NO. 5 STABILITY OF AEROPLANES HUNSAKER AND OTHERS 



61 



The curves of vm of figure 19 show that the damping of the yaw 

 increases with speed approximately as the first power. The damping 

 of Vciw A'r is in magnitude only about y'y the damping of roll Lp. 

 Consequently, the precise determination of Nr is attended with some 

 experimental difficulty. 



It is to be noted that Nr diminishes with the velocity, while at the 

 same time it increases with the angle of attack. The value of Nr at 



.00 y^ 



>3 r!^ 



pi>£ ^ -^ 





S /O /5 ^O ^5 30 ^^ *''=' 



FiG. ig. — Curves of damping coefficient for yawing. 



high speed .35^ is practically equal to its value at low speed .726^. 

 It seems reasonable to expect that at large angles of incidence the 

 damping of yaw due to the wings would be much greater than at 

 small angles were the speed the same. 



For the intermediate "speed i = 6° the coefficient Nr is least. This 

 is due to the fact that from 0° to 6°, IJ drops from - 117. 5 to —65.3 

 feet per second, while from 6° to 12° U drops very little more: only 

 from —65.3 to —54 feet per second. 

 5 



