Rotor Blade Dynamic Mass Adjustment System
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Solution Overview
Problem
The manufacturing and assembly of rotor blades for aircraft introduce variations in weight and weight distribution, leading to potential out-of-balance conditions that are costly to correct and may result in scrapping of assemblies, limiting the severity of balance corrections.
Innovation Solution
A rotor blade assembly with a weighted assembly that includes an actuator to adjust the moment of the blade by moving mass along the chordwise or spanwise direction, allowing for dynamic balancing both statically and during rotation, using a biasing mechanism to counteract centrifugal forces and receiving commands from a flight control computer to optimize balance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If material removal or counterweight adjustment is used to correct balance variations, then balance precision is improved, but device complexity and cost increase due to severe out-of-balance conditions requiring scrapping of rotor blade assemblies
Solution Approach 1:
The patent applies the dynamics principle by replacing static counterweights with a dynamic mass adjustment system. The system includes an actuator that can move a mass along the rotor blade spanwise direction, allowing the balance configuration to be dynamically adjusted. This enables continuous balance correction without requiring multiple discrete counterweight positions or complex mechanical linkages, thereby improving balance precision while maintaining relatively simple device structure.
Solution Approach 2:
The patent applies parameter changes by varying the position of the adjustable mass along the rotor blade to change the moment of inertia distribution. By moving the mass to different spanwise positions, the system can continuously adjust the balance parameters to compensate for manufacturing variations, achieving precise balance correction without requiring severe material removal or complex counterweight assemblies.
2Manufacturing precision
If severe out-of-balance conditions are corrected by removing material or counterweights, then balance is improved, but productivity decreases due to potential scrapping of costly rotor blade assemblies
Solution Approach 1:
The dynamic mass adjustment system allows balance correction without permanent material removal. The actuator can reposition the mass to compensate for balance variations, enabling correction of severe out-of-balance conditions while preserving the rotor blade assembly. This eliminates the need to scrap assemblies that would otherwise require extensive material removal, thereby improving productivity.
Solution Approach 2:
The system enables self-service balance correction by providing an adjustable mass that can be repositioned to compensate for manufacturing variations. This self-adjusting capability allows the rotor blade assembly to achieve proper balance without requiring external intervention through material removal or counterweight installation, reducing production time and preventing scrapping of assemblies.
3Manufacturing precision
If static balancing is performed during manufacture, then initial balance is improved, but dynamic instabilities during flight cannot be addressed
Solution Approach 1:
The patent implements a dynamic balance system that can adjust the mass position during flight to address dynamic instabilities. The actuator can reposition the mass in response to detected vibrations or balance issues, allowing the system to maintain optimal balance under varying flight conditions. This dynamic capability complements the static balancing performed during manufacture, ensuring both initial balance and ongoing dynamic stability.
Solution Approach 2:
The system incorporates feedback mechanisms that can detect dynamic instabilities during flight and trigger mass repositioning to correct the issue. Sensors monitor vibration levels and balance conditions, providing feedback to the control system, which then adjusts the mass position via the actuator to eliminate detected instabilities, thereby maintaining reliability throughout the rotor blade's operational life.
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
This solution enables precise balancing of rotor blades, reducing the need for costly dynamic balancing procedures and eliminating the requirement for weight cups, while addressing dynamic instabilities during flight and the lifetime of the rotor blade assembly.
Implementation Method 1
using a biasing mechanism to counteract centrifugal forces
Implementation Method 2
the biasing mechanism is positioned to counteract a centrifugal force acting on the mass when the rotor blade is rotated about the axis of rotation
Data Source
AI summary
An aircraft rotor blade assembly includes a rotor blade rotatable about an axis of rotation and a weighted assembly mounted to the aircraft rotor blade. The weighted assembly includes an actuator which moves a mass to adjust a moment of the rotor blade assembly when the rotor blade is rotated about the axis of rotation.