Probeless Airspeed Measurement for Propeller Vehicles
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Solution Overview
Problem
Aircraft, especially small unmanned aerial vehicles (UAVs), face challenges in accurately measuring airspeed due to the size constraints of traditional pitot-static probes, which can lead to errors in static pressure measurements and are costly and heavy, making them unsuitable for low-cost vehicles.
Innovation Solution
A method to determine airspeed using propeller power parameters such as power delivered, air density, propeller power coefficient, and advance ratio, and to calculate angle-of-attack by determining dynamic pressure and body normal coefficient without relying on pitot-static probes, utilizing a flight computer and sensors to perform calculations based on lookup curves and equations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional pitot-static probes are used for airspeed measurement, then airspeed can be measured, but the vehicle weight increases and cost increases
Solution Approach 1:
The patent replaces the mechanical pitot-static probe system with a computational method that uses propeller performance parameters (power delivered, air density, propeller power coefficient, advance ratio) to calculate airspeed. This substitution eliminates the need for physical pressure-sensing hardware, thereby reducing vehicle weight while maintaining measurement capability through mathematical relationships derived from propeller theory.
Solution Approach 2:
The patent introduces propeller performance parameters as intermediary variables to bridge the relationship between engine power and airspeed. By using the propeller as a mediator, the system translates mechanical power delivery into airspeed information without requiring direct pressure measurement, thus avoiding the weight penalty of traditional probes.
2Measurement precision
If traditional pitot-static probes are used for airspeed measurement, then airspeed can be measured, but the vehicle cost increases
Solution Approach 1:
The patent replaces expensive mechanical pitot-static probe hardware with a software-based computational approach. By using readily available sensors (propeller RPM, engine power, air density) combined with mathematical calculations, the system achieves airspeed measurement capability without requiring costly precision pressure-sensing components, thereby reducing overall vehicle manufacturing cost.
Solution Approach 2:
The patent creates a virtual model of airspeed measurement through computational algorithms that replicate the function of physical probes. By using mathematical relationships and lookup curves to simulate what a probe would measure, the system achieves the same measurement objective through software rather than expensive hardware.
3Measurement precision
If small vehicles use pitot-static probes, then airspeed can be measured, but measurement errors increase due to tight proximity of static ports to airframe
Solution Approach 1:
The patent eliminates the static pressure measurement function entirely by substituting it with a computational approach. Instead of relying on physically vulnerable static ports that are prone to contamination and positioning errors in small vehicles, the system calculates airspeed from propeller performance parameters, which are not susceptible to the same environmental interference and positioning sensitivity issues.
Data Source
AI summary
An exemplary method to determine an airspeed and an angle of attack of a propeller powered vehicle includes determining the power delivered to the propeller, the air density, a propeller power coefficient, an advance ratio for the propeller, and the airspeed using the advance ratio and determining the angle of attack using the airspeed.