Which is the minimum requirement for pure directional stability?
(a) Slope of yawing moment curve positive
(b) Negative lift curve slope
(c) Negative pitching moment coefficient curve slope
(d) Positive zero lift pitching moment coefficient
This question was addressed to me during an online interview.
I would like to ask this question from Lateral-Directional Static Stability and Control in chapter Stability, Control, and Handling Qualities of Aircraft Design