Aircraft Rear Fuselage Tail Cone Balancer Fitting

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Solution Overview

Problem

The existing method for assembling the tail cone end to the rear fuselage of an aircraft faces challenges due to tolerances and loss of freedom degrees, requiring additional steps and increased costs and time, especially when adjusting the upper fittings, and does not accommodate variations in the auxiliary power unit's air intake location effectively.

Innovation Solution

An adjustable balancer fitting that is locked in Z and Y directions and movable along an X direction, allowing adjustments in these axes, is used to guide and position the upper and lower lugs, enabling the tail cone end to be attached to the rear fuselage without disassembling the balancer, facilitating easier assembly and maintenance by providing a flexible interface point.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the traditional assembly method with fixed balancer position is used, then the structure is simple, but the assembly difficulty increases due to tolerance accumulation and loss of freedom degrees when adjusting upper fittings

Engineering Contradiction:
Improveassembly easeVSAvoidjoint structure complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The balancer fitting is designed with adjustable positioning capabilities along the longitudinal axis of the fuselage, allowing it to move between different positions during assembly. This dynamic adjustment capability enables the balancer to compensate for tolerance variations and maintain proper alignment of the tail cone end with the rear fuselage, thereby facilitating easier assembly operations without requiring complex additional adjustment mechanisms.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The adjustable balancer fitting serves multiple functions: it acts as a structural support element, an alignment guide for the tail cone end, and a tolerance compensation mechanism. By integrating these multiple functions into a single component, the invention avoids the need for separate complex adjustment devices while improving assembly ease.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Adaptability or versatility

If the balancer is disassembled and re-assembled to adjust upper fittings, then the adjustment flexibility improves, but the assembly time and costs increase

Engineering Contradiction:
Improveadjustment flexibilityVSAvoidassembly time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The balancer fitting incorporates adjustable positioning capabilities along the longitudinal axis, allowing continuous or discrete position changes without disassembly. This dynamic adjustment feature provides the necessary flexibility to accommodate different tail cone end positions and tolerance variations, eliminating the need for time-consuming disassembly and reassembly operations while maintaining full adaptability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The adjustable balancer fitting is pre-configured with multiple possible positions along the fuselage longitudinal axis. During assembly, the appropriate position can be selected and locked in advance, allowing subsequent fitting adjustments to proceed smoothly without requiring balancer disassembly. This preliminary positioning capability reduces assembly time while preserving adjustment flexibility.

Inventive Principle:
Principle #10Preliminary action

3Strength

If multiple fittings are adjusted sequentially, then the load distribution is improved, but the stress and tensions on aircraft elements increase during assembly operations

Engineering Contradiction:
Improveload bearing capacityVSAvoidassembly stress
Core Design Contradiction:
StrengthVSStress or pressure

Solution Approach 1:

The adjustable balancer fitting enables dynamic load distribution by allowing position adjustments that optimize the mechanical leverage and load paths during assembly. By positioning the balancer at optimal locations along the fuselage, the system can distribute loads more evenly across the joint, reducing peak stresses and tensions on individual aircraft elements while maintaining overall load bearing capacity.

Inventive Principle:
Principle #15Dynamics

4Manufacturing precision

If the tail cone end is designed with fixed positioning, then the manufacturing precision is high, but the adaptability to different auxiliary power unit locations is reduced

Engineering Contradiction:
Improvepositioning precisionVSAvoidconfiguration adaptability
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The adjustable balancer fitting provides dynamic positioning capability along the fuselage longitudinal axis, allowing the system to adapt to different tail cone end positions and auxiliary power unit locations. This adjustability maintains manufacturing precision by enabling accurate positioning at each specific configuration while simultaneously providing the versatility to accommodate multiple aircraft variants and configurations.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2433861B1Rear fuselage of an aircraft
Publication Date: 2018.11.07 AIRBUS OPERATIONS SL
  • EP2433861B1 patent drawingFigure 1
  • EP2433861B1 patent drawingFigure 2
  • EP2433861B1 patent drawingFigure 3

AI summary

Rear fuselage of an aircraft comprising a tail cone end and a rest of the real fuselage whereby the tail cone end is attached to the rest of the rear fuselage by means of an attachment system comprising two upper lugs, two lower lugs and a detachable balancer fitting. The balancer fitting is an adjustable fitting, being locked in a Z and Y directions of a Cartesian axis and being movable along an X direction of the Cartesian axis providing guidance for the tail cone end and the rest of the rear fuselage.