Aircraft Rotor Blade Interconnects for Ice Protection
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Solution Overview
Problem
Conventional electrical interconnects for aircraft rotor blade ice protection systems face challenges in balancing low resistivity and mechanical integrity, particularly at blade tips with complex geometries, leading to potential mechanical and electrical failures due to excessive heat generation and high spot formation on the blade surface.
Innovation Solution
A mesh or foil conductive body interconnect spanning bus bar segments, with a low thickness and high open area, is used to reduce resistive heating and provide a low-profile, aerodynamically smooth connection, ensuring efficient current carrying capacity without excessive heat generation and mechanical separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wire or wire braid interconnects are used to couple heater elements to power supply, then electrical connectivity is achieved, but excessive heat is generated due to resistivity
Solution Approach 1:
The patent changes the physical parameters of the interconnect by using foil or mesh structures with thickness of 0.003 inches or less, representing a significant reduction from conventional wire gauges. This parameter change reduces resistivity and consequently heat generation while maintaining electrical connectivity across the blade tip assembly.
Solution Approach 2:
The patent employs thin foil or mesh interconnects that conform to the complex blade tip geometry. These thin film structures provide electrical connectivity while minimizing resistive heating, as the reduced thickness directly correlates to lower resistance and heat generation according to the patent's technical disclosure.
2Reliability
If larger wire cross-sectional area is used to reduce resistivity, then electrical efficiency improves, but high spots form on blade surface leading to mechanical separation
Solution Approach 1:
The patent uses thin foil or mesh interconnects with thickness of 0.003 inches or less that conform to the blade tip surface geometry. These thin film structures eliminate high spot formation while maintaining electrical efficiency, as they can be bonded flush with the aerodynamic surface without creating protrusions that would lead to mechanical separation.
Solution Approach 2:
The patent changes the dimensional parameters of the interconnect by reducing thickness to 0.003 inches or less, which simultaneously achieves low resistivity for electrical efficiency and maintains a low profile for mechanical integrity. This parameter optimization resolves the contradiction between electrical performance and mechanical bonding.
3Reliability
If conventional wire interconnects are used at blade tips, then electrical connection is established, but aerodynamic surface continuity is disrupted
Solution Approach 1:
The patent employs thin foil or mesh interconnects that can be bonded to the blade tip assembly in a manner that maintains aerodynamic surface continuity. The thin film structure allows the interconnect to be flush with the aerodynamic surface, eliminating disruptions to surface contour while establishing reliable electrical connections across the blade tip geometry.
4Device complexity
If heater elements are connected in series, then system complexity is reduced, but interconnect current load increases requiring larger gauge wire
Solution Approach 1:
The patent changes the physical parameters of the interconnect by using foil or mesh structures with extremely low thickness (0.003 inches or less), which provides exceptionally low resistivity. This parameter change enables the interconnect to handle high current loads from series-connected heater elements without requiring larger gauge wire, thus maintaining simple series configuration while achieving the required current capacity.
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 effectively reduces heat generation and maintains mechanical integrity, enabling the interconnects to carry current loads similar to heater elements while preventing thermal stress and mechanical bonding failures, thus enhancing the reliability and efficiency of ice protection systems.
Implementation Method 1
An interconnect spans the first and second bus bar segments for resistively generating less heat than each of the bus bar segments for a predetermined current flow
Data Source
Figure 1~2
Figure 3a~4
Figure 5~6
AI summary
A rotary blade (28) includes a blade tip assembly (34) with a first bus bar segment (46) and a main blade assembly (32) with second bus bar segment (48). The first bus bar segment is connected to the blade tip assembly and the second bus bar segment is connected to the main blade assembly. The blade tip assembly is connected to the main blade assembly such that the first and second bus bar segments are longitudinally offset from one another. A low-profile interconnect (100; 200) spans the first and second bus bar segments for resistively generating less heat than the bus bar segments for a predetermined current flow.