THE AERODYNAMICS OF A SPINNING SHELL. 
247 
make a large change in the type of motion, so that the method is now a very sensitive 
one for determining the couple, and no great accuracy of observation is required. 
The yaw developed is also much larger, so that values of the couple are determined 
over a larger range of yaws. 
From the point of view of general aerodynamical theory the results form a preliminary 
contribution to the problem of determining the force system impressed by the air on a 
body moving unsymmetrically through a fluid at velocities at which the compressibility 
of the fluid produces marked effects. 
( bri ns H 
I MUSEUM 
| 25 MAR 22 
I natural 
I H i ST QP2C_ 
