Video explains CoG effects.

[IceFire]

Originally Posted by mark_009_vn

The P-39 should never enter a stall in a turn fully loaded, the problem with the P-39 regarding it's nasty spin characteristics is only when a large amount of 37 mm shells where expended, this caused a shift in CoG and only then would it become dangerous to do acrobatics.

Of course this is not modeled ingame for obvious reasons...

Might also have had to do something with the Pentium III processors we were using when the game came out originally...