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Uncontrolled copy not subject to amendment. Principles of Flight. Principles of Flight. Learning Outcome 5: Be able to apply the principles of flight and control to rotary wing aircraft Part 1. REVISION. Questions. Name the Forces Acting on a Glider in Normal Flight.

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  1. Uncontrolled copy not subject to amendment Principles of Flight

  2. Principles of Flight Learning Outcome 5: Be able to apply the principles of flight and control to rotary wing aircraft Part 1

  3. REVISION

  4. Questions • Name the Forces Acting on a Glider in Normal Flight. • a.Force, Weight and Lift. • b. Drag, Weight and Thrust. • Drag, Weight and Lift. • Drag, Thrust and Lift.

  5. Questions • How does a Glider Pilot Increase the Airspeed? • a.Operate the Airbrakes. • b. Lower the Nose by pushing the Stick Forward. • Raise the Nose by pulling the Stick Back. • Lower the Nose by pulling the Stick Back.

  6. Questions • A Viking Glider descends from 1640 ft (0.5 km). • How far over the ground does it Travel (in still air)? • a.17.5 kms. • b. 35 kms. • 70 kms. • 8.75 kms.

  7. Questions • When flying into a Headwind, the distance covered • over the ground will: • a.Be the same. • b. Decrease. • Increase. • No change.

  8. Propellers • Objectives: • Define Blade Angle and Blade Angle of Attack. • Show with the aid of a diagram the Aerodynamic • Forces acting on a Propeller Blade in flight. • Explain Aerodynamic and Centrifugal Twisting • Moments acting on a propeller. • 4. Explain the effect of changing forward speed on: • a. A Fixed Pitch propeller. • b. A Variable Pitch propeller. • (and thus the advantages of a variable pitch propeller). • 5. Explain the factors causing swings on take-off for: • a. A Nose-Wheel aircraft. • b. A Tail- Wheel aircraft.

  9. Propellers MOD

  10. Propellers(Terminology)

  11. Propellers(Terminology) Airflow due to Rotational Velocity

  12. Propellers(Terminology) Induced Flow Airflow due to Rotational Velocity

  13. Propellers(Terminology) Induced Flow Airflow due to Rotational Velocity Relative Airflow

  14. Propellers(Terminology) Induced Flow Airflow due to Rotational Velocity Chord Line Relative Airflow

  15. Propellers(Terminology) Induced Flow Airflow due to Rotational Velocity Chord Line Relative Airflow  = AofA

  16. Propellers(Terminology) Induced Flow Airflow due to Rotational Velocity Chord Line Relative Airflow  = AofA = Blade Angle 

  17. Approx 4o Angle of Attack Propellers Blade Twist Rotational Velocity Total Inflow

  18. Effect of Airspeed Induced Flow Airflow due to Rotational Velocity   At Zero Airspeed

  19. Effect of Airspeed TAS + Induced Flow =Total Inflow Airflow due to Rotational Velocity (Same) -   At a Forward Airspeed

  20. Effect of Airspeed TAS + Induced Flow =Total Inflow Airflow due to Rotational Velocity (Same) -   At a Forward Airspeed Need larger  for same 

  21. Fine Coarse Effect of Airspeed _ 100% _ 75% Propeller Efficiency at Max Power _ 50% _ 25% True Airspeed

  22. Variable Pitch Pitch ofPropeller Blade _ 100% Fine _ 75% Propeller Efficiency at Max Power Coarse _ 50% _ 25% True Airspeed

  23. Why a different Number of Blades?

  24. Aerodynamic Forces Total Inflow Airflow due to Rotational Velocity RAF 

  25. Aerodynamic Forces Total Inflow Airflow due to Rotational Velocity RAF  Total Reaction

  26. Aerodynamic Forces Total Inflow Airflow due to Rotational Velocity RAF  Drag Lift Total Reaction

  27. Thrust Aerodynamic Forces Total Inflow Airflow due to Rotational Velocity RAF  Total Reaction

  28. Prop Rotational Drag Aerodynamic Forces Total Inflow Airflow due to Rotational Velocity RAF  Thrust Total Reaction

  29. Aerodynamic Forces(Effect of High Speed) TAS+Induced Flow Airflow due to Rotational Velocity RAF  Thrust Slow Speed Fixed Pitch Total Reaction

  30. Aerodynamic Forces(Effect of High Speed) TAS+Induced Flow Airflow due to Rotational Velocity RAF  Thrust High Speed Fixed Pitch Total Reaction

  31. Aerodynamic Forces(Effect of High Speed) TAS+Induced Flow Airflow due to Rotational Velocity RAF  Thrust High Speed Fixed Pitch Total Reaction

  32. Aerodynamic Forces(Effect of High Speed) TAS+Induced Flow Airflow due to Rotational Velocity RAF  Thrust High Speed Fixed Pitch Total Reaction

  33. Aerodynamic Forces(Effect of High Speed) TAS+Induced Flow Airflow due to Rotational Velocity RAF  Thrust High Speed Fixed Pitch NB: Rotational Drag reduced, RPM ?

  34. Aerodynamic Forces(Effect of High Speed) TAS+Induced Flow Airflow due to Rotational Velocity RAF  Thrust High Speed Fixed Pitch NB: Rotational Drag reduced, RPM increases. Don’t exceed limits.

  35. Aerodynamic Forces(Effect of High Speed) TAS+Induced Flow Airflow due to Rotational Velocity RAF  Thrust Slow Speed Variable Pitch Total Reaction

  36. Aerodynamic Forces(Effect of High Speed) Faster TAS+Induced Flow RAF Airflow due to Rotational Velocity  Thrust (eventually reduces) High Speed Variable Pitch Total Reaction (same or possibly greater)

  37. WindmillingPropeller Negative  TAS Airflow due to Rotational Velocity

  38. TR WindmillingPropeller Negative  TAS Airflow due to Rotational Velocity

  39. Negative Thrust (Drag) WindmillingPropeller Negative  TAS TR Airflow due to Rotational Velocity

  40. Negative Rotational Drag (Driving The Propeller) WindmillingPropeller Negative  TAS TR Negative Thrust (Drag) Airflow due to Rotational Velocity

  41. WindmillingPropeller Negative  TAS TR Negative Thrust (Drag) Negative Rotational Drag (Driving The Propeller) This may cause further damage, even Fire. Airflow due to Rotational Velocity

  42. Feathered Propeller Although twisted, in aggregate,blade at “Zero Lift α”. Therefore drag at minimum. Note that in Firefly/Tutor prop goes to “Fine Pitch” if engine rotating, “Coarse Pitch” if engine seized

  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. Take-Off Swings

  45. Take-Off Swings Tail wheel aircraft only: Asymmetric blade effect Gyroscopic effect

  46. Take-Off Swings

  47. Take-Off Swings Affect all aircraft on rotate?

  48. Take-Off Swings All Aircraft: Don’t forget crosswind effect!

  49. Centrifugal Twisting Moment Tries to fine blade off

  50. Relative Airflow Total Reaction Aerodynamic Twisting Moment Tries to coarsen blade up

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