10.31 An airplane flies at 200 km h through still air of specific weight 12 N m3. The propeller is 2.4min diameter and its slipstream has a velocity of 290 km h relative to the fuselage. Calculate

(a) the propeller efficiency,

(b) the velocity through the plane of the propeller,

(c) the power input,

(d) the power output,

(e) the thrust of the propeller, and (f ) the pressure difference across the propeller disk.