Reconfiguration control system for an aircraft wing

• US 7,455,264 B2
• Filed: 08/26/1997
• Issued: 11/25/2008
• Est. Priority Date: 08/26/1997
• Status: Expired due to Term

• Current Assignee: Mcdonnell Douglas Corporation (The Boeing Co.)
• Original Assignee: Mcdonnell Douglas Corporation (The Boeing Co.)
• Inventors: Wakayama, Sean R.
• Primary Examiner(s): DINH, TIEN QUANG
• Application Number:
  US08/917,480
• Publication Number:
  US 20030197097A1
• Time in Patent Office: 4,109 Days
• Field of Search: 244/215, 244/213, 244/199, 244/136, 244/75.R, 244/203
• US Class Current: 244/215
• CPC Class Codes: B64C 2039/105 of blended wing body type
• CPC Class Codes: B64C 3/10 Shape of wings
• CPC Class Codes: B64C 39/10 All-wing aircraft
• CPC Class Codes: B64C 9/12 surfaces of different type or function being simultaneously adjusted
• CPC Class Codes: Y02T 50/10 Drag reduction
• CPC Class Codes: Y02T 50/30 Wing lift efficiency
• CPC Class Codes: Y02T 50/40 Weight reduction

Abstract

Independently deflectable control surfaces are located on the trailing edge of the wing of a blended wing-body aircraft. The reconfiguration control system of the present invention controls the deflection of each control surface to optimize the spanwise lift distribution across the wing for each of several flight conditions, e.g., cruise, pitch maneuver, and high lift at low speed. The control surfaces are deflected and reconfigured to their predetermined optimal positions when the aircraft is in each of the aforementioned flight conditions. With respect to cruise, the reconfiguration control system will maximize the lift to drag ratio and keep the aircraft trimmed at a stable angle of attack. In a pitch maneuver, the control surfaces are deflected to pitch the aircraft and increase lift. Moreover, this increased lift has its spanwise center of pressure shifted inboard relative to its location for cruise. This inboard shifting reduces the increased bending moment about the aircraft'"'"'s x-axis occasioned by the increased pitch force acting normal to the wing. To optimize high lift at low speed, during take-off and landing for example, the control surfaces are reconfigured to increase the local maximum coefficient of lift at stall-critical spanwise locations while providing pitch trim with control surfaces that are not stall critical.

Claims

1. A tailless aircraft, including:

a wing having a trailing edge and independently deflectable flight control surfaces located along the trailing edge, the wing being capable during flight of generating a normal lifting force having a spanwise force distribution across the wing; and

a control surface reconfiguration system wherein, for each of a plurality of different flight conditions, the flight control surfaces are selectively reconfigurable to respective predetermined positions, which in combination, optimize the spanwise force distribution across the wing for each of the plurality of different flight conditions including a low speed flight condition wherein first selected ones of the deflectable flight control surfaces located at stall-critical spanwise locations are positioned to increase a local coefficient of lift and other deflectable flight control surfaces are positioned to control pitch trim.

2. The aircraft as set forth in claim 1, wherein:

the lifting force generates a moment acting on the wing; and

the control surface reconfiguration system also minimizes the moment for at least one of the different flight conditions.

3. The aircraft as set forth in claim 2, wherein:

the control surface reconfiguration system minimizes the moment for structurally crucial flight conditions.

4. The aircraft as set forth in claim 1, wherein the control surface reconfiguration system also trims the wing.

5. The aircraft as set forth in claim 1, wherein:

one of the different flight conditions comprises cruise, with the wing having a lift-to-drag ratio during cruise; and

the control surface reconfiguration system functions to maximize the lift-to-drag ratio of the wing during the cruise flight condition.

7. The aircraft as set forth in claim 1, wherein:

one of the different flight conditions comprises a pitch maneuver; and

,

the control surface reconfiguration system functions to achieve the required lifting force during the pitch maneuver flight condition.

8. The aircraft as set forth in claim 7, wherein:

the aircraft has a longitudinal axis of symmetry; and

,

the control surface reconfiguration system functions to shift the spanwise force distribution towards the longitudinal axis without reducing lifting force, during the pitch maneuver flight condition.

9. The aircraft as set forth in claim 1, wherein the aircraft is a blended wing-body aircraft.

10. The aircraft as set forth in claim 1, wherein the different flight conditions include cruise, takeoff, and pitch maneuvers.

6. The aircraft as set forth in claim l wherein the plurality of flight conditions include a pitch maneuver wherein the deflectable flight control surfaces are positioned to minimize the bending moment with respect to a bend axis of the wing.

11. An aircraft, including:

a wing having a trailing edge and independently deflectable control surfaces located along the trailing edge, the wing being capable during flight of generating a normal lifting force having a spanwise force distribution across the wing; and

reconfiguration means for selectively reconfiguring the control surfaces to respective predetermined positions, which in combination, are effective to optimize the spanwise force distribution across the wing for each of a plurality of different flight conditions including a low speed flight condition wherein selected ones of the deflectable flight control surfaces located at stall-critical spanwise locations are positioned to increase a local coefficient of lift and other deflectable flight control surfaces are positioned to control pitch trim.

12. The aircraft as set forth in claim 11, wherein:

the lifting force generates a moment acting on the wing; and

,

the reconfiguration means functions to minimize the moment for at least one of the different flight conditions.

13. The aircraft as set forth in claim 11, wherein:

the control surface reconfiguration system minimizes the moment for the structurally crucial flight conditions.

14. The aircraft as set forth in claim 11, wherein the reconfiguration means also trims the wing.

15. The aircraft as set forth in claim 11, wherein:

one of the different flight conditions comprises cruise, with the wing having a lift-to-drag ratio during cruise; and

,

the reconfiguration means functions to maximize the lift-to-drag ratio during the cruise flight condition.

16. The aircraft as set forth in claim 11, wherein the plurality of flight conditions include a pitch maneuver wherein the deflectable flight control surfaces are positioned to minimize the bending moment with respect to a bend axis of the wing.

17. The aircraft as set forth in claim 11, wherein:

one of the different flight conditions comprises a pitch maneuver; and

,

the reconfiguration means functions to maximize the lifting force during the pitch maneuver flight condition.

18. The aircraft as set forth in claim 17, wherein:

the aircraft is a blended wing-body with a longitudinal axis of symmetry; and

,

during the pitch maneuver, the reconfiguration means functions to shift the spanwise force distribution towards the longitudinal axis without reducing the lifting force.

19. A method for controlling flight of a blended wing-body, tailless aircraft which includes a wing having a trailing edge and independently deflectable flight control surfaces located along the trailing edge which are deflectable in upward and downward directions, the wing being capable during flight of generating a normal lifting force having a spanwise distribution across the wing, the method including the steps of:

predetermining for each of a plurality of different flight conditions the respective position for each of the flight control surfaces, which in combination, optimize the spanwise force distribution across the wing for each of said different flight conditions including a low speed flight condition wherein first selected ones of the deflectable flight control surfaces located at stall-critical spanwise locations are positioned to increase a local coefficient of lift and other deflectable flight control surfaces are positioned to control pitch trim;

subjecting said aircraft to at least one of said different flight control conditions; and

reconfiguring the control surfaces upwardly or downwardly to the respective predetermined positions when subjecting said aircraft to each of said at least one flight control conditions to optimize the spanwise force distribution across the wing.

20. The method as set forth in claim 19, including the step of reconfiguring the control surfaces to control trim of the aircraft.