Forces Lb. 
THE AERODYNAMICS OF A SPINNING SHELL. 
30 
Fig. 2. Force components on the 3-inch shells A and B, measured in a wind channel at a wind speed 
of 40 f.s., plotted against angle of yaw. 
Shell of form A.—Moment measured about a point 4 - 85 inches from base. 
>> >) B.—Moment measured about a point 4'85 inches from base. 
(a) Measurements at angles of yaw up to 
90 degrees. 
Scales. — Forces 1 unit = O'02 lb 
Moment 1 unit = O'005 lb. feet. 
Yaw 1 unit = 5 degrees. 
(b) Detail of forces at angles up to 20 degrees. 
Scales. — Forces 1 unit = O'005 lb. 
Yaw 1 unit = 2 degrees. 
(c) Detail of moment at angles up to 
20 degrees. 
Scales.—Moment 1 unit = O'002 lb. feet. 
Yaw 1 unit = 2 degrees. 
005 
10 
Yaw Degrees 
2 U 
VOL. CCXXI.-A. 
