Morphing airfoil leading edge

Patent metadata

Field	Value
Publication number	US-2016009372-A1
Application number	US-201414196461-A
Country	US
Kind code	A1
Filing date	Mar 4, 2014
Priority date	Mar 4, 2014
Publication date	Jan 14, 2016
Grant date	—

Abstract

An airfoil may include a leading edge and a shape control mechanism. The leading edge may include a flexible leading edge skin having a first end, a second end, and an arc length defined therebetween. The shape control mechanism may be attached to the flexible leading edge skin at a plurality of support locations and may transition the flexible leading edge skin from a first shape having a first curvature profile to a second shape having a second curvature profile different than the first curvature profile without a change in the arc length.

First claim

What is claimed is:

1 . An airfoil, comprising:
a leading edge including a flexible leading edge skin having a first end, a second end, and an arc length defined therebetween; and a shape control mechanism attached to the flexible leading edge skin at a plurality of support locations and configured to transition the flexible leading edge skin from a first shape having a first curvature profile to a second shape having a second curvature profile different than the first curvature profile without a change in the arc length.

2 . The airfoil of claim 1 , further comprising:
an airfoil main portion adjacent to the leading edge, the first and second end of the leading edge fixedly coupled to the airfoil main portion; and an outer surface of the flexible leading edge skin continuous from a first side of the airfoil main portion to a second side of the airfoil main portion.

3 . The airfoil of claim 1 , further comprising:
an airfoil main portion adjacent the leading edge; and an outer surface of the flexible leading edge skin tangent to an outer surface of the airfoil main portion on both sides of the airfoil when the flexible leading edge skin is in the first shape and in the second shape.

4 . The airfoil of claim 1 , wherein:
the flexible leading edge skin has a variable bending stiffness along the arc length.

5 . The airfoil of claim 4 , wherein:
the flexible leading edge skin is formed of an isotropic material.

6 . The airfoil of claim 5 , wherein:
the isotropic material has a thickness varying along the arc length in a manner causing the bending stiffness of the flexible leading edge skin to vary along the arc length such that a desired curvature profile is formed in the flexible leading edge skin when subjected to a bending moment profile.

7 . The airfoil of claim 4 , wherein:
the flexible leading edge skin is formed of composite material.

8 . The airfoil of claim 7 , wherein:
the composite material is a composite laminate formed of composite plies of fiber-reinforced polymer matrix material.

9 . The airfoil of claim 8 , wherein:
each one of the composite plies has a fiber orientation; and the fiber orientation of at least one of the composite plies varying along the arc length in a manner causing the bending stiffness of the flexible leading edge skin to vary along the arc length such that a desired curvature profile is formed in the flexible leading edge skin when subjected to a bending moment profile.

10 . The airfoil of claim 1 , wherein:
respective portions of the flexible leading edge skin at respective ones of the plurality of support locations have a same curvature in the first shape and in the second shape.

11 . The airfoil of claim 1 , wherein:
a first portion of the flexible leading edge skin at a first one of the plurality of support locations has a higher bending stiffness relative to a bending stiffness of a second portion of the flexible leading edge skin at a second one of the plurality of support locations.

12 . The airfoil of claim 1 , wherein:
the shape control mechanism is configured to control a displacement and/or a slope of respective portions of the flexible leading edge skin at respective ones of the plurality of support locations.

13 . The airfoil of claim 1 , wherein:
the shape control mechanism includes one or more arms extending from an airfoil main portion to one or more of the support locations.

14 . The airfoil of claim 13 , wherein:
the arms include:
a main arm extending from the airfoil main portion to a support location on a forward lower portion of the flexible leading edge skin and configured to control a displacement of a forward lower point on the forward lower portion;
a rotation arm extending from the airfoil main portion to the support location where the main arm is coupled to the forward lower portion and configured to control a slope of the forward lower point;
the shape control mechanism including one or more links extending from one or more arms to one or more locations on an inner side of the flexible leading edge skin, the links including:
an upper link pivotably coupled to the main arm and extending to a forward upper portion of the flexible leading edge skin and configured to control a displacement of a forward upper point on the forward upper portion; and
a lower link pivotably coupled to the main arm and extending to a mid lower portion of the flexible leading edge skin at a location between the forward lower portion and the airfoil main portion and configured to control a displacement of a mid lower point on the mid lower portion; and
the shape control mechanism including an actuator extending from the airfoil main portion and pivotably coupled to at least one of the arms for transitioning the flexible leading edge skin between the first shape and the second shape.

15 . An aircraft, comprising:
an airfoil; a leading edge disposed on the airfoil and including a flexible leading edge skin having a first end, a second end, and an arc length defined therebetween; and a shape control mechanism attached to the flexible leading edge skin at a plurality of support locations and configured to transition the flexible leading edge skin from a first shape having a first curvature profile to a second shape having a second curvature profile different than the first curvature profile without a change in the arc length.

16 . A method of morphing a leading edge of an airfoil, comprising:
controlling a shape control mechanism attached, at a plurality of support locations, to a flexible leading edge skin of the airfoil; transitioning the flexible leading edge skin from a first shape having a first curvature profile to a second shape having a second curvature profile different than the first curvature profile; and maintaining a same arc length of the flexible leading edge skin during the transitioning of the flexible leading edge skin from the first shape to the second shape.

17 . The method of claim 16 , further comprising:
enforcing a displacement and/or a slope change of the leading edge skin for at least one of the support locations during the transitioning of the flexible leading edge skin from the first shape to the second shape.

18 . The method of claim 16 , further comprising:
maintaining a same curvature in the flexible leading edge skin for least one of the support locations during the transitioning of the flexible leading edge skin from the first shape to the second shape.

19 . The method of claim 16 , further comprising:
forming a reflex of curvature in the flexible leading edge skin from concave to convex when transitioning the leading edge skin into the first shape and/or the second shape.

20 . The method of claim 16 , wherein the airfoil further includes an airfoil main portion, the method further comprising:
maintaining a tangency of an outer surface of the leading edge skin to an outer surface of the airfoil main portion on both sides of the airfoil during the transitioning of the flexible leading edge skin from the first shape to the second shape.

21 . The method of claim 16 , further comprising:
changing a camber of the airfoil from a first camber suitable for cruise flight to a second camber suitable for low-speed flight.

22 . The method of claim 21 , further comprising:
reducing a camber of the airfoil by transitioning the flexible leading edge skin from the second shape to a third shape.

23 .

Assignees

• Boeing Co

Inventors

• Grip Robert E
• Brown John J
• Harrison Neal A
• Rawdon Blaine K
• Vassberg John C

Classifications

• B64C3/28 Primary

  Leading or trailing edges attached to primary structures, e.g. forming fixed slots · CPC title

• B64C3/38

  Adjustment of complete wings or parts thereof · CPC title

• B64C3/26

  Construction, shape, or attachment of separate skins, e.g. panels · CPC title

• B64C9/24 Primary

  by single flap · CPC title

• Y02B10/30

  Wind power · CPC title