Increased outlet design of flat-fan nozzle improves octocopter unmanned aerial vehicle sprayer's efficiency

Abstract

Increased interest in unmanned aerial vehicle (UAV) sprayers leads to identifying the factors affecting their efficiency. This study aimed to check and introduce a factor that has not been considered so far – the outlet design of a flat-fan nozzle. In a field experiment, spray drift potential and chemical weed control efficacy (sulfosulfuron against spontaneous barley) from an octocopter UAV sprayer was evaluated as a two-factor randomized complete block design including nozzle type (standard, anti-drift, and air induction) and nozzle outlet design (single, twin, and triplet-orifice). When averaged over nozzle outlet design, 22.9, 31.0, and 39.6% in-swath spray deposition and 66.0, 73.6, and 93.5% spontaneous barley control were obtained for standard, anti-drift, and air induction nozzles, respectively. Also, a similar trend from out-swath spray coverage was observed up to 8 m. In the standard, anti-drift, and air induction nozzles, an outlet design change from single-to triplet-orifice changed in-swath spray coverage by −30.8, +16.4, and +39.4% and herbicide efficacy by −27.1, +27.7, and +19.3%, respectively. The results showed that the outlet design of flat-fan nozzles had a significant interaction effect with the nozzle type. It was suitable with the anti-drift and air induction nozzles but unsuitable with the standard nozzle.