THE AERODYNAMICS OF A SPINNING SHELL. 
23 J 
Some general information can be deduced from tliese curves. At high velocities 
(v/a = 2-0) and large values of S the couple coefficient actually falls below its low 
Fig. 2. Curves of the complete couple coefficient / M (v/a, 8) sin 8 against 8 for various values of vja 
(as shown against the curves). The curves stop at the greatest value of 8 for which observations are 
available. 
The origins of all the curves except for type III. are displaced upwards and can be recovered from the 
fact that all curves pass through their respective origins. The scale of 8 is in degrees. 
velocity (wind channel) value (fig. 2) ; the curve of the couple coefficient against yaw 
has here a large curvature downwards. It is, on the other hand, almost straight in 
the region of the velocity of sound. 
