NAVAL ARCHITECTURE TO AERONAUTICS. 295 
d=15 feet, V=36 miles per hour, thrust = 864 pounds, efficiency = 64 
percent. If these values of d, V, and 7, are substituted in (7) above we have: 
e= = 6 f 
11020 X864 3-970 
1296 X 225 
The actual efficiency and that computed by formula (7) are practically 
identical. The data were not published completely but it is probable that at 
a thrust of about 280 pounds, the particular propeller had an eh in 
the vicinity of 72 per cent. 
Finally from the data available it seems clear that experience with the 
water propeller and methods used in its design can be extended with advan- 
tage to the design of air propellers. 
DISCUSSION. 
Capt. W. IrvinG CHAMBERS, U. S. N., Member (Communicated) :—I am glad 
to see such a creditable paper on this subject by a Naval Architect and I earnestly 
hope that the future pages of these transactions will glow with further evidences of 
an appreciation of the scientific work needed in the development of aviation. 
We have not heard enough about aviation from Naval Architects as yet and I 
presume it is because the science is advancing with such rapid strides that it requires 
practically the undivided attention of anyone who desires to keep up with it and to 
assist in its development. 
A year or two ago aviation took such a prominent place in the public eye that a 
great many people began to look for its speedy adaptation to commercial uses and 
all sorts of extravagant predictions were made, but after the first blush of excitement, 
temperate views began to prevail and the public realized that the science was still 
initsinfancy. Aeronautical periodicals have recently inquired, ‘‘ What is the matter 
with Aviation?” In his reply to this Mr. Hugo Gibson gave an answer which 
accords with my views and I quote the following extract from him, “Aviation is a 
' science, and for its advancement requires an army of scientific workers, it is a seri- 
ous business and when tackled by serious minded engineers, who know how to select 
their designs, forms, material, methods and labor, and who are relieved from the 
necessity of prostituting their product by parsimonious economy, it will become a 
standard money-making business in the provision of the many thousands of ma- 
chines which will be used . . . on land and water . 4 
