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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 sup

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.

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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, the first end and the second end being constrained locations of the flexible leading edge skin;a shape control mechanism attached to the flexible

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, the first end and the second end being constrained locations of the flexible leading edge skin;a shape control mechanism attached to the flexible leading edge skin at a plurality of discrete, fixed 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; andthe shape control mechanism including at least one main arm and at least one rotation arm each directly connected to and extending from an airfoil main portion and coupled to a same support location in a manner such that when the shape control mechanism transitions the leading edge skin from the first shape to the second shape:the main arm enforces a displacement of the leading edge skin at the same support location; andthe rotation arm enforces a slope change of the leading edge skin at the same support location. 2. The airfoil of claim 1, further comprising: the airfoil main portion adjacent to the leading edge, the first and second end of the leading edge fixedly coupled to the airfoil main portion; andan 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: the airfoil main portion adjacent the leading edge; andan 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 is formed of an isotropic material. 5. The airfoil of claim 4, 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. 6. The airfoil of claim 1, wherein: the flexible leading edge skin is formed of composite material. 7. The airfoil of claim 6, wherein: the composite material is a composite laminate formed of composite plies of fiber-reinforced polymer matrix material. 8. The airfoil of claim 7, wherein: each one of the composite plies has a fiber orientation; andthe 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. 9. 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. 10. 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. 11. The airfoil of claim 1, wherein: the shape control mechanism is configured to control a displacement and a slope of respective portions of the flexible leading edge skin at respective ones of the plurality of support locations. 12. The airfoil of claim 1, wherein: the main arm extends to a support location on a forward lower portion of the flexible leading edge skin and is configured to control a displacement of a forward lower point on the forward lower portion;the rotation arm extends to the support location where the main arm is coupled to the forward lower portion and is configured to control a slope of the forward lower point;the shape control mechanism including one or more links extending from the main arm 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; anda 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; andthe 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. 13. 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, the first end and the second end being constrained locations of the flexible leading edge skin; anda shape control mechanism attached to the flexible leading edge skin at a plurality of discrete, fixed 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;the shape control mechanism including at least one main arm and at least one rotation arm each directly connected to and extending from an airfoil main portion and coupled to a same support location in a manner such that when the shape control mechanism transitions the leading edge skin from the first shape to the second shape:the main arm enforces a displacement of the leading edge skin at the same support location; andthe rotation arm enforces a slope change of the leading edge skin at the same support location. 14. A method of morphing a leading edge of an airfoil, comprising: controlling a shape control mechanism attached, at a plurality of discrete, fixed support locations, to a flexible leading edge skin of the airfoil, the shape control mechanism including at least one main arm and at least one rotation arm each directly connected to and extending from an airfoil main portion and coupled to a same support location of the plurality of discrete, fixed support locations, the flexible leading edge skin having a first end, a second end, and an arc length defined therebetween, the first end and the second end being constrained locations of the flexible leading edge skin;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; andmaintaining the arc length of the flexible leading edge skin when transitioning the flexible leading edge skin from the first shape to the second shape; andenforcing, using the main arm and the rotation arm, a respective displacement and a slope change of the leading edge skin at the same support location when transitioning the leading edge skin from the first shape to the second shape. 15. The method of claim 14, 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. 16. The method of claim 14, 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. 17. The method of claim 14, 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. 18. The method of claim 17, further comprising: reducing a camber of the airfoil by transitioning the flexible leading edge skin from the second shape to a third shape. 19. The method of claim 14, wherein the shape control mechanism includes a plurality of links extending from an airfoil main portion of the airfoil to respective ones of the plurality of support locations, the method further comprising: controlling one or more links to control a displacement and/or a slope change of the leading edge skin for at least one of the support locations. 20. The method of claim 19, further comprising: engaging a locking mechanism to prevent movement of the arms and links.