3D-Woven Hollow Composite Propeller Root for Variable Pitch Loads

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Solution Overview

Problem

Existing propeller blades or airfoils for turboprops face challenges in achieving a compact, lightweight design with sufficient mechanical strength to withstand various loads, particularly those involving centrifugal forces and integration with metal shells, while also accommodating variable pitch systems.

Innovation Solution

A manufacturing method for composite material propeller blades or airfoils involves 3D weaving a fibrous blank with a bulb-shaped root portion and an aerodynamic profile, incorporating an unlinked area for a bulb-shaped root preform, and densifying it with a matrix to create a compact, axisymmetrical root that integrates well with propeller rotation systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metallic material is used for propeller blades or airfoils, then mechanical strength is improved, but mass increases

Engineering Contradiction:

Improvemechanical strengthVSAvoidmass

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The patent applies composite materials consisting of fibrous reinforcement (carbon fibers, glass fibers, or aramid fibers) densified by a matrix (polymer, metal, or ceramic) to create propeller blades that are lighter than metallic materials while maintaining sufficient mechanical strength through the synergistic combination of fiber and matrix properties

Inventive Principle:

Principle #40Composite materials

2Adaptability or versatility

If root bulk is reduced for compact integration, then adaptability to variable pitch systems is improved, but manufacturing difficulty increases

Engineering Contradiction:

Improveadaptability to variable pitch systemsVSAvoidmanufacturing difficulty

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The root is segmented into functional zones with different fibrous reinforcement orientations: circumferential fibers for compression resistance, longitudinal fibers for traction and bending, and radial fibers for shear loads. This segmentation allows each zone to be optimized for its specific mechanical function while maintaining overall compactness

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the root are assigned different fibrous reinforcement configurations tailored to their specific load requirements. The circumferential direction uses fibers oriented for compression, the longitudinal direction uses fibers for tension and bending, creating local quality variations that optimize both compactness and structural performance

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If axisymmetrical root shape is adopted for compact integration, then adaptability to rotation systems is improved, but manufacturing precision requirements increase

Engineering Contradiction:

Improveintegration with rotation systemsVSAvoidmanufacturing precision

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

While the overall root shape is axisymmetrical for rotation system integration, the internal fibrous reinforcement structure employs asymmetric orientations in different zones. The circumferential, longitudinal, and radial fiber arrangements create an asymmetric internal architecture that provides the necessary mechanical properties while maintaining external rotational symmetry

Inventive Principle:

Principle #4Asymmetry

4Strength

If additional circumferential compression loads are introduced through metal shell integration, then structural strength is improved, but stress resistance requirements increase

Engineering Contradiction:

Improvestructural strengthVSAvoidstress resistance

Core Design Contradiction:

StrengthVSStress or pressure

Solution Approach 1:

The fibrous reinforcement is pre-configured during manufacturing with circumferential fiber orientations and a bulbous geometry that anticipates and prepares the structure to withstand subsequent circumferential compression loads from metal shell integration, distributing stresses before they are fully applied during operation

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method produces a propeller blade or airfoil with enhanced mechanical strength in traction, bending, and circumferential compression, suitable for integration into variable pitch systems, while maintaining a compact and lightweight design.

Implementation Method 1

producing a one-piece fibrous blank by three-dimensional weaving

Methodology Applied

Scientific EffectThree-dimensional weaving:

Implementation Method 2

densifying the preform with a matrix for obtaining a propeller blade or airfoil, of composite material

Methodology Applied

Scientific EffectDensification:

Data Source

PatentUS12485627B2Propeller blade or airfoil with hollow composite root

Publication Date: 2025.12.02 SAFRAN SA

AI summary

A propeller blade or airfoil of a turboprop of composite material includes a fibrous reinforcement densified by a matrix, the propeller blade or airfoil including, in a span direction, a root and an aerodynamic profile. The fibrous reinforcement includes a fibrous preform having a three-dimensional weave with a root preform portion present in the root and an aerodynamic preform portion present in the aerodynamic profile, the root and aerodynamic preform portions being linked to one another by the three-dimensional weave. The root preform portion of the fibrous preform includes an unlinked area delimiting an internal root recess forming a cavity opening at a free end of the root.