Aircraft Exhaust Duct Alignment via Drag Link Mechanism

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Solution Overview

Problem

Conventional aircraft exhaust systems face issues with exhaust duct misalignment due to engine movement relative to the airframe, leading to poor exhaust gas flow, overheating, and adverse effects on engine compartment and other components.

Innovation Solution

An engine exhaust system with a slip joint and drag link mechanism maintains concentric alignment between primary and secondary exhaust ducts, allowing for relative axial movement while keeping the ducts aligned through uni-ball connectors and a high-temperature o-ring seal, supporting vertical and horizontal loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the primary exhaust duct is attached directly to the engine and the secondary exhaust duct is attached to the airframe, then the exhaust system can accommodate engine movement, but the ducts become non-concentric leading to poor exhaust gas flow and overheating

Engineering Contradiction:

Improveaccommodation of engine movementVSAvoidexhaust gas flow quality

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

A drag link is introduced as an intermediary component between the primary and secondary exhaust ducts. This drag link maintains the concentric alignment of the ducts while allowing the engine to move relative to the airframe, thus mediating between the need for adaptability and the need for reliable exhaust flow

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The exhaust system employs a dynamic configuration where the drag link can move axially to accommodate engine movement while maintaining duct alignment. The system transitions from a static rigid connection to a dynamic adjustable connection that preserves concentricity throughout the range of motion

Inventive Principle:

Principle #15Dynamics

2Reliability

If the primary and secondary exhaust ducts are rigidly connected to maintain alignment, then concentric alignment is maintained, but the system cannot accommodate engine movement relative to the airframe

Engineering Contradiction:

Improveduct alignmentVSAvoidaccommodation of engine movement

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The system uses a dynamic drag link connection that maintains duct alignment through controlled movement. The drag link translates axial motion into maintained concentricity, allowing the system to adapt to engine movement while preserving reliable exhaust flow geometry

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If the exhaust ducts are allowed to move independently, then engine movement is accommodated, but turbulent flow and direct impingement of hot exhaust gas on duct surfaces occur

Engineering Contradiction:

Improveengine movement accommodationVSAvoidoverheating of secondary duct

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The drag link serves as a mediator that couples the primary and secondary ducts axially, ensuring they move together in unison. This prevents independent movement that would cause misalignment, turbulent flow, and direct impingement of hot exhaust gas on the secondary duct surface

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS8123159B2Engine exhaust system

Publication Date: 2012.02.28 TEXTRON INNOVATIONS INC

AI summary

An exhaust system for an aircraft has a primary exhaust duct for communicating exhaust gas from an engine exhaust exit and is configured for movement with the engine. A secondary exhaust duct is in fluid communication with the primary exhaust duct and is movably mounted to the airframe. The system has means for maintaining a generally consistent relative alignment between the primary duct and the secondary duct.