The effect of viscous damping on spin stability of a rigid body with a fixed point

McGill and Long (1975) clarified the regions of stability and instability for an arbitrary rigid body spinning about a vertical centroidal principal axis through a fixed point. On a parameter plane, it was found that regions of both Liapunov stability and infinitesimal stability existed along with instability zones. The present paper shows that for the problem at hand the results can go either way, i.e., some regions of both Liapunov and infinitesimal stability can remain stable while others become destabilized. In general it should be expected that damping will always destabilize the infinitesimal but not the Liapunov regions in problems where they both exist.