Flush-Mounted Static Pressure Probe with Laser Anemometry
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Solution Overview
Problem
Conventional anemobarometric measurement systems on aircraft are prone to icing, leading to unreliable measurements and high electrical consumption due to protuberant probes, and non-protuberant systems are costly, difficult to install, and sensitive to aircraft skin imperfections, while also compromising stealth and flight domain completeness.
Innovation Solution
A static pressure measurement probe system with a base and local pressure tapping coupled to a pressure sensor, featuring optical windows and micro-lidars for anemometry measurements within the airflow limit layer, reducing icing sensitivity and RADAR/thermal signatures, and eliminating the need for pneumatic tubes, with a cost-effective and robust design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If protuberant probes (Pitot probes, incidence probes, sideslip probes) are used for measurements, then measurement capability is provided, but icing occurs leading to unreliable measurements and high electrical consumption for de-icing
Solution Approach 1:
The patent extracts the harmful protuberant probe structures from the aircraft surface and replaces them with flush-mounted pressure tappings. The static pressure is measured through holes tapped directly into the aircraft skin, eliminating the need for external protruding probes that are susceptible to icing accumulation.
Solution Approach 2:
The patent replaces the mechanical protuberant probe system with an optical measurement system using micro-LIDAR. The LIDAR measures airspeed and flow characteristics optically through the flush-mounted pressure tappings, substituting mechanical probing with non-contact optical detection that is immune to icing.
2Object-affected harmful factors
If flush systems (non-protuberant systems) are used to mitigate icing problems, then icing resistance is improved, but cost increases and installation becomes difficult due to sensitivity to aircraft skin imperfections
Solution Approach 1:
The patent applies local quality by creating highly localized pressure measurement zones through precisely drilled tappings with specific diameter ratios (hole diameter to skin thickness between 0.5-2.0). Each tapping location is carefully selected and sized to minimize sensitivity to surrounding skin imperfections while maintaining accurate static pressure measurement.
Solution Approach 2:
The patent changes the geometric parameters of the pressure tappings, specifically optimizing the ratio of hole diameter to skin thickness and the depth of the tapping. These parameter adjustments make the flush system less sensitive to variations in aircraft skin quality and easier to install across different aircraft types.
3Reliability
If protuberant probes are reheated to prevent icing, then measurement reliability is maintained, but RADAR echo and infrared thermal emission increase compromising stealth
Solution Approach 1:
The patent removes the heated probe structures that generate RADAR and thermal signatures. By using flush-mounted unheated pressure tappings combined with optical LIDAR measurement, the system eliminates the sources of detectable electromagnetic and thermal emissions while maintaining measurement capability.
Solution Approach 2:
The patent replaces the thermal de-icing system with an optical measurement system. Instead of heating probes to prevent icing, the flush-mounted tappings are used with LIDAR to optically measure flow characteristics, eliminating the need for thermal management and associated stealth compromises.
4Device complexity
If conventional speed measurement based on Pitot probe is used, then simplicity is maintained, but accuracy is reduced due to inability to measure true airspeed and density
Solution Approach 1:
The patent creates a multi-functional measurement system where the flush-mounted pressure tappings serve multiple purposes: static pressure measurement for airspeed calculation, reference pressure for LIDAR anemometry, and flow characterization. This universal approach provides both conventional and true airspeed measurements from a single integrated system.
Solution Approach 2:
The patent introduces the LIDAR anemometry system as an intermediary measurement tool that uses the flush-mounted pressure tappings as reference points. The LIDAR measures scattered light from aerosols or particles in the airflow relative to the pressure tapping locations, enabling precise airspeed and density measurements that complement the conventional pressure-based system.
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 system provides reliable, low-cost, and stealthy static pressure measurements throughout the flight domain, resistant to icing and impacts, with reduced RADAR and thermal signatures, and accurate air speed vector components close to the measurement point.
Implementation Method 1
a laser anemometry probe configured to take anemometry measurements in an imaginary cylinder centred on the static pressure tapping
Implementation Method 2
an optical window that is transparent to a laser radiation
Data Source
AI summary
A static pressure measurement probe system comprises: a base to be fixed onto the cockpit of an aircraft; at least one local pressure tapping formed through the base and coupled to a pressure measurement sensor; for each local pressure tapping, at least two assemblies each comprising an optical window that is transparent to a laser radiation and a laser anemometry probe configured to take anemometry measurements in an imaginary cylinder centred on the local pressure tapping and of a diameter less than 3 cm and of a height less than 4 cm counted from the outer end of the local pressure tapping, so that the measurements are within the airflow limit layer.