Murray Anderson wrote:

The SRBs probably are dynamically stable when flying alone. They have

that skirt at the bottom to act as small tail feathers. Now suppose
you
put a 5-meter wide, 18 meter long upper stage on top, and a CEV under

a payload fairing on top of that (say 5 meters by 10 meters). Then if
you
trace the projection onto a piece of cardboard, cut it out and
balance it,
you get a rough approximation to the CP, which is way in front of the
CG,

I used to do this when building Estes model rockets! [BTW, I lost two
Saturn V's to rocket motor failures - Estes replaced them both]


even when the SRB has burned half its propellant. The stuff up front
destroys stability if it's less dense than the stuff behind.

Good point. I've got Missile Datcom. Might be interesting to play with
that and the SRB/CEV design - see just how bad it is. Hmm...

Jon