CHAPTER VII 



EQUILIBRIUM AND CONTROL 



In an aerodrome it is essential not only that its component parts shall be 

 so disposed that the initial equilibrium is correct and highly stable, but also 

 that some efficient means be provided for quicklj and accurately restoring the 

 equilibrium, if for any reason it is disturbed. If the aerodrome is of sufficient 

 size and power to carry a human being it is, of course, possible merely to sup- 

 ply an efficient means of controlling the lateral and horizontal equilibrium of 

 the machine and depend upon the intelligence and skill of the operator, as de 

 veloped by practice and experience, to maintain the proper equilibrium of the 

 machine while in the air. This method, however, is open to the objection thai no 

 matter how skilled the aviator may be there remains the probability of a seri- 

 ous if not fatal accident as the result of any momentary lapse or diversion of 

 attention until the " sense of equilibrium " has been developed. One of the 

 chief problems, therefore, which had impressed itself from the beginning of 

 the work, was to devise some means by which the equilibrium of the aerodrome 

 would be automatically maintained under the varying conditions of flight, so as 

 to leave the aviator free, as far as possible, to control the direction of flight 

 and to devote his attention to other important matters connected with the 

 proper functioning of the various parts of the aerodrome. In the develop- 

 ment of the models it had been absolutely necessary to develop some efficient 

 automatic control, as they were far too small to carry an aviator, and the con- 

 ditions of flight in the open air, even on the calmest day, were such that con- 

 stant readjustments of the equilibrium were necessary. The success attained 

 in the automatic control of the equilibrium of the models had been so great, 

 and so much time would have been required for an aviator to acquire skill 

 sufficient to control a machine without such automatic equilibrium, that it was 

 considered both expedient and safe to embody in the large aerodrome the plans 

 which had proved so successful in the models. It was necessary, however, to 

 provide in addition in the large machine means whereby the aviator could quickly 

 and accurately either modify the action of the automatic devices or, if desired, 

 entirely supersede the automatic control by purely manual control. Three dis- 

 tinct problems were, therefore, encountered in connection with the equilibrium 

 and control of the large aerodrome. In the first place, the machine as a whole 

 had to be so designed, and its component parts so disposed as to secure a highly 

 stable initial equilibrium; second, automatic means had to be provided for main 



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