This paper presents research on the power delivery efficiency of wheeled tractors and its dependence on wheel slippage of central and eccentric drawbar forces on unplowed and plowed stubble. For this purpose, mathematical models and one algorithm were developed. | Research Article Turk J Agric For 36 (2012) 486-500 © TÜBİTAK doi: Influence of eccentric drawbar force on power delivery efficiency of a wheeled tractor Mirko SIMIKIĆ1,*, Nebojša DEDOVIĆ1, Lazar SAVIN1, Milan TOMIĆ1, Hasan Hüseyin SİLLELİ2, Ondrej PONJIČAN1 1 Department of Agricultural Engineering, Faculty of Agriculture, University of Novi Sad, 21000 Novi Sad - SERBIA 2 Department of Agricultural Machinery, Faculty of Agriculture, Ankara University, 06130 Aydınlıkevler, Ankara - TURKEY Received: ● Accepted: Abstract: Power delivery efficiency shows how much engine power is used for a tractor drawbar. Eccentric traction is a factor influencing the power delivery efficiency of a wheeled tractor. It occurs as a consequence of the offset position of a tractor implement, that is, when the traction line of the tractor and resistance line of the implement are parallel and do not coincide. This paper presents research on the power delivery efficiency of wheeled tractors and its dependence on wheel slippage of central and eccentric drawbar forces on unplowed and plowed stubble. For this purpose, mathematical models and one algorithm were developed. The best power delivery efficiency of the tractor on both unplowed and plowed stubble surfaces was obtained with central drawbar force. Power delivery efficiency of the tractor on unplowed stubble decreased by if eccentricity increased up to m and by if eccentricity increased up to m. Power delivery efficiency of the tractor on plowed stubble decreased by if eccentricity increased up to m and decreased by if eccentricity increased up to m. Key words: Eccentric drawbar force, power delivery efficiency, slippage, wheeled tractor Introduction The primary purpose of agricultural tractors, especially those in the middle to high power range, is to perform drawbar work (Zoz and Grisso 2003). Drawbar power is defined as the product of .