Structurally biased proprotor blade assembly

Patent metadata

Field	Value
Publication number	US-10239604-B2
Application number	US-201615161215-A
Country	US
Kind code	B2
Filing date	May 21, 2016
Priority date	May 21, 2016
Publication date	Mar 26, 2019
Grant date	Mar 26, 2019

Abstract

A tiltrotor aircraft includes a fuselage, a wing member extending from the fuselage, an engine disposed relative to the wing member and a proprotor mechanically coupled to the engine. The proprotor includes a plurality of proprotor blade assemblies each including a spar and a sheath extending spanwise along the spar forming the leading edge of the proprotor blade assembly. The spar has a root section, a main section and a tip section. The spar has a generally oval cross section at radial stations along the main section and a first edge having a structural bias relative to a generally oppositely disposed second edge at the radial stations along the main section.

First claim

What is claimed is:

1. A proprotor blade assembly comprising:
a spar having a root section, a main section and a tip section, the spar having a generally oval cross section at radial stations along the main section, the spar having a first edge and a generally oppositely disposed second edge, the first edge having a structural bias relative to the second edge at the radial stations along the main section, the wall thickness of the first edge and the wall thickness of the second edge each having a decreasing spanwise taper as the radial station increases along the main section; and
a sheath extending spanwise along a leading edge of the spar.

2. The proprotor blade assembly as recited in claim 1 wherein the first edge of the spar further comprises the leading edge of the spar.

3. The proprotor blade assembly as recited in claim 1 wherein the thickness of the first edge of the spar is greater than the thickness of the second edge of the spar at the radial stations along the main section of the spar.

4. The proprotor blade assembly as recited in claim 1 wherein the thickness of the first edge of the spar is at least 50% greater than the thickness of the second edge of the spar at the radial stations along the main section of the spar.

5. The proprotor blade assembly as recited in claim 1 wherein the thickness of the first edge of the spar is between about 50% and about 120% greater than the thickness of the second edge of the spar at the radial stations along the main section of the spar.

6. The proprotor blade assembly as recited in claim 1 wherein the first edge of the spar further comprises a cured laminate of overlapping broad goods layers.

7. The proprotor blade assembly as recited in claim 6 wherein the overlapping broad goods layers extend between about 180 degrees and about 290 degrees around the spar.

8. The proprotor blade assembly as recited in claim 1 wherein the second edge of the spar further comprises a cured laminate of butt-spliced broad goods layers.

9. The proprotor blade assembly as recited in claim 1 wherein the second edge of the spar further comprises a cured laminate of staggered butt-spliced broad goods layers.

10. The proprotor blade assembly as recited in claim 1 wherein the spar further comprises a monolithic structure formed by curing a plurality of composite broad goods material layers.

11. The proprotor blade assembly as recited in claim 10 wherein the plurality of composite broad goods material layers is selected from the group consisting of fiberglass fabric, carbon fabric, fiberglass tape, carbon tape and combinations thereof.

12. The proprotor blade assembly as recited in claim 1 wherein the spar further comprises simple geometric surfaces with smooth transitions.

13. The proprotor blade assembly as recited in claim 1 wherein the sheath extends along the full span of the spar.

14. The proprotor blade assembly as recited in claim 1 wherein the sheath further comprises a structural member of the proprotor blade assembly.

15. The proprotor blade assembly as recited in claim 1 further comprising a filler assembly disposed between the spar and the sheath.

16. The proprotor blade assembly as recited in claim 1 further comprising an upper skin and a lower skin each extending spanwise along the spar forming upper and lower surfaces of the proprotor blade assembly.

17. The proprotor blade assembly as recited in claim 1 wherein the root section of the spar further comprises an integral cuff.

18. The proprotor blade assembly as recited in claim 17 wherein the spar has redundant centrifugal force retention load paths through the integral cuff.

19. A rotorcraft, comprising:
a fuselage;
a wing member extending from the fuselage;
an engine disposed relative to the wing member; and
a proprotor mechanically coupled to the engine, the proprotor including a plurality of proprotor blade assemblies each comprising:
a spar having a root section, a main section and a tip section, the spar having a generally oval cross section at radial stations along the main section, the spar having a first edge and a generally oppositely disposed second edge, the first edge having a structural bias relative to the second edge at the radial stations along the main section, the wall thickness of the first edge and the wall thickness of the second edge each having a decreasing spanwise taper as the radial station increases along the main section; and
a sheath extending spanwise along a leading edge of the spar.

20. The rotorcraft as recited in claim 19 wherein the engine is rotatably mounted relative to the wing member.

Assignees

• Bell Helicopter Textron Inc

Inventors

• Foskey Christopher
• Burnett Michael
• Bosworth Jeffrey
• Paulson Jared Mark
• Mcintyre Joel
• Oldroyd Paul K

Classifications

• B64C11/26 Primary

  Fabricated blades · CPC title

• B64C29/0033

  the propellers being tiltable relative to the fuselage · CPC title

• B64C27/473

  Constructional features · CPC title

• B64C11/24

  Hollow blades · CPC title

• B64C2027/4736

  from composite materials · CPC title