Use of auxiliary rudders for yaw control at low speed

• US 8,960,594 B2
• Filed: 10/27/2011
• Issued: 02/24/2015
• Est. Priority Date: 11/02/2010
• Status: Active Grant

• Current Assignee: Skyworks Global Inc.
• Original Assignee: Groen Brothers Aviation Inc.
• Inventors: Groen, David L.
• Primary Examiner(s): Sanderson, Joseph W
• Application Number:
  US13/282,985
• Publication Number:
  US 20120104156A1
• Time in Patent Office: 1,216 Days
• Field of Search: 244/6, 244/7.R, 244/8, 244/17.11, 244/17.19, 244/87
• US Class Current: 244/17.11
• CPC Class Codes: B64C 2027/8245 using air jets
• CPC Class Codes: B64C 2027/8272 comprising fins, or movable rudders
• CPC Class Codes: B64C 2027/8281 comprising horizontal tail planes
• CPC Class Codes: B64C 27/025 Rotor drives, in particular for taking off; Combination of autorotation rotors and driven rotors
• CPC Class Codes: B64C 27/027 Control devices using other means than the rotor
• CPC Class Codes: B64C 27/18 the means being jet-reaction apparatus
• CPC Class Codes: B64C 27/82 characterised by the provision of an auxiliary rotor or fluid-jet device for counter-balancing lifting rotor torque or changing direction of rotorcraft
• CPC Class Codes: B64C 39/04 having multiple fuselages or tail booms
• CPC Class Codes: B64C 5/02 Tailplanes
• CPC Class Codes: B64C 5/06 Fins B64C5/08 takes precedence
• CPC Class Codes: B64C 9/00 Adjustable control surfaces or members, e.g. rudders trimming stabilising surfaces B64C5/10
• CPC Class Codes: B64C 9/34 collapsing or retracting against or within other surfaces or other members

Abstract

Apparatus and methods for controlling yaw of a rotorcraft in the event of one or both of low airspeed and engine failure are disclosed. A yaw propulsion provides a yaw moment at low speeds. The yaw propulsion device may be an air jet or a fan. A pneumatic fan may be driven by compressed air released into a channel surrounding an outer portion of the fan. The fan may be driven by hydraulic power. Power for the yaw propulsion device and other system may be provided by a hydraulic pump and/or generator engaging the rotor. Low speed yaw control may be provided by auxiliary rudders positioned within the stream tube of a prop. The auxiliary rudders may one or both of fold down and disengage from rudder controls when not in use.

Claims

1. A rotorcraft comprising:

an airframe including

a cabin portion supporting flight controls and a seat to receive a pilot,

a tower portion fixed to the cabin portion and extending upward therefrom,

an empennage extending from the cabin portion away therefrom,

a first vertical stabilizer mounted to the empennage,

a first rudder secured to pivot with respect to the first vertical stabilizer, and

a horizontal stabilizer connected to the empennage;

a rotor rotatably mounted to the tower to rotate about an axis of rotation offset from the first vertical stabilizer and the horizontal stabilizer;

a propulsion source mounted to the airframe and directing air flow across the vertical stabilizer;

a first auxiliary rudder mounted to the horizontal stabilizer and spaced from the first vertical stabilizer; and

a controller receiving yaw control inputs from a pilot and selectively actuating the first auxiliary rudder in response to the yaw control inputs exclusively at airspeeds of the rotorcraft below an airspeed threshold and actuating the first rudder without actuating the first auxiliary rudder in response to the yaw control inputs at airspeeds of the rotorcraft above the airspeed threshold.

2. The rotorcraft of claim 1, wherein the first auxiliary rudder is hinged to the horizontal stabilizer and pivotable with respect thereto between a deployed position, extending substantially vertically, and a stowed position, substantially aligned with and aerodynamically proximate the horizontal stabilizer.

3. The rotorcraft of claim 2, wherein the controller is computerized and programmed to control movement of the first auxiliary rudder from the stowed position to the deployed position upon detecting an airspeed of the aircraft below the airspeed threshold.

4. The rotorcraft of claim 2, wherein the vertical stabilizer further comprises a receptacle sized to receive at least a portion of the first auxiliary rudder when the first auxiliary rudder is in the stowed position.

5. The rotorcraft of claim 1, wherein the first auxiliary rudder is one of a plurality of auxiliary rudders offset from one another and on opposite surfaces of the horizontal stabilizer.

6. The rotorcraft of claim 1, further comprising:

a second empennage extending away from the cabin portion;

a second vertical stabilizer secured to the second empennage; and

a second rudder pivotably mounted to move with respect to the second vertical stabilizer.

7. The rotorcraft of claim 1, further comprising:

the propulsion source centrally mounted to drive an air stream away from the cabin portion and toward the horizontal stabilizer;

the first and second rudders spaced apart and pivoting with respect to the first and second vertical stabilizers, respectively.

8. The rotorcraft of claim 7, further comprising:

a second auxiliary rudder, spaced from the first auxiliary rudder,

the first and second auxiliary rudders operable independently from the first and second rudders.

9. The rotorcraft of claim 8, further comprising:

cooperative linkage connecting the first and second auxiliary rudders to move in coordination with one another;

the first and second auxiliary rudders positioned to re-direct a central portion of the airstream therebetween upon pivoting of the first and second auxiliary rudders; and

the first and second auxiliary rudders positioned to fit at least partially into recesses fitted thereto and formed in the vertical stabilizer.

10. The rotorcraft of claim 1, wherein:

the propulsion source defines a stream tube extending rearwardly therefrom;

the first auxiliary rudder is positioned within the stream tube; and

the first rudder and first vertical stabilizer are not positioned within the stream tube.

11. A rotorcraft comprising:

an airframe including

first and second vertical stabilizers mounted to the airframe, each of the first and second horizontal stabilizers having a rudder mounted thereto, and

a horizontal stabilizer mounted to the airframe between the first and second vertical stabilizers;

a rotor rotatably mounted to the airframe and rotatable about an axis of rotation, the axis of rotation offset from the horizontal stabilizer and first and second vertical stabilizers;

a propulsion system mounted to the airframe and oriented to direct air flow over the vertical stabilizer, the propulsion system defining a stream tube;

an auxiliary rudder mounted to the horizontal stabilizer positioned between the first and second vertical stabilizers; and

a controller programmed to receive yaw control inputs from a pilot and to actuate the auxiliary rudder in response to the yaw control inputs only for airspeeds of the rotorcraft below an airspeed threshold.

12. The rotorcraft of claim 11, wherein the auxiliary rudder is hingedly mounted to the horizontal stabilizer and is rotatable between a stowed position and a deployed position, the auxiliary rudders being oriented parallel to the horizontal stabilizer in the stowed position.

13. The rotorcraft of claim 12, wherein the controller is programmed to acutate the auxiliary rudder from the stowed to the deployed position upon detecting an airspeed of the aircraft below the airspeed threshold.

14. The rotorcraft of claim 12, wherein the horizontal stabilizer further comprises a receptacle sized to receive at least a portion of the auxiliary rudder when the auxiliary ruder is in the stowed position.

15. The rotorcraft of claim 11, wherein the auxiliary rudder is one of a plurality of auxiliary rudders positioned offset from one another and on opposing surfaces of the horizontal stabilizer.

16. A rotorcraft comprising:

an airframe including

a cabin portion supporting flight controls and a seat to receive a pilot,

a tower portion fixed to the cabin portion and extending upward therefrom,

first and second empennages extending from proximate the cabin portion away therefrom,

first and second vertical stabilizers mounted to the first and second empennages, respectively,

first and second rudders secured to pivot with respect to the first and second vertical stabilizers, respectively, and

a horizontal stabilizer connected to extend between the first and second empennages;

a rotor, rotatably mounted to the tower to rotate about an axis of rotation offset from the horizontal stabilizer and the first and second vertical stabilizers;

a propulsion source mounted to the airframe and directing air flow across the horizontal stabilizer;

a first auxiliary rudder mounted to the horizontal stabilizer and spaced from the first and second vertical stabilizers; and

a controller receiving yaw control inputs from the pilot and selectively actuating the first auxiliary rudder in response to the yaw control inputs exclusively at airspeeds of the rotorcraft below an airspeed.

17. The rotorcraft of claim 16, wherein the first auxiliary rudder is hinged to the horizontal stabilizer and pivotable with respect thereto between a deployed position, extending substantially vertically, and a stowed position, substantially aligned with and aerodynamically proximate the horizontal stabilizer.

18. The rotorcraft of claim 16, wherein:

the controller is computerized and programmed to control movement of the first auxiliary rudder from the stowed position to the deployed position upon detecting an airspeed of the aircraft below the airspeed threshold;

the horizontal stabilizer further comprises a receptacle sized to receive at least a portion of the first auxiliary rudder when the first auxiliary rudder is in the stowed position;

the horizontal stabilizer is secured to extends between the first and second empennages;

the propulsion source is centrally mounted to drive an air stream away from the cabin portion and toward the horizontal stabilizer;

a second auxiliary rudder is spaced from the first auxiliary rudder and the first and second auxiliary rudders are connected to be operable independently from the first and second rudders, and positioned to re-direct a central portion of the airstream therebetween upon pivoting of the first and second auxiliary rudders; and

the first and second auxiliary rudders are positioned to fit at least partially into recesses fitted thereto and formed in the horizontal stabilizer.

19. The rotorcraft of claim 16, further comprising a sensor, connected to sense airspeed of the rotorcraft and provide to the controller a parameter reflecting the airspeed.

20. The rotorcraft of claim 16, wherein the horizontal stabilizer further comprises a recess formed to receive the first auxiliary rudder at airspeeds above the threshold airspeed.