Helicopter Rotor Blade Balancing via Density Scanning

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Solution Overview

Problem

Current methods for balancing helicopter rotor blades are inefficient, particularly in determining chord-wise balance, requiring extensive static and dynamic testing, and are challenging when dealing with composite materials used in modern rotor blades, which are difficult to repair and maintain.

Innovation Solution

The method involves scanning rotor blades using computer densitometry or CT systems to acquire density data, processing it to create a relative density distribution model, merging it with weight data to predict a desired weight distribution, and using dynamic models to simulate and adjust the balance, potentially reducing the need for multiple flight tests.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If static testing is used to determine rotor blade balance, then span-wise balance can be measured, but chord-wise balance determination is ineffective and time-consuming

Engineering Contradiction:
Improvechord-wise balance measurementVSAvoidtesting time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces traditional mechanical static testing methods with a computational approach. A computer model simulates the rotor blade's dynamic behavior during rotation, allowing prediction of chord-wise balance characteristics without physical testing. The model uses blade geometry, material properties, and weight distribution data to calculate balance parameters, eliminating the need for time-consuming static tests while providing accurate measurements.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If dynamic testing with multiple flight tests is performed to adjust chord-wise balance, then accurate balance can be achieved, but the process requires extensive time and resources

Engineering Contradiction:
Improvechord-wise balance measurementVSAvoidbalancing efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The patent performs preliminary computational analysis before actual flight testing. The computer model predicts the optimal weight distribution and balance characteristics in advance, allowing engineers to pre-determine the necessary adjustments. This preliminary action reduces the number of iterative flight tests needed, as the initial configuration is already optimized based on simulation results, thereby improving productivity while maintaining measurement precision.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If traditional testing methods are used for repaired composite rotor blades, then balance can be assessed, but the process is extremely time-consuming and complex

Engineering Contradiction:
Improvebalance assessment accuracyVSAvoidrepair evaluation time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces complex mechanical testing procedures with a computational evaluation system. After repair, the computer model incorporates the modified blade geometry and material properties to simulate balance characteristics. This substitution provides reliable assessment of repaired blades without requiring extensive physical testing, significantly reducing the time needed for repair evaluation while maintaining accuracy through sophisticated modeling of the repaired structure's mechanical behavior.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 approach allows for more precise and efficient balancing of rotor blades, reducing the time and effort required for chord-wise balance adjustments and improving the handling of composite materials, potentially leading to improved flight performance and reduced maintenance costs.

Implementation Method 1

scanning by a scanner the rotor blade to acquire the density data

Methodology Applied
Scientific EffectComputer densitometry:

Implementation Method 2

scanning by a scanner the rotor blade to acquire the density data

Methodology Applied
Scientific EffectComputer tomography: Tomography

Data Source

PatentEP2612812B1Methods and systems for helicopter rotor blade balancing
Publication Date: 2019.07.10 THE BOEING CO
  • EP2612812B1 patent drawingFigure 1~2
  • EP2612812B1 patent drawingFigure 3

AI summary

Methods and systems for balancing helicopter rotor blades are disclosed. In some examples, density data of a rotor blade may be acquired by scanning the rotor blade. In some examples, a three-dimensional model of a rotor blade may be merged with density data of the rotor blade. In some examples, simulations may be performed to predict flight data associated with a modeled rotor blade. In some examples, a database may be referenced to predict a desired weight balance of a rotor blade.