All these years I've been using only 1 shear pin in fiberglass rockets unaware that they could "bind" due to the "uneven retention". And my rockets were apparently unaware as well.
It's that Statics 201 vs. Dynamics 203 thing again. You can sit your 100 pounds on your 1 square foot butt all day, but if someone kicks you with 100 foot-pounds....
Yes, I know. Units. That is the point. That little bitty shear pin can resist 31 pounds force applied carefully, but it has little capacity to absorb energy. That is why it fails, and the high-angular-momentum rocket pieces are flying off in opposite directions, long before it can twist the rocket pieces into a binding situation.
"Long" being relative to milliseconds.
and both are free!
