically relative to the air stream generated in reaction to the aerodynamic lift of the main rotor on either side of the fuselage so that the longitudinal aerodynamic coefficient C T of the aerodynamic profiles are different on either side of the fuselage;
wherein the movement of each flap is defined by a deflection angle, with a first deflection angle δ 1 of each flap situated on the first side of the fuselage being greater than an inversion deflection angle δ i and less than a stall deflection angle δ D , while a second deflection angle δ 2 of each flap situated on the second side of the fuselage is less than the inversion deflection angle δ i , the longitudinal aerodynamic coefficient C T of each wing-and-flap assembly being zero for a deflection angle of the flaps equal to the deflection angle δ i , the stall deflection angle δ D corresponding to aerodynamic stall of each flap.

2. An aircraft according to claim 1 , wherein the longitudinal aerodynamic forces are in opposite directions on either side of the fuselage.

3. An aircraft according to claim 1 , wherein the first deflection angle δ 1 and the second deflection angle δ 2 are symmetrical about the inversion deflection angle δ i .

4. An aircraft according to claim 1 , wherein the first deflection angle δ 1 is determined with a non-zero safety margin Δδ 0 relative to the stall deflection angle δ D , and the second deflection angle δ 2 is determined with a deflection angle difference Δδ 1 relative to the first deflection angle δ 1 such that δ 1 =δ D −Δδ 0 and δ 2 =δ 1 −Δδ 1 .

5. An aircraft according to claim 4 , wherein the deflection angle difference Δδ 1 lies in the range ten degrees to fifteen degrees (10° to 15°).

6. An aircraft according to claim 4 , wherein the safety margin Δδ 0 lies in the range two degrees to five degrees (2° to 5°).

7. An aircraft according to claim 1 , wherein the movement of each flap is defined by a deflection angle, and each wing has a mechanical abutment limiting the movements of the flaps, a first mechanical abutment being positioned on each first wing situated on the first side of the fuselage so as to limit the deflection angle of each flap situated on the first side of the fuselage to a first maximum deflection angle δ max1 , a second mechanical abutment being positioned on each second wing situated on the second side of the fuselage so as to limit the deflection angle of each flap situated on the second side of the fuselage to a second maximum deflection angle δ max2 .

8. An aircraft according to claim 7 , wherein the first abutment is positioned with a safety margin Δδ 0 relative to a stall deflection angle δ D of the flap and the second mechanical abutment is positioned with a deflection angle difference Δδ 1 relative to the first abutment, the stall deflection angle δ D corresponding to aerodynamic stall of each flap.

9. An aircraft according to claim 1 , wherein the first side and the second side of the fuselage are determined depending on the direction of rotation of the main rotor so that the additional torque opposes the rotor torque C R .

10. An aircraft according to claim 1 , wherein each flap has a chord length lying in the range 20% to 35% of the chord length of each wing.

11. An aircraft according to claim 1 , wherein each flap is movable in pivoting relative to each wing, and the center of pivoting of a flap is situated inside the wing and close to the pressure side of the wing.

12. An aircraft according to claim 1 , wherein the aircraft has a single wing that is an aerodynamically common wing extending on both sides of the longitudinal direction X.

13. An aircraft according to claim 1 , wherein the aircraft has two wings comprising two aerodynamically distinct wings, a first wing being situated on a first side of the fuselage relative to the longitudinal direction X, and a second wing being situated on a second side of the fuselage relative to the longitudinal direction X.

14. An aircraft according to claim 1 , wherein the aircraft has at least one propulsive propeller positioned on each wing, and each flap is positioned on each wing outside a zone that is affected by an air stream from a propulsive propeller.

15. A method of generating an additional torque for a compound aircraft, the aircraft being situated in a reference frame constituted by a longitudinal direction X extending from the front of the aircraft towards the rear of the aircraft, an elevation direction Z extending upwards perpendicularly to the longitudinal direction X, and a transverse direction Y extending from left to right perpendicularly to the longitudinal and elevation directions X and Z, the aircraft comprising:
a fuselage;
a main rotor situated above the fuselage, being provided with a plurality of blades and driven in rotation about an axis that is substantially parallel to the elevation direction Z and that serves to provide the aircraft with lift as a result of the aerodynamic lift of the blades;
a main anti-torque device generating a main torque opposing the rotor torque C R generated as a result of rotating the main rotor;
at least one wing situated beneath the main rotor and extending substantially in the transverse direction Y; and
at least two flaps situated beneath the main rotor, at least one flap being situated on a first side of the fuselage relative to the longitudinal direction X, at least one flap being situated on a second side of the fuselage relative to the longitudinal direction X, each flap extending substantially in the transverse direction Y, each flap being connected to a wing and being movable relative to the wing, each wing co-operating with the flap(s) connecte

Assignees

• Airbus Helicopters

Inventors

• Toulmay Francois

Classifications

• B64C29/0025

  the propellers being fixed relative to the fuselage · CPC title

• B64C9/18

  by single flaps · CPC title

• B64C3/32

  specially adapted for mounting power plant · CPC title

• B64C3/00

  Wings (ornithopter wings B64C33/02) · CPC title

• B64C27/26 Primary

  characterised by provision of fixed wings · CPC title