Aircraft Nacelle Interface Assembly for Drag Reduction

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Solution Overview

Problem

Modern aircraft nacelle designs with translatable structures experience relative movement at interfaces due to air turbulence and vibrations, leading to increased drag from airflow impediments when stowed.

Innovation Solution

A nacelle design featuring a stationary support and interlocking components within an interface assembly that maintains a predetermined axial gap and radial alignment between translatable structures, such as a fanlet and thrust reverser sleeve, to control and stabilize their positions during stowed conditions, reducing aerodynamic drag.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If translatable structures are allowed to move freely at the interface, then the device complexity is reduced and ease of operation is improved, but relative movement creates excessive airflow impediments and increases drag

Engineering Contradiction:

Improveease of operationVSAvoiddrag

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

An interface assembly acts as an intermediary between the fanlet and thrust reverser sleeve, providing controlled connection points that allow relative movement while maintaining proper alignment and minimizing gap variations, thus reducing drag without restricting operational freedom

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The interface assembly incorporates dynamic elements that adapt to relative movements between translatable structures during operation, allowing the system to maintain optimal aerodynamic characteristics while accommodating operational requirements

Inventive Principle:

Principle #15Dynamics

2Object-affected harmful factors

If translatable structures are constrained to maintain precise relative position, then aerodynamic drag is reduced, but the device complexity increases due to additional interface assembly components

Engineering Contradiction:

ImprovedragVSAvoiddevice complexity

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The interface assembly is segmented into multiple discrete components (first and second interlocking components with respective features) that can be independently manufactured and assembled, distributing the complexity across manageable parts rather than a single complex assembly

Inventive Principle:

Principle #1Segmentation

3Manufacturing precision

If the interface assembly includes multiple interlocking components, then the manufacturing precision and control of relative position are improved, but the ease of manufacture decreases

Engineering Contradiction:

Improvemanufacturing precisionVSAvoidease of manufacture

Core Design Contradiction:

Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The interface control function is segmented across multiple interlocking components, allowing each component to be manufactured to standard tolerances and assembled to achieve the required overall precision, rather than requiring a single complex component with tight tolerances

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The interlocking components are designed with universal features that can be integrated with different translatable structure configurations, allowing the same interface assembly design to serve multiple manufacturing and assembly purposes

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS10428763B2Controlling a relative position at an interface between translating structures of an aircraft nacelle

Publication Date: 2019.10.01 ROHR INC

AI summary

A nacelle is provided for an aircraft propulsion system. This nacelle includes a stationary support, a fanlet, a thrust reverser sleeve and an interface assembly providing an interface between the stationary support, the fanlet and the thrust reverser sleeve where the fanlet and the thrust reverser sleeve are respectively in stowed positions. The stationary support extends circumferentially about an axial centerline. The fanlet includes an inlet structure and a fan cowl. The fanlet is configured to translate axially along the centerline. The thrust reverser sleeve is configured to translate axially along the centerline. The interface assembly includes a pair of interlocking components, wherein a first of the interlocking components is mounted to the fanlet at the aft end of the fanlet.