An axial flow fan has a hub diameter of 1.5 m and a tip diameter of 3 m. It rotates at 250 rpm and handles an airflow rate of 12.5 cubic meters per second. Assume that the velocity of flow is independent of radius and that the energy transfer per unit length of the blade is constant. Further, assume ‘no-shock’ condition at the inlet. The blade outlet angle at the tip is 20 degrees. Find the blade inlet angles at the hub (β1h) and the tip (β1t), and the theoretical head (Euler head), He, developed by the fan.