文稿加拿大学习加国stability142.pptxVIP

Stability - 1.42 Section 5 in the Transport Canada Study and Reference Guide;Lesson Objectives;Stability - how the airplane reacts to a disturbance in flight. To be more specific, stability of an aeroplane means its ability to return to some particular condition of flight ( after having been slightly disturbed from that condition) without any efforts on the part of the pilot. Reference:Mechanics of Flight ,A.Kermode;Static Stability - the initial tendency of the airplane to restore itself to equilibrium when disturbed in flight. Dynamic Stability - the overall characteristics of the airplane when disturbed from flight. More specifically, it is how the airplane behaves over a period of time after a disturbance which is the dynamic stability characteristic.;Definitions;Positive Static;;;Airplane Axis;Longitudinal Stability; Longitudinal stability is stability about the lateral axis. ( stability in pitch ) A/C are normally designed with the C of G (center of gravity ) ahead of the C of P ( center of pressure ). The location of the CG is probably the most important consideration in pitch ( longitudinal ) stability. ;Longitudinal Stability;;;Notice the change in C of G position compared to the previous slide;Note in this case, that the C of G is now behind the Center of Pressure;Achieving Longitudinal Stability - Trim;Achieving Longitudinal Stability - Trim;Achieving Longitudinal Stability - Trim;Achieving Longitudinal Stability - Trim;Longitudinal Stability;Yaw Stability;?Directional Stability;Directional Stability;;Fin and Directional Stability;;Lateral Stability; Lateral stability is achieved through: Dihedral Sweepback Keel Effect Proper distribution of weight ;The most common method of obtaining lateral stability is by the use of a dihedral angle on the wings. When the wings are inclined upward from the horizontal it is referred to as dihedral. If the wings are inclined downward from the horizontal, it is referred to as anhedral.;Lateral Stability;Dihedral at