Aircraft Engine Mount Linkage for Thermal Expansion
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Solution Overview
Problem
Conventional aircraft engine mounting arrangements struggle to accommodate thermal expansion, leading to misalignment and lateral displacement of the engine, particularly due to localized expansion, which can cause off-axis loading and torque issues.
Innovation Solution
An engine mounting assembly with first and second spaced support formations on the engine and corresponding mounting formations on the aircraft, connected by inwardly extending links with offset connection formations and an intermediate link, which provides a force path to react loads and maintain engine alignment, accommodating thermal expansion and torque while minimizing lateral displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional two-link or three-link mounting arrangement is used, then the engine can be supported and torque capability is maintained, but localised thermal expansion causes lateral and downward displacement of the engine casing, leading to misalignment with the exhaust system
Solution Approach 1:
The mounting arrangement is divided into multiple independent link arms (first link, second link, third link) that can move and pivot independently relative to each other and the mounting block. This segmentation allows each link to accommodate thermal expansion in different directions without causing overall misalignment of the engine with the exhaust system.
Solution Approach 2:
The link arms are designed with pivot points and flexible connections that allow dynamic movement and adjustment. The links can pivot and move to accommodate thermal expansion and contraction of the engine casing, maintaining proper alignment while supporting torque loads.
2Object-affected harmful factors
If a third link arm is added to mitigate lateral displacement from thermal expansion, then alignment is improved, but the space between the casing and mounting block becomes insufficient to accommodate the additional link
Solution Approach 1:
The third link arm is positioned and oriented in a specific spatial arrangement that utilizes available space efficiently. By strategically positioning the third link to react torque loads from a location spaced from the casing centre-line, the design accommodates the additional link without requiring excessive space between the casing and mounting block.
3Object-affected harmful factors
If the link arms are positioned to accommodate thermal expansion, then alignment is maintained, but the mounting structure becomes more complex with multiple link attachment points
Solution Approach 1:
The mounting block and link arms are designed to perform multiple functions simultaneously. The link arms serve both to support the engine weight and to accommodate thermal expansion, while also providing torque reaction capabilities. This multi-functionality reduces the need for separate specialized components and simplifies the overall structure.
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
The solution effectively communicates loads from one link to another, maintaining engine alignment and balancing torque, thus minimizing lateral displacement and ensuring the engine's centerline remains constant, even under thermal expansion and torque loads.
Implementation Method 1
thermal expansion of the engine that can occur in use. Thermal expansion is transient and may occur in a localised region or regions of the engine casing rather than in a uniform manner
Data Source
AI summary
An engine mount, for mounting the casing of an aircraft engine to the fuselage or wing of an aircraft, e.g. via a pylon, including first and second links having connector formations for connection to respective mounting and support formations on the engine casing and aircraft mounting structure. Each of the first and second links is typically connected by a pin between the mounting and support formations. Each link has a further connector formation arranged such that the connector formation of the first link is offset from the connector formation of the second link. The connector formations are joined by an intermediate link. The mount allows lateral forces and torque to be resolved in such a way as to substantially avoid lateral displacement of the engine away from a central plane. The intermediate link may also provide a failsafe catcher arrangement in the event that the first or second link fail.