That rocket does not look like an unstable disaster to me, it looks like a reasonable design that should work. Powerful thrust vectoring engine, much taller than wide, etc. Initar, what happens if you disable the upper 3.75m tank until it is needed? I think that would help keep the CoM further forward and the rocket more stable. So it was an unstable disaster of a rocket after all... BTW, in case you missed why I called it that, it was partially _because_ it was far from enough 'taller than wide', had a beast of an engine on something that looks like a fat dwarf.