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Advanced Aerodynamics

Advanced Aerodynamics. Fundamental Flight Maneuvers. Straight and Level Turns Climbs Descents. Four Aerodynamic Forces. Lift Thrust Drag Weight When are they in equilibrium?. Four Aerodynamic Forces. In steady-state or unaccelerated straight and level flight

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Advanced Aerodynamics

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  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

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

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

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

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

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

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

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

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

  29. 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

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

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

  32. Ground Effect • Where is ground effect found?

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

  34. 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

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

  36. 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

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

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

  39. 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

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

  41. High Drag Devices • Spoilers • Speed Brakes

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

  43. 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

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

  45. 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.

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

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