Variable-pitch ringed rotors for aircraft

Patent metadata

Field	Value
Publication number	US-10875636-B2
Application number	US-201816196950-A
Country	US
Kind code	B2
Filing date	Nov 20, 2018
Priority date	Nov 20, 2018
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

A rotor system for a rotorcraft has a hub rotatable about an axis and a plurality of blades coupled to the hub for rotation therewith about the axis. Each blade is capable of rotation about a pitch axis relative to the hub, and a ring couples adjacent blades to each other.

First claim

What is claimed is:

1. A rotor system for a rotorcraft, the rotor system comprising:
a hub rotatable about an axis;
a plurality of blades coupled to the hub for rotation therewith about the axis, each blade being capable of rotation about a pitch axis relative to the hub;
a ring coupling adjacent blades to each other;
a plurality of first bearings, each first bearing pivotally coupling the ring to a leading edge of one of the blades; and
a plurality of second bearings, each second bearing pivotally coupling the ring to a trailing edge of one of the blades.

2. The system of claim 1 , wherein the ring is configured to react its own centrifugal force.

3. The system of claim 1 , further comprising:
a rotor dampening system located near the ring.

4. The system of claim 1 , wherein each bearing is radial and is configured to allow one axis of rotation.

5. The system of claim 1 , wherein each bearing is spherical.

6. The system of claim 1 , wherein the ring is formed from a plurality of ring sections, and each ring section is rigid.

7. The system of claim 1 , wherein the circumference of the ring is adjustable.

8. The system of claim 1 , wherein a cross-sectional property of the ring varies at different circumferential locations.

9. The system of claim 1 , further comprising:
a plurality of shrouds, each shroud covering an interface between the ring and one of the plurality of blades.

10. The system of claim 1 , wherein the circumferential shape of the ring during use is one of a circle, a diamond, and a cloverleaf.

11. The system of claim 1 , wherein the ring forms a rotor duct that rotates with the plurality of blades.

12. A rotorcraft having a rotor system comprising a plurality of blades driven by a hub, the rotorcraft comprising:
a ring coupling the plurality of blades together at a tip portion of each of the plurality of blades;
wherein the ring comprises at least one of:
an adjustable circumference;
a cross-sectional property that varies at different circumferential locations; and
a plurality of shrouds, each shroud covering an interface between the ring and one of the plurality of blades.

13. The rotorcraft of claim 12 , wherein the ring is a flexible chain.

14. The rotorcraft of claim 12 , wherein the ring is a flexible cable.

15. The rotorcraft of claim 12 , wherein a preload is applied to the ring during installation.

16. The rotorcraft of claim 12 , wherein the ring forms a rotor duct that rotates with the plurality of blades.

17. The rotorcraft of claim 12 , further comprising:
a bearing rotationally coupling each of the plurality of blades to the ring.

18. The rotorcraft of claim 12 , further comprising:
an interface located between each blade of the plurality of blades and the ring, the interface comprising;
a first member extending from the blade; and
an aperture located in the ring;

wherein the first member extends through the aperture of the ring.

19. A method of adding inertia to the rotor of a rotorcraft, the method comprising:
coupling adjacent blades of the rotor with a ring; and
adjusting the circumference of the ring.

20. The method of claim 19 , wherein the circumference is adjusted to cause the circumferential shape of the ring during use to be one of a circle, a diamond, and a cloverleaf.

Assignees

• Bell Helicopter Textron Inc
• Textron Innovations Inc

Inventors

• Sinusas Eric Albert
• Parham Jr Thomas C
• Brand Albert Gerard

Classifications

• B64C27/20 Primary

  Rotorcraft characterised by having shrouded rotors, e.g. flying platforms · CPC title

• B64C27/001

  Vibration damping devices · CPC title

• B64C27/473

  Constructional features · CPC title

• F04D29/326

  comprising a rotating shroud · CPC title

• B64C27/51

  Damping of blade movements · CPC title