1. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Aerodynamics Chapter 2 Stability and Control

2. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-1. Positive static stability: tends to return to center.

3. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-2. Neutral static stability: no tendency to return.

4. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-3. Negative static stability: tends to diverge.

5. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-4. Damped oscillation—dynamically stable.

6. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-5. Undamped oscillation—dynamically neutral.

7. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-6. Divergent oscillation—dynamically unstable.

8. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-7. Lift counteracts weight, thrust counteracts drag in straight-and-level flight (moments neutralized by stabilizers and trim). Total weight includes download on the tail.

9. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-8. Thrust and drag form a pitching couple.

10. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-9. The lift–weight couple and the thrust–drag couple may be balanced.

11. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-10. Following a loss of thrust the lift–weight couple pitches the airplane nose-down.

12. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-11. The horizontal stabilizer provides the final balancing moment.

13. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-12. Propeller slipstream affects the force generated by the horizontal stabilizer.

14. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-13. Angular movement can occur about three axes.

15. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-14. Rolling about the longitudinal axis.

16. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-15. Pitching about the lateral axis.

17. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-16. Yawing about the vertical axis.

18. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-17. Longitudinal stability following an uninvited nose-up pitch.

19. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-18. Longitudinal stability following an uninvited nose-down pitch.

20. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-19. Longitudinal stability is provided by the tail feathers of a dart.

21. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-20. A forward CG—greater longitudinal stability.

22. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-21. Directional stability following an uninvited yaw.

23. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-22. Wing dihedral.

24. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-23. Dihedral corrects an uninvited roll.

25. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-24. Sweepback corrects uninvited roll.

26. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-25. High keel surfaces and a low CG correct uninvited roll.

27. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-26. A high wing tends to level the wings.

28. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-27. Roll causes yaw.

29. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-28. The CG must remain within the area bounded by the wheels.

30. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-29. A destabilizing crosswind.

31. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-30. Yaw causes roll.

32. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-31. The primary flight controls: elevator, ailerons, and rudder.

33. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-32. The elevator is the primary pitching control.

34. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-33. A butterfly tail (early Beech Bonanza model).

35. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-34. Separate horizontal stabilizer and elevator.

36. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-35. Stabilator.

37. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-36. The ailerons–one up, one down–provide a rolling moment.

38. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-37. The rising wing has increased aileron drag, causing adverse yaw effect.

39. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-38. Differential ailerons reduce adverse yaw.

40. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-39. Frise-type ailerons equalize aileron drag and reduce adverse yaw.

41. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-40. Aileron/rudder interconnect can reduce adverse yaw.

42. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-41. Left rudder pressure—the nose yaws left.

43. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-42. Yaw is followed by roll.

44. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-43. The controls are more powerful with increased airflow.

45. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-44. The slipstream only affects the elevator and rudder.

46. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-45. Hinge moment at the control surface.

47. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-46. Inset hinge balance (at left) and horn balance (at right).

48. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-47. The balance tab.

49. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-48. Anti-balance tab on stabilator.

50. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-49. The anti-balance tab opposes further control deflection and provides feel.

51. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-50. An elevator trim tab.

52. © 2009 Aviation Supplies & Academics, Inc. All Rights Reserved. The Pilot’s Manual – Ground School Figure 2-51. A mass balance moves the control’s CG forward to prevent flutter.