Propeller Blade Icephobic Coating Centrifugal Shedding

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Solution Overview

Problem

Existing aircraft propeller blade deicing systems, particularly electrical heater systems, are inefficient in power consumption and can be hazardous due to excessive heating and ice reformation, and are prone to damage, while also risking aerodynamic efficiency and fuselage safety from large ice shedding.

Innovation Solution

A propeller blade with an icephobic coating along its leading edge, extending from the radially inner to outer regions, utilizing materials like PTFE to reduce the cohesive bond strength between ice and blade, allowing ice to self-shed under centrifugal forces, thereby eliminating the need for electrical deicing and reducing system reliance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an electrical heater system is used to prevent ice accumulation on propeller blades, then ice buildup is controlled, but electrical power consumption increases significantly

Engineering Contradiction:

Improveice buildup controlVSAvoidelectrical power consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The propeller blade utilizes its own rotational motion to generate centrifugal forces that automatically shed ice accumulations. The rotation-driven centrifugal force eliminates the need for external electrical heating systems, allowing the blade to self-clear ice without additional power consumption from the aircraft's electrical system.

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The patent replaces the electrical heating system with a mechanically-driven ice shedding mechanism. Instead of using electrical energy to melt ice, the system uses the mechanical centrifugal force generated by propeller rotation to physically throw ice off the blade surface.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If electrical heaters are used excessively to remove ice, then ice is removed effectively, but melted ice runs back and reforms behind the deiced area creating hazardous conditions

Engineering Contradiction:

Improveice removal effectivenessVSAvoidice reformation hazard

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

Instead of heating the blade to melt ice and relying on drainage, the patent inverts the approach by using centrifugal force to directly eject ice accumulations from the blade surface. This prevents the melting and runback problem by mechanically throwing ice off the leading edge area where it forms.

Inventive Principle:

Principle #13The other way round (Inversion)

3Reliability

If electrical heating blankets extend to the propeller centrebody to effectively remove ice, then deicing coverage is improved, but aerodynamic interface with the nacelle is compromised

Engineering Contradiction:

Improvedeicing coverageVSAvoidaerodynamic interface

Core Design Contradiction:

ReliabilityVSShape

Solution Approach 1:

The patent extracts the heating elements from the propeller blade design, eliminating the need for heating blankets that would interfere with the aerodynamic interface between the blade and nacelle. The mechanical ice shedding mechanism requires no physical components on the blade surface, preserving clean aerodynamic contours.

Inventive Principle:

Principle #2Taking out (Extraction)

4Reliability

If a heater element is damaged in the electrical heating system, then the entire element stops functioning, but localized damage should ideally allow partial operation

Engineering Contradiction:

Improvesystem functionalityVSAvoidsystem failure impact

Core Design Contradiction:

ReliabilityVSEase of repair

Solution Approach 1:

The mechanical ice shedding function is distributed throughout the propeller blade structure through its rotation, rather than relying on a single centralized heating element. This segmentation means that no single point of failure can disable the entire ice protection function, as the centrifugal force is generated by the rotating blade as a whole.

Inventive Principle:

Principle #1Segmentation

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 icephobic coating effectively reduces ice buildup and shedding radius, conserves electrical power, enhances reliability and maintainability, and ensures safe ice shedding without damage to the deicing system, while being applicable to both new and existing blades.

Implementation Method 1

utilizing materials like PTFE to reduce the cohesive bond strength between ice and blade

Methodology Applied

Scientific EffectCohesive bond strength reduction: Cohesion

Implementation Method 2

a radially outer region located between the blade root and the blade tip at a position where rotational forces on the blade are sufficient, in use, to remove ice from an uncoated blade

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentUS8851858B2Propeller blades having icephobic coating

Publication Date: 2014.10.07 GE AVIATION SYST LTD

AI summary

A propeller blade for rotation about a hub assembly is provided, wherein the propeller blade defines a radial direction along its length from a blade root to a blade tip, the propeller blade comprising: a radially inner region; a radially outer region located between the blade root and the blade tip at a position where rotational forces on the blade are sufficient, in use, to remove ice from an uncoated blade; a coating disposed at least along a leading edge of the propeller blade, the coating comprising an icephobic material, wherein the coating extends along the propeller blade from the radially inner region to the radially outer region.