Kaplan, Sargent and Goodman 
timates obtained from the first ''pass'' used as the initial guess for 
the second pass, The results are shown in Figure 11 for the manner 
in which the parameter values change as functions of time. It is seen 
that all of the parameter values stabilized except for Ks which tended 
to fall off toward the end of the maneuver, Examination of the various 
motion and deflection time histories showed erratic fluctuations in 
6¢ in this region , so that the value of Ky before the fall-off was 
retained. These coefficient values obtained from Experiment 1 were 
then used as the initial guess values from analysis of another maneu- 
ver of the craft, denoted as Experiment 4 ( the control deflection for 
that case is shown in Figure 10). 
In the analysis of Experiment 4 the initial value of K, 
was inadvertently takenas .05 instead of .50. However the esti- 
mate of Kg rapidly moved back to a reasonable value as time in- 
creased in the first pass. All of the other parameters did not show 
much change from their initial values, which were taken from the 
results of Experiment 1 and from the first pass for the second pass 
case, An illustration of the variation of the parameters during the 
analysis of Experiment 4 is given in Figure 12. A tabulation of the 
values obtained from analysis of the full scale hydrofoil data is given 
below in Table 4. 
Table 4 
Hydrofoil Parameters-System Identification Using Full Scale Data 
Parameter Estimated Value 
K Be 
e 
K, acts. 
K, Oi 
K, 14 
wri cat 
Cc, pg M0, 
A 
1 
—— me Oi 
G; 
a 1. 30 
C zs 
1664 
