Ducted rotor blade tip extension

Patent metadata

Field	Value
Publication number	US-11286036-B2
Application number	US-201816159178-A
Country	US
Kind code	B2
Filing date	Oct 12, 2018
Priority date	Oct 12, 2018
Publication date	Mar 29, 2022
Grant date	Mar 29, 2022

Abstract

A rotor system is provided in one example embodiment and may include a rotor duct; at least one rotor blade, wherein the at least one rotor blade comprises a tip end; and a tip extension affixed at the tip end of the at least one rotor blade, wherein the tip extension is comprised, at least in part, of a flexible material and the rotor blade has a fixed extended length based on the tip extension. The tip extension may provide a clearance distance between the tip extension and the rotor duct.

First claim

What is claimed is:

1. A rotor system comprising:
a rotor duct;
at least one rotor blade, wherein the at least one rotor blade comprises a tip end; and
a tip extension affixed at the tip end of the at least one rotor blade, wherein the tip extension is comprised, at least in part, of a flexible material and the rotor blade has a fixed extended length based on the tip extension, the tip extension covers an entirety of an outboard surface of the tip end, and a cross-section of the tip extension comprises an airfoil shape.

2. The rotor system of claim 1 , wherein the tip extension provides a clearance distance between the tip extension and the rotor duct.

3. The rotor system of claim 1 , wherein an outboard end of the tip extension comprises a plurality of flexible elements.

4. The rotor system of claim 3 , wherein at least one of:
the plurality of flexible elements are linear between a top surface and a bottom surface of the tip extension;
the plurality of flexible elements are curved between a top surface and a bottom surface of the tip extension; and
the plurality of flexible elements are a plurality of flexible bristles.

5. The rotor system of claim 1 , wherein the tip extension has a shape that matches a shape of the at least one rotor blade.

6. The rotor system of claim 1 , wherein one of:
an inboard end of the tip extension extends into the tip end of the at least one rotor blade;
the tip end of the at least one rotor blade extends into an inboard end of the tip extension; and
an inboard end of the tip extension is mechanically affixed to at least one attachment element of the at least one rotor blade.

7. The rotor system of claim 1 , wherein the flexible material is an elastomer.

8. The rotor system of claim 1 , wherein an outboard end of the tip extension comprises the flexible material and an inboard end of the tip extension comprises a non-flexible material.

9. The rotor system of claim 8 , wherein the inboard end of the tip extension comprises at least one attachment element for affixing the tip extension to the rotor blade.

10. The rotor system of claim 1 , wherein the tip extension is entirely comprised of the flexible material.

11. An aircraft comprising:
a fuselage; and
at least one rotor system, the at least one rotor system comprising:
a rotor duct;
at least one rotor blade, wherein the at least one rotor blade comprises a tip end; and
a tip extension affixed at the tip end of the at least one rotor blade, wherein the tip extension is comprised, at least in part, of a flexible material and the rotor blade has a fixed extended length based on the tip extension, the tip extension covers an entirety of an outboard surface of the tip end, and a cross-section of the tip extension comprises an airfoil shape.

12. The aircraft of claim 11 , wherein the tip extension provides a clearance distance between the tip extension and the rotor duct.

13. The aircraft of claim 11 , wherein an outboard end of the tip extension comprises a plurality of flexible elements.

14. The aircraft of claim 13 , wherein at least one of:
the plurality of flexible elements are linear between a top surface and a bottom surface of the tip extension;
the plurality of flexible elements are curved between a top surface and a bottom surface of the tip extension; and
the plurality of flexible elements are a plurality of flexible bristles.

15. The aircraft of claim 11 , wherein the tip extension has a shape that matches a shape of the at least one rotor blade.

16. The aircraft of claim 11 , wherein one of:
an inboard end of the tip extension extends into the tip end of the at least one rotor blade;
the tip end of the at least one rotor blade extends into an inboard end of the tip extension; and
an inboard end of the tip extension is mechanically affixed to at least one attachment element of the at least one rotor blade.

17. The aircraft of claim 11 , wherein an outboard end of the tip extension comprises the flexible material and an inboard end of the tip extension comprises a non-flexible material.

18. The aircraft of claim 17 , wherein the inboard end of the tip extension comprises at least one attachment element for affixing the tip extension to the rotor blade.

19. The aircraft of claim 11 , wherein the tip extension is entirely comprised of the flexible material.

20. The aircraft of claim 11 , wherein the aircraft is a vertical take-off and landing aircraft.

Assignees

• Bell Helicopter Textron Inc
• Textron Innovations Inc

Inventors

• Groninga Kirk L
• Robertson Daniel B
• Louis Matthew Edward
• Vaughn Robert Glenn
• Ryan Michael J
• Achttien Brent Randal

Classifications

• B29C39/18

  incorporating preformed parts or layers, e.g. casting around inserts or for coating articles {(B29C39/206 takes precedence)} · CPC title

• B29L2031/087

  Propellers · CPC title

• F16J15/3288

  Filamentary structures, e.g. brush seals · CPC title

• B64C11/001 Primary

  Shrouded propellers · CPC title

• B64C29/0033

  the propellers being tiltable relative to the fuselage · CPC title