Shock Strut Percolation Seal for Faster Landing Gear Readiness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aircraft landing gear systems face inefficiencies due to percolation of gas and oil between chambers in shock struts, particularly when retracted, leading to delayed readiness for landing as the shock strut is not optimized for efficient operation with gas in the lower chamber, exacerbated by cold cruising altitudes.
Innovation Solution
A shock strut design incorporating a percolation seal that restricts liquid flow between chambers, coupled with a fluid source to control the seal's inflation and deflation based on the landing gear's retraction and extension state, ensuring optimal fluid distribution for efficient landing gear operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the shock strut is retracted to a position above horizontal for an extended period, then the gas and oil can separate and settle into their respective chambers due to gravity, but this causes percolation of gas into the lower chamber and oil into the upper chamber, reducing landing gear efficiency
Solution Approach 1:
The percolation seal is inflated during the retraction phase to prevent gas and oil from mixing in the first place. By taking preliminary action to seal the chambers during retraction, the system avoids the need for prolonged settling time and ensures fluid layers remain stable, allowing the landing gear to be ready within the prescribed time window.
Solution Approach 2:
The percolation seal transitions from deflated to inflated state dynamically based on the shock strut's position and operational phase. During retraction, the seal inflates to prevent percolation; during extension, it deflates to allow fluid exchange. This dynamic adaptation resolves the contradiction between maintaining fluid stability and achieving timely landing readiness.
2Productivity
If a percolation seal is introduced to restrict liquid flow between chambers, then percolation is prevented and landing gear readiness is improved, but the device complexity increases
Solution Approach 1:
The percolation seal is implemented as a flexible bladder or diaphragm that can be inflated or deflated as needed. This flexible membrane approach adds minimal structural complexity compared to rigid sealing mechanisms, while effectively preventing percolation when inflated and allowing fluid exchange when deflated.
Solution Approach 2:
The percolation seal is controlled through pneumatic or hydraulic pressure systems that inflate or deflate the seal based on shock strut position. This uses existing fluid pressure systems in the landing gear to control the seal, avoiding the need for separate mechanical actuation systems and minimizing added complexity.
3Reliability
If the percolation seal is inflated to prevent liquid flow, then percolation is restricted, but the seal requires additional control mechanisms and fluid management systems
Solution Approach 1:
The percolation seal system is integrated with the existing shock strut operation, using the same fluid pressure that extends and retracts the landing gear to inflate and deflate the seal. The seal automatically inflates during retraction and deflates during extension without requiring separate control systems, achieving self-service operation that maintains reliability while minimizing added complexity.
Solution Approach 2:
The percolation seal serves multiple functions: it prevents percolation during retraction, allows fluid exchange during extension, and can potentially serve as a position indicator. By making the seal multi-functional and integrating it with existing systems, the patent reduces the need for additional dedicated control mechanisms.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution prevents percolation, maintaining oil in the lower chamber and allowing the landing gear to be ready for landing within a prescribed time, enhancing shock strut performance and reducing the time required for landing gear extension.
Implementation Method 1
a percolation seal configured to restrict a flow of liquid between the shock strut cylinder and the shock strut piston
Implementation Method 2
coupled with a fluid source to control the seal's inflation and deflation based on the landing gear's retraction and extension state
Implementation Method 3
Gas is known to leak into the lower chamber and oil into the upper chamber when the shock strut is in the retracted position; and, more particularly, when the shock strut is retracted to a position above a horizontal configuration where a portion of the lower chamber is positioned above a portion of the upper chamber
Data Source
AI summary
A shock strut is disclosed. The shock strut may include a shock strut cylinder, a shock strut piston that is slidably disposed within the shock strut cylinder, a metering pin, and a percolation seal configured to restrict a flow of liquid between the shock strut cylinder and the shock strut piston.