Aircraft Nacelle Duct Connection with Internal Access

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Solution Overview

Problem

Existing aircraft nacelle connections require removable covers for accessing connecting elements, increasing on-board mass and complicating the assembly process due to the need for external access.

Innovation Solution

A single series of connecting elements is used to connect the air inlet and engine ducts, made of composite material, allowing internal access and elimination of external cowls, with recesses in acoustic panels to house connecting element heads and O-rings for sealing, and deformable connecting blades for stress management.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If removable covers are provided on the outer wall to access connecting elements, then the connecting elements can be accessed from outside the nacelle, but the on-board mass increases and the structure becomes more complex

Engineering Contradiction:
ImproveAccess to connecting elementsVSAvoidOn-board mass
Core Design Contradiction:
Ease of operationVSWeight of moving object

Solution Approach 1:

The patent inverts the conventional approach by enabling access to connecting elements from inside the nacelle rather than outside. The connecting elements are designed with internal access features, eliminating the need for external removable covers. This inversion resolves the contradiction by removing the covers (reducing mass) while maintaining accessibility through the alternative internal route.

Inventive Principle:
Principle #13The other way round (Inversion)

2Strength

If multiple series of connecting elements are used to link ducts and panels, then structural integrity is improved, but the number of connecting elements increases and assembly complexity increases

Engineering Contradiction:
ImproveStructural integrityVSAvoidNumber of connecting elements
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges multiple separate connection systems into a single integrated series of connecting elements. Instead of having separate connecting elements for linking ducts to panels and panels to each other, the invention uses one unified series of connecting elements that performs all these functions. This merging maintains structural integrity while reducing the total number of connecting elements and simplifying assembly.

Inventive Principle:
Principle #5Merging (Combining)

3Weight of moving object

If composite materials are used for acoustic panels and ducts, then weight is reduced, but the number of connecting elements increases when integrated with metal flanges

Engineering Contradiction:
ImproveNacelle weightVSAvoidNumber of connecting elements
Core Design Contradiction:
Weight of moving objectVSDevice complexity

Solution Approach 1:

The patent employs composite materials for acoustic panels and ducts to achieve weight reduction. The composite structure is designed to integrate directly with the connecting elements, eliminating the need for separate metal flanges. This direct integration maintains the weight benefits of composite materials while avoiding the increase in connecting elements that would result from adding metal flange interfaces.

Inventive Principle:
Principle #40Composite materials

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 design reduces on-board mass, simplifies assembly by allowing internal access, and enhances structural integrity through efficient stress distribution and sealing.

Implementation Method 1

an acoustically resistive layer 24

Methodology Applied
Scientific EffectAcoustic absorption: Acoustic Absorption

Implementation Method 2

at least one alveolar layer 26

Methodology Applied
Scientific EffectAcoustic dampening: Acoustic Absorption

Data Source

PatentEP3309078B1Aircraft nacelle comprising a connection between an air intake duct and an engine duct
Publication Date: 2019.06.05 AIRBUS OPERATIONS (SAS)
  • EP3309078B1 patent drawingFigure 1~2
  • EP3309078B1 patent drawingFigure 3A~5
  • EP3309078B1 patent drawingFigure 6~8

AI summary

The object of the invention is an aircraft nacelle which includes a duct attached to an air inlet (50) and a duct attached to a motor (56), a linkage (76) between the duct attached to the air inlet (50) and the duct attached to the motor (56) which includes: - a sleeve (78) which receives one end of a first duct (52) and is attached to a second duct (54), - connecting elements (80) which connect the sleeve (78) and the first duct (52) and which are distributed over the entire circumference of the nacelle, each connecting element (80) having a threaded rod oriented in a radial direction and being configured to allow its tightening from inside the first duct (52).