If you ask an aerospace engineer, what the fundamental requirement for static longitudinal stability of an airplane is, he or she will tell you that “Cm-alpha needs to be negative”. If you face a pilot with the same question, most likely you will be shown the typical “marble in the bowl” sketch and some “wing/tail - up/down force” picture. The engineer’s answer is physically correct but sounds somewhat diffuse, the pilot’s answer sounds more straight-forward, but might be qui