An example of these characteristics has been given in figure 4.4. Thelift coefficient increases almost linearly with the angle of attack until a maximum value is reached, whereupon the wing is said to ”stall”. At small angles of attack, the center of the lift forces acts at about e=c t 0:25. At higher angles of attack - before stalling of the wing - the low starts to separate at the suction side of the wing and the center of the lift force shifts backwards, for instance to about e=c t 0:40.
The moment ppp about the rudder stock is: