Aircraft Probe Placement for Static Pressure Determination

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Solution Overview

Problem

Existing aircraft systems require multiple measurement probes and complex calculations to determine static pressure at infinity upstream, which increases system complexity and operational safety constraints.

Innovation Solution

The aircraft is equipped with two multifunction measurement probes, one placed in a zone where the pressure coefficient is unique to local incidence, allowing determination of static pressure at infinity from a single probe, and a second probe in a symmetrical zone for redundancy, simplifying the system and enhancing safety.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If multiple measurement probes are used to determine static pressure at infinity upstream, then measurement reliability is improved, but device complexity increases

Engineering Contradiction:
Improvemeasurement reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The fuselage is divided into distinct zones based on pressure coefficient characteristics. The first zone has a unique pressure coefficient function of local incidence, while the second zone has a different function. This segmentation allows selective placement of measurement probes in optimal locations, enabling accurate static pressure determination with fewer probes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the fuselage are assigned different functional qualities based on their pressure coefficient characteristics. By placing measurement probes specifically in zones where the pressure coefficient is a unique function of local incidence, the system achieves reliable measurements with reduced probe requirements, thus lowering device complexity while maintaining reliability.

Inventive Principle:
Principle #3Local quality

2Measurement precision

If multiple measurement probes are used to determine flight parameters, then measurement precision is improved, but system complexity increases

Engineering Contradiction:
Improvemeasurement precisionVSAvoidsystem complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The pressure coefficient functions for different fuselage zones are predetermined and stored in memory before flight. During operation, the microprocessor simply retrieves the appropriate function based on probe location and inputs local incidence measurements to calculate static pressure at infinity upstream, eliminating the need for complex real-time computations and multiple probes.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system changes the parameter of probe placement location from arbitrary positions to specifically optimized zones on the fuselage. By selecting zones where pressure coefficient has a unique functional relationship with local incidence, the system achieves precise measurements with simplified calculation requirements, reducing overall system complexity.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If measurements are taken at multiple distinct locations, then static pressure determination accuracy is improved, but operational safety constraints increase

Engineering Contradiction:
Improvestatic pressure determination accuracyVSAvoidoperational safety constraints
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

A single measurement probe in the first zone performs multiple functions: it measures local incidence, determines the pressure coefficient through the unique function relationship, and calculates static pressure at infinity upstream. This multi-functionality eliminates the need for multiple probes at distinct locations, reducing operational safety constraints while maintaining measurement accuracy.

Inventive Principle:
Principle #6Universality (Multi-functionality)

4Device complexity

If a single measurement probe is used, then device complexity is reduced, but measurement reliability deteriorates

Engineering Contradiction:
Improvedevice complexityVSAvoidmeasurement reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The mechanical approach of using multiple physical probes is replaced with a computational approach using predetermined pressure coefficient functions stored in memory. The microprocessor uses these functions along with local incidence measurements to reliably determine static pressure at infinity upstream, achieving reliable measurements with a single probe by substituting mechanical redundancy with computational processing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical 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

This configuration enables the determination of flight parameters, including static pressure at infinity, from a single measurement probe, reducing system complexity and improving operational safety by providing redundant measurements.

Implementation Method 1

the measurement probes 6A, 6B each comprise means for measuring the static pressure 8A, respectively 8B, means for measuring the local incidence 10A, respectively 10B and means for measuring the total pressure 12A, respectively 12B

Methodology Applied
Scientific EffectPitot tube principle: Pitot Tube

Data Source

PatentEP2821347B1Aircraft including a measuring probe and method for determining flight parameters of such an aircraft
Publication Date: 2017.08.09 THALES SA
  • EP2821347B1 patent drawingFigure 1
  • EP2821347B1 patent drawingFigure 2~4
  • EP2821347B1 patent drawingFigure 5~6

AI summary

An aircraft comprising a fuselage (4) and a first measuring probe (6A) including means for measuring local angle of attack, means for measuring static pressure, and optionally means for measuring total pressure. The fuselage (4) includes at least one first zone (14) where the aircraft pressure coefficient is a single function of the local angle of attack regardless of the aircraft's angle of attack and sideslip values, and the first measuring probe (6A) is arranged in said first zone (14).