Abstract
The authors showed that in Kazakhstan northern region grain harvesters of 4, 5 and 6 classes did not provide the required level of productivity due to low yields. Longer harvesting period increased product losses. It was found that the harvesting machines were working in the incomplete loading mode of the thresher. The authors revealed the discrepancy between the standard sizes of the used reaping machines and regional zonal features. (Research purpose) To substantiate the parameters of headers and reaper-headers for combine harvesters in the incomplete loading mode of the thresher. (Materials and methods) The authors performed technical and economic calculations according to the criterion of operating costs for direct combining with a yield of 0.5 to 2.5 tons per hectare. The calculation was carried out for combine harvesters Vector-410 (class 4), Acros-550 (class 5), Essil-760 (class 6), aggregated with headers of different working widths. (Results and discussion) The authors determined that for the combine Vector-410 the rational width of the header was 9 meters in the yield range of 0.5-1.5 tons per hectare, and with a yield of 2.0-2.5 tons per hectare – 7-9 meters. For the combine Acros-550 the rational width of the reaper-header was 16 meters with a yield of 0.5-1.0 tons per hectare, with 1.5 tons per hectare - 9-12 meters, and with 2.0-2.5 tons per hectare – 7-9 meters. For the combine Essil-760 these values were 16; 12 and 9 meters respectively. (Conclusions) It was found that when comparing grain harvesters of 4, 5 and 6 classes with a yield of 0.5-2.0 tons per hectare, the lowest operating costs were provided by Acros-550 and Essil-760; with a yield of 2.0 tons per hectare - Vector-410; with a yield of 2.5 tons per hectare the Acros-550 was more effective.