Gas Turbine Engine Axial Separation via Height-Adjusted Fastening
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Solution Overview
Problem
Large gas turbine engines are often too big to fit in cargo aircraft holds, necessitating axial separation of fan cases and core engines during transportation, with tight tolerances requiring precise control to prevent damage from relative movement.
Innovation Solution
A method involving support tooling to carefully remove and realign fastenings, minimizing rotational misalignment by adjusting the relative height of components, ensuring precise alignment and preventing contact during separation and reassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the engine is transported as a complete unit, then transportation is simpler, but the engine cannot fit in the cargo aircraft hold
Solution Approach 1:
The engine is divided into two separate components: the fan case assembly and the core engine assembly. This segmentation allows each component to fit within the cargo aircraft hold dimensions while maintaining the ability to reassemble them into the complete engine unit at the destination.
2Loss of time
If fastenings are removed quickly to separate components, then separation time is reduced, but rotational misalignment causes contact and damage between components
Solution Approach 1:
Before removing all fastenings, two opposite fastenings are removed first to allow controlled height adjustment and alignment of the components. This preliminary alignment action prevents rotational misalignment and potential damage during the subsequent removal of remaining fastenings and separation process.
Solution Approach 2:
The support tooling is designed with adjustable height capability, allowing dynamic adjustment of component relative positions during the fastening removal process. This dynamic adjustment ensures continuous alignment and prevents misalignment damage as fastenings are progressively removed.
3Manufacturing precision
If tight tolerances are maintained between fan case and core engine, then assembly precision is improved, but rotational misalignment during separation causes contact and damage
Solution Approach 1:
Two opposite fastenings are removed first to enable height adjustment and realignment of apertures before complete separation. This preliminary realignment action ensures that even with tight tolerances, no contact or damage occurs during the separation process.
Solution Approach 2:
The support tooling acts as an intermediary device that maintains precise alignment and control of component positions during separation. It provides the necessary adjustment capability to accommodate tight tolerances while preventing misalignment damage.
4Productivity
If multiple fastenings are removed simultaneously, then separation efficiency is improved, but rotational misalignment increases causing damage
Solution Approach 1:
The fastening removal process is segmented into distinct phases: first removing two opposite fastenings to enable alignment, then adjusting height, and finally removing remaining fastenings. This segmented approach maintains precision while achieving efficient separation.
Solution Approach 2:
The preliminary removal of two opposite fastenings creates the necessary freedom for height adjustment and alignment before completing the separation. This preliminary action prevents misalignment damage while maintaining overall separation efficiency.
Data Source
AI summary
A method of axially separating an annular system, such as a gas turbine engine (10), comprising first (34) and second (36) annular components. An annular array of fastenings (42) couples the first (34) and second (36) components together axially. The first (34) and second (36) components are supported by support tooling. The fastenings (42) are removed to leave one fastening (42) located on each side of the system. One of the remaining fastenings (42) is removed. The relative height of the first (34) and second (36) components is adjusted so that the apertures (46, 48) for the fastening (42) removed at the previous step are aligned. Then the final fastening (42) is removed.