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Po f lo5 p1

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constant speed propeller aircraft

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Po f lo5 p1

  1. 1. Uncontrolled copy not subject to amendment <ul><li>Principles of Flight </li></ul>
  2. 2. Principles of Flight <ul><li>Learning Outcome 5: </li></ul><ul><li>Be able to apply the principles of flight and control to rotary wing aircraft </li></ul><ul><li>Part 1 </li></ul>
  3. 3. REVISION
  4. 4. Questions <ul><li>Name the Forces Acting on a Glider in Normal Flight. </li></ul><ul><li>a. Force, Weight and Lift. </li></ul><ul><li>b. Drag, Weight and Thrust. </li></ul><ul><li>Drag, Weight and Lift. </li></ul><ul><li>Drag, Thrust and Lift. </li></ul>
  5. 5. Questions <ul><li>How does a Glider Pilot Increase the Airspeed? </li></ul><ul><li>a. Operate the Airbrakes. </li></ul><ul><li>b. Lower the Nose by pushing the Stick Forward. </li></ul><ul><li>Raise the Nose by pulling the Stick Back. </li></ul><ul><li>Lower the Nose by pulling the Stick Back. </li></ul>
  6. 6. Questions <ul><li>A Viking Glider descends from 1640 ft (0.5 km). </li></ul><ul><li>How far over the ground does it Travel (in still air)? </li></ul><ul><li>a. 17.5 kms. </li></ul><ul><li>b. 35 kms. </li></ul><ul><li>70 kms. </li></ul><ul><li>8.75 kms. </li></ul>
  7. 7. Questions <ul><li>When flying into a Headwind, the distance covered </li></ul><ul><li>over the ground will: </li></ul><ul><li>a. Be the same. </li></ul><ul><li>b. Decrease. </li></ul><ul><li>Increase. </li></ul><ul><li>No change. </li></ul>
  8. 8. Propellers <ul><li>Objectives: </li></ul><ul><li>Define Blade Angle and Blade Angle of Attack. </li></ul><ul><li>Show with the aid of a diagram the Aerodynamic </li></ul><ul><li>Forces acting on a Propeller Blade in flight. </li></ul><ul><li>Explain Aerodynamic and Centrifugal Twisting </li></ul><ul><li>Moments acting on a propeller. </li></ul><ul><li>4. Explain the effect of changing forward speed on: </li></ul><ul><li>a. A Fixed Pitch propeller. </li></ul><ul><li>b. A Variable Pitch propeller. </li></ul><ul><li>(and thus the advantages of a variable pitch propeller). </li></ul><ul><li>5. Explain the factors causing swings on take-off for: </li></ul><ul><li>a. A Nose-Wheel aircraft. </li></ul><ul><li>b. A Tail- Wheel aircraft. </li></ul>
  9. 9. Propellers MOD
  10. 10. Propellers (Terminology)
  11. 11. Propellers (Terminology) Airflow due to Rotational Velocity
  12. 12. Propellers (Terminology) Induced Flow Airflow due to Rotational Velocity
  13. 13. Propellers (Terminology) Induced Flow Airflow due to Rotational Velocity Relative Airflow
  14. 14. Propellers (Terminology) Induced Flow Airflow due to Rotational Velocity Relative Airflow Chord Line
  15. 15. Propellers (Terminology) Induced Flow Airflow due to Rotational Velocity Relative Airflow   = AofA Chord Line
  16. 16. Propellers (Terminology) Induced Flow Airflow due to Rotational Velocity Relative Airflow    = AofA  = Blade Angle Chord Line
  17. 17. Total Inflow Propellers Blade Twist Rotational Velocity Approx 4 o Angle of Attack
  18. 18. Effect of Airspeed Induced Flow Airflow due to Rotational Velocity   At Zero Airspeed
  19. 19. Effect of Airspeed Induced Flow Airflow due to Rotational Velocity (Same)  At a Forward Airspeed  = Total Inflow TAS + - 
  20. 20. Effect of Airspeed Induced Flow Airflow due to Rotational Velocity (Same)   = Total Inflow TAS + -  At a Forward Airspeed Need larger  for same 
  21. 21. Effect of Airspeed _ _ _ _ 100% 75% 50% 25% True Airspeed Propeller Efficiency at Max Power Fine Coarse
  22. 22. Pitch of Propeller Blade _ _ _ _ 100% 75% 50% 25% True Airspeed Fine Coarse Propeller Efficiency at Max Power Variable Pitch
  23. 23. Why a different Number of Blades?
  24. 24. Aerodynamic Forces Total Inflow Airflow due to Rotational Velocity RAF 
  25. 25. Aerodynamic Forces Total Inflow Airflow due to Rotational Velocity RAF Total Reaction 
  26. 26. Aerodynamic Forces Total Inflow Airflow due to Rotational Velocity RAF Lift Drag Total Reaction 
  27. 27. Aerodynamic Forces Total Inflow Airflow due to Rotational Velocity RAF Total Reaction  Thrust
  28. 28. Aerodynamic Forces Total Inflow Airflow due to Rotational Velocity RAF Total Reaction  Thrust Prop Rotational Drag
  29. 29. Aerodynamic Forces (Effect of High Speed) TAS+Induced Flow Airflow due to Rotational Velocity RAF Total Reaction  Thrust Slow Speed Fixed Pitch
  30. 30. TAS+Induced Flow Airflow due to Rotational Velocity RAF Total Reaction  Thrust High Speed Fixed Pitch Aerodynamic Forces (Effect of High Speed)
  31. 31. TAS+Induced Flow Airflow due to Rotational Velocity RAF Total Reaction  Thrust High Speed Fixed Pitch Aerodynamic Forces (Effect of High Speed)
  32. 32. TAS+Induced Flow Airflow due to Rotational Velocity RAF Total Reaction  Thrust High Speed Fixed Pitch Aerodynamic Forces (Effect of High Speed)
  33. 33. TAS+Induced Flow Airflow due to Rotational Velocity RAF NB: Rotational Drag reduced, RPM ?  Thrust High Speed Fixed Pitch Aerodynamic Forces (Effect of High Speed)
  34. 34. TAS+Induced Flow Airflow due to Rotational Velocity RAF NB: Rotational Drag reduced, RPM increases. Don’t exceed limits.  Thrust High Speed Fixed Pitch Aerodynamic Forces (Effect of High Speed)
  35. 35. TAS+Induced Flow Airflow due to Rotational Velocity RAF Total Reaction  Thrust Slow Speed Variable Pitch Aerodynamic Forces (Effect of High Speed)
  36. 36. Faster TAS+Induced Flow Airflow due to Rotational Velocity RAF Total Reaction  Thrust (eventually reduces) High Speed Variable Pitch (same or possibly greater) Aerodynamic Forces (Effect of High Speed)
  37. 37. Windmilling Propeller Negative    TAS Airflow due to Rotational Velocity
  38. 38. Windmilling Propeller Negative   TAS Airflow due to Rotational Velocity TR
  39. 39. Windmilling Propeller Negative   TAS Airflow due to Rotational Velocity TR Negative Thrust (Drag)
  40. 40. Windmilling Propeller Negative   TAS Airflow due to Rotational Velocity TR Negative Thrust (Drag) Negative Rotational Drag (Driving The Propeller)
  41. 41. Windmilling Propeller Negative   TAS Airflow due to Rotational Velocity TR Negative Thrust (Drag) Negative Rotational Drag (Driving The Propeller) This may cause further damage, even Fire.
  42. 42. Feathered Propeller Note that in Firefly/Tutor prop goes to “Fine Pitch” if engine rotating, “Coarse Pitch” if engine seized Although twisted, in aggregate, blade at “Zero Lift α ”. Therefore drag at minimum.
  43. 43. Take-Off Swings All Aircraft: Torque Reaction means greater rolling resistance on one wheel Helical slipstream acts more on one side of the fin than the other
  44. 44. Take-Off Swings
  45. 45. Take-Off Swings Tail wheel aircraft only: Asymmetric blade effect Gyroscopic effect
  46. 46. Take-Off Swings
  47. 47. Take-Off Swings Affect all aircraft on rotate?
  48. 48. Take-Off Swings All Aircraft: Don’t forget crosswind effect!
  49. 49. Centrifugal Twisting Moment Tries to fine blade off
  50. 50. Aerodynamic Twisting Moment Tries to coarsen blade up Relative Airflow Total Reaction
  51. 51. Aerodynamic Twisting Moment Windmilling Tries to fine blade off Relative Airflow Total Reaction
  52. 52. ANY QUESTIONS?
  53. 53. Propellers <ul><li>Objectives: </li></ul><ul><li>Define Blade Angle and Blade Angle of Attack. </li></ul><ul><li>Show with the aid of a diagram the Aerodynamic </li></ul><ul><li>Forces acting on a Propeller Blade in flight. </li></ul><ul><li>Explain Aerodynamic and Centrifugal Twisting </li></ul><ul><li>Moments acting on a propeller. </li></ul><ul><li>4. Explain the effect of changing forward speed on: </li></ul><ul><li>a. A Fixed Pitch propeller. </li></ul><ul><li>b. A Variable Pitch propeller. </li></ul><ul><li>(and thus the advantages of a variable pitch propeller). </li></ul><ul><li>5. Explain the factors causing swings on take-off for: </li></ul><ul><li>a. A Nose-Wheel aircraft. </li></ul><ul><li>b. A Tail- Wheel aircraft. </li></ul>
  54. 55. Questions <ul><li>Blade Angle of Attack is between? </li></ul><ul><li>a. The Chord and Relative Airflow. </li></ul><ul><li>b. The Rotational Velocity and the Relative Airflow. </li></ul><ul><li>The Total Reaction and the Chord. </li></ul><ul><li>Lift and Drag. </li></ul>
  55. 56. Questions <ul><li>Increasing speed with a fixed pitch propeller will? </li></ul><ul><li>a. Be more efficient. </li></ul><ul><li>b. Reduce efficiency. </li></ul><ul><li>Make no difference. </li></ul><ul><li>Increase the Engine speed. </li></ul>
  56. 57. Questions <ul><li>The Forces trying to alter the Propeller Blade </li></ul><ul><li>Angle of Attack are? </li></ul><ul><li>a. ATM and CTM. </li></ul><ul><li>b. CDM and ATM. </li></ul><ul><li>CTM and REV. </li></ul><ul><li>AOA and ATM. </li></ul>
  57. 58. Questions <ul><li>The Resultant Forces that a Propeller produce are? </li></ul><ul><li>a. Lift and Thrust. </li></ul><ul><li>Thrust and Propeller Rotational Drag. </li></ul><ul><li>Drag and Total Reaction. </li></ul><ul><li>d. Drag and Thrust. </li></ul>

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