Aircraft Propulsion Unit Mounting Cradle with Guided Thrust Reverser
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Solution Overview
Problem
Modern turbojet engine nacelles with thrust reverser devices face challenges such as deformation forces and geometrical variations during relative displacement, leading to reduced mechanical strength and compromised operation, especially in large and flexible structures, requiring improved mounting and dismounting processes.
Innovation Solution
A system with a supporting structure forming a cradle, featuring longitudinal spars with guiding rails for the thrust reverser cowl and cascades, allowing for longitudinal movement and easy installation/removal by releasing front and rear suspensions, and incorporating a retaining mechanism to prevent spar spacing, ensuring the thrust reverser follows engine movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the nacelle structure is made flexible to accommodate large propulsion units, then the nacelle can support larger engines, but the structure becomes susceptible to deformation forces and geometrical variations during relative displacement
Solution Approach 1:
The supporting structure is divided into modular components including spars, rails, and suspension elements that can be independently assembled and maintained. This segmentation allows the large nacelle structure to be built from smaller, stronger modules rather than one large flexible structure.
Solution Approach 2:
The supporting structure incorporates dynamic elements such as movable rails and adjustable suspensions that adapt to relative displacement between the engine and pylon while maintaining structural integrity. This allows the structure to remain strong while accommodating movement.
2Reliability
If the thrust reverser device is integrated into the nacelle structure, then the braking function is provided, but the installation and removal time of the propulsion unit is increased
Solution Approach 1:
The thrust reverser device is designed as a separable component that can be independently installed or removed from the supporting structure. The cowl and cascade elements are modular, allowing rapid deployment without requiring complete disassembly of the propulsion unit.
Solution Approach 2:
The supporting structure includes pre-integrated mounting points and alignment features for the thrust reverser device. This preliminary preparation allows the thrust reverser to be quickly installed or removed without complex alignment procedures during propulsion unit changes.
3Reliability
If the supporting structure includes rails for guiding the cowl and cascades, then the thrust reverser kinematics are maintained, but the device complexity increases
Solution Approach 1:
The rails serving the thrust reverser device are designed to perform multiple functions: guiding the cowl movement, supporting the cascade vanes, and providing structural attachment points. This multi-functionality reduces the number of separate components needed while maintaining proper kinematics.
Data Source
AI summary
The present disclosure concerns a system for installing and removing a propulsion unit on a pylon of an aircraft, a propulsion unit of the type including a nacelle and a turbojet engine, the turbojet engine being linked on the pylon by at least one front suspension and one rear suspension. The system includes a supporting structure which is adapted to support a thrust reverser device, a front suspension of the turbojet engine, which carries a front part of the supporting structure, and which is removably fastened on a front part of the pylon, and a rear suspension of the turbojet engine which carries a rear part of the supporting structure, and which is removably fastened on a rear part of the pylon, and the disengagement of said suspensions of the pylon allowing removing the propulsion unit mounted on the pylon.