Propeller Blade Retaining Structure for Uncontained Debris

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Solution Overview

Problem

Aircraft turbomachines face the risk of uncontained engine rotor failure (UERF) due to propeller blade fractures, which can damage adjacent turbomachines and the fuselage, necessitating costly and mass-intensive solutions like anti-debris shields or elongating the tail cone.

Innovation Solution

Integration of a radial blade retaining structure within the propeller, which extends around the rotation axis and includes an abutment to retain blade debris, eliminating the need for additional shields or tail cone elongation by containing debris radially.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If anti-debris shields are integrated into the fuselage to prevent blade debris damage, then safety against uncontained engine rotor failure is improved, but mass and cost increase

Engineering Contradiction:

Improvesafety against blade debris damageVSAvoidmass of fuselage

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The invention extracts the blade retention function from the fuselage structure and relocates it to the propeller blades themselves through integrated retaining structures. This removes the need for separate anti-debris shields in the fuselage, thereby reducing fuselage mass while maintaining safety against uncontained rotor failure.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The retaining structures are nested within the blade assembly, with retention features integrated into the blade root and hub structure. This nested arrangement allows the retention system to be contained within the existing propeller geometry, eliminating the need for external fuselage-mounted shields.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If anti-debris shields are integrated into the fuselage to prevent blade debris damage, then safety against uncontained engine rotor failure is improved, but manufacturing cost increases

Engineering Contradiction:

Improvesafety against blade debris damageVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The retaining structures are merged with the existing blade and hub components, combining multiple functions (blade attachment, structural support, and debris retention) into integrated assemblies. This reduces the total number of separate components and assembly operations, thereby lowering manufacturing cost.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If the tail cone is elongated to move turbomachines aft of the pressurized compartment, then safety against blade debris damage to the fuselage is improved, but mass and cost increase

Engineering Contradiction:

Improvesafety against blade debris damageVSAvoidmass of aircraft

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The invention extracts the blade retention function from the aircraft airframe structure and relocates it to the propeller blades themselves. This allows the turbomachines to remain in their optimal aerodynamic positions without requiring tail cone elongation, thereby maintaining aircraft mass efficiency while ensuring safety against uncontained rotor failure.

Inventive Principle:

Principle #2Taking out (Extraction)

4Weight of moving object

If a radial blade retaining structure is integrated into the propeller, then mass and cost penalties are reduced, but device complexity increases

Engineering Contradiction:

Improvemass of propeller assemblyVSAvoidcomplexity of blade retention system

Core Design Contradiction:

Weight of moving objectVSDevice complexity

Solution Approach 1:

The invention applies retention features locally at critical locations within the blade assembly (blade roots, hub, and retaining rings) rather than requiring a comprehensive fuselage-wide shield system. This localized approach reduces overall system mass while the modular nature of the retaining features keeps complexity manageable through standardization.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

Instead of containing debris externally through fuselage shields, the invention inverts the approach by implementing retention features within the blade assembly itself that actively prevent debris ejection. This internal retention strategy reduces the need for heavy external protective structures.

Inventive Principle:

Principle #13The other way round (Inversion)

Data Source

PatentUS9902501B2Propeller for an aircraft turbomachine, including a blade retaining structure through which the aerodynamic part of each blade passes

Publication Date: 2018.02.27 AIRBUS OPERATIONS (SAS)

AI summary

A propeller for a turbomachine intended to be driven in rotation about a propeller rotation axis and including variable pitch blades. The propeller further includes a structure for radial retention of the blades in the event of them breaking. The retaining structure extends around the propeller rotation axis and has the aerodynamic part of each blade of the propeller pass through it. Moreover, each aerodynamic part is equipped with an abutment configured to be retained radially by the retaining structure in the event of a blade fracture causing a fracture in the aerodynamic part radially inside the abutment.