Describe the failure mode of 'Spiral-Out' and its relationship to centrifugal force and groove geometry.

'Spiral-out' is a unique failure mode where a spiral ring literally 'unwinds' out of its groove. This is typically driven by centrifugal forces in high-speed rotating shafts. As the shaft spins, the ring's mass generates a radial force $F_c = m ω^2 R$. This force causes the ring to expand. If the expansion is enough to lift the ring's ends out of the groove, the 'leading end' can catch on the housing, causing the entire ring to be pulled out in a spiral fashion. This is catastrophic. Prevention involves using a 'Self-Locking' ring, where a tab on the inner turn locks into a notch on the outer turn. This mechanical link prevents the turns from separating radially, effectively increasing the 'Centrifugal Capacity' by several thousand RPM.