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SOME APPLICATIONS OF THE PRINCIPLES OF NAVAL 
ARCHITECTURE TO AERONAUTICS. 
By Navat Constructor WiLLIAmM McENTEE, U.S. N., MEMBER. 
{Read at the eighteenth general meeting of the Society of Naval Architects and Marine Engineers, held in 
New York, November 16 and 17, rg11.] 
Considering the essential similarity of the problems involved in aero- 
nautics and in naval architecture, it is a singular fact that with the develop- 
ment of the first, both theoretically and experimentally, but little has been 
done by the trained naval architect. So far as known, none of the men 
whose names are well known as leaders in this field have been educated in 
its kindred and elder branch of engineering. 
There is no doubt that many difficulties could have been avoided by the 
earlier experimenters and many practical advantages can be gained to-day 
by those engaged in aeronautical engineering through the use of some of the 
fundamental principles of naval architecture. For example, Langley has 
stated in his memoirs, written after a number of years of investigation and 
experiment, that as regards the stability of an aeroplane, longitudinal sta- 
bility is difficult to obtain, but that transverse stability is comparatively an 
easy matter. Practical experience shows the facts to be the reverse. There 
were no really successful aeroplanes until sufficient transverse stability 
had been obtained by the introduction of warping wings, or other similar 
devices. At one time Langley also thought that frictional resistance was 
but a small part of the total resistance to the motion of plane surfaces 
through the air at small angles of inclination, and therefore, that as the speed 
of a given aeroplane increased beyond a certain amount the power required 
to propel it would continually decrease. The naval architect always on guard 
as regards the transverse stability of ships and with his knowledge of fric- 
tional resistance of water and increase of power required with increase in 
speed of a ship would hardly have fallen into these errors. 
As in naval architecture, the practical elements dealt with in aeronautics 
are: Weight or displacement, buoyancy, stability, resistance, propulsion, 
and speed. For higher theoretical investigations the mathematics of stream 
lines or fluid motion are equally applicable to each. 
At the present time the aeroplane appears to promise greater returns in 
usefulness and in any case its development has recently been so rapid that it 
attracts more interest than does the dirigible. For thisreason the present 
discussion will be limited to aeroplanes and deal only with questions of 
stability and propulsion. 
