which multiplies the camber of a two-term foil in an infinite medium, and then adjust the angle of 

 attack and the point drag to meet the conditions of the given lift and leading-edge cavity thickness; 

 Case 2 - find the camber and the angle of attack to meet the conditions without introducing a point 

 drag. If the specified leading-edge thickness is not large enough to produce a cavity longer than 1 .5 

 chord lengths, a point drag is added to produce a 1.5-chord cavity length without changing the lift 

 coefficient. If the given camber factor is too large the angle of attack may be negative, i.e. less than 

 the shock-free angle of attack. In this case, the given camber of the shock-free foil is reduced to 

 meet the given lift coefficient without the negative angle of attack. 



The pitch distributions for Models 3770 and 3870 are shown in Figures 2-4 for various leading- 

 edge cavity thicknesses which are shown in Figures 5 and 6 along with the various design thrust 

 coefficients Cj. for Case 1 and Case 2. In the figures, a group of four numbers or symbols (A, B, C, 

 D) indicates: A = camber, B = thrust coefficient, C = efficiency, and D = leading-edge cavity 

 thickness distribution, as shown in Figures 5 and 6. Radial sections that have finite-length cavities 



1.0 



P/D 



0.6 



T I I | 



O POINTS FOR FINITE CAVITY LENGTH 



CAMBER FACTOR, Cy, e, CAVITY THICKNESS TYPE (FIG. 5) 



(1, 1.125, 47.7, A) 



(1.5, 1.05, 50.3, A) 



(1, 1.05, 49.2, A) 



MODEL 3770 Ml. 0.984, 50.3, C) (1, 0.985, 50.1, A) 



(1.5, 0.985, 52.0) 



Tit TAN/3j (C T = 1.05) 



?rr TAN 0j (C T = 0.985) 



0.2 



0.6 



r/R 



Figure 2 - Pitch Distributions of Lifting Line Design 

 for Supercavitating Propeller Model 3770, Case 1 



10 



