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XVII. Notices respecting New Boohs. 



Applied Aerodynamics. By Leonard Bairstow, F.RS., C.B.E. ; 

 expert adviser on Aerodynamics to the Air Ministry, &c. 

 Longmans, Green & Co. 1920. 560 pages. 



r PHE engineer and mechanical constructor will appreciate this 

 -*- book highly for the numerical information provided by the 

 author, in official contact with the collection of confidential data ; 

 this information is given clearly to the eye in the plentiful supply 

 of diagrams and tables, result of experiment in the wind channel, 

 and up in the laboratory of the air. 



And the practical engineer will not be able to take up the usual 

 ungrateful attitude, and disparage the theory preliminary to an 

 ascent from the ground ; but he will learn to realise the importance 

 of calculation required to ensure the stability, and the possibility 

 of descent without a crash. 



In the early days the enthusiast was prepared to take this risk 

 of his neck and life, if only he could fly for once ; and the difficulty 

 he dreaded most was in the preliminary run required before leaving 

 the ground in taking off. This difficulty was soon overcome with 

 the extra power provided, and a flying start comparatively short 

 is found to suffice. 



But when he flies a swift powerful large heavy machine, the 

 landing speed mounts up to a dangerous extent ; and one of the 

 chief problems of flight awaiting solution is how to diminish this 

 landing speed as much as possible, by the artificial aid of aileron 

 and air break. 



Might is hardly over ten years old, and may be said to date 

 from Bleriot's Channel crossing. A preliminary chapter of his- 

 torical interest could give us in a score of pages the chief events 

 leading up to success and Victory. 



The first essential was an engine of small weight per horse-power, 

 and here the motor car came in, and made the flying machine a 

 present ready made of the petrol motor, internal combustion. 



Maxim could not succeed, with all his mechanical skill in the 

 reduction of the weight of engine to about half a pound per horse- 

 power, as he was obliged to take a steam-boiler up in the air as 

 well, and here he was beaten. 



Gyroscopic and heeling effect were bugbears feared in the 

 early days, to be corrected by a brace of screws, right and left 

 handed. But the Vickers-Vimy Atlantic machine to be seen today 

 in the Science Museum has both screws left-handed ; the ad- 

 vantage of interchangeability outweighs any of these imaginary 

 complaints. Colonel Cody might easily have left the ground at 

 Farnborough if he had not been obsessed with these ideas, and 

 had coupled up his engine into the direct drive of a single 

 vscrew. 



In an instructional treatise a short initial chapter would be 



