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Q8. A model propeller of 0.4 m diameter and 0.95 pitch ratio, is tested under conditions of constant speed of advance of 1.25 m/s in fresh water of density 1000 kg/m³.

The thrust and torque values for a range of rotational speeds are given in Table Q8.

(a) Draw Curves Of propeller efficiency and delivered power against real slip ratio for the model propeller.  (9)

(b) Using the curves drawn in Q8(a), determine EACH Of the following:

(i) the model propeller rotational speed for maximum efficiency; (4)

(ii) the delivered for a geometrically Similar ships propeller of 6.5 m diameter, operating in sea water of density 1025 kg/m³ at a real slip ratio of 0.3, given that delivered power is proportional to (diameter)^3.5 (3)