Rotor blade

• US 5,074,753 A
• Filed: 10/16/1989
• Issued: 12/24/1991
• Est. Priority Date: 10/16/1989
• Status: Expired due to Term

• Current Assignee: Bell Helicopter Michigan Inc (Textron Inc)
• Original Assignee: Bell Helicopter Textron Incorporated (Textron Inc)
• Inventors: Schellhase, Ernst C., Covington, Cecil E., Robinson, Madison K.
• Primary Examiner(s): Look, Edward K.
• Assistant Examiner(s): LARSON, JAMES
• Application Number:
  US07/422,118
• Time in Patent Office: 799 Days
• Field of Search: 416/131, 416/141, 416/142, 416/204 R, 416/222, 416/229 R, 416/230, 416/238, 416/239
• US Class Current: 416/141
• CPC Class Codes: B64C 27/48 Root attachment to rotor head
• CPC Class Codes: F01D 5/147 Construction, i.e. structural features, e.g. of weight-saving hollow blades F01D5/148, F01D5/16 and F01D5/20 take precedence; blade shape F01D5/141; blades with cooling or heating channels or cavities F01D5/18; heating, heat-insulating or cooling means on blades F01D5/18
• CPC Class Codes: F01D 5/286 Particular treatment of blades, e.g. to increase durability or resistance against corrosion or erosion F01D5/288 takes precedence
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A composite rotor blade comprising an outboard portion defining an airfoil surface, an inboard portion defining an end tang having a mounting section and an extension lug section. The mounting section of the end tang having at least one mounting aperture with an axis parallel to the chordline of the airfoil for mounting of the blade, and the extension lug section having at least one extension lug extending inboard of the mounting aperture to provide a lever surface for interaction with suitable mounting mechanisms.

Claims

1. A helicopter rotor blade comprising:

(a) an outboard end forming an airfoil surface defining a chordline and beamline and forming a blade tip; and

(b) an end tang forming the inboard end of the helicopter rotor blade which defines a mounting aperture having an axis substantially parallel to the chordline of the outboard end and an extension lug portion extending inboard of said mounting aperture and having lever surfaces oriented with respect to said beamline to resist bending of the helicopter rotor blade along the beamline, said extension lug portion having a length which is from 3% to 7% of the length of the helicopter rotor blade as measured from the mounting aperture to the blade tip.

2. The helicopter rotor blade of claim 1, further comprising a reinforcing band attached to the extension lug portion.

3. A rotor blade comprising:

(a) an outboard end forming an airfoil surface defining a chordline and beam; and

(b) an end tang forming an inboard end of the rotor blade and attached to said outboard end, said tang end having fore and aft spaced apart extensions extending in a plane substantially parallel to the beam of the outboard end, each extension defining a mounting aperture, said aperture being co-axially aligned on an axis substantially parallel to the chordline of the outboard end, each of said fore and aft extensions extending inboard of said mounting apertures to define an extension lug having lever surfaces which are coated with a self-lubricating plastic material.

4. The rotor blade of claim 3, further comprising a reinforcing band attached to the at lease one extension lug.

5. A helicopter rotor blade for mounting to a hub grip of a helicopter comprising:

(a) an outboard end defining an airfoil surface which has a chordline and beamline; and

(b) an end tang attached to the outboard end having at least two spaced apart extensions extending inboard from said outboard end, at least one of said spaced apart extensions defining a mounting aperture with an axis substantially parallel to the chordline, and at least one of said spaced apart extensions defining an extension lug extending inboard of said mounting aperture to provide at least one lever surface to coact with the hub grip to resist beamwise bending of the helicopter rotor blade.

8. The helicopter rotor blade of claim 5, further comprising a reinforcing band attached to the extension lug of said fore tang extension.

6. A helicopter rotor blade for mounting to a hub grip of a helicopter, comprising:

(a) an outboard portion of composite material forming an airfoil surface and defining a chordline and beam;

(b) a first plurality of filament reinforced composite belts extending inboard from the outboard portion of the airfoil forming a fore tang extension defining a mounting aperture having an axis substantially parallel to the chordline of the outboard portion, said fore tang extension extending further inboard of said mounting aperture to provide an extension lug having lever surfaces to coact with the hub grip to resist bending of the helicopter rotor blade along the beam thereof; and

(c) a second plurality of filament reinforced composite belts extending inboard of said outboard portion forming an aft tang extension spaced apart from said fore tang extension in a direction along the chordline and defining a mounting aperture having an axis substantially parallel to the chordline of the outboard portion, and said aft tang extension further extending inboard of the mounting aperture formed thereby to provide an extension lug having lever surfaces to coact with said hub grip to resist bending of the helicopter rotor blade along the beam thereof.

7. The helicopter rotor blade of claim 6, wherein composite material is selected from composite sheets having reinforcing elements selected from the group consisting of carbon, graphite, boron, fiberglass, and polymeric filaments, and combinations thereof.

9. The helicopter rotor blade of claim 6, further comprising a reinforcing band attached to the extension lug of said aft tang extension.

10. A rotor blade comprising:

(a) an outboard end made of composite material defining an airfoil surface which has a chordline and beam;

(b) a first plurality of composite filament wound belts extending inboard from said outboard end and forming a first end tang, said first end tang defining a first mounting aperture and a first extension lug extending inboard of said first mounting aperture, said first mounting aperture having an axis substantially parallel to said chordline of said outboard end, said first extension lug formed from a laminate comprising;

(i) an inner belt layer having two inner belts extending from said outboard end which are spaced apart by an inner belt filler element of reinforced composite material;

(ii) a shear web layer of composite material adjacent to said inner belt layer and lying in a plane generally perpendicular to said chordline of said outboard end;

(iii) an outer belt layer formed by an outer belt which loops around said first mounting aperture, said loop being held in a spaced apart configuration by a filler element of reinforced composite material and an inboard filler element of reinforced composite material extending inboard from the inboard end of said outer belt to form part of the first extension lug; and

(iv) at least one additional layer as defined in (i), (ii), or (iii) arranged in a predetermined order and laminated together with the other layers.

11. The rotor blade of claim 10, further comprising:

(a) a second plurality of composite filament wound belts extending inboard from said outboard end and forming a second end tang spaced apart from said first end tang and defining a second mounting aperture in alignment with said first mounting aperture and a second extension lug extending inboard of said second mounting aperture, said second mounting aperture having an axis substantially parallel to said chordline of said outboard end, said second extension lug formed from a laminate comprising;

(i) an inner belt layer having two inner belts extending from said outboard end which are spaced apart by an inner belt filler element of reinforced composite material;

(ii) a shear web layer of composite material adjacent to said inner belt layer and lying in a plane generally perpendicular to said chordline of said outboard end;

(iii) an outer belt layer formed by an outer belt which loops around said second mounting aperture, said loop being held in a spaced apart configuration by a filler element of reinforced composite material and an inboard filler element of reinforced composite material extending inboard from the inboard end of said outer belt to form part of the second extension lug; and

(iv) at least one additional layer as defined in (i), (ii) or (iii) arranged in a predetermined order and laminated together with the other layers.

12. The rotor blade of claim 11, wherein said reinforced composite material has reinforcing elements selected from the group consisting of carbon, graphite, boron, aramid fibers, and combinations thereof.

13. The rotor blade of claim 10, wherein said filler elements are oriented such that the reinforcing elements are oriented from ±

15°

to ±

90°

from the beamline of said rotor blade.

14. The rotor blade of claim 11, wherein said filler elements are oriented such that the reinforcing elements are oriented from ±

15°

to ±

90°

from the beamline of said rotor blade.

15. The rotor blade of claim 10, wherein said filler elements and at lease one shear web layer are oriented such that the reinforcing elements are oriented from ±

25°

to ±

35°

from the beamline of said rotor blade.

16. The rotor blade of claim 11, wherein said filler elements and shear web layer are oriented such that the reinforcing elements are oriented from ±

25°

to ±

35°

from the beamline of said rotor blade.

17. The rotor blade of claim 10, further comprising a reinforcing band attached to the first extension lug.

18. The rotor blade of claim 11, further comprising a reinforcing band attached to the second extension lug.