Joining structural members using foam

1. A method of forming an aircraft component, the method comprising:

providing an aircraft skin member selected from a rotor blade, a fuselage, a tail-boom, an empennage, a horizontal stabilizer, a control surface, a wing, or an internal-to-external fuselage transition for an aircraft;

bonding a first end of a honeycomb structure to a surface of the aircraft skin member, the honeycomb structure comprising a plurality of connected cells;

spraying foam on a second end of the honeycomb structure, the second end opposite the first end; and

curing the foam on the second end of the honeycomb structure.

2. The method of claim 1 , wherein the aircraft skin member is a first aircraft skin member and the honeycomb structure is a first honeycomb structure, and wherein the method further comprises:

bonding a first end of a second honeycomb structure to a surface of a second aircraft skin member, the second honeycomb structure comprising a plurality of connected cells;

positioning an end of the first aircraft skin member adjacent an end of the second aircraft skin member to form a void in which the foam on the first honeycomb structure is positioned adjacent the second honeycomb structure;

spraying foam in the void and on a second end of the second honeycomb structure and the foam on the first honeycomb structure, the second end of the second honeycomb structure opposite the first end of the second honeycomb structure; and

curing the foam on the second end of the second honeycomb structure and the foam on the first honeycomb structure.

3. The method of claim 1 , wherein the aircraft skin member is a first aircraft skin member and the honeycomb structure is a first honeycomb structure, and wherein the method further comprises, before spraying foam on the second end of the first honeycomb structure and curing the foam on the second end of the first honeycomb structure:

bonding a first end of a second honeycomb structure to a surface of a second aircraft skin member, the second honeycomb structure comprising a plurality of connected cells;

positioning an end of the first aircraft skin member adjacent an end of the second aircraft skin member to form a void in which the first honeycomb structure is positioned adjacent the second honeycomb structure;

spraying foam in the void and on the second end of the first honeycomb structure and a second end of the second honeycomb structure, the second end of the second honeycomb structure opposite the first end of the second honeycomb structure; and

curing the foam on the second end of the first honeycomb structure and the second end of the second honeycomb structure.

4. The method of claim 1 , wherein the aircraft skin member is a first aircraft skin member and the honeycomb structure is a first honeycomb structure, and wherein the method further comprises:

bonding a first end of a second honeycomb structure to a surface of a second aircraft skin member, the second honeycomb structure comprising a plurality of connected cells;

spraying foam on a second end of the second honeycomb structure, the second end opposite the first end of the second honeycomb structure;

curing the foam on the second end of the second honeycomb structure;

positioning an end of the first aircraft skin member adjacent an end of the second aircraft skin member to form a void in which the foam on the first honeycomb structure is positioned adjacent the foam on the second honeycomb structure;

spraying foam in the void and on the foam on the first honeycomb structure and the foam in the second honeycomb structure; and

curing the foam sprayed in the void and on the foam on the first honeycomb structure and the foam in the second honeycomb structure.

5. The method of claim 1 , wherein spraying the foam on the second end of the honeycomb structure comprises spraying a quantity of foam to fill at least a portion of a volume of the plurality of connected cells of the honeycomb structure.

6. The method of claim 1 , wherein spraying the foam on the second end of the honeycomb structure comprises spraying a quantity of foam to form a foam thickness that is greater than a height of a tallest cell of the plurality of connected cells.

7. The method of claim 1 , wherein the aircraft skin member is included in a helicopter blade.

8. The method of claim 1 , wherein the surface of the aircraft skin member is at least one of a flat surface, an open contoured surface or a closed contoured surface.

9. The method of claim 1 , wherein bonding the first end of a honeycomb structure to the surface of the aircraft skin member comprises bonding the first end of the honeycomb structure in an undeformed state to the surface.

10. The method of claim 1 , further comprising deforming the honeycomb structure before bonding the first end of the honeycomb structure to the surface of the aircraft skin member.

11. A method of forming an aircraft component, the method comprising:

providing an aircraft skin member selected from a rotor blade, a fuselage, a tail-boom, an empennage, a horizontal stabilizer, a control surface, a wing, or an internal-to-external fuselage transition for an aircraft;

bonding a first end of a honeycomb structure to a surface of the aircraft skin member, the honeycomb structure comprising a plurality of connected cells, each cell comprising a plurality of surfaces, wherein adjacent cells share a common vertical surface;

spraying foam in a fluid state on a second end of the honeycomb structure, the second end opposite the first end; and

curing the foam on the second end of the honeycomb structure from the fluid state to a solid state to bond the foam in the solid state to the aircraft skin member.

12. The method of claim 11 , wherein the aircraft skin member is a first aircraft skin member and the honeycomb structure is a first honeycomb structure, and wherein the method further comprises:

bonding a first end of a second honeycomb structure to a surface of a second aircraft skin member, the second honeycomb structure comprising a plurality of connected cells;

positioning an end of the first aircraft skin member adjacent an end of the second aircraft skin member to form a void in which the foam on the first honeycomb structure is positioned adjacent the second honeycomb structure;

spraying foam in a liquid state in the void and on a second end of the second honeycomb structure and the foam in the solid state on the first honeycomb structure, the second end of the second honeycomb structure opposite the first end of the second honeycomb structure; and

curing the foam in the liquid state on the second end of the second honeycomb structure and the foam in the solid state on the first honeycomb structure to a solid state to attach the first aircraft skin member to the second aircraft skin member.

13. The method of claim 11 , wherein the aircraft skin member is a first aircraft skin member and the honeycomb structure is a first honeycomb structure, and wherein the method further comprises, before spraying foam on the second end of the first honeycomb structure and curing the foam on the second end of the first honeycomb structure:

bonding a first end of a second honeycomb structure to a surface of a second aircraft skin member, the second honeycomb structure comprising a plurality of connected cells;

positioning an end of the first aircraft skin member adjacent an end of the second aircraft skin member to form a void in which the first honeycomb structure is positioned adjacent the second honeycomb structure;

spraying foam in a liquid state in the void and on the second end of the first honeycomb structure and a second end of the second honeycomb structure, the second end of the second honeycomb structure opposite the first end of the second honeycomb structure; and

curing the foam in the liquid state on the second end of the first honeycomb structure and the second end of the second honeycomb structure to a solid state to attach the first aircraft skin member to the second aircraft skin member.

14. The method of claim 11 , wherein the aircraft skin member is a first aircraft skin member and the honeycomb structure is a first honeycomb structure, and wherein the method further comprises:

bonding a first end of a second honeycomb structure to a surface of a second aircraft skin member, the second honeycomb structure comprising a plurality of connected cells;

spraying foam in a liquid state on a second end of the second honeycomb structure, the second end opposite the first end of the second honeycomb structure;

curing the foam in the liquid state on the second end of the second honeycomb structure to a solid state;

positioning an end of the first aircraft skin member adjacent an end of the second aircraft skin member to form a void in which the foam in the solid state on the first honeycomb structure is positioned adjacent the foam in the solid state on the second honeycomb structure;

spraying foam in a liquid state in the void and on the foam in the solid state on the first honeycomb structure and the foam in the solid state in the second honeycomb structure; and

curing the foam in the liquid state sprayed in the void and on the foam in the solid state on the first honeycomb structure and the foam in the solid state in the second honeycomb structure to a solid state to attach the first aircraft skin member to the second aircraft skin member.