Presentation Transcript

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
51. Total Reaction Relative Airflow

    Aerodynamic Twisting Moment Windmilling

    Tries to fine blade off
52. ANY QUESTIONS?
53. 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.
54. Questions Blade Angle of Attack is between? a.The Chord and Relative Airflow. b. The Rotational Velocity and the Relative Airflow. The Total Reaction and the Chord. Lift and Drag.
55. Questions Increasing speed with a fixed pitch propeller will? a.Be more efficient. b. Reduce efficiency. Make no difference. Increase the Engine speed.
56. Questions The Forces trying to alter the Propeller Blade Angle of Attack are? a.ATM and CTM. b. CDM and ATM. CTM and REV. AOA and ATM.
57. Questions The Resultant Forces that a Propeller produce are? a.Lift and Thrust. Thrust and Propeller Rotational Drag. Drag and Total Reaction. d. Drag and Thrust.