Adjustable Propeller Blade Treatments for Destructive Sound Interference

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Solution Overview

Problem

The increasing presence of aerial vehicles, particularly unmanned aerial vehicles, in residential areas poses a challenge in managing noise pollution due to their propellers, as existing technologies do not effectively control or alter the sound generated by these vehicles.

Innovation Solution

Propeller blades are treated with various designs and materials that disrupt airflow and absorb sound, allowing propellers to generate interfering sounds or dampen noise, and include active treatments that can be moved to further alter sound output based on measured noise levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If propeller blade treatments are added to disrupt airflow and absorb sound, then noise control is improved, but device complexity increases

Engineering Contradiction:
Improvenoise controlVSAvoiddevice complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent applies different treatments to different portions of the propeller blade surfaces. The leading edge receives a leading edge treatment with specific geometric features, while the trailing edge receives a trailing edge treatment with different features. This localized approach allows each region to address specific noise generation mechanisms, improving overall noise control without requiring complete redesign of the entire blade.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The noise control system is segmented into distinct treatments applied to different blade surfaces. The leading edge treatment and trailing edge treatment are separate components that can be independently designed and optimized. This segmentation allows for modular implementation and easier maintenance while achieving comprehensive noise reduction through combined effects.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If active treatments are added that can be moved to alter sound output, then noise control adaptability is improved, but device complexity increases

Engineering Contradiction:
Improvenoise control adaptabilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent incorporates movable elements in the trailing edge treatment that can change their configuration. These dynamic features allow the treatment to adapt its geometry based on operating conditions, enabling the propeller to optimize noise control performance across different flight regimes while maintaining the core functional design.

Inventive Principle:
Principle #15Dynamics

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 propeller blade treatments effectively reduce and alter the overall sound generated by aerial vehicles, providing noise control and minimizing disturbance to residents.

Implementation Method 1

the propellers may generate sounds that destructively interfere with each other, thereby reducing or altering the overall sound generated by the aerial vehicle

Methodology Applied
Scientific EffectDestructive interference: Interference

Implementation Method 2

The propeller blade treatments may disrupt the airflow around the propeller blades as they rotate and/or absorb sound generated by the propeller blade as it rotates

Methodology Applied
Scientific EffectSound absorption: Acoustic Absorption

Data Source

PatentEP3741664B1Propeller blade treatments for sound control
Publication Date: 2026.02.11 AMAZON TECH INC
  • EP3741664B1 patent drawingFigure 1
  • EP3741664B1 patent drawingFigure 2A~2B
  • EP3741664B1 patent drawingFigure 3A~3B

AI summary

Sounds are generated by an aerial vehicle during operation. For example, the motors and propellers of an aerial vehicle generate sounds during operation. Disclosed are systems, methods, and apparatus for actively adjusting the position of one or more propeller blade treatments of a propeller blade of an aerial vehicle during operation of the aerial vehicle. For example, the propeller blade may have one or more propeller blade treatments that may be adjusted between two or more positions. Based on the position of the propeller blade treatments, the airflow over the propeller is altered, thereby altering the sound generated by the propeller when rotating. By altering the propeller blade treatments on multiple propeller blades of the aerial vehicle, the different sounds generated by the different propeller blades may effectively cancel, reduce, and/or otherwise alter the total sound generated by the aerial vehicle.