Question

Which of the following is correct?

(a) Dutch roll is not considered as a longitudinal mode

(b) Lift curve slope is defined as ratio of lift to thrust

(c) Stability and controllability are same

(d) Dynamic stability of aircraft does not depend upon any parameter

I got this question in homework.

This interesting question is from Dynamic Stability in chapter Stability, Control, and Handling Qualities of Aircraft Design

Answer 1

Correct option is (a) Dutch roll is not considered as a longitudinal mode

To elaborate: Dutch roll is not longitudinal mode. Typical longitudinal modes include phugoid mode and short period mode. Lift curve slope is defined as ratio of change in lift coefficient to the change in AOA. Stability and controllability are inverse of each other.