measurement and theoretical prediction of blade loading of CP propellers. 
Work under the other sections of this program will be reported separately. 
The present report presents experimental results obtained on a model 
of the CP propeller on the DD-963 Class Destroyer. The results of similar 
experiments on a model of the FF-1088 were reported in Reference 2. 
BACKGROUND 
Extreme care must be taken to design the blades and pitch-changing 
mechanisms of high power CP propellers so that they possess adequate 
strength including consideration of yield and fatigue stresses. This 
requires an accurate estimate of the maximum time-average and alternating 
loads under all operating conditions. High time-average and alternating 
loads occur at steady full-power ahead conditions and during high-speed 
maneuvers including full-power crash astern, full-power crash ahead, and 
full-power turns. In addition, the influence of the seaway may substan- 
tially increase the time-average and alternating loads. At present there 
appears to be no confirmed technique whereby the pertinent loads can be 
predicted to the desired accuracy. Schwanecke and Weeeldeneae reviewed the 
factors affecting blade loading for propellers in general, and Rurseesiieey 
and Hawdon et ee discussed some of the factors peculiar to blade loading 
of CP propellers. 
Sogetaiil, R.J. et al, “Experimental Determination of Mean and Unsteady 
Loads on a Model CP Propeller Blade for Various Simulated Modes of Ship 
Operation," The Eleventh Symposium on Naval Hydrodynamics sponsored Jointly 
by the Office of Naval Research and University College London, Mechanical 
Engineering Publications Limited, London and New York, pp 789-823, 832-834, 
(April 1976); also "Experimental Unsteady and Mean Loads on a CP Propeller 
Blade of the FF-1088 for Simulated Modes of Operation," David Taylor Naval 
Ship Research and Development Center Report 76-0125, October 1976. 
Scehmemcekes H. and R. Wereldsma, "Strength of Propellers Considering 
Steady and Unsteady Shaft and Blade Forces, Stationary and Nonstationary 
Environmental Conditions," Proceedings of the Thirteenth International 
Towing Tank Conference, Report of the Propeller Committee, Appendix 2b, 
Vol. 2, pp 495-526 (1972). 
sRucetelinn A.A., "Hydrodynamics of Controllable Pitch Propellers," 
Shipbuilding Publishing House, Leningrad (1968). 
5 
Hawdon, L. et al, "The Analysis of Controllable-Pitch Propeller Char- 
acteristics at Off-Design Conditions," Transactions of the Institute of 
Marine Engineers, Vol. 88, Series A, Part 4, pp 162-184 (1976). 
3 
