Internal Lightning Arrester for Aircraft Radome Drag Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Composite structures used in aircraft radomes are vulnerable to lightning strikes, leading to potential damage and aerodynamic disturbances that increase drag and fuel consumption, as conventional lightning protection methods are not suitable for transparent surfaces and can disrupt airflow.
Innovation Solution
A composite lightning arrester system with electrically conductive strips placed on the internal side of the structure, connected to ground through attachment elements with insulating inserts and non-conductive paste, minimizing surface disruption and maintaining radar transparency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional lightning strips are arranged on the outer surface of the radome, then lightning energy dissipation is effective, but aerodynamic disturbances are generated that increase drag
Solution Approach 1:
The patent inverts the conventional approach by placing the conductive strip on the inner surface of the radome rather than the outer surface. The attachment elements protrude inward from the inner surface, allowing the strip to be positioned inside the radome structure. This inversion eliminates the need for external protrusions that disrupt airflow, thereby reducing aerodynamic drag while maintaining lightning protection functionality.
Solution Approach 2:
The patent transitions the lightning protection system from a two-dimensional external surface arrangement to a three-dimensional internal configuration. By moving the conductive strip to the inner surface and using attachment elements that protrude inward, the system utilizes the third dimension (radome thickness) to achieve protection without external protrusions, solving the aerodynamic drag problem.
2Reliability
If lightning strips are fixed to the radome surface, then lightning current can be dissipated, but the projections from the surface disturb the air flow
Solution Approach 1:
Instead of having attachment elements protrude outward from the external surface (which disturbs airflow), the patent inverts the configuration so that attachment elements protrude inward from the inner surface. The conductive strip is positioned inside the radome, parallel to the external surface, eliminating any protrusions that would interfere with external airflow and maintain optimal air flow speed.
3Reliability
If metal mesh is inserted into the radome structure surface, then lightning protection is provided, but radar wave transparency is reduced
Solution Approach 1:
The patent extracts the conductive strip from the external surface or embedded position and relocates it to the inner surface of the radome. This extraction from the radar wave path eliminates the interference with radar wave transparency while maintaining the lightning protection function, as the strip remains electrically connected to the radome structure through the attachment elements.
Solution Approach 2:
The attachment elements serve as intermediaries that provide electrical connection between the conductive strip (positioned inside the radome) and the radome structure. This intermediary connection allows the strip to be positioned inside the radome away from the external surface, providing lightning protection without interfering with radar wave transparency.
4Reliability
If lightning arrester strips are placed on the external surface, then lightning strike protection is achieved, but maintenance requires radome removal to replace damaged strips
Solution Approach 1:
By inverting the position of the conductive strip to the inner surface of the radome and using attachment elements that protrude inward, the patent enables access to the strip from the inside of the radome. This allows maintenance personnel to reach and replace damaged strips without removing the radome, significantly improving ease of repair while maintaining lightning protection.
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
Effectively dissipates lightning energy without damaging the structure or disturbing airflow, reducing drag and fuel consumption while ensuring radar transparency.
Implementation Method 1
The high density electric currents which then pass through these composite structures can seriously damage them
Implementation Method 2
the electrically conductive strip is intended to be placed on the opposite side of the structure to this external surface while being connected to ground
Implementation Method 3
said system comprises an electrically insulating sheath covering said electrically conductive strip
Implementation Method 4
the radome when it constitutes the 'nose' of an aircraft has a generally conical shape to ensure good penetration into the air
Implementation Method 5
These aerodynamic disturbances generate increased drag in particular by triggering the transition from laminar to turbulent flow
Data Source
Figure 1a~1b
Figure 2~3
Figure 4~5
AI summary
The invention relates to an anti-lightning system for a composite structure having an external surface intended to be subjected to an air flow (20), said system comprising at least one electrically conducting strip (13) and fasteners attaching this strip to said structure. According to the invention, with this structure comprising holes intended to accept the fastenings for the strip, at least some of these fastenings comprise an attachment element (15) that attaches the lightning to this structure. This attachment element (15) is intended to be inserted in the hole with its upper part (19) substantially flush with the external surface of the structure, this attachment element (15) being in electrical contact with the electrically conducting strip (13). The electrically conducting strip (13) is intended to be positioned on the opposite side of the structure to the external surface (10) and electrically earthed.