Multiple-Yoke Main Rotor Assembly for Load Distribution
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Solution Overview
Problem
Existing rotor assemblies for rotary-wing aircraft lack the capability to efficiently distribute load and provide independent flapping and relative motion between rotors, limiting their performance in terms of thrust, speed, and load-carrying capacity.
Innovation Solution
A multiple-yoke main rotor assembly with teetering or gimbaled configurations, where each yoke is connected to the rotor mast with a unique flap axis, allowing for independent flapping and relative lead/lag motion between rotors, thereby distributing load effectively and enhancing thrust generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single-yoke rotor assembly is used, then the structure is simple, but the load distribution and thrust generation capability are limited
Solution Approach 1:
The rotor assembly is segmented into multiple independent yokes (first yoke and second yoke), each capable of independent flapping motion. This segmentation allows the rotor to distribute load across multiple blades more effectively and generate greater total thrust, directly resolving the contradiction between thrust capability and structural simplicity.
Solution Approach 2:
The patent introduces a new degree of freedom by allowing the first and second yokes to flap independently about separate flap axes. This multi-dimensional motion capability enables complex load distribution patterns and improved aerodynamic efficiency, enhancing thrust generation without requiring a fundamentally different structural approach.
2Adaptability or versatility
If rotors are connected rigidly, then the structure is stable, but independent flapping and lead/lag motion are restricted
Solution Approach 1:
The connection between the first and second yokes is made dynamic rather than rigid, allowing relative motion in multiple directions (flapping, lead/lag). This dynamic connection maintains stability during normal operation while enabling the adaptability needed for independent blade motion and load distribution, resolving the contradiction between stability and versatility.
Solution Approach 2:
By segmenting the rotor into independently connected yokes, each yoke can flap and move relative to the other about their respective flap axes. This segmentation provides the adaptability for independent motion while the overall rotor assembly maintains structural integrity through the connected yoke system.
3Quantity of substance
If load is concentrated on individual blades, then the blade structure is simpler, but the overall load-carrying capacity is reduced
Solution Approach 1:
The rotor assembly is divided into multiple yokes with multiple blades each, creating a segmented load distribution system. This segmentation allows loads to be distributed across more blades and yokes simultaneously, increasing the overall load-carrying capacity without requiring excessively complex individual blade structures.
Solution Approach 2:
The multiple-yoke configuration enables the rotor to utilize more blades than a single-yoke design, distributing the total load across a greater number of lifting surfaces. This partial action approach (using multiple yokes instead of one) achieves higher load capacity while keeping individual blade designs relatively simple.
Data Source
AI summary
The present application includes a main rotor assembly for an aircraft. The rotor assembly has a main rotor mast configured for rotation about a mast axis and two yokes pivotally connected to the mast for rotation therewith about the mast axis. Each yoke is independently pivotable relative to the mast about at least one flap axis that is generally perpendicular to the mast axis. In at least one embodiment, a torque splitter connects the yokes and allows for limited rotation of the yokes relative to each other about the mast axis. Each yoke is configured for the attachment of rotor blades extending generally radially relative to the mast axis.