Propeller Blade Angle Feedback Shielding Against Magnetism

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing propeller blade angle feedback systems are vulnerable to magnetism and arc issues, particularly during lightning strikes, leading to inaccurate measurements due to magnetization and electrical conductivity, which affects the reliability and precision of propeller control.

Innovation Solution

Implementing a non-conductive material for the propeller rods and feedback ring components, or using insulating layers and high magnetic permeability materials to shield the feedback ring from magnetism and electrical conductivity, thereby preventing false triggering of sensors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a phonic wheel (beta ring) is used for propeller blade angle feedback, then blade angle measurement is enabled, but the system becomes vulnerable to magnetism and arc interference leading to inaccurate measurements

Engineering Contradiction:

Improveblade angle measurement accuracyVSAvoidfeedback system reliability

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

The patent introduces a non-conductive feedback ring as an intermediary component that replaces the traditional conductive phonic wheel. This non-conductive ring acts as a mediator between the propeller blades and the sensor system, preventing direct electrical contact and thus eliminating arc formation and magnetic interference while still enabling optical or electromagnetic detection of blade angle position

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the traditional mechanical/electrical phonic wheel system with a non-conductive feedback ring system that uses optical or electromagnetic sensing instead of direct electrical contact. This substitution eliminates the harmful electrical conductivity and magnetic susceptibility of the original mechanical system while preserving the measurement function

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If conductive materials are used for feedback ring components, then electrical conductivity is maintained, but magnetism and arc issues occur during lightning strikes

Engineering Contradiction:

Improveprotection against lightning strikeVSAvoidmagnetism and arc interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The non-conductive feedback ring serves as an intermediary barrier that prevents lightning-induced electrical currents and magnetic fields from directly affecting the sensor system. This intermediary layer blocks the transmission of harmful electrical and magnetic energy while allowing the feedback function to continue operating

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent converts the harmful effect of electrical conductivity into a beneficial property by using non-conductive materials that naturally resist electrical current and magnetic interference. The material property that would normally be considered a disadvantage (non-conductivity) is transformed into a protective feature that prevents lightning strike damage and arc formation

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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

Enhances the reliability and accuracy of propeller blade angle measurements by preventing magnetism and arc-related interference, ensuring precise control of propeller operations.

Implementation Method 1

feedback ring (204) made from a non-conductive material to electrically isolate the position markers (202) from the feedback rods (306)

Methodology Applied

Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 2

at least one shielding element positioned between the propeller and the feedback ring to reduce or remove the electrical conductive path

Methodology Applied

Scientific EffectMagnetic shielding: Magnetic Field

Data Source

PatentEP4039584B1Propeller blade angle feedback arrangement and method

Publication Date: 2025.10.08 PRATT & WHITNEY CANADA CORP

Figure 1
Figure 2
Figure 3

AI summary

A blade angle feedback ring assembly (200) for an aircraft propeller rotatable about a longitudinal axis (A) and having an adjustable blade angle is provided. A feedback ring (204) is coupled to the propeller to rotate therewith and to move along a longitudinal axis (A) with adjustment of the blade angle. A plurality of rods are coupled to the feedback ring (204) and extend along a direction substantially parallel to the longitudinal axis (A), the rods configured to support the feedback ring (204) for longitudinal sliding movement along the longitudinal axis (A) with adjustment of the blade angle. At least one shielding element is provided between the feedback ring (204) and the propeller for shielding the feedback ring (204) from electromagnetism.