# US 11,027,836 B2 · Rotorcraft with canted coaxial rotors

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- Number: US 11,027,836 B2
- Document ID: US11027836B2
- Status: Granted
- Kind: B2
- Application number: 16/035,245
- Filed: 2018-07-13
- Published: 2020-01-16
- Granted: 2021-06-08
- Earliest claimed: 2018-07-13
- Assignees: The Boeing Company
- Applicants: The Boeing Company
- Inventors: Roger W. Lacy; Michael J. Duffy; David H. Mason
- Web page: https://patentgrep.com/patent/US11027836B2

## CPC

- B64C 27/52: Tilting of rotor bodily relative to fuselage (of see-saw type construction B64C27/43)
- B64U 10/10: Rotorcrafts
- B64U 10/16: with five or more distinct rotor axes, e.g. octocopters
- B64U 30/24: Coaxial rotors
- G05D 1/0808: {specially adapted for aircraft}
- B64C 2027/8227: {comprising more than one rotor}
- B64C: AEROPLANES; HELICOPTERS
- B64U: UNMANNED AERIAL VEHICLES [UAV]; EQUIPMENT THEREFOR
- G05D: SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES

## Abstract

A rotorcraft has a frame and a plurality of rotors connected to the frame. The frame has a roll axis and a pitch axis. Each of the rotors includes a rotor shaft. The rotor shaft of each of the rotors is canted with respect to at least one of the roll axis and the pitch axis. The rotor shaft of each of the rotors may be canted between 3 and 15 degrees. Each of the rotors may be a co-axial co-rotating rotor. The rotors may be oriented in opposing pairs across the frame. Both rotors in each opposing pair rotate in the same direction. The rotorcraft may include at least two additional rotors, each having a forward cant. Each of the additional rotors may be a co-axial contra-rotating rotor.

## Claims

### Claim 1

A rotorcraft, comprising:
a frame, having a roll axis, a pitch axis, and a yaw axis; and
a plurality of rotors, connected to the frame,
wherein
the pitch axis is perpendicular to the roll axis;
the plurality of rotors comprises at least four rotors,
two of the at least four rotors are configured for counter-clockwise rotation,
another two of the at least four rotors are configured for clockwise rotation,
each of the plurality of rotors comprises a rotor shaft, canted with respect to at least one of the roll axis and the pitch axis,
each of the plurality of rotors comprises an upper rotor and a lower rotor, and
the lower rotor of each of the plurality of rotors is co-axial with the upper rotor of each of the plurality of rotors and is configured to rotate in a direction, in which the upper rotor of each of the plurality of rotors is configured to rotate; and
at least two additional rotors, comprising a rotor shaft,
wherein
each of the at least two additional rotors comprises an upper rotor and a lower rotor, and
the lower rotor of each of the at least two additional rotors is co-axial with the upper rotor of the at least two additional rotors and is configured to rotate in a direction, opposite to that, in which the upper rotor of the at least two additional rotors is configured to rotate.

### Claim 2 (depends on 1)

The rotorcraft of claim 1, wherein the rotor shaft of each of the plurality of rotors is canted at an angle between 3 and 15 degrees with respect to at least one of the roll axis and the pitch axis of the frame.

### Claim 3 (depends on 2)

The rotorcraft of claim 2, wherein the rotor shaft of each of the at least two additional rotors is canted with respect to an axis, perpendicular to the pitch axis of the frame, so that a forward thrust component is created when the at least two additional rotors are rotated.

### Claim 4 (depends on 3)

The rotorcraft of claim 3, wherein the rotor shaft of each of the at least two additional rotors is canted with respect to the axis, perpendicular to the pitch axis of the frame, at an angle between 3 and 15 degrees.

### Claim 5 (depends on 1)

The rotorcraft of claim 1, wherein the rotor shaft of each of the plurality of rotors is canted at an angle between 3 and 15 degrees with respect to the roll axis of the frame.

### Claim 6 (depends on 5)

The rotorcraft of claim 5, wherein the rotor shaft of each of the plurality of rotors is canted at an angle between 3 and 15 degrees with respect to the pitch axis of the frame.

### Claim 7 (depends on 6)

The rotorcraft of claim 6, wherein the rotor shaft of each of the plurality of rotors is canted at a fixed angle with respect to the roll axis and the pitch axis of the frame.

### Claim 8 (depends on 6)

The rotorcraft of claim 6, wherein the rotor shaft of each of the at least two additional rotors is canted with respect to an axis, perpendicular to the pitch axis of the frame, at an angle between 3 and 15 degrees.

### Claim 9 (depends on 6)

The rotorcraft of claim 6, wherein the angle, at which the rotor shaft of each of the plurality of rotors is canted with respect to the roll axis is equal to the angle, at which the rotor shaft of each of the plurality of rotors is canted with respect to the pitch axis.

### Claim 10 (depends on 5)

The rotorcraft of claim 5, wherein each of the at least four rotors produces a thrust component, oriented perpendicular to an imaginary ray, extending from the yaw axis of the frame.

### Claim 11 (depends on 1)

The rotorcraft of claim 1, wherein the rotorcraft has a gross weight of 500 pounds or more or a payload capacity from about 100 to about 1000 pounds.

### Claim 12 (depends on 1)

The rotorcraft of claim 1, wherein:
the at least four rotors and the at least two additional rotors are oriented in a hexagonal pattern, and the two additional rotors are aligned along the pitch axis of the frame.

### Claim 13 (depends on 1)

The rotorcraft of claim 1, wherein the rotor shaft of each of the at least two additional rotors is parallel to the yaw axis of the frame.

### Claim 14 (depends on 1)

The rotorcraft of claim 1, wherein for each of the plurality of rotors, a lateral distance of the upper rotor to the roll axis of the frame is smaller than a lateral distance of the lower rotor to the roll axis of the frame.

### Claim 15 (depends on 1)

The rotorcraft of claim 1, wherein the rotor shaft of each of the plurality of rotors is canted at an angle of more than 15 degrees with respect to at least one of the roll axis and the pitch axis of the frame.

### Claim 16

A rotorcraft, comprising:
a frame, having a roll axis, a pitch axis, and a yaw axis;
at least four rotors, connected to the frame and oriented across the frame in pairs of opposing rotors,
wherein
both rotors in each of the pairs of opposing rotors are rotatable in the same direction,
each of the at least four rotors has an axis of rotation that is non-parallel and non-perpendicular to the yaw axis of the frame,
each of the at least four rotors comprises an upper rotor and a lower rotor, and
the lower rotor of each of the at least four rotors is co-axial with the upper rotor of each of the at least four rotors and is configured to rotate in a direction, in which the upper rotor of each of the at least four rotors is configured to rotate; and
at least two additional rotors, each having an axis of rotation,
wherein
each of the at least two additional rotors comprises an upper rotor and a lower rotor, and
the lower rotor of each of the at least two additional rotors is co-axial with the upper rotor of the at least two additional rotors and is configured to rotate in a direction, opposite to that, in which the upper rotor of the at least two additional rotors is configured to rotate.

### Claim 17 (depends on 16)

The rotorcraft of claim 16, wherein each of the at least four rotors produces a thrust component, oriented perpendicular to an imaginary ray, extending from the yaw axis of the frame.

### Claim 18 (depends on 16)

The rotorcraft of claim 16, wherein the axis of rotation of each of the at least two additional rotors is canted with respect to an axis that is perpendicular to the pitch axis of the frame at an angle between 3 and 15 degrees.

### Claim 19 (depends on 16)

The rotorcraft of claim 16, wherein the axis of rotation of each of the at least four rotors is canted at an angle between 3 and 15 degrees with respect to the roll axis of the frame.

### Claim 20 (depends on 19)

The rotorcraft of claim 19, wherein the axis of rotation of each of the at least four rotors is canted at an angle between 3 and 15 degrees with respect to the pitch axis of the frame.

### Claim 21 (depends on 20)

The rotorcraft of claim 20, wherein the angle of the axis of rotation of each of the at least four rotors with respect to the roll axis of the frame is equal to the angle of the axis of rotation of each of the at least four rotors with respect to the pitch axis of the frame.

### Claim 22 (depends on 19)

The rotorcraft of claim 19, wherein the axis of rotation of each of the at least two additional rotors is canted with respect to an axis, perpendicular to the pitch axis of the frame, to create a forward thrust component when the at least two additional rotors are rotated.

### Claim 23 (depends on 22)

The rotorcraft of claim 22, wherein the axis of rotation of each of the at least two additional rotors is canted with respect to the axis, perpendicular to the pitch axis of the frame, at an angle between 3 and 15 degrees.

### Claim 24 (depends on 16)

A method of operating the rotorcraft of claim 16, the method comprising:
supplying power to the at least four rotors of the rotorcraft, wherein a first pair of opposing rotors of the pairs of opposing rotors comprises a first rotor and a third rotor, located on opposite sides of both the roll axis and the pitch axis of the rotorcraft, and a second pair of opposing rotors of the pairs of opposing rotors comprises a second rotor and a fourth rotor, located on the opposite sides of both the roll axis and the pitch axis;
supplying power to the at least two additional rotors of the rotorcraft and causing the at least two additional rotors to rotate, wherein the at least two additional rotors are each canted at an angle at which rotation of the at least two additional rotors produces a thrust component, parallel to the roll axis of the frame, and a thrust component, parallel to the yaw axis of the frame;
causing the first pair of opposing rotors to each rotate about the axis of rotation of a respective one of the first pair of opposing rotors in a first direction and causing the second pair of opposing rotors to each rotate about the axis of rotation of a respective one of the second pair of opposing rotors in a second direction, opposite the first direction; and
initiating a yawing maneuver that increases a rotational speed of the first pair of opposing rotors so that thrust is produced by the first pair of opposing rotors, wherein a component of the thrust is non-parallel to the yaw axis of the frame.

### Claim 25 (depends on 24)

The method of claim 24, wherein the component of the thrust is oriented perpendicular to an imaginary ray, extending from the yaw axis of the frame.

### Claim 26 (depends on 16)

The rotorcraft of claim 16, wherein the axis of rotation of each of the at least two additional rotors is parallel to the yaw axis of the frame.

### Claim 27 (depends on 16)

The rotorcraft of claim 16, wherein for each of the at least four rotors, a lateral distance of the upper rotor to the roll axis of the frame is smaller than a lateral distance of the lower rotor to the roll axis of the frame.