Drawbar Performance Prediction of Agricultural Tractors

A project was undertaken to study the influence of soil, tyre and system parameters on performance of three traction tyres commonly used on Indian tractors. Developed experimental facilities include tyre test carriage with continuous recording of input torque, drawbar pull, tyre sinkage and forward speed. Deflection and contact characteristics were made using multiple overlay technique and present universal characteristic of tyre was modified for a group of tyres. Zero condition was established on hard surface highlighting the weakness of specified zero conditions. Traction prediction equations were developed and compared with existing models using mobility number approach. The unique values of optimum normal load, maximum drawbar pull and optimum pull to weight ratio were determined at 20, 25 and 30 per cent slip. Selection of optimum size tyre for tractors on the basis of weight power utilization and soil tyre interface was also done.