Puddling characteristics and performance of the tilling wheel of a float-assisted tiller

Float-assisted tiller is used for tillage operations under lowland conditions. It is an alternative to carabao (Bubalus bubalis) or two-wheel tractor (walking-type). A float-assisted tiller consists of a front-mounted cage wheel (tilling wheel) and a float on which the engine is mounted. The tilling wheel has the same configuration as that of a lowland two-wheel tractor's cage wheel. The cage wheel-like configuration of the tilling wheel produces traction and floatation for the tiller. The high-speed wheel rotation and spikes of the tilling wheel produce similar cutting effects as that of rotary tiller. The study aimed to determine the effects of lug angle (13 deg C and 0 deg C), blade shape (triangular, rectangular, and no blades), forward speed (0.5, 1.0 and 1.5 kph) and shaft speed (200, 250 and 300 rpm) on the puddling characteristics and performance of the tilling wheel. The experiments were done using a single tilling wheel in a laboratory soil bin using Maahas clay. Torque transducer, speed shaft sensor and load cells were used to measure forces. The highest maximum draft of 191.1 N was attained on the 1st pass using triangular blades set at 13 deg C lug angle, 200 rpm shaft speed and 1.5 kph forward speed. In general, maximum draft was obtained on the 1st pass for all lug angles and blade shaped. Maximum draft is not affected by the lug angle and blade shape. The highest average axle power of 1,264.4 W was obtained on the 1st pass using rectangular blades set at 300 rpm and 1.5 kph. Average axle power is affected by the lug angle, blade shape, forward speed, number of passes and shaft speed.The highest performance index of 1,334.6 m sup 3/MJ was noted on the 3rd pass using triangular blades set at 13 deg C lug angle, 200 rpm and 1.5 kph. Performance index is affected by the lug angle, blade shape, forward speed and number of passes. The mean differences of performance index among forward speeds are significant only between 0.5 and 1.0 kph. The mean differences of performance index among passes are not significant between 2nd and 3rd pass. The highest tractive efficiency was 11.2% on the 1st pass with triangular blades (13 deg C lug angle), 200 rpm and 1.5 kph. The mean differences of performance index and tractive efficiency between blade shape are not significant between rectangular and no blades. The best blade configuration for float-assisted tiller would be triangular blades with 13 deg C lug angle of its performance index and tractive efficiency.