Angle-of-Attack Sensor With Sloped Faceplate for Ice Control
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Solution Overview
Problem
Angle of attack sensors with rotatable vanes face accuracy degradation due to icing conditions, which are exacerbated by the need for significant electrical power usage for heating elements to prevent ice accumulation, leading to inefficiencies and performance issues.
Innovation Solution
The design incorporates a sloped faceplate with a frustoconical exterior surface that redirects ice and water away from the vane, combined with a direct thermal conduction path to the rotational position sensor, minimizing power consumption and maintaining sensor accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heating elements are used to prevent ice accumulation on the vane and faceplate, then reliability is improved, but use of energy deteriorates
Solution Approach 1:
The patent converts the harmful effect of ice accumulation into a beneficial thermal conduction path. The ice that would normally degrade sensor accuracy is redirected to conduct heat away from the rotational position sensor, preventing overheating and reducing power consumption. This is achieved through the sloped faceplate geometry that channels ice and water toward the sensor housing, creating a natural heat sink that eliminates the need for high-power heating elements.
Solution Approach 2:
The sensor housing serves dual functions: it protects the rotational position sensor and acts as a heat sink. The housing's thermal mass and connection to the aircraft structure provide passive cooling, reducing reliance on active heating elements. The system uses its own structure (the housing) to manage thermal conditions, eliminating the need for separate cooling or heating systems.
2Reliability
If heating elements are used to prevent ice accumulation, then reliability is improved, but device complexity deteriorates
Solution Approach 1:
The patent eliminates complex heating elements by converting the harmful ice accumulation into a beneficial thermal management solution. The sloped faceplate redirects ice to serve as a heat sink, naturally cooling the sensor housing without requiring active heating or cooling systems. This passive thermal management approach replaces complex active thermal control systems with simple geometric design.
Solution Approach 2:
The patent extracts the thermal management function from the heating elements and transfers it to the sensor housing and ice/water accumulation. Instead of using heating elements to actively prevent ice formation, the system allows ice to form and use it passively for cooling the sensor housing, thereby removing the need for complex heating element systems.
3Manufacturing precision
If a flat faceplate is used, then manufacturing precision is improved, but object-affected harmful factors deteriorate
Solution Approach 1:
The patent applies a curved or sloped faceplate geometry instead of a flat surface. The sloped profile causes ice and water to naturally drain away from the vane and sensor housing through gravity and surface tension, preventing accumulation. This geometric modification maintains manufacturing feasibility while effectively eliminating the harmful effects of ice buildup that plague flat-faceplate designs.
Solution Approach 2:
The faceplate employs an asymmetric sloped profile rather than a symmetric flat surface. The slope is designed to direct ice and water flow in specific directions away from critical components, creating an asymmetric thermal and fluid management system that prevents ice accumulation on the vane and sensor housing while remaining manufacturable.
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 prevents ice accumulation on the vane and faceplate, ensuring accurate angle of attack measurements while reducing power consumption and heater complexity, thus enhancing sensor performance and reliability.
Implementation Method 1
The exterior surface of the faceplate has a sloped profile from the periphery to the central opening
Implementation Method 2
Aerodynamic forces acting on the rotatable vane cause the vane to align with the direction of the oncoming airflow
Implementation Method 3
angle of attack sensors utilizing rotatable vanes typically include heating elements to prevent accretion of ice on the vane and faceplate
Implementation Method 4
The design incorporates a sloped faceplate with a frustoconical exterior surface that redirects ice and water away from the vane, combined with a direct thermal conduction path to the rotational position sensor
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
An angle of attack sensor includes a housing having an open end and a closed end, a faceplate positioned on the open end of the housing, the faceplate comprising a periphery at an outer edge of the faceplate, a central opening, and an exterior surface extending from the periphery to the central opening, and a vane assembly extending through the central opening of the faceplate. The exterior surface of the faceplate has a sloped profile from the periphery to the central opening.