Main rotor blade with composite integral skin and cuff

Patent metadata

Field	Value
Publication number	US-9745056-B2
Application number	US-201313894046-A
Country	US
Kind code	B2
Filing date	May 14, 2013
Priority date	May 14, 2013
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

A main rotor blade assembly is provided including a spar which comprises a main section. A main core is positioned adjacent a trailing side of the main section of the spar. A tip assembly includes a main tip core and a tip end pocket core. The tip assembly is positioned adjacent an outboard end of the main core and the spar such that the main tip core is substantially aligned with a longitudinal axis of the main core and the tip end pocket core is substantially aligned with a longitudinal axis of the spar. At least a portion of both the main tip core and the tip end pocket core comprises a high density core. An upper composite skin and a lower composite skin extend over the spar, the main core, the main tip core, and the tip end pocket core. A portion of the upper composite skin and the lower composite skin has a thickness sufficient to be load bearing.

First claim

What is claimed is:

1. A main rotor blade assembly comprising:
a spar having a main section;
a main core positioned adjacent a trailing side of the main section of the spar;
a tip assembly including a main tip core and a tip end pocket core, the tip assembly being positioned adjacent an outboard end of the main core and the spar such that the main tip core is substantially aligned with a longitudinal axis of the main core and the tip end pocket core is substantially aligned with a longitudinal axis of the spar, wherein at least a portion of both the main tip core and the tip end pocket core comprises a high density core; and
an upper composite skin and a lower composite skin, wherein both the upper composite skin and the lower composite skin extend over the spar, the main core, the main tip core, and the tip end pocket core, and at least a portion of the upper composite skin and the lower composite skin has a thickness sufficient to be load bearing.

2. The main rotor blade assembly according to claim 1 , wherein the spar is configured to directly connect to a rotor hub.

3. The main rotor blade assembly according to claim 1 , wherein the high density core has a density in the range of about 5.1 pounds per cubic foot and about 10.0 pounds foot.

4. The main rotor blade assembly according to claim 3 , wherein the tip end pocket core includes a first tip end pocket core piece and a second tip end pocket core piece.

5. The main rotor blade assembly according to claim 4 , wherein both the first tip end pocket core piece and the second tip end pocket core piece are fabricated from a glass honeycomb core.

6. The main rotor blade assembly according to claim 5 , wherein both the first tip end pocket core piece and the second tip end pocket core piece are fabricated from a high density core.

7. The main rotor blade according to claim 3 , wherein the main core includes a polyamide honeycomb core having a density less than or equal to portion of high density core.

8. The main rotor blade according to claim 3 , wherein the main core includes a first main core piece, a second main core piece, and a third main core piece.

9. The main rotor blade according to claim 7 , wherein the first main core piece includes a medium density core having a density in the range of about 2.1 pounds per cubic foot to about 5.0 and the second main core piece and the third main core piece include a low density core having a density in the range of about 1.0 pounds per cubic foot to about 2.0 pounds per cubic foot.

10. The main rotor blade according to claim 3 , wherein the main tip core assembly is positioned directly adjacent the main core and the tip end pocket core.

11. The main rotor blade according to claim 10 , wherein the main tip core includes a polyamide honeycomb core and a glass honeycomb core.

12. The main rotor blade according to claim 11 , wherein the main tip core includes a first main tip core piece, a second main tip core piece, and a third main tip core piece.

13. The main rotor blade according to claim 12 , wherein the first main core piece includes a medium density having a density in the range of about 2.1 pounds per cubic foot to about 5.0 pounds per cubic foot, the second and third main core piece includes a low density core having a density in the range of about 1.0 pounds per cubic foot to about 2.0 pounds per cubic foot.

14. The main rotor blade according to claim 1 , wherein each of the upper composite skin and the lower composite skin have a thickness sufficient to carry about 45% of a load applied to a tip of the main rotor blade.

15. The main rotor blade according to claim 1 , wherein both the upper composite skin and the lower composite skin are fabricated from a composite material including at least one of graphite and fiberglass fibers.

16. A method of assembling a main rotor blade comprising:
forming a main core, main tip core, and tip end pocket core using at least one composite material;
connecting an upper skin and a lower skin to the main core, main tip core, and tip end pocket core, the upper skin and the lower skin having a thickness sufficient to be load bearing;
machining the main core, main tip core, and tip end pocket core, to a desired size and shape; and
positioning the upper skin, lower skin, main core, main tip core, and tip end pocket core adjacent a rigid spar such that the main tip core and tip end pocket core extend from the rigid spar.

17. The method according to claim 16 , wherein the main core is formed by bonding together a first main core piece, a second main core piece, and a third main core piece.

18. The method according to claim 16 , wherein the main tip core is formed by bonding together a first main tip core piece, a second main tip core piece, and a third main tip core piece.

19. The method according to claim 16 , wherein the tip end pocket core is formed by bonding together a first tip end pocket core piece and a second tip end pocket core piece.

20. The method according to claim 16 , further comprising curing the spar, upper skin, lower skin, main core, main tip core, and tip end pocket core.

21. The method according to claim 16 , further comprising positioning a tip cap over an end of the upper skin and lower skin, tip end pocket core assembly and the main tip core assembly.

22. The method according to claim 21 , further comprising positioning a tip leading edge assembly over a leading edge of the spar, the tip leading edge assembly being configured to overlap a portion of the tip cap.

23. The method according to claim 16 , wherein:
the main core has a first core density,
the main tip core has a second core density,
the tip end pocket core has a third core density, and
the third core density is greater than the first and second core densities.

Assignees

• Sikorsky Aircraft Corp

Inventors

• Leahy Kevin P
• Simkulak Richard Joseph

Classifications

• B64C27/473 Primary

  Constructional features · CPC title

• B64C27/463

  Blade tips · CPC title

• Y10T29/49337

  Composite blade · CPC title