Composite Helicopter Tail Boom Attachment Ring

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Solution Overview

Problem

Conventional helicopter tail boom connection interfaces face challenges such as corrosion issues, fatigue sensitivity, weight, integration difficulties, and limited clearance for larger tail rotor shafts due to the use of metallic components, which affect operational efficiency and maintenance.

Innovation Solution

A composite tail boom design featuring a tubular tail boom cone and a composite attachment ring segment with a clamp ring section and scarf section, connected to the fuselage via tension members, exploiting the benefits of composite materials for improved fatigue resistance and reduced weight, while maintaining easy assembly and interchangeability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If metallic components are used in tail boom connection interfaces, then structural strength is achieved, but corrosion issues and fatigue sensitivity occur

Engineering Contradiction:
Improvestructural strengthVSAvoidcorrosion resistance and fatigue resistance
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The patent applies composite materials (specifically carbon fiber reinforced plastic) to manufacture the entire tail boom including the connection interface region. This replaces traditional metallic components with composite structures that inherently resist corrosion and fatigue, eliminating the need for separate corrosion protection measures while maintaining structural strength through the anisotropic properties of composite materials.

Inventive Principle:
Principle #40Composite materials

2Strength

If metallic connection interfaces are used, then structural integrity is maintained, but weight increases

Engineering Contradiction:
Improvestructural integrityVSAvoidtail boom weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The tail boom is constructed entirely from composite materials which have a superior strength-to-weight ratio compared to metals. The composite structure achieves the required structural integrity at significantly reduced weight, contributing to the overall weight reduction of the helicopter while maintaining the load-bearing capacity of the tail boom connection interface.

Inventive Principle:
Principle #40Composite materials

3Strength

If traditional metallic tail boom designs are used, then structural strength is achieved, but clearance for larger tail rotor shafts is limited

Engineering Contradiction:
Improvestructural strengthVSAvoidclearance for tail rotor shaft
Core Design Contradiction:
StrengthVSLength of moving object

Solution Approach 1:

The composite tail boom design allows for greater design flexibility in achieving the required structural strength. The anisotropic nature of composite materials enables optimization of fiber orientation to provide strength where needed while allowing increased clearance in other areas. This flexibility permits larger tail rotor shafts to be accommodated without compromising structural integrity, as the composite structure can be tailored to specific load requirements rather than relying on isotropic metallic properties.

Inventive Principle:
Principle #40Composite materials

4Adaptability or versatility

If separate manufacturing of tail boom and fuselage is implemented, then replacement ability is achieved, but integration difficulties occur at connection interfaces

Engineering Contradiction:
Improvereplacement abilityVSAvoidconnection interface integration
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The composite tail boom is manufactured as a single integral piece including the connection interface region, eliminating the need for separate assembly of metallic components. The composite structure allows for complex integrated geometries to be formed in one manufacturing process, simplifying the connection interface design while maintaining the ability to replace the entire tail boom assembly. This integral construction reduces the number of parts and assembly steps while preserving replacement capability.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3225537B1A helicopter with a fuselage and a composite tail boom
Publication Date: 2019.07.24 AIRBUS HELICOPTERS DEUT GMBH
  • EP3225537B1 patent drawingFigure 1
  • EP3225537B1 patent drawingFigure 2
  • EP3225537B1 patent drawingFigure 3~4

AI summary

The invention is related to a helicopter 1 with a fuselage 2 and a composite tail boom 3, the composite tail boom comprising at least a tubular tail boom cone 3b and a composite attachment ring segment 7 that defines a mating face, the mating face being connected to the fuselage at an associated connection interface 6 by means of a plurality of tension members that are oriented longitudinally with respect to a longitudinal extension direction of the composite tail boom 3, the plurality of tension members being distributed over a perimeter of the composite attachment ring segment 7, the composite attachment ring segment 7 comprising a clamp ring section with a plurality of tension member accommodations, the clamp ring section defining the mating face of the composite attachment ring segment 7, wherein the plurality of tension members is at least partly accommodated in the plurality of tension member accommodations.