The new chapters 7 and 8 have been added to report KD 551 in which aerodynamic characteristics are given for rectangular flat plates with different aspect ratios. Chapter 7 is called: “Determination of the moment coefficient Cmh around a point H for a square plate”. Chapter 8 is called: “Determination of the moment coefficient Cmh around a point H for an aspect ratio 1 : 5”. This information is important if a vane is rotating around an axis which is lying behind the airfoil nose. This axis should not be taken too far from the airfoil nose other wise the vane becomes instable.