Influence of Unmanned Aerial Vehicle (UAV) Payloads and Flight Speeds on Pesticide Droplet Deposition: Indoor Testing Rig Study

This study aims to determine droplet deposition resulting from dynamic change in payloads and flight speeds of Unmanned Aerial Vehicle (UAV) during operation. The study was conducted at Universiti Putra Malaysia, Serdang, Malaysia. The Advansia A1 hexacopter was first set to fly at combinations of 3 payloads (3.3, 6.6, and 9.9 kg) with 3 flight speeds (3, 5 and 7 m/s) to collect individual rotor RPM, which will later be used to set the rotors’ speed during indoor testing experiment. During the experiment, actual pesticide (Alosa EC) was used at 0.5% concentration in the spray deposition test. The droplet deposition sample was collected using water-sensitive paper and analyzed with DepositScan software. Result obtained showed that the droplet size, number of droplets per area and deposition rate were significantly affected by the UAV’s flight speed at a significant level of P< 0.05, with all the deposition characteristics tested reduced as the flight speed increased. Due to the travelling pattern of the UAV, the amount of deposition during the accelerating and decelerating phases was found to be 2 to 8.5 times higher compared to the amount of deposition during the stable phase. As a conclusion, the travelling pattern of UAV varied with the flight speed along the pathway, which had an effect on the deposition rate. The obtained finding is remarkable, critical and useful in managing UAV and improving the spraying deposition.