VII 



REMARKS ON THE COMPASS IN AERONAUTICS. 



By LOUIS A. BAUER. 



The few remarks which I am able to contribute to the discussion 

 of the papers we have just had the pleasure of listening to, relate to 

 the use of the compass in aerial navigation. 



The recent great progress in aeronautical art and in the construc- 

 tion of ships to navigate the air, have called renewed attention to 

 the importance of perfecting the magnetic compass used in steering 

 the craft, and to the need of studying the " vagaries of the fickle 

 needle." Just as in ocean navigation, it has become necessary in 

 aerial navigation, though not yet to the same degree of refinement 

 as in ocean work, to determine the effects on the compass of the 

 magnetic materials used in the construction and in the equipment of 

 the aircraft. The airship-compass must, accordingly, be compen- 

 sated, and allowance for any outstanding errors must be made in 

 steering a course with it. 



The satisfactory solutions of the various problems are especially 

 difficult for the heavier-than-air type of airship. One of the chief 

 points of difference between the aeroplane-compass and the ocean- 

 ship-compass consists in the form of damping device (horse-hair 

 packing, for example) which must be used to overcome, as well as 

 possible, the very excessive vibration caused by the engine driving 

 the aeroplane. 



Besides the so-called " magnetic-deviation errors " of the com- 

 pass, arising from the magnetic materials in the vicinity of the com- 

 pass, there are other errors which make themselves seriously felt 

 only, however, while the aeroplane is turning. The latter are called 

 " dynamic-deviation errors " ;, their magnitude depends upon the tilt 

 of the aeroplane, the magnetic dip, and the heading or course of 

 the airship. 



When the aeroplane is turning, it is tilted towards the center of 



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