The full-scale data used for correlation are preliminary values of 
strains ¢« measured* at several chordwise stations at r=0.35R and r=0.45R 
on both sides of the blade on the DD-963 CP propeller. Both time-average 
strains per revolution and variation of strain with blade angular posi- 
tion were recorded during full-power stready-ahead operation. By inter- 
polation, values of radial strain at the spindle axis at r=0.4R were ob- 
tained. Assuming that the variation in radial strain is proportional to 
the variation in total (hydrodynamic, centrifugal, and gravitational) 
bending moment; i.e., that (e /[€ ) = /Mo 4)? these full- 
(M 
10.4 ax r0.4 0. 4vrax 
scale data indicate that (M /M. ,) = 1.48. From the model data 
0. 4uax 0.4 
[Me -)— ll W43and) OM 
0.4 say 
( 0.3 
M /M,. ,) = 1.56. A cursory evaluation 
0. 3ax 0.4 
of the variation of the full scale strain with blade angular position indi- 
cates that it follows trends similar to the bending moment determined from 
the model experiments. The correlation with full scale data presented 
here is preliminary; a more thorough correlation with the full scale data 
will be undertaken when analysis of the full scale data is complete. 
Theoretical calculations of hydrodynamic loads were made by using 
the method of Tsakonas et afi, 22 
which is based on unsteady lifting- 
surface theory and the method of Mecarehy co a quasi-steady technique 
which utilizes the open-water characteristics of the propeller. Although 
the method of McCarthy is a simple quasi-steady technique, it was judged 
that this method should be suitable to the cases under consideration in 
this report because the dominant unsteady loading occurs at a low reduced 
frequency and the dominant first harmonic of the wake is in phase radially 
*The full-scale measurements were conducted by personnel in DTINSRDC 
Code 1962 under the direction of G.P. Antonides. The results presented 
here are preliminary, and thorough analysis of the data is continuing. 
The details of this full-scale trial will be reported in a future DINSRDC 
report. 
a ieaoncice S. et al, "Documentation of a Computer Program for the 
Pressure Distribution, Forces and Moments on Ship Propellers in Hull 
Wakes," (In Four Volumes), Stevens Institute of Technology, Davidson 
Laboratory Report SIT-DL-76-1863 (January 1976). Revised April 1977. 
43 
