Waterjet Propulsion 



JPi==:R\ 



h 



CHANNEL BOTTOM 



Fig. 11 - Experimental apparatus for test- 

 ing waterjet systems in the hydronautics 

 high-speed channel 



CONCLUDING REMARKS .^v- : 



In conclusion, it may be stated that, particularly at high speeds, waterjet 

 propulsion promises to be competitive with the supercavitating propeller. How- 

 ever, before the promise is fulfilled, considerable work remains to be done. 

 This work is principally engineering design and experimental development. The 

 most urgent research needs are: 



(1) Light-weight cavitation-free pumps, including the influence of non- 

 uniform inflow. 



(2) Inlet hydrodynamics, including nonzero incidence: 



a. boundary -layer ingestion 



b. ram recovery 



c. external drag 



d. cavitation characteristics 



e. air ingestion 



f. off-design performance— variable area. 



ACKNOWLEDGMENTS 



The author gratefully acknowledges the provision of Figs. 7 and 8 by C. T, 

 Ray of the Boeing Co. and Figs. 9 and 10 by L. Arcand of the Pratt and Whitney 

 Co. 



1053 



