Aircraft Fuselage Fitting Structure for Secure, Accessible Disassembly

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Solution Overview

Problem

Conventional orbital joints for attaching aircraft fuselage sections are heavy, complex, and do not allow easy access to internal fuel tanks, particularly in hydrogen-powered aircraft, necessitating a robust and accessible joint solution.

Innovation Solution

A fitting structure comprising a butt-strap, connecting frame, and stabilizers with annular geometries, allowing secure attachment and disassembly of fuselage sections using discrete fasteners, with stabilizers enhancing load transfer and facilitating access to internal components.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional orbital joints are used to attach fuselage sections, then structural strength is ensured, but device complexity and weight increase

Engineering Contradiction:
Improvestructural strengthVSAvoidjoint complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The orbital joint is divided into discrete modular components: a connecting frame with stabilizers attached to the first fuselage section, and a butt-strap with coupling shovels attached to the second fuselage section. This segmentation allows the joint to be assembled from separate elements rather than a monolithic structure, reducing overall complexity while maintaining strength through the distributed connection system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connecting frame acts as an intermediary element between the two fuselage sections, providing a standardized interface that simplifies the attachment process. The stabilizers and coupling shovels serve as intermediary components that facilitate connection without requiring direct complex integration between the fuselage sections themselves.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Strength

If conventional orbital joints are used to attach fuselage sections, then structural strength is ensured, but weight increases

Engineering Contradiction:
Improvestructural strengthVSAvoidjoint weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The connection system applies local quality by concentrating structural reinforcement only where needed at the joint interfaces. The stabilizers and coupling shovels are positioned specifically at the ends of stringers and at critical attachment points, providing localized strength enhancement without the uniform weight penalty of conventional orbital joints throughout the entire fuselage section.

Inventive Principle:
Principle #3Local quality

3Strength

If conventional orbital joints are used, then fuselage sections are securely attached, but access to internal fuel tanks is blocked

Engineering Contradiction:
Improveattachment securityVSAvoidaccess to fuel tanks
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The joint system transitions from a static permanent connection to a dynamic removable connection. The discrete components can be assembled to provide secure attachment during operation, and then disassembled to provide access to fuel tanks during maintenance. This dynamic capability allows the joint to adapt between two operational states: secured during flight, accessible during ground maintenance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The segmented modular design enables easy disassembly by allowing each component (connecting frame, stabilizers, butt-strap, coupling shovels) to be independently removed. This segmentation provides maintenance access by enabling the joint to be taken apart without affecting the integrity of the fuselage sections themselves, unlike conventional orbital joints that would require cutting or complex removal procedures.

Inventive Principle:
Principle #1Segmentation

4Strength

If precise manufacturing is used to ensure intimate contact at junction, then mechanical continuity is achieved, but manufacturing complexity increases

Engineering Contradiction:
Improvemechanical continuityVSAvoidjunction interface precision
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The connecting frame and stabilizers serve as intermediary components that absorb dimensional variations between fuselage sections. Rather than requiring the fuselage sections themselves to be precisely fitted together, the intermediary components provide the necessary alignment and tolerance accommodation, reducing the manufacturing precision requirements of the base fuselage structures while still achieving continuous load transfer.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The design incorporates adjustable parameters in the stabilizer and coupling shovel configurations, allowing for compensation of dimensional variations. The modular nature enables adjustment of connection parameters during assembly to accommodate manufacturing tolerances, reducing the need for extremely precise junction interface manufacturing.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4596393A1Fitting structure for aircraft fuselage
Publication Date: 2025.08.06 AIRBUS OPERATIONS SL
  • EP4596393A1 patent drawingFigure 1
  • EP4596393A1 patent drawingFigure 2
  • EP4596393A1 patent drawingFigure 3~4

AI summary

Fitting structure for aircraft fuselage configured to attach a first aircraft fuselage section (201) to a second aircraft fuselage section (202), and comprising: a connecting frame (100) comprising an annular geometry and configured to be attached to a fuselage skin (203) of the first aircraft fuselage section (201) with the intermediation of a butt-strap (103); the butt-strap (103), comprising an annular geometry and protruding beyond the first aircraft fuselage section (201) towards the second aircraft fuselage section (202), and; a plurality of stabilizers (106), comprising a main body with a first lateral flap (107) and a second lateral flap (108); wherein each stabilizer (106) is configured to be attached to the connecting frame (100) in correspondence with the first lateral flap (107), and to the fuselage skin (203) of the second aircraft fuselage section (202), with the intermediation of the butt-strap (103), in correspondence with the second lateral flap (108).