Wing extension winglets for tiltrotor aircraft

Patent metadata

Field	Value
Publication number	US-10266252-B2
Application number	US-201615269862-A
Country	US
Kind code	B2
Filing date	Sep 19, 2016
Priority date	Sep 19, 2016
Publication date	Apr 23, 2019
Grant date	Apr 23, 2019

Abstract

A pylon assembly for a tiltrotor aircraft includes a rotor assembly operable to rotate between a generally vertical orientation, in a VTOL flight mode, and a generally horizontal orientation, in a forward flight mode, and having an intermediate orientation therebetween, in a conversion flight mode. The rotor assembly includes a proprotor operable to produce a slipstream. A wing extension, positioned outboard of the rotor assembly, has a minimal dimension and an outboard end. A winglet is coupled to the outboard end of the wing extension and has a minimal dimension. The wing extension and the winglet are operable to rotate generally with the rotor assembly such that the minimal dimensions of the wing extension and the winglet remain in the slipstream of the proprotor.

First claim

What is claimed is:

1. A pylon assembly for a tiltrotor aircraft comprising:
a fixed pylon having an outboard end and an inboard portion;
a rotor assembly rotatably coupled to the inboard portion of the fixed pylon, the rotor assembly operable to rotate between a generally vertical orientation, in a VTOL flight mode, and a generally horizontal orientation, in a forward flight mode, and having an intermediate orientation therebetween, in a conversion flight mode, the rotor assembly including a proprotor operable to produce a slipstream;
a wing extension outboard of the rotor assembly, the wing extension having a forward edge and an outboard end; and
a winglet coupled to the outboard end of the wing extension, the winglet having a forward edge;
wherein the wing extension and the winglet form an angle of less than or equal to 90 degrees such that the winglet is substantially noncontributing to the forward-facing profile of the wing extension in the conversion flight mode, thereby reducing drag of the tiltrotor aircraft during forward motion in the conversion flight mode;
wherein the wing extension is rotatably coupled to the outboard end of the fixed pylon such that the rotor assembly and the wing extension are separated by the fixed pylon;
wherein the winglet is dihedral; and
wherein the wing extension and the winglet are operable to rotate in synchrony with the rotor assembly such that the forward edges of the wing extension and the winglet remain in the slipstream of the proprotor.

2. The pylon assembly as recited in claim 1 wherein the winglet enables drag reduction of the tiltrotor aircraft during forward motion in the conversion flight mode.

3. The pylon assembly as recited in claim 1 wherein the winglet enables drag reduction of the tiltrotor aircraft during forward motion in the conversion flight mode by enabling the wing extension to have a reduced span.

4. The pylon assembly as recited in claim 1 wherein the winglet adds a trailing vortex drag-reducing characteristic to the wing extension.

5. The pylon assembly as recited in claim 1 wherein the intermediate orientation of the rotor assembly is in a range between 50 and 70 degrees from the generally horizontal orientation.

6. The pylon assembly as recited in claim 1 wherein the winglet reduces induced drag in the forward flight mode.

7. The pylon assembly as recited in claim 1 wherein the winglet is selected from the group consisting of a combination dihedral and anhedral winglet, a forward swept winglet, an aft swept winglet, a C-shaped winglet, a Z-shaped winglet and a box-like winglet.

8. The pylon assembly as recited in claim 1 wherein a transition between the wing extension and the winglet is selected from the group consisting of an angled transition and a curved transition.

9. The pylon assembly as recited in claim 1 wherein the winglet further comprises a positive dihedral winglet.

10. The pylon assembly as recited in claim 1 wherein the winglet forms a vertical plane.

11. The pylon assembly as recited in claim 1 wherein the winglet forms a vertical plane protruding from the top of the wing extension.

12. The pylon assembly as recited in claim 1 wherein the fixed pylon is interposed between the rotor assembly and the wing extension.

13. The pylon assembly as recited in claim 1 wherein the wing extension and the winglet form an acute angle.

14. The pylon assembly as recited in claim 1 wherein the wing extension is actively actuated independently of the rotor assembly.

15. The pylon assembly as recited in claim 1 further comprising a linkage arm coupling the wing extension to the rotor assembly.

16. The pylon assembly as recited in claim 1 wherein the winglet has a vertical length of at least 20 percent of the horizontal length of the wing extension.

17. The tiltrotor aircraft as recited in claim 1 wherein the fixed pylon houses an engine interposed between the rotor assembly and the wing extension.

18. A tiltrotor aircraft having a VTOL flight mode, a forward flight mode and a conversion flight mode, the tiltrotor aircraft comprising:
a fuselage;
first and second wings supported by the fuselage, the first and second wings each having an outboard end; and
first and second pylon assemblies positioned, respectively, proximate the outboard ends of the first and second wings, each of the pylon assemblies comprising:
a fixed pylon having an outboard end and an inboard portion;
a rotor assembly rotatably coupled to the inboard portion of the fixed pylon, the rotor assembly operable to rotate between a generally vertical orientation, in the VTOL flight mode, and a generally horizontal orientation, in the forward flight mode, and having an intermediate orientation therebetween, in the conversion flight mode, the rotor assembly including a proprotor operable to produce a slipstream;
a wing extension outboard of the rotor assembly, the wing extension having a forward edge and an outboard end; and
a winglet coupled to the outboard end of the wing extension, the winglet having a forward edge;
wherein the wing extension and the winglet form an angle of less than or equal to 90 degrees such that the winglet is substantially noncontributing to the forward-facing profile of the wing extension in the conversion flight mode, thereby reducing drag of the tiltrotor aircraft during forward motion in the conversion flight mode;
wherein the wing extension is rotatably coupled to the outboard end of the fixed pylon such that the rotor assembly and the wing extension are separated by the fixed pylon;
wherein the winglet is dihedral; and
wherein the wing extension and the winglet are operable to rotate in synchrony with the rotor assembly such that the forward edges of the wing extension and the winglet remain in the slipstream of the proprotor.

19. The tiltrotor aircraft as recited in claim 18 wherein, for each pylon assembly, the wing extension and the winglet are rotatable about a horizontal axis of the tiltrotor aircraft.

20. The tiltrotor aircraft as recited in claim 18 wherein each of the winglets is selected from the group consisting of a combination dihedral and anhedral winglet, a forward swept winglet, an aft swept winglet, a C-shaped winglet, a Z-shaped winglet and a box-like winglet.

Assignees

• Bell Helicopter Textron Inc

Inventors

• Anderson Adam Bryant
• Ivans Steven Ray
• Chavez Jeremy Robert

Classifications

• B64U10/10

  Rotorcrafts · CPC title

• B64C3/385

  Variable incidence wings · CPC title

• B64C27/82

  characterised by the provision of an auxiliary rotor or fluid-jet device for counter-balancing lifting rotor torque or changing direction of rotorcraft · CPC title

• B64C2027/8263

  comprising in addition rudders, tails, fins, or the like · CPC title

• B64C29/0033

  the propellers being tiltable relative to the fuselage · CPC title