Aircraft Propulsion Unit Cowl Actuation Mechanism
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Solution Overview
Problem
Existing propulsion assembly systems for aircraft are heavy and complex due to the need for dual deployment lengths and stabilizers in COS cylinders and HOR connecting rods to support both regular and irregular maintenance operations, increasing manufacturing costs and weight.
Innovation Solution
Sizing the cylinder, safety rod, and main fitting to allow only regular maintenance operations, with a secondary fitting providing the necessary support for irregular maintenance, reducing the overall weight and complexity by eliminating the need for dual deployment lengths and stabilizers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If COS cylinders and HOR connecting rods are designed with dual deployment lengths and stabilizers to support both regular and irregular maintenance operations, then the propulsion assembly can perform both types of maintenance, but the weight and complexity of the nacelle increases
Solution Approach 1:
The maintenance system is segmented into two independent parts: a basic COS cylinder configuration for regular maintenance, and optional stabilizer assemblies with extended deployment lengths for irregular maintenance. This segmentation allows the aircraft to operate with minimal weight for routine maintenance while having the option to add weight only when irregular maintenance is anticipated.
Solution Approach 2:
The system transitions from a static, always-heavy configuration to a dynamic configuration where stabilizers and extended deployment mechanisms can be activated only when needed for irregular maintenance operations. This dynamic approach allows the nacelle to adapt its weight and capability profile based on operational requirements.
2Adaptability or versatility
If COS cylinders and HOR connecting rods are designed with dual deployment lengths and stabilizers to support both regular and irregular maintenance operations, then the propulsion assembly can perform both types of maintenance, but the device complexity increases
Solution Approach 1:
The complex dual-deployment system is divided into separate functional modules: a basic COS cylinder for regular maintenance, and distinct stabilizer assemblies that can be independently activated for irregular maintenance. This modular segmentation reduces overall system complexity by allowing each component to be optimized for its specific function rather than designing a single complex mechanism to handle all scenarios.
Solution Approach 2:
The stabilizer assemblies and extended deployment mechanisms are pre-configured as optional add-on components rather than integrated into the basic COS cylinder design. This preliminary preparation allows the system to maintain simplicity for regular operations while having pre-engineered solutions readily available when irregular maintenance is required.
3Adaptability or versatility
If dual deployment lengths and stabilizers are added to COS cylinders and HOR connecting rods, then both regular and irregular maintenance operations are supported, but manufacturing costs increase
Solution Approach 1:
The manufacturing process is segmented into two distinct production streams: standard COS cylinders and connecting rods for regular maintenance, and optional stabilizer assemblies with extended deployment mechanisms for irregular maintenance. This segmentation allows manufacturers to produce the basic components at lower costs while offering the expensive enhanced components as optional add-ons, reducing overall manufacturing costs for the majority of units.
Solution Approach 2:
Instead of manufacturing all COS cylinders and connecting rods with the complex dual-deployment capability, the patent applies enhanced features (extended deployment lengths and stabilizers) only locally to specific components when irregular maintenance capability is required. This local quality approach significantly reduces manufacturing costs by producing simple, inexpensive basic components for most applications.
Data Source
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AI summary
The present invention relates to a propulsion unit (101) for an aircraft, including: a stationary assembly; a cowl, which is pivotable between an operating position and a maintenance position allowing access to the turbojet for regular maintenance operations and irregular maintenance operations; at least one actuator (123) secured to the stationary assembly via a main fitting (125) mounted on the stationary assembly and rigidly connected to the movable cowl; at least one safety rod (129) rigidly connected to the movable cowl and to the stationary assembly via said main fitting. The propulsion assembly according to the invention is characterised in that: the actuator (123) is sized such as to allow the cover to alternate between an operating position and a position for regular maintenance only; the safety rod (129) is sized such as to hold the cover in the position for regular maintenance only; and the main fitting (125) is sized such as to allow regular maintenance operations only. The assembly is also characterised in that it includes a secondary fitting (145) mounted on the main fitting (125), sized such as to allow irregular maintenance operations, and supporting at least said actuator (123) when the cover is in an irregular maintenance position.