SECTION G: CARDIFF, 1920. 



ADDRESS 



TO THE 



ENGINEERING SECTION 



BY 



Professor C. F. JENKIN, C.B.E., M.A., 



PRESIDENT OF THE SECTION. 



The importance of research in all branches of industry is now becoming 

 fuJly recognised. It is hardly necessary to point out the great possi- 

 bilities of the Board of Scientific and Industrial Eesearch, formed 

 just before the war, or to lay str-ess on the attention which has been 

 called to the need for research by events during the war. Probably 

 in no branch of the Semces was more research work done than in 

 the Air Service, and the advances made in all directions in connection 

 with flying were astonishing. My own work was confined to problems 

 connected with materials of construction, and as a result of that work 

 I have come to the conclusion that the time has come when the funda- 

 mental data on which the engineering theories of the strength and 

 suitability of materials are based require thorough overhauling and 

 revision. I believe that the present is a favourable time for this work, 

 but I think that attention needs to be drawn to it, lest research work 

 is all diverted to the problems which attract more attention, owing 

 to their being in the forefront of the advancing engineering knowledge, 

 and lest the necessary drudgery is shirked in favour of the more 

 exciting new discoveries. 



It has been very remarkable how again and again in aeroplane 

 engineering the problems to be solved have raised fundamental ques- 

 tions in the strength and properties of materials which had never been 

 adequately solved. Some of these questions related to what may be 

 termed theory, and some related to the physical properties of materials. 

 I propose to-day to describe some of these problems, and to suggest 

 tlie direction in which revision and extension of our fundamental 

 fheories and data are required and the lines on which research should 

 be undertaken. Let us consider first one of the oldest materials of 

 construction — timber. Timber was of prime importance in aircraft 

 construction. The first peculiarity of this material which strikes us 

 is that it is anisotropic. Its grain may be used to locate three principal 

 axes — along the grain, radially across the grain, and tangentially across 

 the gi-ain. It is curious that there do not appear to be generally 

 recognised teraris for these three fundamental directions. A very few 



