Hydrofoil Motions in a Random Seaway 

 Coefficients 



Cp = drag coefficient = Drag/qS^, 

 Cl = lift coefficient = Lift/qS 

 Cl = lift- curve slope = dCL/da 



a 



Cl = lift- curve slope = dCL/dh 



h 



C£ = rolling moment coefficient = L/qSb 

 C^ = pitching moment coefficient = M/qSb 

 C^ = yawing moment coefficient = N/qSb 



Subscripts 



( )^ = steady- state or reference condition 



( ) p denotes front foil 



( )^ denotes main foil 



( )l denotes left-hand side of main foil 



( )r denotes right-hand side of main foil 



( )^ denotes wave 



ACKNOWLEDGMENTS 



The authors wish to thank the Royal Canadian Navy for permission to use 

 much of the information presented in this paper. We gratefully acknowledge the 

 advice and assistance of R. W. Becker, E. R. Case, P. A. Maritan and A. C. 

 Stonell. 



Thanks are also due to E. Ball, F. Miller, Mrs. N. lies and Miss L. Wilkin- 

 son for the preparation of the manuscript. 



REFERENCES 



1. Etkin, B.: Dynamics of Flight. John Wiley and Sons, Inc., New York 1959. 



2. Duncan, W. J.: Control and Stability of Aircraft. Cambridge University 

 Press, Cambridge 1952. 



651 



