Methods for forming rotor blades having foam cores

Patent metadata

Field	Value
Publication number	US-11027465-B2
Application number	US-201816141127-A
Country	US
Kind code	B2
Filing date	Sep 25, 2018
Priority date	Sep 25, 2018
Publication date	Jun 8, 2021
Grant date	Jun 8, 2021

Abstract

A method is provided in one example embodiment and may include positioning at least one nozzle within a hollow portion of a rotor blade at a distance associated with a span of the rotor blade and providing, via the at least one nozzle, a liquid foam mixture in the hollow portion, wherein the liquid foam expands and becomes a solid foam material that fills the hollow portion of the rotor blade. Another method is provided in another example embodiment and may include providing a plurality of openings for a rotor blade that are positioned proximate to a hollow portion of the rotor blade and providing a liquid foam mixture in the hollow portion of the rotor blade through at least one opening of the rotor blade, wherein the liquid foam mixture expands and becomes a solid foam material that fills the hollow portion of the rotor blade.

First claim

What is claimed is:

1. A method comprising:
positioning at least one nozzle within a hollow portion of a rotor blade at a distance associated with a span of the rotor blade, wherein the hollow portion of the rotor blade has a fixed volume between an outboard end and an inboard end of the rotor blade; and
providing, via the at least one nozzle, a liquid foam mixture in the hollow portion, wherein the liquid foam expands and becomes a solid foam material that fills the hollow portion of the rotor blade;
wherein the hollow portion of the rotor blade is defined, at least in part, by an aft wall of a spar of the rotor blade, at least a portion of an inner surface of an upper skin of the rotor blade, at least a portion of an inner surface of a lower skin of the rotor blade, and a forward wall of a trailing edge wedge of the rotor blade for the span of the rotor blade.

2. The method of claim 1 , wherein the distance is based, at least in part, on a center of the fixed volume of the hollow portion of the rotor blade.

3. The method of claim 1 , wherein providing the liquid foam mixture in the hollow portion further comprises at least one of:
moving the rotor blade away from the at least one nozzle at one or more rates as the liquid foam mixture is provided in the hollow portion of the rotor blade;
removing the at least one nozzle from the hollow portion at one or more rates as the liquid foam mixture is provided in the hollow portion of the rotor blade;
adjusting a flow rate that the liquid foam mixture is provided in the hollow portion of the rotor blade;
tilting the rotor blade along an inboard-outboard axis as the liquid foam mixture is provided in the hollow portion of the rotor blade; and
tilting the rotor blade along a forward-aft axis during as the liquid foam mixture is provided in the hollow portion of the rotor blade.

4. The method of claim 3 , wherein tilting the rotor blade along the inboard-outboard axis includes tilting the outboard end of the rotor blade downward between 15 degrees and 75 degrees.

5. The method of claim 3 , wherein tilting the rotor blade along the forward-aft axis includes tilting a leading edge of the rotor blade downward between 15 degrees and 75 degrees.

6. The method of claim 3 , further comprising one of:
heating the liquid foam mixture; and
cooling the liquid foam mixture.

7. The method of claim 6 , wherein heating the liquid foam mixture includes heating the liquid foam mixture to a temperature greater than 100 degrees Fahrenheit.

8. The method of claim 6 , wherein cooling the liquid foam mixture includes cooling the liquid foam mixture to a temperature less than 70 degrees Fahrenheit.

9. The method of claim 1 , wherein the distance is one of a plurality of distances associated with the span of the rotor blade, and providing the liquid foam mixture further comprises:
providing the liquid foam mixture in the hollow portion between the outboard end and the inboard end of the rotor blade at each distance of the plurality of distances, wherein the position of the at least one nozzle at each distance is maintained for a period of time and wherein the period of time at each distance is the same or different.

10. The method of claim 1 , further comprising:
providing at least one opening for the hollow portion of the rotor blade to allow outgassing as the liquid foam mixture expands and becomes the solid foam material.

11. The method of claim 1 , wherein the solid foam material adheres to an upper skin of the rotor blade, a lower skin of the rotor blade, a spar of the rotor blade, and a trailing edge wedge of the rotor blade.

12. A method comprising:
providing a plurality of openings for a rotor blade, wherein the plurality of openings are positioned proximate to a hollow portion of the rotor blade, and the hollow portion of the rotor blade has a fixed volume between an outboard end and an inboard end of the rotor blade; and
providing a liquid foam mixture in the hollow portion of the rotor blade through at least one opening of the plurality of openings of the rotor blade, wherein the liquid foam mixture expands and becomes a solid foam material that fills the hollow portion of the rotor blade;
wherein the at least one opening of the plurality of openings has an inboard-outboard diameter and a forward-aft diameter, and the inboard-outboard diameter and the forward-aft diameter are different.

13. The method of claim 12 , wherein providing the liquid foam mixture in the hollow portion of the rotor blade further comprises:
pouring the liquid foam mixture into the hollow portion using at least one opening of the plurality of openings.

14. The method of claim 12 , wherein the liquid foam mixture is provided into the hollow portion of the rotor blade at a particular opening located at a distance that is based, at least in part, on a center of the fixed volume of the hollow portion rotor blade between the outboard end and the inboard end of the rotor blade.

15. The method of claim 12 , wherein the fixed volume of the rotor blade comprises a plurality of sub-volumes and the liquid foam mixture is provided into the hollow portion of the rotor blade at a plurality of openings, wherein each opening is located at a distance that is based, at least in part, on a center of each sub-volume.

16. The method of claim 12 , wherein providing the liquid foam mixture in the hollow portion further comprises at least one of:
tilting the rotor blade along an inboard-outboard axis as the liquid foam mixture is provided in the hollow portion of the rotor blade; and
tilting the rotor blade along a forward-aft axis during as the liquid foam mixture is provided in the hollow portion of the rotor blade.

17. The method of claim 12 , wherein providing the liquid foam mixture in the hollow portion further comprises:
injecting the liquid foam mixture through at least one opening of the plurality of openings using a foam delivery system, wherein the liquid foam mixture is injected through the at least one opening at one or more flow rates.

18. The method of claim 17 , wherein the at least one opening is located at one of:
an inboard end of the rotor blade;
an upper skin of the rotor blade;
a lower skin of the rotor blade; and
a trailing edge of the rotor blade.

19. The method of claim 17 , further comprising at least one of:
tilting the rotor blade along an inboard-outboard axis as the liquid foam mixture is injected; and
tilting the rotor blade along a forward-aft axis during as the liquid foam mixture is injected.

20. The method of claim 19 , further comprising one of:
heating the liquid foam mixture prior to the injecting; and
cooling the liquid foam mixture prior to the injecting.

21. The method of claim 12 , wherein providing at least one opening of the plurality of openings allows outgassing as the liquid foam mixture expands and becomes the solid foam material.

22. The method of claim 12 , wherein:
at least one opening is provided through a skin of the rotor blade; and
at least one opening is provided through a trailing edge of the rotor blade.

23. The method of claim 12 , further comprising:
sealing the plurality of openings of the rotor blade after the liquid foam mixture expands and becomes the solid foam material.

24. The method of claim 23 , wherein the plurality of openings are sealed using a composite material.

25. The method of claim 12 , wherein the hollow portion o

Assignees

• Bell Helicopter Textron Inc
• Textron Innovations Inc

Inventors

• Cordell James A
• Mishra Suvankar
• Haldeman Andrew Paul
• Wrabel Jesse J
• Hampton Dalton T

Classifications

• B29C44/18 Primary

  Filling preformed cavities {(B29C44/1204 takes precedence)} · CPC title

• B29C44/60

  Measuring, controlling or regulating · CPC title

• B29L2031/087

  Propellers · CPC title

• F05D2300/612

  Foam · CPC title

• B64C27/473

  Constructional features · CPC title