Two-Piece Firewall Assembly for Rotary Aircraft Engine Maintenance
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Solution Overview
Problem
In rotary aircraft, the existing designs of inlet plenum assemblies with fixed firewalls and walls complicate the removal of engines for servicing, as they form a barrier that requires partial disassembly, including disengagement of the drive shaft and reduction gearbox, making the process cumbersome and time-consuming.
Innovation Solution
A two-piece firewall and inlet plenum wall assembly, where the upper components are removably attached to the lower, fixed components, allowing for easier detachment and removal of the engine as a complete assembly, including the drive shaft and reduction gearbox, facilitating maintenance and servicing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed firewall and inlet plenum wall assembly is used, then fire protection is provided, but engine removal for servicing becomes complicated and time-consuming
Solution Approach 1:
The firewall assembly is divided into an upper portion and a lower portion that can be separated from each other. The upper portion is removable from the lower portion, allowing the engine to be accessed and removed without dismantling the entire firewall structure. This segmentation maintains fire protection where needed while providing access for maintenance.
Solution Approach 2:
The firewall assembly transitions from a static, fixed structure to a dynamic, configurable structure. The upper portion can be removed when engine servicing is needed and reinstalled when the engine is replaced or maintenance is complete. This dynamic capability allows the same structure to serve both fire protection and maintenance access requirements.
2Strength
If a fixed firewall and inlet plenum wall assembly is used, then structural integrity is maintained, but maintenance complexity increases
Solution Approach 1:
By segmenting the firewall into upper and lower portions with defined interfaces, the structure maintains its overall integrity when assembled while becoming simpler to maintain. The segmentation allows targeted access to the engine without requiring disassembly of the entire firewall, reducing maintenance complexity.
Solution Approach 2:
The upper portion is designed to be removable in advance, preparing the structure for future maintenance operations. This preliminary design consideration ensures that when maintenance is needed, the engine can be accessed quickly without complex disassembly procedures, reducing overall maintenance complexity.
3Reliability
If a fixed firewall assembly is used, then fire barrier protection is provided, but engine accessibility for maintenance is reduced
Solution Approach 1:
The firewall is segmented into removable upper and lower portions, creating a design that provides fire barrier protection when assembled but allows easy access to the engine when the upper portion is removed. This segmentation resolves the contradiction between protection and accessibility.
Solution Approach 2:
The firewall assembly becomes dynamic, allowing it to transition between a closed fire barrier configuration during operation and an open configuration during maintenance. The upper portion can be removed to provide engine accessibility and then reinstalled to restore fire protection, maintaining both requirements.
Data Source
AI summary
In one embodiment, there is described an inlet plenum assembly for a rotary aircraft, including: an inlet plenum defined on a first side by an inlet plenum wall and on a second side by a forward firewall assembly; the inlet plenum wall having a mechanical interface for receiving a reduction gearbox (RGB) to provide reduction gearing to the drive shaft; and the forward firewall assembly having an inlet aperture configured to receive a drive shaft to rotatably couple to an engine; wherein the forward firewall assembly includes a forward firewall upper and a forward firewall lower, the forward firewall upper configured to removably seat to the forward firewall lower.