Canard control system for aircraft

• US 4,848,700 A
• Filed: 04/16/1987
• Issued: 07/18/1989
• Est. Priority Date: 04/16/1987
• Status: Expired due to Fees

• Current Assignee: John A. Lockheed
• Original Assignee: John A. Lockheed
• Inventors: Lockheed, John A.
• Primary Examiner(s): Barefoot, Galen
• Application Number:
  US07/038,953
• Time in Patent Office: 824 Days
• Field of Search: 244/45 R, 244/45 A, 244/46, 244/48, 244/89, 244/220, 244/221, 244/225, 244/75 R
• US Class Current: 244/45.00A
• CPC Class Codes: B64C 5/04 Noseplanes
• CPC Class Codes: B64C 9/12 surfaces of different type or function being simultaneously adjusted
• CPC Class Codes: Y02T 50/30 Wing lift efficiency

Abstract

A system with a canard disposed in a cage with canard fore and aft movement within the cage for trimming purposes. Rails support the cage and include both horizontal and inclined segments with the cage and canard inclined by the latter segments to increase the canard angle of attack to preserve the canard-stallfirst characteristic of the aircraft. A combined canard and flap control assures automatic advancement and inclining of the canard to counteract forward pitching of the aircraft caused by flap deployment.

Claims

1. A flight control system for an aircraft having a canard and a main wing with wing flaps, said system comprising,

a canard positionable toward and away from the aircraft center of gravity,

canard carrier means within the forward portion of the fuselage and adapted for generally fore and aft movement with at least a portion of said movement being along a path inclined to the aircraft longitudinal axis for increasing the canard angle of attack,

flap and canard control means coupled to the main wing flaps and to said canard carrier whereby said carrier and the canard carried thereby are advanced away from the aircraft center of gravity when said flaps are deployed to alter the canard moment arm and to thereby maintain canard and main wing lift forces substantially in equilibrium relative the aircraft center of gravity, and

canard trim means coupled to said canard for varying canard lift independently and without movement of said canard carrier means.

2. The flight control system claimed in claim 1 wherein said canard carrier means includes a cage, said canard entrained for fore and aft movement within said cage.

3. The flight control system claimed in claim 2 wherein said canard carrier means includes a rail assembly, said cage carried by said rail assembly.

4. The flight control system claimed in claim 3 wherein said rail assembly includes an upwardly inclined forward segment for inclining said cage and the canard carried thereby to increase the canard angle of attack.

5. The flight control system claimed in claim 4 wherein said cage and canard are inclined to increase the canard angle of attack simultaneously with and directly proportional to flap deployment to maintain the aircraft lift forces in substantial equilibrium.

6. The flight control system claimed in claim 2 wherein said cage defines an open area, said canard having a central portion slidably entrained within said open area of the cage and permitting canard movement relative said cage for aircraft trimming purposes.

7. A flight control system for an aircraft having a main wing and wing flaps, said system comprising,

a canard,

canard carrier means mounted in the aircraft fuselage, said carrier means including a cage within which said canard is movably mounted and rail means transversed by said cage, said rail means having an inclined segment and a substantially horizontal segment whereby said canard may be located respectively to the aircraft longitudinal axis to vary canard angle of attack and along said axis to vary the canard moment arm,

flap and canard control means coupled to said flaps and said cage for positioning same along said rails, and

trim means coupled to said canard to position same within said cage.

8. In combination,

a canard disposed transversely of the forward portion of an aircraft fuselage and having a central portion within said fuselage,

a cage also disposed within the forward portion of the aircraft fuselage and positionable fore and aft, said cage defining an open area to receive said central portion of the canard, means movably mounting said canard in said cage for fore and aft travel of the canard, canard control means coupled to said cage to position the cage fore and aft, and

canard trim means including a control in the aircraft cockpit and coupled to said central portion of the canard to position same toward and away from the aircraft center of gravity for trimming of the aircraft.

9. The combination claimed in claim 8 additionally including rail means within the forward portion of the aircraft fuselage and on which said cage is movably mounted.

10. The combination claimed in claim 9 wherein said rail mesans includes both horizontal and inclined segments whereby the canard may be positioned relative the aircraft center of gravity and additionally relative the aircraft longitudinal axis with the latter positioning causing alteration of the canard angle of attack.

11. The combination claimed in claim 8 wherein said canard trim means includes a splined shaft.