Response
Manipulation of the equations of motion yields a second order homogeneous linear differential equation in the angle of attack :
The qualitative behavior of this equation is considered in the article on directional stability. Since and are both negative, the damping is positive. The stiffness does not only depend on the static stability term, it also contains a term which effectively determines the angle of attack due to the body rotation. The distance of the center of lift, including this term, ahead of the centre of gravity is called the maneuver margin. It must be negative for stability.
This damped oscillation in angle of attack and yaw rate, following a disturbance, is called the 'weathercock' mode, after the tendency of a weathercock to point into wind.
Read more about this topic: Stability Derivatives
Famous quotes containing the word response:
“It does me good to write a letter which is not a response to a demand, a gratuitous letter, so to speak, which has accumulated in me like the waters of a reservoir.”
—Henry Miller (1891–1980)
“There is ... but one response possible from us: Force, Force to the uttermost, Force without stint or limit, the righteous and triumphant Force which shall make Right the law of the world and cast every selfish dominion down in the dust.”
—Woodrow Wilson (1856–1924)
“The reason can give nothing at all Like the response to desire.”
—Wallace Stevens (1879–1955)