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Propeller Based Propulsion

Propeller Based Propulsion. P M V Subbarao Professor Mechanical Engineering Department. Both Lift and Thrust using Pure Wright Brother’s Idea!!!. Working Principle of Propeller Aircraft. Anatomy of Propeller. Velocity & Force Vectors across A Propeller. Force Vectors. Velocity Vectors.

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Propeller Based Propulsion

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  1. Propeller Based Propulsion P M V Subbarao Professor Mechanical Engineering Department Both Lift and Thrust using Pure Wright Brother’s Idea!!!

  2. Working Principle of Propeller Aircraft

  3. Anatomy of Propeller

  4. Velocity & Force Vectors across A Propeller Force Vectors Velocity Vectors

  5. Creation of Useful Velocity Triangle The propeller blade will be set at a given geometric pitch angle () The local velocity vector will create a flow angle of attack () on the section A-A. V0 -- axial flow at propeller disk, V2 -- Angular flow velocity vector V1 -- section local flow velocity vector, summation of vectors V0 and V2

  6. Forces Generated by An Infinitesimal Blade Element V1 V0 V2 = r The elemental thrust (dT) and torque (dQ) of this blade element can thus be written as

  7. Static Performance of an Airfoil

  8. Force System on an Airfoil • The surface pressure is non-dimensionalised using the dynamic pressure, giving the pressure coefficient, :

  9. Static Performance of An Airfoil Static stall

  10. Local Forces on A Blade Element : Propeller For a constant V1 Steady stall V0 V1

  11. Lift and drag coefficients for the NACA 0012 symmetric airfoil : Preferred Reynolds Number Range

  12. Lift and drag coefficients for the NACA 63(2)-215 airfoil : Preferred Reynolds Number Range

  13. Dynamic Performance of an Airfoil • Consider an airfoil of chord length of c, pitching about the mid-chord at a constant pitch rate (rad/s). • Define, the reduced frequency as NACA 0015 Comparison with the steady-state case indicates that the airfoil can generate increasing lift forces beyond the critical stall angle of attack with increasing reduced frequency

  14. Enhanced Lift due to Dynamic State of Airfoli

  15. Forces Generated by An Infinitesimal Blade Element V1 V0 V2 = r The elemental thrust (dT) and torque (dQ) of this blade element can thus be written as For each blade element:

  16. Infinitesimal Propeller Element

  17. Forces Generated by An Infinitesimal Propeller Element If the number of propeller blades is (B) then, The incremental thrust generated by the rotor is: The driving torque on the rotor shaft is: The incremental Power input to the shaft is:

  18. Total Power Input to the Propeller The absorbed poweris often non-dimensionalized with respect to as a power coefficient CP:

  19. Capacity of A Successful Propeller

  20. Engines to drive propeller

  21. Propellers for Helicopter Each rotor blade (1) is connected to the hub (2) and rotating mast by a feathering hinge (3), which allows it to swivel.

  22. A pitch link (a short rod) attached to each blade (4) can tilt it to a steeper or shallower angle according to the position of the rotating upper swash plate (5). • Swash plate spins on bearings around the static lower swash plate (6). • That's how a chopper hovers and steers and it's described in more detail later in this article.

  23. The two swash plates are moved up and down or tilted to the side by the pilot's cyclic and collective cockpit contro. The rotor is powered by a driveshaft (7) connected to a transmission and gearbox (8). • The same transmission powers a second, longer driveshaft (9) connected to a gearbox that spins the tail rotor (10). • The power from both rotors comes from one or two turboshaft jet engines (11).

  24. Thrust + Lift Weight + Drag Vertical Ascent

  25. Resultant Lift Thrust Forward Flight

  26. Thrust + Lift Weight+ Drag Hover

  27. Thrust + Lift Weight + Drag Vertical Descent

  28. Resultant Lift Thrust Rearward Flight

  29. Resultant Resultant Lift Lift Side Thrust Side Thrust Sideward Flight

  30. Bell 429Exceptional Speed and Class Leading Performance

  31. The Structure of PW207 Series • Single stage, centrifugal compressor :Compact and efficient, Radial inlet with screen for FOD protection, No overboard compressor bleed. • Reverse flow combustor: Low smoke, high stability, easy starting, durable. • Single stage high pressure turbine : Advanced technology and low parts count for long life and low maintenance cost • Single-stage shrouded power turbine : High efficiency and low vibration • Combined Reduction and Accessory gearbox • Two-stage, compact drive train with precise electronic torquemeter and integrated oil tank.

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