Hadler and He eke r 



(«^ 



THRUST COEFFICIENT, C^ 

 Fig. 22 - C^ - T7g - J diagram of propeller 3768 partially submerged 



helpful. Three flow regions are distinguishable for surface ventilated foils 

 as follows: 



Base-Vented Region. In this regime the cavity springs from the blunt trail- 

 ing edge of the foil and trails aft. At this condition the foil develops its approxi- 

 mate design lift. This is also the condition in which the foil develops its highest 

 lift-to-drag ratio. K the foil has some reduction in thickness at the trailing edge 

 the ventilation probably starts from a separation point near the point of maxi- 

 mum thickness. 



Partially Cavitating Region. In this regime a vapor cavity of less than one 

 chord length exists on the suction side of the foil. At this condition the foil force 

 and moment coefficients are usually unsteady. 



1472 



