The maximum spread in values of effective horsepower is about 4 percent. Models 3,4, 6, 

 and 8 showed the best resistance characteristics, while Model 7 had the most unfavorable. 



ACKNOWLEDGMENTS 



The author gratefully acknowledges the assistance of Ms. Laurie M. Higgins and Messrs. 

 William G. Day, Eugene E. West, Leonard B. Crook, Neil E. Oliver, and Nicholas Santelli for 

 their assistance in conducting the experiments on which this report is based. 



21 



