Page 16 - Demo

15conducted trials with such aircraft, from small aircraft flying in the controlled conditions of the University of Auckland Boundary Layer Wind Tunnel, located in the Newmarket Campus, to outdoors flying with a DJIMatrice 350. However, multirotors typically have poor range and endurance, limiting their area coverage. The use of a fixed-wing aircraft overcomes this hurdle, but brings an even bigger challenge: the aircraft cannot hover. If the unsteady wind varies in space and time, and so does the aircraft, how do you resolve the data recorded back to the point of interest? The aircraft velocity can be subtracted from the sensor reading to account for its direct contribution, but this can suffer from noise, which can cause the wind data to be lost beneath the relatively high speed of the aircraft. It also does not account for the spatial variability of the area which the aircraft is passing over. Therefore, this project is focused on the data collection and correction aspect.The first stage consisted of ground-based tests, using a moving probe in the wind tunnel. Providing a known path for the probe and controlled wind conditions, this has provided an assessment of how the data is influenced by probe motion at various speeds relative to the of the wind, and differing levels of unsteadiness. The second stage is now underway, which moves from the rigidly-defined motion of the test rig and controlled wind of the wind tunnel, to real-world flight testing.The sensor on a rotating boom for controlled-motion tests in the University of Auckland Boundary Layer Wind Tunnel. The grid beyond the rig is to induce an unsteady flow in the normally-steady wind tunnel. Photo: Dominic WangThe aircraft used is called Kuaka, a modified Volantex Ranger 2400. With a 2.4 m wingspan, this aircraft was chosen as an off-the-shelf airframe with a high payload capability and potential for later work with long endurance. The aircraft is fitted with a Holybro Pixhawk 6C Mini autopilot, providing a degree of autonomy for longer surveys, and uses Radiomaster telemetry transmitters and receivers. The biggest change, however, is the LiCor Li-550P ultrasonic anemometer projecting out the top of the forward fuselage. This is our wind measurement sensor, which can measure the wind in three directions up to 30 times per second. In addition, it can measure temperature, pressure and humidity, providing a compact and highly portable weather system. So far, Kuaka has not flown with the sensor fitted, instead focusing on checking flight systems and allowing the crew to become more familiar with the aircraft in flight. The support of the Tamaki Model Aircraft Club (www.tmac.co.nz) in this work has been invaluable. The airfield out at Pt England provides a good ground surface for rolling takeoffs, and plenty of room to manoeuvre as Kuaka is put through its paces. It also is very convenient for accessing from central Auckland. The support and encouragement from club members, and their advice, has also been a highlight of this project.Moving forwards, the sensor will be installed on the aircraft to begin collecting atmospheric data. Later flights will be conducted near NIWA meteorological stations, for validating the data collected by the aircraft against the state-of-the-art. It is hoped that the coming years will see the aircraft start to move into ore complex terrain, and so unlock the end goal of providing quality wind data for the numerical weather prediction models in regions which have not previously been detailed.This project is funded by the University of Auckland Warwick and Judy Smith Engineering Endowment Fund. Details on the project can also be found at Kuaka, the University of Auckland Fixed-Wing RPA, flying at the Tamaki Model Aircraft Club airfield, Pt England.https://dtrg.org/projects/current-research-projects/#WindDrone