Fibre-Reinforced Tension-Torque-Transmission Element for Fenestron Blades
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Solution Overview
Problem
Existing tension-torque-transmission elements for rotor blades in helicopters, particularly those made of metal, have a short service life and lack damage tolerance, making them impractical for use in rotary wing aircraft.
Innovation Solution
A tension-torque-transmission element is designed in a fibre-reinforced composite material with layered flat fibre layers, featuring a rectangular cross-section and connecting eyes for optimal load distribution, allowing for separate production and installation, which reduces weight, production, and maintenance efforts while ensuring long service life and damage tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metal is used for tension-torque-transmission elements, then load resistance is improved, but weight increases and service life decreases
Solution Approach 1:
The patent applies composite materials consisting of multiple fibre layers (unidirectional and multiaxial fibres) combined with a plastic matrix to create a tension-torque-transmission element that achieves both high load resistance and long service life. The composite structure provides damage tolerance and resistance to fatigue cracking, resolving the contradiction between strength and service life while maintaining acceptable weight.
2Strength
If metal tension-torque-transmission elements are used, then load resistance is improved, but weight increases
Solution Approach 1:
The composite material construction using fibre-reinforced plastic provides high strength-to-weight ratio, achieving the required load resistance with significantly reduced weight compared to metal equivalents.
Solution Approach 2:
The transmission element is divided into multiple discrete fibre layers with specific orientations (0°, ±45°, 90°) that are separately placed and cured. This segmentation allows optimization of each layer for specific load directions, achieving high strength with minimal material usage and reduced weight.
3Device complexity
If integrated design of tension-torque-transmission element in rotor blade is used, then structural complexity is reduced, but production and maintenance effort increases
Solution Approach 1:
The tension-torque-transmission element is designed as a separate, modular component that can be manufactured independently from the rotor blade. This segmentation simplifies production by allowing specialized manufacturing processes for the transmission element itself, while also enabling easier inspection and maintenance without disassembling the entire rotor blade assembly.
4Ease of manufacture
If separate production of tension-torque-transmission element is used, then production effort is reduced, but manufacturing precision requirements increase
Solution Approach 1:
By producing the transmission element as a separate modular component, the patent enables specialized manufacturing processes that can achieve high precision in the transmission element itself, while the overall assembly process remains simple. The element can be manufactured with precise fibre placement and curing, then easily installed into the rotor blade.
Data Source
AI summary
A tension-torque-transmission element (3; 3′; 4) for a rotor blade of a rotary wing aircraft (helicopter), in particular for a fenestron blade of a tail rotor, with a connecting section on the blade side and a connecting section (30; 30′; 40) on the axis side, with a connecting eye (32) on each connecting section, and with a torque-transmission section (34; 34′; 44) that connects the connecting sections (30; 30′; 40), is improved in that the tension-torque-transmission element (3; 3′; 4) is designed in a fiber-reinforced composite design including several layers (A to G) of a textile fabric. A method for producing such a tension-torque-transmission element (3; 3′; 4) is also described.