\"I 



ENGINEERING ASPECTS. 

 By JEROME C. HUNSAKER, Eng.D. 



1. It is of especial significance that the American Philosophical 

 Society devotes an afternoon to aeronautics and of especial signifi- 

 cance to the Navy that the problems of aeronautics have been so 

 clearly stated to you here today. For these problems are unfortu- 

 nacely not only perplexing but pressing, and engineering progress 

 cannot wait for a satisfactory solution. Just now we are forced to 

 adopt rather daring assumptions and to extrapolate to a truly alarm- 

 ing extent our experimental data. 



2. I was sorry to arrive too late to hear Professor Webster's 

 treatment of the dynamical aspects of the subject, but I shall have, 

 of course, the opportunity for a more leisurely study of his paper 

 when it appears in printed form. 



3. Professor Durand's estimate of the economical size of aero- 

 planes is especially timely as we are building all sizes now in search 

 of the most useful, and it is indeed encouraging to have Professor 

 Durand as authority for making haste slowing in expanding the 

 dimensions of the existing types. If I understand him correctly, 

 the weight of the structure of aeroplane wings may be assumed to 

 increase more rapidly than their carrying power so that there must be 

 a limiting size for any given system of construction beyond which 

 it is uneconomical to go. I believe this conclusion to be entirely true 

 provided, as Professor Durand carefully states, the same system of 

 construction be used for a family of similar structures. However, 

 I would consider that it would not be good engineering to use the 

 same material or even the same system of distributing material, for 

 large and for small structures. For example, it is not economical to 

 apply the materials and methods of construction used in small boats 

 to large ships. Where we would use solid spruce beams for small 

 wings, larger wings would have hollow spruce beams, and perhaps 



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