Rotor Blade Collective Alignment Ground Test

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Solution Overview

Problem

Conventional methods for evaluating the alignment of rotary aircraft rotor blades require expensive, time-consuming special flight tests, which are complex and dependent on ambient air conditions and pilot skill, making them inefficient and unsafe.

Innovation Solution

A system and method using a processor and memory-based device to evaluate the collective alignment of rotor blades on the ground by measuring engine torque and air density altitude, comparing torque values to predetermined limits, and providing an indication of the alignment condition, eliminating the need for auto-rotative flight tests.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If special flight tests are conducted to evaluate rotor blade alignment, then measurement accuracy is improved, but loss of time and cost increase significantly

Engineering Contradiction:
Improverotor blade alignment measurementVSAvoidtest duration
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces the mechanical flight test system with a ground-based measurement system using sensors and processors to evaluate rotor blade alignment through vibration analysis and operational data, eliminating the need for time-consuming flight tests while maintaining measurement accuracy

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

Solution Approach 2:

The system performs preliminary alignment evaluation on the ground before flight using torque and vibration measurements during normal operations, allowing alignment assessment to be conducted in advance rather than requiring dedicated flight test time

Inventive Principle:
Principle #10Preliminary action

2Measurement precision

If special flight tests are conducted to evaluate rotor blade alignment, then measurement accuracy is improved, but device complexity and pilot skill requirements increase

Engineering Contradiction:
Improverotor blade alignment measurementVSAvoidtest system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The system uses the aircraft's own operational characteristics (vibrations, torque, operational parameters) during normal ground operations to perform self-diagnosis of rotor blade alignment, eliminating the need for complex external test equipment and specialized pilot procedures

Inventive Principle:
Principle #25Self-service

3Reliability

If special flight tests are conducted to evaluate rotor blade alignment, then reliability of alignment assessment is improved, but safety risks increase due to dependency on ambient air conditions

Engineering Contradiction:
Improvealignment assessment reliabilityVSAvoidambient air condition dependency
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent extracts the alignment measurement process from the flight environment and relocates it to ground-based operations, removing the harmful dependency on ambient air conditions, turbulence, and other flight-related variables that compromise test reliability

Inventive Principle:
Principle #2Taking out (Extraction)

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

Enables efficient and reliable evaluation of rotor blade alignment without the need for special flight tests, reducing costs and improving safety by providing a ground-based solution for assessing blade alignment, thus ensuring proper aircraft performance.

Implementation Method 1

determine an air density altitude based on a location of the aircraft

Methodology Applied
Scientific EffectAtmospheric pressure measurement: Pressure Gradient

Implementation Method 2

determine a torque value for each engine of the aircraft

Methodology Applied
Scientific EffectTorque measurement: Torque

Data Source

PatentEP3584159B1Determining rotorcraft collective adjustment during ground test
Publication Date: 2023.01.25 SIMMONDS PRECISION PRODUCTS INC
  • EP3584159B1 patent drawingFigure 1
  • EP3584159B1 patent drawingFigure 2
  • EP3584159B1 patent drawingFigure 3

AI summary

A method for evaluating a collective alignment of rotor blades (215) for an aircraft while the aircraft is on the ground is disclosed. The method includes evaluating a collective condition for an aircraft, via an auto-rotative test flight and d etermining a first engine torque value for the aircraft while the aircraft is on the ground and the aircraft rotor blades are at a normal speed. The method further includes associating the first engine torque value with the collective condition; determining a second engine torque value for the aircraft while the aircraft is on the ground and the aircraft rotor blades are operated at a normal speed; and providing an indication of the collective condition if the second engine torque value is within a tolerance limit of the first torque value.