Ill 



MECHANICAL ASPECTS OF AERONAUTICS. 

 Bv W. F. DURAND, Ph.D. 



Scope of Paper. 



The present paper deals with heavier-than-air machines only. 

 No attempt will be made to describe the present situation in compre- 

 hensive detail. The achievements of the past and the present condi- 

 tion of the art of aeroplane design, construction and operation must. 

 for the most part, be assumed. The purpose of the paper will be 

 rather to point out the more important problems pressing for solu- 

 tion, the elements in the broad problem of aeronautics which we may 

 reasonably hope to improve, and so far as the author is able, to indi- 

 cate the directions in which improvement may be sought. 



The subject will be considered under the following general 

 heads : 



Structure of Aeroplane. 



Power Plant. 



Propulsion. 



Structure of AiiROPLANE. 



As a problem in engineering design the aeroplane presents the 

 following features. 



Required a structure coherent as a whole, provided with large 

 fiat or gently curved surfaces for realizing the necessary support, 

 with suitable accommodation for the personnel, and with suitable 

 structures for supporting a prime mover and for receiving the thrust 

 of a propeller, fitted also with suitable auxiliary guiding surfaces for 

 control in the air, and with suitable strength in all its parts to resist 

 with a reasonable margin of safety the stresses to which it will be 

 subject in the accidents of aerial navigation. 



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