eng Estonian Academic Agricultural Society Agraarteadus 1024-0845 2228-4893 2021-06-26 32 1 41 48 10.15159/jas.21.15 article Yevhen Ihnatiev 1 Volodymyr Bulgakov 2 Vitaliy Bonchik 3 Zinoviy Ruzhylo 2 Anatoliy Zaryshnyak 4 Volodymyr Volskiy 5 Viktor Melnik 6 Jüri Olt 7 Dmytro Motornyi Tavria State Agrotechnological University, 18B Khmelnytsky Ave., UA 72310, Melitopol, Zaporozhye Region, Ukraine National University of Life and Environmental Sciences of Ukraine, 15 Heroyiv Oborony St., Kyiv, UA 03041, Ukraine State Agrarian and Engineering University in Podilia, 13 Shevchenko St., Kamenets-Podilsky, UA 32300, Ukraine The National Academy of Agrarian Sciences of Ukraine, 9 Mikhail Omelyanovich-Pavlenko St., Kyiv, UA 01010, Ukraine National Scientific Centre, Institute for Agricultural Engineering and Electrification, 11 Vokzalna St., Glevakcha 1, Vasylkiv District, UA 08631, Kyiv Region, Ukraine Kharkiv Petro Vasylenko National Technical University of Agriculture, 44 Alchevskih St., Kharkiv, UA 61002, Ukraine Estonian University of Life Sciences, Institute of Technology, 56 Fr. R. Kreutzwaldi St., 51006 Tartu, Estonia. jyri.olt@emu.ee The experimental research was carried out on a specially designed laboratory-and-field test unit with the use of a hydraulic vertical rotor drive and strain-gauge equipment mounted on a tractor as well as the set of interchangeable coupling pieces for setting the machine's operating duty. Research into the process of breaking two adjacent potato row beds with the vanes of a vertical rotor has been undertaken. A design and process schematic model has been proposed for the operation of the potato harvester. Experimental research into the geometrical parameters of the potato row has been carried out to select the design parameters of potato harvesters. Based on the results obtained during the experimental investigations, the rational ranges have been established for the work process of the rotary potato harvester, the methods of engineering clod breaking tools have been developed. Following the completion of the full factorial experiment, regression functions have been generated. Their analysis has proved that the following factors have the greatest impact on the optimisation parameters: the rotor diameter and the clearance between the rotor and the spherical discs. The following parameters have been optimised based on the response surface analysis: soil separation ratio S = 93.5%, tuber damage rate Pb = 0.97%, total power consumption by unit operation Nа = 18.27 kW, at the following pre-set values of the factors: nр = 77 min–1, Vm = 2.2 m∙s–1, dр = 0.825 m, l2 = 0.3 m. The maximum discrepancy between the results of the theoretical and experimental investigations for determining the design and process parameters of the potato harvester does not exceed 15%. The completed economic testing has proved the advantages of the experimental potato harvester as compared to the existing ones. That said, the separation ratio of the pilot machine is equal to S = 91.4%, which is 23% higher than in the reference case, while its tuber damage rate is equal to 1.14%, which is 5.0% better than in the reference case. The recommendations for the selection of the rational operation duty of the rotary potato harvester as well as the methods for the engineering analysis of the design and process parameters of clod breaking tools have been developed. http://agrt.emu.ee/pdf/2021_1_ihnatiev.pdf clod-crushing potato harvester rotor soil separation