Zigzag Drainage Cap for Aircraft Hollow Space Water Ingress
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Solution Overview
Problem
Current drainage and venting systems for aircraft hollow spaces, particularly near fuel tanks, fail to prevent ingress of spray water and do not meet EASA/FAR certification requirements for permanent drainage and venting, leading to corrosion and explosion risks.
Innovation Solution
A drainage end cap device with a mounting unit and a removably attached drainage cap featuring a zigzagged drainage channel and plastic components, which allows for efficient drainage and venting while preventing spray water ingress, and is designed for easy assembly and disassembly, installation near antennas, and resistance to icing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If through holes are provided in the bottom shell for drainage, then fluid can be drained from hollow spaces, but spray water can ingress into the hollow spaces during hovering over water
Solution Approach 1:
The drainage channel is designed with a zigzag path that creates preliminary resistance to incoming spray water. The multiple directional changes in the channel require the water to overcome gravitational and inertial forces at each turn, preventing easy ingress into the hollow space while still allowing drainage of accumulated fluid.
2Object-affected harmful factors
If check valves with weir gates are used to prevent water ingress, then water can be kept out during ditching, but the valves are prone to corrosion and cannot operate under icing conditions
Solution Approach 1:
The drainage cap with drainage channel is designed as a simple, replaceable component that can be easily removed and replaced. Rather than attempting to make the drainage system corrosion-proof or ice-resistant, the design accepts that the cap may deteriorate over time or become blocked by ice, but allows for quick replacement to restore functionality.
Solution Approach 2:
The drainage cap is designed as a separate, removable component that can be easily extracted from the mounting unit. This allows the drainage function to be maintained while enabling quick replacement if the cap becomes corroded or blocked by ice, separating the drainage function from the protective function.
3Object-affected harmful factors
If manually lockable plugs are used for drainage, then spray water ingress can be prevented, but the plugs do not allow permanent venting required by EASA/FAR regulations
Solution Approach 1:
The drainage cap is designed to be removable and replaceable rather than permanently fixed. This dynamic design allows the system to switch between different operational states: during normal operation the cap provides spray water protection while allowing venting, and when maintenance is needed the cap can be removed for cleaning or replacement, thus adapting to different operational requirements including permanent venting needs.
4Reliability
If metallic components are used in check valves, then drainage function can be achieved, but electromagnetic compatibility is influenced and radar detection occurs
Solution Approach 1:
The drainage cap and mounting unit are designed using non-metallic materials such as plastic or composite materials instead of traditional metallic components. This parameter change in material composition maintains the structural integrity and drainage function while eliminating the electromagnetic compatibility issues and radar detection problems associated with metallic parts.
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 ensures permanent drainage and venting of aircraft hollow spaces, reducing corrosion risks and preventing explosive gas accumulation, while being compliant with certification regulations and minimizing aerodynamic drag.
Implementation Method 1
drained fluid can flow through the drainage channel from the hollow space to an outside of the aircraft in a flow direction that is at least partly zigzagged over a longitudinal extension of the drainage cap
Data Source
Figure 1
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AI summary
The invention is related to a drainage end cap device 6 for draining fluid from a hollow space in a vehicle, comprising a mounting unit 7 that is durably mountable in a super-imposed manner onto a drainage opening 2d provided in an outer shell 2c of a vehicle, wherein a drainage cap 8 with a drainage channel 8b is provided, said drainage cap 8 being removably mountable to said mounting unit 7.