Dual-Plane Rotor Mast Attenuator for Helicopter Vibration Control
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Solution Overview
Problem
Rotary-wing aircraft experience vibrations due to rotor operations, which are difficult to predict and can reduce component lifespan and passenger comfort, with existing vibration attenuation systems adding significant mass and lacking active control capabilities.
Innovation Solution
A mast- or hub-mounted vibration attenuator using dual-plane, spool-shaped spinners with eccentric weights that rotate relative to the rotor mast, capable of passive or active configuration to minimize shear forces and generate opposing moments, reducing vibrations with reduced mass and enhanced control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If conventional vibration attenuation systems are used, then vibrations are reduced, but the mass of the system increases significantly
Solution Approach 1:
The vibration attenuation system is divided into multiple independent spinners (first and second spinners) that can be positioned at different locations along the rotor mast. Each spinner can independently generate counter-moments, allowing the system to achieve effective vibration reduction with smaller, distributed mass rather than a single large mass, thereby reducing the overall mass penalty.
Solution Approach 2:
The patent transitions from conventional single-plane vibration attenuation to dual-plane attenuation by positioning spinners at different locations along the rotor mast axis. This spatial distribution in the axial dimension allows each spinner to target specific vibration frequencies and modes more effectively, improving vibration reduction efficiency per unit mass.
2Object-affected harmful factors
If conventional vibration attenuation systems are used, then vibrations are reduced, but active control capabilities are lacking
Solution Approach 1:
The spinners are designed with adjustable rotational speeds that can be dynamically controlled to match different rotor operating conditions. The system can adapt to varying vibration frequencies and modes by adjusting the spinner speeds, providing active control capability that was missing in conventional passive vibration attenuation systems.
Solution Approach 2:
The system incorporates sensors that detect vibration levels and feed this information back to the control system, which then adjusts the spinner rotational speeds accordingly. This closed-loop feedback mechanism enables active control and adaptation to changing flight conditions, allowing the system to optimize vibration reduction performance in real-time.
3Reliability
If vibration attenuation systems are added to reduce vibrations, then component lifespan is extended, but device complexity increases
Solution Approach 1:
The vibration attenuation system is integrated with the existing rotor mast structure, combining the attenuation function with the support structure. The spinners are mounted on the rotor mast and utilize its structural integrity, thereby avoiding the need for separate mounting structures and reducing overall system complexity while still achieving vibration reduction and extended component lifespan.
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 solution effectively reduces vibrations by generating a whirling moment that opposes rotor-induced moments, minimizing shear forces and extending component lifespan while maintaining reduced mass and offering active control options for optimized performance.
Implementation Method 1
The spinners are configured to generate a whirling moment that opposes a moment created during operation of an aircraft rotor
Implementation Method 2
dual-plane, spool-shaped spinners with eccentric weights that rotate relative to the rotor mast
Implementation Method 3
The spinners rotate relative to the rotor and are positionable to configurations between and including a minimum-moment configuration, which produces a small moment or no moment, and a maximum-moment configuration
Data Source
AI summary
A vibration attenuator is configured for use on an aircraft rotor rotatable about a mast axis and has upper and lower weight assemblies, each comprising a weight with a center of gravity being a radial distance from the mast axis. The weight assemblies are configured for rotation together relative to the rotor at a selected angular rate about the mast axis, the weights being located on opposing sides of the mast axis. A first motor is configured for selective translation of one of the weight assemblies relative to the other weight assembly along the mast axis between a minimum-moment configuration, in which the centers of gravity of the weights revolve about the mast axis in the same plane, and a maximum-moment configuration, in which the centers of gravity of the weights revolve about the mast axis in different planes for producing a whirling moment about the mast axis.