Dynamites of Naval Craft - System Identtficatton 
applied to the data still did not allow proper identification of the 
required parameters by the iteration method, and hence the sequential 
estimation technique was applied. 
The equations representing the hydrofoil craft motion for 
the full scale case were simplified to represent only heave and pitch, 
as previously considered for the computer generated data. However 
nonlinear lift terms were still retained while the added mass terms 
were kept fixed (assumed known) at the values 350 slugs forward and 
950 slugs for the rear foil. The equations contain expressions for 
the lift forces on the forward and rear foil, which are represented in 
terms of the lift coefficients as : 
2 
w w 
J F p obs 
CL ne areas oe eer gat (42) 
F 
where Aipiud aE y 
EF soriode «wailing BL, (43) 
= = ; 
it C, ve 
2 
w Ww 
R R 
= 6 " 
CL ( + Kp, +7") z+, E2) (44) 
R 
Pee AB YS 
F, + Z Zz R (45) 
oo 
Ree ee B 
The 10 unknown parameters are K, , K, ‘ A, on Dy C, ee 
K,, Az, Bg, C which are similar to the coefficients previously 
represented ; i.e. en = C3, Ky =. Cy.» Kap =e CouuwKon =e Gy9 . 
The representation of F, and F, in Equations (43) and (45) was 
proposed as the required form for the depth effect on lift by the spon- 
soring agency, who supplied the proposed mathematical model. 
The analysis of the full scale data was applied to the 
first maneuver (Experiment 1) in the vertical plane, with the initial 
guess of the coefficients taken from the results of the computer 
generated data analysis discussed above, and the initial values of the 
coefficients in the depth terms F, , and F, were takenas 1.0. 
A 10 sec. data portion was analyzed twice, with the parameter es- 
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