The spin damping moment
Abbreviations
c
_{spin}
Spin damping moment coefficient;
c
_{spin}
(B,Ma.Re
)
M
_{S}
Spin damping moment
More Abbreviations
Explanation
Skin friction at the bullet's surface retards its spinning motion. The spin damping moment (also: roll damping moment) is given by the above formula. The spin damping coefficient depends on bullet geometry and the flow type (laminar or turbulent).