Advanced Aerodynamics

1. Advanced Aerodynamics

2. Fundamental Flight Maneuvers • Straight and Level • Turns • Climbs • Descents

3. Four Aerodynamic Forces • Lift • Thrust • Drag • Weight • When are they in equilibrium?

4. Four Aerodynamic Forces • In steady-state or unaccelerated straight and level flight • What happens when you initiate a climb?

5. Four Aerodynamic Forces • Lift briefly exceeds weight. • Rearward component of the Lift adds to drag • Upward component of Thrust is called the Lift of Thrust

6. Four Aerodynamic Forces • Once the climb is established, the forces are again balanced

7. Lift • Which of Newton’s laws of motion are used to describe lift?

8. Lift • Second law of motion says that a force results whenever a mass is accelerated F = ma • Third law states for every action there is an equal and opposite reaction

9. Bernoulli’s Principle • As the velocity of a fluid increase, its internal pressure decreases • High pressure under the wing and lower pressure above the wing’s surface

10. Lift • In what direction does lift act? • Perpendicular to the relative wind • Drag acts parallel to the flight path in the same direction as the relative wind

11. Lift • Angle of incidence • Angle of attack • Washout

12. Lift Equation • L = CLV2r/2 S • If the angle of attack and other factors remain constant and airspeed is doubled lift will be four times greater

13. Controlling Lift • What are four ways commonly used to control lift?

14. Controlling Lift • Increase airspeed • Change the angle of attack • Change the shape of the airfoil • Change the total area of the wings

15. Angle of Attack • Directly controls the distribution of pressure acting on a wing. By changing the angle of attack, you can control the airplane’s lift, airspeed and drag.

16. Angle of Attack • Angle of attack at which a wing stalls remains constant regardless of weight, dynamic pressure, bank angle or pitch attitude.

17. Angle of Attack • When the angle of attack of a symmetrical airfoil is increased, the center of pressure will remain unaffected.

18. Angle of Attack • At high angle of attack, pressure increases below the wing, and the increase in lift is accompanied by an increase in induced drag.

19. Flaps • What are the four types of flaps found on general aviation aircraft?

20. Flaps • Plain • Split • Slotted • Fowler

22. Leading Edge Devices • Slot • Slats • Leading Edge Flaps

24. Drag • Induced drag is a by-product of lift and is greatly affected by changes of airspeed.

25. Wing Planform • Name several wing shapes and their advantages?

26. Wing Planform • Elliptical - Excellent load distribution for high-G maneuvering and low drag for high speeds • Rectangular - stall first at root, least expensive

27. Wing Planform • Tapered - Favorable stall characteristics with good load distribution, saves weight • Delta - supersonic flight

29. Wing Planform • How do you find the Aspect Ratio of an airplane?

30. Wing Planform • Found by dividing the wingspan by the average cord. • What is a typical aspect ratio for typical training aircraft? • Gliders?

31. Wing Planform • Gliders - 20 to 30 • Training Aircraft - 7 to 9

32. Wing Planform • What is sweep? • A line connecting the 25% cord points of all the wing ribs which is not perpendicular to the longitudinal axis of the plane is said to be swept • The sweep can be forward but most are back

33. Wing Planform • What is a device that is used to block or diffuse wing tip vortices?

34. Wing Planform • Winglets • Winglets can increase fuel efficiency at high speeds at altitudes by as much as 16 to 26%

36. Ground Effect • Where is ground effect found?

37. Ground Effect • Within one wingspan of the ground • An airplane leaving ground effect will experience an increase in what kind of drag?

38. Ground Effect • Induced Drag • Induced Drag is only about half of its usual value when the wing is at 10% of its span above the ground

39. Drag • What kind of drags rate of increase is proportional to the square of the airspeed?

40. Drag • What kind of drags rate of increase is proportional to the square of the airspeed? • Parasite Drag • What kinds of drag make up parasite Drag

41. Drag • Form Drag - based on the shape of the plane, how well streamlined and amount of frontal area.

42. Drag • Interference Drag - created when the airflow around one part of the airplane interacts with the airflow around another. • Skin Friction Drag - surface friction

43. Total Drag • The sum of the induced drag and the parasite drag. • Total drag is lowest at the airspeed which produces the highest ratio of lift to drag L/Dmax

44. Total Drag • Best power-off glide range • Greatest Range

45. High Drag Devices • Spoilers • Speed Brakes

46. Spoilers • What are the advantages of using spoilers?

47. Spoilers • Rapid descent without reducing power, engine stays warm • Maintain normal descent speed • Help slow to landing gear extension speed • Descent rapidly through icing • Stay at high altitudes longer

48. Thrust • Opposes drag. If greater than drag, the airplane is accelerating • A pound of Thrust must be available for each pound of drag.

49. Thrust • Power is the rate at which work is done. It takes less power to do the same amount of work at a slower rate.

50. Propeller Efficiency • High angle of attack at root, low angle of attack at tip • Elliptical planform • High Aspect ratio