Composite Propeller Hub Rotor Design for Weight Reduction
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Solution Overview
Problem
Conventional rotor designs for rotorcrafts face issues with weight reduction while maintaining structural integrity and efficiency, as they are prone to load-induced degradation, affecting reliability and maintainability.
Innovation Solution
A rotor design featuring a blade retention cuff, a titanium horseshoe-shaped yoke, and a graphite epoxy composite propeller hub, with pin-attached rotor blades that can fold and bearings to manage centrifugal forces, ensuring structural integrity and reduced weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional rotor designs are used, then structural integrity is maintained, but weight is excessive and drag is high
Solution Approach 1:
The patent applies composite materials throughout the rotor structure, including graphite epoxy composite for the hub, titanium for the yoke, and composite laminates for the blades. These materials provide high strength-to-weight ratios, enabling weight reduction while maintaining structural integrity under operational loads.
Solution Approach 2:
The patent changes the structural parameters by transitioning from conventional solid metal construction to composite materials with optimized fiber orientations. The composite laminates are designed with specific ply arrangements to achieve required strength properties while minimizing weight, representing a fundamental parameter change in the structural approach.
2Loss of energy
If conventional rotor designs are used, then structural integrity is maintained, but drag is high and efficiency is reduced
Solution Approach 1:
The patent employs thin-walled composite structures for the hub and blades, optimized to provide necessary strength while minimizing cross-sectional area and drag. The aerodynamic surfaces are designed with precise thickness distributions to reduce form drag while maintaining structural adequacy.
Solution Approach 2:
Composite materials enable streamlined, aerodynamically optimized shapes with high strength-to-weight ratios. The blade and hub geometries are tailored to minimize drag while the composite construction ensures structural integrity, achieving both low drag and high strength simultaneously.
3Productivity
If weight is reduced in rotor design, then efficiency improves, but reliability degrades due to load handling
Solution Approach 1:
The composite materials provide high specific strength and stiffness, enabling weight reduction while maintaining or improving load handling capability. The titanium yoke and composite hub are designed to distribute and manage operational loads effectively, ensuring reliability despite reduced weight.
Solution Approach 2:
The rotor structure employs local quality optimization where composite laminates are tailored with specific fiber orientations and thicknesses in different regions to handle local stress patterns. This ensures that each area of the structure has the precise properties needed for its loading conditions, maximizing both efficiency and reliability.
4Ease of repair
If conventional rotor designs are used, then reliability is maintained, but maintainability is reduced
Solution Approach 1:
The rotor is divided into discrete, modular components including separate blades, hub, and yoke assemblies. This segmentation enables individual components to be inspected, maintained, or replaced independently, improving maintainability while the overall design maintains reliability through proper load path management across component interfaces.
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 design achieves a lightweight rotor hub with enhanced reliability and maintainability, capable of withstanding operational loads and improving aircraft efficiency by distributing loads effectively within composite laminates.
Implementation Method 1
an inboard bearing is located in the interior of the yoke configured to restrain centrifugal force
Implementation Method 2
an outboard bearing comprising a radial element is configured to contact a top-side of the blade retention cuff when the rotor blade is subjected to an upward force
Data Source
AI summary
A rotor includes a blade retention cuff configured to receive a rotor blade; a yoke coupled to the blade retention cuff; and a rigid propeller shaped hub configured to enclose at least a portion of the blade retention cuff and at least a portion of the yoke.