Angle of Attack Sensor With Integral Bearing Cage and Local Heating
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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 power consumption of heating elements used to prevent ice accumulation, and misalignment issues between bearings affect sensitivity and accuracy.
Innovation Solution
An angle of attack sensor with a frustoconical faceplate having an integral bearing support cage and a direct thermal conduction path from the faceplate heater to the rotational position sensor, combined with a tailored heating pattern to efficiently distribute heat and minimize power usage, ensuring precise alignment of bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heating elements are used to prevent ice accumulation on the faceplate and vane, then reliability under icing conditions is improved, but energy consumption increases significantly
Solution Approach 1:
The heating elements are strategically positioned to provide localized heating only at critical areas (leading edge of faceplate and vane root) where ice accumulation most severely impacts sensor reliability. This selective heating approach maintains protection against icing while minimizing overall energy consumption compared to heating the entire faceplate surface.
Solution Approach 2:
The heating system applies heat selectively to partial regions rather than the entire faceplate, using just enough thermal energy to prevent ice accumulation at critical locations. This partial action approach achieves the necessary reliability improvement without the excessive energy consumption that would result from comprehensive heating.
2Ease of manufacture
If traditional separate bearing supports are used, then ease of manufacture is improved, but manufacturing precision of bearing alignment deteriorates
Solution Approach 1:
The bearing supports are merged into a single integral structure formed as part of the faceplate itself, eliminating the need for separate bearing support components. This integration ensures precise bearing alignment through monolithic construction while maintaining ease of manufacture through conventional faceplate fabrication processes.
Solution Approach 2:
The faceplate structure serves multiple functions: it provides the aerodynamic surface, structural support, and integrated bearing support structure. By making the bearing supports integral to the faceplate, the design achieves precise alignment without adding separate components, demonstrating multi-functionality that improves both manufacturing precision and structural efficiency.
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 and maintains accurate angle of attack measurements by minimizing power consumption and ensuring precise bearing alignment, enhancing sensitivity and reliability under icing conditions.
Implementation Method 1
a direct thermal conduction path from the faceplate heater 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 is positioned on the open end of the housing. The faceplate comprises an integral bearing support cage that extends into the housing and is configured to accept a first bearing and a second bearing, a periphery at an outer edge of the faceplate, a central opening, and an exterior surface extending from the periphery to the central opening. A vane assembly extends through the central opening of the faceplate. A vane shaft extends into the housing and is connected to the vane assembly, and a rotational position sensor is connected to the vane shaft.