Unmanned Aircraft Systems Performance in a Climate-Controlled Laboratory

Abstract

Despite many research studies focus on strategies to improve autopilot capabilities and bring artificial intelligence onboard Unmanned Aircraft Systems (UAS), there are still few experimental activities related to these vehicle performance under unconventional weather conditions. Air temperature and altitudes directly affect thrust and power coefficients of small scale propeller for UAS applications. Reynolds numbers are usually within the range 10,000 to 100,000 and important aerodynamic effects, such as the laminar separation bubbles, occur with a negative impact on propulsion performance. The development of autonomous UAS platforms to reduce pilot work-load and allow Beyond Visual Line of Sight (BVLOS) operations requires experimental data to validate capabilities of these innovative vehicles. High quality data are needed for a deep understanding of limitations and opportunities of UAS under unconventional flight conditions. The primary objective of this article is to present the characterization of a propeller and a quadrotor capabilities in a pressure-climate-controlled chamber. Mechanical and electrical data are measured with a dedicated test setup over a wide range of temperatures and altitudes. Test results are presented in terms of thrust and power coefficient trends. The experimental data shows low Reynolds numbers are responsible for degraded thrust performance. Moreover, details on brushless motor capabilities are also discussed considering different temperature and pressure conditions. The experimental data collected in the test campaign will be leveraged to improve UAS design, propulsion system modelling as well as to provide guidelines for safe UAS operations in extreme environments.

Sensors and Measurements for UAV Safety: An Overview

“…Often UAVs are asked to operate in harsh environments, characterized for example by low temperatures and high altitudes. However there are few research works including investigations into the UAV performance in those conditions, which are essential to ensure safe operations [95]. At low temperature, the main factor affecting UAV performance is ice accumulation on propellers [95,96].…”

“…However there are few research works including investigations into the UAV performance in those conditions, which are essential to ensure safe operations [95]. At low temperature, the main factor affecting UAV performance is ice accumulation on propellers [95,96]. However, the UAV performance is also dependent on the Reynolds number derived from air temperature and pressure conditions [95].…”

“…At low temperature, the main factor affecting UAV performance is ice accumulation on propellers [95,96]. However, the UAV performance is also dependent on the Reynolds number derived from air temperature and pressure conditions [95].…”

“…Interesting experimental activities aimed at investigating the influence of pressure and temperature at low Reynolds number on the UAV performance, in a climate controlled facility, can be found in [95,[97][98][99]. In particular, both the temperature and pressure effects on the propeller thrust [97,99] and the isolated rotor and full UAV performance data under unconventional atmosphere conditions [95] were investigated. The experimental setup used in [95] was realized to avoid the effects that extreme temperatures can have on sensors in terraXcube, Eurac Research laboratory.…”

“…In particular, both the temperature and pressure effects on the propeller thrust [97,99] and the isolated rotor and full UAV performance data under unconventional atmosphere conditions [95] were investigated. The experimental setup used in [95] was realized to avoid the effects that extreme temperatures can have on sensors in terraXcube, Eurac Research laboratory. Here, extreme environmental conditions can be simulated in a controllable and safe way.…”