AIRCRAFT

• US 20100252690A1
• Filed: 11/20/2008
• Published: 10/07/2010
• Est. Priority Date: 11/21/2007
• Status: Active Grant

• Current Assignee: Qinetiq Limited (QinetiQ Group PLC)
• Original Assignee: Qinetiq Limited (QinetiQ Group PLC)
• Inventors: Stoackley, Steven John, Stoackley, Jon Robert, Hothi, Inderpal Singh
• Granted Patent: US 8,434,710 B2
• Time in Patent Office: Days
• US Class Current: 244/7.B
• CPC Class Codes: B64C 39/024 of the remote controlled vehicle type, i.e. RPV
• CPC Class Codes: B64U 10/25 Fixed-wing aircraft VTOL aircraft B64U10/20
• CPC Class Codes: B64U 30/297 Tilting rotors
• CPC Class Codes: B64U 50/19 using electrically powered motors
• CPC Class Codes: B64U 50/31 generated by photovoltaics
• CPC Class Codes: B64U 60/50 with landing legs
• CPC Class Codes: B64U 70/80 Vertical take-off or landing, e.g. using rockets rotorcrafts B64U10/10; VTOL aircraft B64U10/20

Abstract

An unmanned aerial vehicle (UAV) in the form of a “tail sitter” flying wing adapted for vertical take off and landing and transitions between flight as a helicopter and wing-borne flight. The vehicle is electrically powered from onboard batteries and equipped with rotors on miniature helicopter rotor heads at the tips of the wing for both lift, during take off and landing, and forward thrust. In planform the wing comprises, to each side of its longitudinal axis, an inner section with swept back leading and trailing edges, and an outer section with a leading edge more perpendicular to the longitudinal axis, being only mildly swept back or substantially unswept, and a swept forward trailing edge.

Claims

1. An aircraft comprising a fixed wing airframe equipped with a pair of contra-rotatable rotors positioned to provide forward thrust for wing-borne flight, both the collective and cyclic pitch of the blades of said rotors being controllable in use;

and structure by which the aircraft can stand on the ground with the chord direction of said wing and the axes of rotation of said rotors pointing upwards;

whereby the aircraft is capable of vertical take off and landing and flight as a helicopter under lift produced by said rotors, capable of wing-borne flight under thrust produced by said rotors, and capable of transition between such helicopter and wing-borne flight without tilting of said rotor axes relative to said wing or tilting of said wing relative to the remainder of the airframe (if any).

2. An aircraft according to claim 1 wherein in planform said wing comprises, to each side of its longitudinal axis, an inner section with a swept back leading edge and an outer section with a leading edge more perpendicular to said longitudinal axis.

3. An aircraft according to claim 2 wherein the leading edges of said outer sections are mildly swept back or substantially unswept.

4. An aircraft according to claim 2 wherein the trailing edges of said inner sections are swept back.

5. An aircraft according to claim 4 wherein the sweep angles of the leading and trailing edges of said inner sections are substantially the same.

6. An aircraft according to claim 2 wherein the trailing edges of said outer sections are swept forward.

7. An aircraft according to claim 2 comprising stabilising fins disposed substantially at the respective junctions between said inner and outer sections of said wing.

8. An aircraft according to claim 7 wherein said structure by which the aircraft can stand on the ground comprises or is attached to said fins.

9. An aircraft according to claim 2 wherein the discs of said rotors do not project substantially into the spaces ahead of the respective adjacent inner sections of said wing.

10. An aircraft according to claim 1 wherein said rotors are mounted substantially at respective tips of said wing.

11. An aircraft according to claim 1 wherein said airframe is in the form of a flying wing.

12. An aircraft according to claim 1 comprising a central pod extending forwardly from said wing and housing sensory, communications, navigational and/or control equipment.

13. An aircraft according to claim 1 wherein said rotors are powered by an onboard electricity source.

14. An aircraft according to claim 13 wherein said rotors are powered by respective batteries or fuel cells housed adjacent to the respective rotor.

15. An aircraft according to claim 1, being an unmanned aerial vehicle.

16. A method of roll control for a fixed wing aircraft, said aircraft being equipped with a pair of rotors spaced transversely of the aircraft to provide forward thrust for wing-borne flight, at least the cyclic pitch of the blades of said rotors being controllable in use;

wherein the aircraft is controlled in roll by controlling the pitch of said rotor blades cyclically to produce differential thrust between upper and lower sectors of the rotor discs in opposite senses between said rotors.

18. A method according to claim 16, wherein:

the pair of rotors are contra-rotatable;

the cyclic pitch and a collective pitch of the blades of said rotors are controllable in use;

the aircraft further comprises structure by which the aircraft can stand on the ground with a chord direction of said wing and axes of rotation of said rotors pointing upwards; and

the aircraft is capable of;

vertical take off and landing and flight as a helicopter under lift produced by said rotors,

wing-borne flight under thrust produced by said rotors, and

transition between said helicopter and wing-borne flight without tilting of said rotor axes relative to said wing or tilting of said wing relative to a remainder of the airframe (if any).

17. A method of controlling an aircraft to hover over a fixed position in wind, said aircraft comprising a fixed wing airframe equipped with a pair of contra-rotatable rotors positioned to provide forward thrust for wing-borne flight, both the collective and cyclic pitch of the blades of said rotors being controllable in use, whereby the aircraft is capable both of flight as a helicopter under lift produced by said rotors and wing-borne flight under thrust produced by said rotors;

the method comprising orienting the aircraft in helicopter flight with the span direction of the fixed wing generally normal to the wind and the aircraft tilted into the wind by cyclic control of the pitch of said blades so that said wing is at a high angle of attack to the wind flow and generates a component of lift to assist the lift of said rotors.