Rotor Blade Tip Replacement With Bonded Modular Tip Sections

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Solution Overview

Problem

Conventional rotor blades experience significant structural degradation and are labor-intensive to maintain due to the complex geometry of their tip sections, which are subjected to high stresses and strains from aerodynamic forces, making replacement of the tip sections difficult and time-consuming.

Innovation Solution

A method involving the removal of the existing tip section, preparation of the rotor blade surface, and the use of a holding fixture and bonding fixture to cure a replacement tip section, which can be of similar or different shape, using heat and pressure to ensure a secure and aerodynamically optimal bond.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the tip section is designed with complex geometry (anhedral or non-straight form) to improve aerodynamic performance, then the blade performance is improved, but the structural degradation and wear occur more rapidly due to high stresses and strains

Engineering Contradiction:

Improveblade performanceVSAvoidstructural degradation

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The rotor blade is divided into separable sections: a main blade body and a replaceable tip section. The tip section can be removed and replaced independently when it experiences wear or degradation, while the main blade body remains intact. This segmentation allows the high-performance complex geometry to be maintained in the tip section while enabling its replacement without replacing the entire blade, thus resolving the contradiction between performance and reliability.

Inventive Principle:

Principle #1Segmentation

2Strength

If the tip section is integrally bonded to the blade during primary assembly with mechanical fasteners to create redundant joints, then the structural strength is improved, but the replacement of additional length of the tip becomes difficult and labor intensive

Engineering Contradiction:

Improvebonded joint strengthVSAvoidtip section replacement

Core Design Contradiction:

StrengthVSEase of repair

Solution Approach 1:

The blade is segmented into a main body and a tip section that can be separated. The tip section includes a tip core and tip skins that form a complete replaceable unit. This segmentation enables the tip section to be replaced as a single module without affecting the main blade structure, resolving the contradiction between maintaining strong bonds during operation and enabling easy replacement during maintenance.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The tip section is pre-assembled with its core and skins bonded together before installation on the main blade. This preliminary assembly creates a ready-to-install module that simplifies the replacement process, as the entire tip section can be removed and replaced as one unit rather than assembling multiple components during maintenance operations.

Inventive Principle:

Principle #10Preliminary action

3Productivity

If the tip section is replaced to extend the length of the blade, then the blade performance is improved, but the replacement process becomes relatively difficult and labor intensive due to complex geometry

Engineering Contradiction:

Improveblade performanceVSAvoidmaintenance time

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The blade is divided into a main body and a replaceable tip section with a standardized interface. This segmentation allows the tip section to be removed and replaced without complex disassembly of the entire blade structure, significantly reducing maintenance time and labor requirements while enabling performance improvements through tip section replacement or extension.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The tip section design with a standardized interface and modular construction makes it universally replaceable and adaptable. The same replacement procedure can be used for various tip section configurations, and the modular design allows for easy extension of blade length by adding longer tip sections, providing multi-functionality for both replacement and extension operations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This method allows for efficient replacement of rotor blade tip sections, improving aerodynamic performance and reducing maintenance time and complexity, enabling modifications to existing blades rather than requiring new fabrication.

Implementation Method 1

curing the replacement tip section includes applying heat to the replacement tip section

Methodology Applied

Scientific EffectHeat: Heating

Implementation Method 2

positioning a bonding fixture about the replacement tip section

Methodology Applied

Scientific EffectPressure: Pressure Increase

Data Source

PatentUS12129023B2Method of removal and replacement of a tip section of a rotor blade

Publication Date: 2024.10.29 SIKORSKY AIRCRAFT CORP

AI summary

A method of mounting a replacement tip section to an exposed end of a rotor blade includes removing an existing tip section from the rotor blade to create the exposed end of the rotor blade, installing the rotor blade having the exposed end onto a holding fixture, assembling the replacement tip section about the exposed end of the rotor blade, positioning a bonding fixture about the replacement tip section, and curing the replacement tip section to the exposed end of the rotor blade.