Aircraft Engine Rear Attachment Axial Shift
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Solution Overview
Problem
Existing aircraft engine mounting systems with rear engine attachments linked to the inter-turbine casing result in increased width, causing aerodynamic disturbances and performance issues due to the need for overdimensioning of surrounding structures.
Innovation Solution
A rear engine attachment assembly with a novel distribution of connecting rods in multiple axial planes, including a shear pin for transverse force spreading, reduces the overall width and mass, eliminating the need for intermediate structures and simplifying the design to enhance aerodynamic integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rear engine attachment is linked to the inter-turbine casing to reduce deformations, then blade-tip clearance control is improved, but the overall width of the attachment increases causing aerodynamic disturbances
Solution Approach 1:
The rear engine attachment is divided into multiple connecting rods (first connecting rod, second connecting rod, third connecting rod) arranged in different axial planes. This segmentation allows the attachment to maintain structural integrity and control blade-tip clearance while reducing the overall width in any single transverse plane, thereby minimizing aerodynamic disturbances.
Solution Approach 2:
The connecting rods are distributed across multiple axial planes (first axial plane, second axial plane, third axial plane) rather than being concentrated in a single plane. This multi-dimensional arrangement reduces the transverse width footprint while maintaining the necessary structural support for blade-tip clearance control.
2Object-affected harmful factors
If the rear engine attachment width is reduced to improve aerodynamic performance, then aerodynamic integration is enhanced, but the structural complexity increases
Solution Approach 1:
The attachment structure is segmented into multiple connecting rods with different functions: the first connecting rod handles vertical forces, the second connecting rod handles transverse forces, and the third connecting rod provides additional support. This segmentation allows each component to be optimized for its specific function while collectively achieving a compact width.
Solution Approach 2:
The rear engine attachment assembly performs multiple functions simultaneously: it provides structural support, controls blade-tip clearance, spreads forces in multiple directions, and minimizes aerodynamic interference. The multi-functional design justifies the increased structural complexity by delivering multiple benefits from a single integrated assembly.
3Object-affected harmful factors
If connecting rods are distributed in multiple axial planes to reduce width, then aerodynamic integration is improved, but the number of components increases
Solution Approach 1:
The attachment is segmented into three distinct connecting rods, each articulated with the inter-turbine casing at different axial positions. This segmentation enables the distribution of loads across multiple planes while maintaining a compact overall footprint that improves aerodynamic integration.
Solution Approach 2:
Multiple connecting rods are merged into a single integrated rear engine attachment assembly that is articulated with the inter-turbine casing as one unit. This merging approach, while increasing the number of components, provides cohesive structural support and simplified installation compared to separate attachment systems.
Data Source
AI summary
In order to reduce the width of the attachment between the rear portion of an aircraft engine and its attachment pylon, an engine assembly attachment include an assembly of rear engine attachments comprising a first connecting rod laid out in a longitudinal and median vertical plane, a second connecting rod substantially laid out tangentially to the inter-turbine case, and a rear engine attachment for transversely spreading the loads, axially shifted rearwards relatively to the first and second connecting rods, and comprising a shear pin oriented along a vertical direction of the engine assembly.