k 



been shown to have some degree of verification. The method of determina- 

 tion of the hydroelastic parameters for these control surfaces is given in 

 References 5,6, and 7. Methods for determining certain damping terms 

 from observations, originally omitted from the flutter equations in 

 Reference 2, can now be included and are given in Reference 8. Related 

 studies of the static and dynamic loads on the rudder of a ship during a 

 steady horizontal maneuver, which is also of interest in the treatment of 

 flutter, were undertaken in References 9 and 10. 



The Bureau of Ships, recognizing the parallel need for the explora- 

 tion of the possibility of the occurrence of flutter in hydrofoil craft, 

 requested the David Taylor Model Basin to undertake a similar hydro- 

 elastic study for these craft. To achieve this objective, in this report 

 equations are derived for predicting the critical flutter speed of a 

 rigid foil flexibly attached to a uniform mass-elastic (i.e., nonrigid) 

 free-free beam immersed in a fluid moving with uniform velocity. The 

 analysis includes the two-dimensional quasi-steady expression for 

 hydrodynajnic force and moment on the foil. The relative influences upon 

 the vibrations, critical flutter speeds, and frequencies of the values of 

 the various parameters of the beajn-foil system are discussed in detail. 

 Certain special cases are also considered. A survey of the work performed 

 in this report is given in the Summary. 



