Thesis (M.Eng.) - Asian Institute of Technology, 1993

A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering.

This research was carried out to investigate the problems associated with the working of locally- made rice combine harvester used by the farmers and the contractors in Thailand. The study was divided into four sections. Firstly the farmer's opinion was obtained about rice combine harvester during the process of data collection. Secondly, the information about the machine performance and field problems was gathered from the contractors through a comprehensive questionnaire. Thirdly, the manufacturing process was observed, analyzed and evaluated. Lastly, the field performance of the machine was evaluated through observations in 29 fields in the four provinces in the Northern Thailand. The results of the study infer that the farmers were satisfied with the performance of the machine. The contractors were not satisfied and wanted improvements in the machine and the availability of the spare parts. The design of the threshing unit and its position, and the transmission system of the rice combine harvester needed improvements. Effective field capacity of the rice combine harvester ranged from 0.1- 0.7 ha/h, with an average of 0.4 ha/h and the total grain losses varied from 1.3- 10.8% of grain yield, with an average of 4.8%. The field efficiency varied from 28% to 92% with an average of 66%. Considering the present rate of manual harvesting as Bht 3,206/ha, the break ·even area was found to be 105 ha. The economic analysis further showed that the pay back period was less than two years, if the machine could harvest 640 ha/year.