Francis turbine works under a total head of 25 ?m. ?The outer and inner diameters of the runner are 0.70 ?m and 0.35 ?m respectively. The vane tip is radial at the inlet and the flow leaves the turbine radially. The inlet guidevane angle is 12º. ?Calculate the speed of the runner and the vane angle at the exit, if the velocity of flow is constant at 4.0 ?m/s. ?Assume the hydraulic efficiency as 0.90. ?peed of the turbine is 9.2 , ?estimate the maximum overall efficiescy.