# US 2013/0280084 A1 · Propeller blade with internal stiffener

> Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt

- Number: US 2013/0280084 A1
- Document ID: US20130280084A1
- Status: Published application
- Kind: A1
- Application number: 13/449,902
- Filed: 2012-04-18
- Published: 2013-10-24
- Earliest claimed: 2012-04-18
- Assignees: Hamilton Sundstrand Corporation
- Inventors: David P. Nagle; Paul A. Carvalho
- Web page: https://patentgrep.com/patent/US20130280084A1

## CPC

- B64C 11/26: Fabricated blades
- Y10T 29/49332: Propeller making
- B64C: AEROPLANES; HELICOPTERS
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

A propeller blade includes a foam core having a slot formed through it from a camber side to a face side, an internal stiffener disposed through the slot and including flanges in contact with both the camber and face sides and a structural layer that surrounds at least a portion of the foam core and in contact with the flanges on both the camber and face sides.

## Claims

### Claim 1

A propeller blade comprising:
a foam core having a slot formed through it from a camber side to a face side;
an internal stiffener disposed through the slot and including flanges in contact with both the camber and face sides; and
a structural layer that surrounds at least a portion of the foam core and in contact with the flanges on both the camber and face sides.

### Claim 2 (depends on 1)

The propeller blade of claim 1, wherein the foam core includes recesses formed therein.

### Claim 3 (depends on 2)

The propeller blade of claim 2, wherein the flanges are disposed at least partially within the recesses.

### Claim 4 (depends on 1)

The propeller blade of claim 1, wherein the flanges of the internal stiffener and the structural layer both include a resin disposed in and between them.

### Claim 5 (depends on 1)

The propeller blade of claim 1, wherein the internal stiffener is formed of one of: carbon cloth, fiberglass, aramid cloth or a combination thereof.

### Claim 6 (depends on 1)

The propeller blade of claim 1, further comprising:
one or more layers of fiberglass or carbon at least partially disposed between the foam core and the structural layer.

### Claim 7 (depends on 6)

The propeller blade of claim 6, wherein the fiberglass is disposed in one of the recesses between the foam core and at least one the flanges.

### Claim 8 (depends on 1)

The propeller blade of claim 1, further comprising:
a root disposed within the structural layer at an end of the propeller blade.

### Claim 9 (depends on 1)

The propeller blade of claim 1, wherein the foam core is formed of one or more of: polyurethane (PU), polyisocyanurate, and polymethacrylimide (PMI).

### Claim 10 (depends on 1)

The propeller blade of claim 1, wherein the structural layer is formed of a resin-impregnated fiber material.

### Claim 11

A method of forming a propeller blade comprising:
providing a mold;
forming a foam core in the mold that includes a face side and a camber side;
forming a slot through the foam core that connects the face side and the camber side;
placing an internal stiffener through the hole;
folding the internal stiffener such that it includes at face flange that contacts the face side of the foam core and a camber flange that contacts the camber side of the foam core; and
forming a structural layer that surrounds the foam core and contacts face and camber flanges.

### Claim 12 (depends on 11)

The method of claim 11, further comprising:
injecting a resin into the structural layer, the face flange and the camber flange.

### Claim 13 (depends on 11)

The method of claim 11, further comprising:
placing peel plies in the mold;
wherein the foam core is formed by providing a foam into the mold after the peel plies have been placed in the mold.

### Claim 14 (depends on 13)

The method of claim 13, further comprising:
removing the peel plies to form recesses in the mold on the face side and the camber side.

### Claim 15 (depends on 14)

The method of claim 14, wherein face flange is folded into the recess on the face side and the camber flange is folded into the recess on the camber side.