Aerodynamic Probe Incidence Measurement via Dynamic Tap Selection
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Solution Overview
Problem
Existing aerodynamic probes for measuring local incidence on aircraft surfaces face challenges such as limited precision, measurement chain saturation, and flow detachment at high incidences, particularly in determining the angle of attack and sideslip angles.
Innovation Solution
A probe with a fixed appendage and multiple pressure taps on its nose, where the calculation means select the taps providing the best measurement precision, allowing for accurate determination of local incidence across a wide range by choosing taps that avoid separated airflow regions and using differential pressure measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a fixed appendage with pressure taps is used to measure local incidence, then the device complexity is reduced compared to mobile probes, but measurement precision deteriorates due to flow detachment at high incidences
Solution Approach 1:
The probe body is divided into multiple pressure taps (at least five) positioned at different locations on the nose surface. This segmentation allows the system to select appropriate taps based on flow conditions, maintaining measurement precision across a wide incidence range while using a simple fixed structure.
Solution Approach 2:
The system dynamically selects which pressure taps to use for measurement based on the current flow conditions and incidence angle. The calculation means choose from among the pressure taps those allowing the best local incidence measurement precision, adapting to varying flight conditions without mechanical movement.
2Measurement precision
If the gain of the measurement chain is increased to obtain sufficient precision, then measurement precision improves, but the measurement chain saturates quickly
Solution Approach 1:
Multiple pressure taps are distributed across the nose surface at different positions and angles. This allows the system to segment the measurement function across multiple sensors, enabling precise measurement at low incidences while avoiding saturation at high incidences by selecting appropriate taps for each condition.
Solution Approach 2:
The system changes the operational parameters by selecting different pressure tap combinations based on the incidence angle. At low incidences, taps providing high precision are selected; at high incidences, taps that avoid flow detachment are chosen, effectively changing the measurement configuration to match flight conditions.
3Adaptability or versatility
If pressure taps are positioned to capture high incidence angles, then the measuring range is extended, but flow detachment occurs causing measurement distortion
Solution Approach 1:
The system dynamically evaluates flow conditions and selects pressure taps that remain in attached flow regions even at high incidences. The calculation means identify taps providing the best measurement precision under current conditions, avoiding taps affected by flow detachment while maintaining an extended measuring range.
Solution Approach 2:
The system uses feedback from pressure measurements to determine which taps are affected by flow detachment. Based on this feedback, the calculation means select appropriate taps for calculation, ensuring measurement accuracy across the full incidence range by adapting to real-time flow conditions.
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
This approach enhances measurement precision and range, effectively capturing high incidence angles without flow detachment, providing reliable data for aircraft piloting.
Implementation Method 1
at least five pressure taps arranged on a nose of the probe body... pressure measurement means associated with the pressure taps
Implementation Method 2
differential measurement between two pressure taps placed on the nose of the fixed appendix, one located on the underside of the appendix and the other on the extrados
Data Source
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AI summary
The invention relates to a local incidence measurement probe for attachment to a wall (11) and a method for implementing the probe. The probe (10) comprises at least five pressure ports (16, 17, 18) arranged on a nose (15) of the probe body (13), pressure measurement means associated with the pressure ports (16, 17, 18), and calculation means capable of determining the incidence of the flow relative to the principal direction (14) of the probe body (13) as a function of the pressures measured by the pressure measurement means. According to the invention, the calculation means are configured to select, from among the pressure ports (16, 17, 18), those that provide the best accuracy in measuring the local incidence and to calculate the local incidence relative to the principal direction (14) from the pressure measurements taken at the selected pressure ports (16, 17).