Helicopters

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Helicopters

  1. 1. VI. Helicopters <ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  2. 2. Helicopters History <ul><li>1483, DaVinci </li></ul><ul><ul><li>Developed “Helix” </li></ul></ul><ul><ul><li>Kind of aerial screw </li></ul></ul><ul><ul><li>Shows basic understanding that the atmosphere can support weight but no provisions for torque on fuselage </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  3. 3. Helicopters History <ul><li>1800s, Forlanini (Italy) </li></ul><ul><ul><li>Used steam engine </li></ul></ul><ul><ul><li>Counter-rotating “butterfly” wings </li></ul></ul><ul><ul><li>Could ascend (without pilot) to 40 feet for about 20 minutes </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  4. 4. Helicopters History <ul><li>1907, Cornu (France) </li></ul><ul><ul><li>First piloted helicopter </li></ul></ul><ul><ul><li>Flew for few seconds </li></ul></ul><ul><ul><li>Used internal combustion engine </li></ul></ul><ul><ul><li>No controls but well balanced </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  5. 5. Helicopters History <ul><li>1909, Igor Sikorsky (Russia) </li></ul><ul><ul><li>Small counter-rotating coaxial rotors </li></ul></ul><ul><ul><li>First use of airfoil shaped rotors </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  6. 6. Helicopters History <ul><li>1920s, Petroczy & Von Karmon (Austria) </li></ul><ul><ul><li>Counter-rotating, coaxial, airfoil rotors </li></ul></ul><ul><ul><li>3 40HP engines </li></ul></ul><ul><ul><li>No controls, just made to lift straight up </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  7. 7. Helicopters History <ul><li>1923, de Bothezat (U.S.) </li></ul><ul><ul><li>4 rotors </li></ul></ul><ul><ul><li>Complicated power transmission system </li></ul></ul><ul><ul><li>Low power </li></ul></ul><ul><ul><li>Several flights of 1 minute @ 6 feet </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  8. 8. Helicopters History <ul><li>1923, de la Cierva (Spain) </li></ul><ul><ul><li>Developed Autogyro </li></ul></ul><ul><ul><li>Solved some control problems by allowing rotors to Flap </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  9. 9. Helicopters History <ul><li>1936, Focke-Wulfe (Germany) </li></ul><ul><ul><li>FW-61 established endurance & speed records </li></ul></ul><ul><ul><li>Mostly flown by Hannah Reich </li></ul></ul><ul><ul><li>Flown inside stadium for most of records </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  10. 10. Helicopters History <ul><li>1939, Sikorsky (U.S.) </li></ul><ul><ul><li>Developed VS-300 </li></ul></ul><ul><ul><li>Broke all FW-61 records </li></ul></ul><ul><ul><li>Used 3-bladed main rotor, vertical 2-bladed tail rotor & 2 horizontal 2-bladed outrigger rotors for stability and control </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  11. 11. Helicopters Configurations <ul><li>Autogyros </li></ul><ul><ul><li>Developed by de la Cierva </li></ul></ul><ul><ul><li>Uses free-spinning main rotor with airplane-like engine/prop for forward motion </li></ul></ul><ul><ul><li>No power to main rotor, spins from air action = can’t hover or ascend vertically </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  12. 12. Helicopters Configurations <ul><li>Dual Rotor </li></ul><ul><ul><li>2 counter rotating main rotors </li></ul></ul><ul><ul><ul><li>No tail rotor needed </li></ul></ul></ul><ul><ul><ul><li>May be separate or coaxial </li></ul></ul></ul><ul><ul><li>Used extensively through history, today few (Boeing, Kaman) </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  13. 13. Helicopters Configurations <ul><li>Single Rotor </li></ul><ul><ul><li>Most used design </li></ul></ul><ul><ul><li>1 main rotor for lift and control </li></ul></ul><ul><ul><li>Tail rotor for anti-torque </li></ul></ul><ul><ul><ul><li>FAA calls it “Auxiliary Rotor” </li></ul></ul></ul><ul><ul><ul><li>More precisely known as “Anti-torque Rotor” </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  14. 14. Helicopters Configurations <ul><li>Single Rotor </li></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>Hughes Helicopter H-17 Skycrane 1952 Function: transport Crew: 2 Engines: 1 * G.E. J35 Rotor Span: 130ft Length: Height: 30ft Disc Area: Empty Weight: Max.Weight: 46000lb Speed: Ceiling: Range: 65km Load: 25000lbs Hot Cycle Blades
  15. 15. Helicopters Configurations <ul><li>Tilt Rotor </li></ul><ul><ul><li>Bell V-22 </li></ul></ul><ul><ul><li>Engines and main rotors (“PropRotors”) mounted on wingtips </li></ul></ul><ul><ul><ul><li>Rotate so rotor is horizontal (on top) to takeoff and land like helicopter </li></ul></ul></ul><ul><ul><ul><li>Rotate so rotor is vertical to act like prop for high speed forward flight </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  16. 16. Helicopters Types of Rotors <ul><li>General </li></ul><ul><ul><li>All must change blade angle or Pitch for control actions </li></ul></ul><ul><ul><li>Called “Feathering” </li></ul></ul><ul><ul><li>Is rotation around the span axis of the blade </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  17. 17. Helicopters Types of Rotors <ul><li>General </li></ul><ul><ul><li>Some also: </li></ul></ul><ul><ul><ul><li>Flap or Teeter </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  18. 18. Helicopters Types of Rotors <ul><li>General </li></ul><ul><ul><li>Some also: </li></ul></ul><ul><ul><ul><li>Lead/Lag (Hunt or Drag) </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  19. 19. Helicopters Types of Rotors <ul><li>Semi-Rigid Rotor </li></ul><ul><ul><li>2-bladed </li></ul></ul><ul><ul><li>Blades Feather and entire rotor Teeters </li></ul></ul><ul><ul><li>No Hunting action allowed </li></ul></ul><ul><ul><li>Very popular in early Bell designs (and others) </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  20. 20. <ul><li>Semi-Rigid </li></ul><ul><ul><li>Bell 206 </li></ul></ul>Helicopters Types of Rotors <ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  21. 21. Helicopters Types of Rotors <ul><li>Fully Articulated Rotor </li></ul><ul><ul><li>3 or more blades </li></ul></ul><ul><ul><li>Blades can Feather, individually Flap, and Hunt </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul><ul><ul><li>Hunting limited by mechanical Dampers </li></ul></ul>
  22. 22. Helicopters Types of Rotors <ul><li>Fully Articulated </li></ul><ul><ul><li>Is most complicated but smoothest in flight </li></ul></ul><ul><ul><li>Problem: Ground Resonance potential </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  23. 23. Helicopters Types of Rotors <ul><li>Fully Articulated </li></ul><ul><ul><li>Hughes 500 (McDonnell-Douglas, Boeing) </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  24. 24. Helicopters Types of Rotors <ul><li>Fully Articulated </li></ul><ul><ul><li>Sikorsky S58 </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  25. 25. Helicopters Types of Rotors <ul><li>Fully Articulated </li></ul><ul><ul><li>AStar 350 </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  26. 26. Helicopters Types of Rotors <ul><li>Rigid </li></ul><ul><ul><li>2 or more blades </li></ul></ul><ul><ul><li>Blades Feather but all other forces absorbed by bending of the blades </li></ul></ul><ul><ul><li>Strongest and most maneuverable but needs composites to withstand fatigue </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  27. 27. Helicopters Forces on the Rotors <ul><li>Static Forces </li></ul><ul><ul><li>Gravity pulls down and blades can bend relatively low </li></ul></ul><ul><ul><ul><li>Called Droop </li></ul></ul></ul><ul><ul><li>All need some kind of Droop (Static) Stop to prevent too low and possible Tail Boom strike </li></ul></ul><ul><ul><ul><li>Especially for Fully Articulated at low RPM </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  28. 28. Helicopters Forces on the Rotors <ul><li>Turning Forces </li></ul><ul><ul><li>Centrifugal Force tries to hold the blades straight out but lift tries to bend up </li></ul></ul><ul><ul><li>Result is Coning </li></ul></ul><ul><ul><ul><li>Upward bending into Cone shape </li></ul></ul></ul><ul><ul><ul><li>More lift = more Coning </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  29. 29. Helicopters Forces on the Rotors <ul><li>Torque </li></ul><ul><ul><li>From Newton’s 3 rd Law </li></ul></ul><ul><ul><li>Main rotor turns in one direction = fuselage tries to turn opposite (Torque) </li></ul></ul><ul><ul><li>Is directly proportional to power applied to M/R </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  30. 30. Helicopters Forces on the Rotors <ul><li>Torque </li></ul><ul><ul><li>Compensated for by Tail Rotor thrust </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>What happens if Tail Rotor fails during flight?
  31. 31. Helicopters Forces on the Rotors <ul><li>Torque </li></ul><ul><ul><li>Compensated for by Tail Rotor thrust or counter-rotating M/Rs </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  32. 32. Helicopters Forces on the Rotors <ul><li>Torque </li></ul><ul><ul><li>Problem: Tail Rotor causes “Translating Tendency” or “Drift” </li></ul></ul><ul><ul><ul><li>Is movement of entire helicopter in direction of T/R thrust (to right in U.S.) </li></ul></ul></ul><ul><ul><ul><li>Compensated by slight tilt of M/R mast to left </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  33. 33. Helicopters Forces on the Rotors <ul><li>Gyroscopic Precession </li></ul><ul><ul><li>Any rotating body (M/R) acts like a Gyroscope and exhibits 2 characteristics: </li></ul></ul><ul><ul><ul><li>Rigidity </li></ul></ul></ul><ul><ul><ul><li>Precession </li></ul></ul></ul><ul><ul><li>Rigidity resists the change from it’s position in relation to space, not the Earth </li></ul></ul><ul><ul><li>Precession is the fact that the effect of any upsetting force applied to the body is felt 90 o later in direction of rotation </li></ul></ul><ul><ul><ul><li>Affects the design and rigging of the M/R </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  34. 34. Helicopters Forces on the Rotors <ul><li>Gyroscopic Precession </li></ul><ul><ul><li>For flight = need to tilt “Rotor Disk” in direction of desired flight </li></ul></ul><ul><ul><ul><li>Changes lift & thrust vectors toward that direction = movement of helicopter </li></ul></ul></ul><ul><ul><li>To accomplish = need to make pitch change 90 o earlier </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>De sired direction of flight
  35. 35. Helicopters Forces on the Rotors <ul><li>Gyroscopic Precession </li></ul><ul><ul><li>For flight = need to tilt “Rotor Disk” in direction of desired flight </li></ul></ul><ul><ul><ul><li>Changes lift & thrust vectors toward that direction = movement of helicopter </li></ul></ul></ul><ul><ul><li>To accomplish = need to make pitch change 90 o earlier </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  36. 36. Helicopters Forces on the Rotors <ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  37. 37. Helicopters Forces on the Rotors <ul><li>Ground Effect </li></ul><ul><ul><li>Increased lift within ½ rotor diameter of ground </li></ul></ul><ul><ul><li>“Cushion of Air” </li></ul></ul><ul><ul><li>Comes from change in angle of attack near ground because relative wind changes </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  38. 38. Helicopters Forces on the Rotors <ul><li>Ground Effect </li></ul><ul><ul><li>Out of Ground Effect (OGE) </li></ul></ul><ul><ul><ul><li>Rotor wash is free to accelerate straight down = given angle of attack and lift and large tip vortex </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>Rotation Angle of Attack Downwash Relative Wind
  39. 39. Helicopters Forces on the Rotors <ul><li>Ground Effect </li></ul><ul><ul><li>In Ground Effect (IGE) </li></ul></ul><ul><ul><ul><li>Rotor wash is forced to move outward as well as down = reduced down vector = increased angle of attack + smaller tip vortex </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>Downwash Rotation Angle of Attack Relative Wind
  40. 40. Helicopters Forces on the Rotors <ul><li>Flight Forces </li></ul><ul><ul><li>Same as airplane: </li></ul></ul><ul><ul><ul><li>Lift up </li></ul></ul></ul><ul><ul><ul><li>Weight (Gravity) down </li></ul></ul></ul><ul><ul><ul><li>Thrust forward and up </li></ul></ul></ul><ul><ul><ul><li>Drag back and down </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  41. 41. Helicopters Forces on the Rotors <ul><li>Flight Forces </li></ul><ul><ul><li>In hover: </li></ul></ul><ul><ul><ul><li>Lift and Thrust both act up </li></ul></ul></ul><ul><ul><ul><li>Weight and Drag act down </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  42. 42. Helicopters Forces on the Rotors <ul><li>Flight Forces </li></ul><ul><ul><li>Forward Flight: </li></ul></ul><ul><ul><ul><li>Thrust vector tilted in desired direction = overall loss of upward lift = need more power applied </li></ul></ul></ul><ul><ul><ul><li>Similar to airplane in turn </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  43. 43. Helicopters Flight Conditions <ul><li>Dissymmetry of Lift </li></ul><ul><ul><li>At a hover with no wind the rotor blades are all traveling at the same speed in relation to the air around them </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  44. 44. Helicopters Flight Conditions <ul><li>Dissymmetry of Lift </li></ul><ul><ul><li>Any relative air motion (wind or flight) = blade going into wind ( Advancing Blade ) travels faster than Retreating Blade </li></ul></ul><ul><ul><ul><li>Think in terms of Airspeed </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>100 mph
  45. 45. Helicopters Flight Conditions <ul><li>Dissymmetry of Lift </li></ul><ul><ul><li>Faster airfoil = more lift on Advancing side (and less lift on Retreating side) </li></ul></ul><ul><ul><li>Lift not equal = Dissymmetry of Lift </li></ul></ul><ul><ul><li>Without compensation = roll to left (and gets more severe with speed increase) </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  46. 46. Helicopters Flight Conditions <ul><li>Dissymmetry of Lift </li></ul><ul><ul><li>Compensated for by allowing the blades to Flap or the rotor to Teeter </li></ul></ul><ul><ul><ul><li>Advancing blade Flaps (Teeters) up = decrease in angle of attack due to upward vector of Relative Wind </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  47. 47. Helicopters Flight Conditions <ul><li>Dissymmetry of Lift </li></ul><ul><ul><li>Compensated for by allowing the blades to Flap or the rotor to Teeter </li></ul></ul><ul><ul><ul><li>Retreating blade Flaps (Teeters) down = increase in angle of attack due to Relative Wind change </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  48. 48. Helicopters Flight Conditions <ul><li>Coriolis Effect </li></ul><ul><ul><li>Caused by Flapping or Teetering up </li></ul></ul><ul><ul><li>Blade flaps up = Center of Mass moves closer to axis of rotation = RPM increases </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  49. 49. Helicopters Flight Conditions <ul><li>Coriolis Effect </li></ul><ul><ul><li>The inertia of the rotor stays constant so as the Axis of Rotation is reduced the Speed of Rotation must increase </li></ul></ul><ul><ul><li>Is same as skater in spin with arms out then speeds up when arms are moved in to sides </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  50. 50. Helicopters Flight Conditions <ul><li>Coriolis Effect </li></ul><ul><ul><li>Creates force to accelerate the blade (Hunting action) </li></ul></ul><ul><ul><li>Fully Articulated head allows limited Hunting action </li></ul></ul><ul><ul><ul><li>Uses hydraulic or composite dampers to minimize movement </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  51. 51. Helicopters Flight Conditions <ul><li>Coriolis Effect </li></ul><ul><ul><li>Semi-Rigid usually uses “UnderSlung Rotor Head” </li></ul></ul><ul><ul><ul><li>Teetering Axis is above Feathering Axis (“Delta Hinge” arrangement) = as teeters it also swings to high side </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  52. 52. Helicopters Flight Conditions <ul><li>Coriolis Effect </li></ul><ul><ul><li>Semi-Rigid usually uses “UnderSlung Rotor Head” </li></ul></ul><ul><ul><ul><li>Center of Mass of the Rotor then stays basically in line with driveshaft/mast </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  53. 53. Helicopters Flight Conditions <ul><li>Translational Lift </li></ul><ul><ul><li>Increased lift during the translation to forward flight from a hover </li></ul></ul><ul><ul><li>Occurs between 16 and 24 knots airspeed </li></ul></ul><ul><ul><ul><li>Feel vibration and definite increase in lift (that point is called “Effective Translational Lift”) </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  54. 54. Helicopters Flight Conditions <ul><li>Translational Lift </li></ul><ul><ul><li>At hover and below 15 knots , the ground is forcing the rotor downwash outward and creating some turbulence around rotor blades </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  55. 55. Helicopters Flight Conditions <ul><li>Translational Lift </li></ul><ul><ul><li>At hover and below 15 knots , the ground is forcing the rotor downwash outward and creating some turbulence around rotor blades </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul><ul><ul><li>Above 15 kts , the blades “bite” into undisturbed air = more efficient = less power needed </li></ul></ul>
  56. 56. Helicopters Flight Conditions <ul><li>Translational Lift </li></ul><ul><ul><li>Above about 50 knots , drag starts to increase greatly and we need more power to further accelerate </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  57. 57. Helicopters Flight Conditions <ul><li>Transverse Flow Effect </li></ul><ul><ul><li>At slow airspeeds (less than 20 kts.) = air through rear of rotor is accelerated downward longer than air at front = decrease in angle of attack in rear </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  58. 58. Helicopters Flight Conditions <ul><li>Transverse Flow Effect </li></ul><ul><ul><li>Effect felt 90 o later = drift to right </li></ul></ul><ul><ul><li>Pilot must compensate with some left Cyclic to keep going in a straight line </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  59. 59. Helicopters Flight Conditions <ul><li>Transverse Flow Effect </li></ul><ul><ul><li>As airspeed increases = entire rotor has basically undisturbed airflow = no Transverse Flow Effect is felt </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  60. 60. Helicopters Flight Conditions <ul><li>Autorotations </li></ul><ul><ul><li>Flight with no engine power applied to the main rotors </li></ul></ul><ul><ul><li>Air is normally drawn down through rotors but if have engine failure = aircraft drops and wind goes up through rotors = keeps them rotating at near normal RPM </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  61. 61. Helicopters Flight Conditions <ul><li>Autorotations </li></ul><ul><ul><li>When engine fails, pilot lowers Collective stick to bottom = sets in minimal angle on all blades and adjusts Cyclic to certain forward airspeed </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  62. 62. Helicopters Flight Conditions <ul><li>Autorotations </li></ul><ul><ul><li>With Relative Wind from underneath and forward: </li></ul></ul><ul><ul><ul><li>Lift and Drag vectors are changed so Resultant is forward of Axis of Rotation = tries to accelerate rotor and is called Autorotative Force </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  63. 63. Helicopters Flight Conditions <ul><li>Autorotations </li></ul><ul><ul><li>With Relative Wind from underneath and forward: </li></ul></ul><ul><ul><ul><li>Occurs in middle 25 – 75% of rotor </li></ul></ul></ul><ul><ul><ul><li>Is called the Autorotative (Autorotation) Region </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  64. 64. Helicopters Flight Conditions <ul><li>Autorotations </li></ul><ul><ul><li>With Relative Wind from underneath and forward: </li></ul></ul><ul><ul><ul><li>In outer 30% of rotor = blade twist makes the angle of attack low and the speed makes the drag high </li></ul></ul></ul><ul><ul><ul><li>Resultant is behind the Axis of Rotation </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  65. 65. Helicopters Flight Conditions <ul><li>Autorotations </li></ul><ul><ul><li>With Relative Wind from underneath and forward: </li></ul></ul><ul><ul><ul><li>Is a Decelerating force (Anti-Autorotative Force) and is called the Driven (or Propeller) Region </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  66. 66. Helicopters Flight Conditions <ul><li>Autorotations </li></ul><ul><ul><li>With Relative Wind from underneath and forward: </li></ul></ul><ul><ul><ul><li>Inner 25% has an angle of attack higher than the Critical Angle of the airfoil = Stall Region and also creates an Anti-Autorotative Force </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  67. 67. Helicopters Flight Conditions <ul><li>Autorotations </li></ul><ul><ul><li>At some forward airspeed these forces combine to stabilize the RPM (achieve equilibrium) </li></ul></ul><ul><ul><li>RPM means Inertia = energy available to use when near the ground </li></ul></ul><ul><ul><ul><li>This Autorotation RPM is critical rigging adjustment </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  68. 68. Helicopters Flight Conditions <ul><li>Autorotations </li></ul><ul><ul><li>At about 50 feet above the ground, the pilot pulls back on the Cyclic to flare the aircraft (pulls the nose up some = reduced airspeed) </li></ul></ul><ul><ul><ul><li>= momentary increase in airflow and higher RPM (= more inertia) </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  69. 69. Helicopters Flight Conditions <ul><li>Autorotations </li></ul><ul><ul><li>At about 10 feet above the ground, the pilot pulls up on the Collective and starts to use that energy in the rotor to cushion the landing </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  70. 70. Helicopters Flight Conditions <ul><li>Autorotations </li></ul><ul><ul><li>Also leads manufacturers to publish “Height-Velocity Diagram” in Flight Manual </li></ul></ul><ul><ul><li>Also known as the “Dead Man’s Curve” </li></ul></ul><ul><ul><li>If fly in shaded area combinations of Height (Altitude) and Velocity = can’t successfully Autorotate </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  71. 71. Helicopters Flight Conditions <ul><li>Retreating Blade Stall </li></ul><ul><ul><li>As we move forward = Retreating Blade flaps down to compensate for Dissymmetry of Lift by increasing the angle of attack </li></ul></ul><ul><ul><li>At some high forward airspeed (especially if the rotor RPM is allowed to get low) a portion of the airfoil (rotor disk) will exceed the Critical Angle of Attack and Stall </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  72. 72. Helicopters Flight Conditions <ul><li>Retreating Blade Stall </li></ul><ul><ul><li>Generally occurs at the 7 – 9 o’clock position (looking down on the rotor = left rear of rotor) = vibrations + nose pitches up </li></ul></ul><ul><ul><ul><li>gyroscopic precession = loss of lift in rear of rotor </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  73. 73. Helicopters Flight Conditions <ul><li>Retreating Blade Stall </li></ul><ul><ul><li>Nose pitch up = excessive angle of attack in front (stall) = loss of lift on left and roll to left </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  74. 74. Helicopters Flight Conditions <ul><li>Vortex Ring State (Settling With Power) </li></ul><ul><ul><li>If descending at 300 fpm or more + less than 10 mph forward airspeed + 20 to 100% power applied = can descend inside rotor downwash </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  75. 75. Helicopters Flight Conditions <ul><li>Vortex Ring State (Settling With Power) </li></ul><ul><ul><li>Blades produce tip vortices (like any airfoil) + upward flow of air in middle of rotor (from descent) = Vortex across entire rotor = loss of lift and increased descent rate </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  76. 76. Helicopters Flight Conditions <ul><li>Vortex Ring State (Settling With Power) </li></ul><ul><ul><li>Increasing power to control descent rate = increases problem by increasing the amount of vortex created </li></ul></ul><ul><ul><li>Must accelerate out of it or descend below it (if there’s enough altitude) </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  77. 77. Helicopters Flight Conditions <ul><li>Vortex Ring State (Settling With Power) </li></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  78. 78. Helicopters Flight Conditions <ul><li>Ground Resonance </li></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>http://www.chinook-helicopter.com/Fundamentals_of_Flight/Ground_Resonance/Ground_Resonance.html
  79. 79. Helicopters Controls <ul><li>Axes of Flight </li></ul><ul><ul><li>Same as airplane: Longitudinal Axis = Roll, Lateral Axis = Pitch, Vertical Axis = Yaw </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  80. 80. Helicopters Controls <ul><li>Flight Controls </li></ul><ul><ul><li>3 basic controls: Cyclic, Collective, Pedals </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  81. 81. Helicopters Controls <ul><li>Flight Controls </li></ul><ul><ul><li>3 basic controls: Cyclic, Collective, Pedals </li></ul></ul><ul><ul><li>Cyclic: </li></ul></ul><ul><ul><ul><li>Controls Pitch and Roll </li></ul></ul></ul><ul><ul><ul><li>Tilts rotor disk in desired direction of movement </li></ul></ul></ul><ul><ul><ul><li>Is primary airspeed and flight path control (pitch & roll) </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  82. 82. Helicopters Controls <ul><li>Axes of Flight </li></ul><ul><ul><li>Cyclic: </li></ul></ul><ul><ul><ul><li>Uses Swashplate to do job </li></ul></ul></ul><ul><ul><ul><ul><li>Is device with rotating component and stationary component </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Connected by double-row ball bearing </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Lower (stationary) part connected to Cyclic stick via push-pull tubes and/or hydraulics </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Upper (rotating) part connected to main blades and rotates with them </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  83. 83. Helicopters Controls <ul><li>Axes of Flight </li></ul><ul><ul><li>Cyclic: </li></ul></ul><ul><ul><ul><li>Uses Swashplate to do job </li></ul></ul></ul><ul><ul><ul><ul><li>Pilot pushes Cyclic stick in direction of desired movement </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Swashplate is tilted to change M/R blade pitch a different amount depending on where it is in rotation </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>The pitch changes cyclically as it rotates </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Direction of tilt is designed to take Gyroscopic Precession into account </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>May or may not tilt same as rotor disk action </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  84. 84. Helicopters Controls <ul><li>Axes of Flight </li></ul><ul><ul><li>Cyclic: </li></ul></ul><ul><ul><ul><li>Example system: Huey (Bell UH-1) </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>Fore & Aft tubes Lateral tubes
  85. 85. Helicopters Controls <ul><li>Axes of Flight </li></ul><ul><ul><li>Collective: </li></ul></ul><ul><ul><ul><li>Changes the pitch of all blades the same amount at the same time (collectively) </li></ul></ul></ul><ul><ul><ul><li>Controls the overall lift generated by the rotors </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  86. 86. Helicopters Controls <ul><li>Axes of Flight </li></ul><ul><ul><li>Collective: </li></ul></ul><ul><ul><ul><li>Uses the Swashplate to do the job by raising or lowering it to change the pitch on all blades </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  87. 87. Helicopters Controls <ul><li>Axes of Flight </li></ul><ul><ul><li>Collective: </li></ul></ul><ul><ul><ul><li>Collective stick also has engine throttle(s) </li></ul></ul></ul><ul><ul><ul><ul><li>Motorcycle style rotating throttle except must rotate away from you to increase </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Turbines usually governed so open throttle wide open and let governor keep RPM steady </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  88. 88. Helicopters Controls <ul><li>Axes of Flight </li></ul><ul><ul><li>Collective: </li></ul></ul><ul><ul><ul><li>Example system: Hughes (Schweizer) 269 </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  89. 89. Helicopters Controls <ul><li>Axes of Flight </li></ul><ul><ul><li>Pedals: </li></ul></ul><ul><ul><ul><li>Control Yaw by controlling the thrust of the Tail Rotor (on single-rotor helicopters) and driven by main transmission so will still work if engine quits </li></ul></ul></ul><ul><ul><ul><ul><li>Dual rotors = differential cyclic control by pedals </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Coaxial rotors = rudder in rotor downwash </li></ul></ul></ul></ul><ul><ul><ul><li>Push left pedal to yaw to the left, right pedal to yaw to the right </li></ul></ul></ul><ul><ul><ul><ul><li>Left pedal increases T/R thrust </li></ul></ul></ul></ul><ul><ul><ul><li>Needed especially during slow and high power conditions (I.e. takeoff and landing) </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  90. 90. Helicopters Controls <ul><li>Axes of Flight </li></ul><ul><ul><li>Tail Rotor Types: </li></ul></ul><ul><ul><ul><li>Semi-rigid </li></ul></ul></ul><ul><ul><ul><ul><li>Most common until recently </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Usually 2-bladed </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Has same Dissymmetry of Lift problems as M/R so will teeter usually (some let blades flap) </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  91. 91. Helicopters Controls <ul><li>Axes of Flight </li></ul><ul><ul><li>Tail Rotor Types: </li></ul></ul><ul><ul><ul><li>Semi-rigid </li></ul></ul></ul><ul><ul><ul><ul><li>Most common until recently </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Usually 2-bladed </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Has same Dissymmetry of Lift problems as M/R so will teeter usually (some let blades flap) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Most use Offset Hinges so pitch is physically changed as rotor teeters = minimal actual teetering action </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  92. 92. Helicopters Controls <ul><li>Axes of Flight </li></ul><ul><ul><li>Tail Rotor Types: </li></ul></ul><ul><ul><ul><li>Fenestron </li></ul></ul></ul><ul><ul><ul><ul><li>French design </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Enclosed multi-bladed variable-pitch fan </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Safer and quieter </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  93. 93. Helicopters Controls <ul><li>Axes of Flight </li></ul><ul><ul><li>Tail Rotor Types: </li></ul></ul><ul><ul><ul><li>NOTAR </li></ul></ul></ul><ul><ul><ul><ul><li>Developed by Hughes Helicopters (then McDonnell-Douglas now Boeing) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Uses fan inside tail boom with exhaust out side of boom through variable vent connected to pedals </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Also uses Coanda Effect from rotor downwash </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Air flowing over the curved surface “sticks” to that surface and creates lift sideways </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  94. 94. Helicopters Controls <ul><li>Miscellaneous </li></ul><ul><ul><li>Stabilizer surfaces </li></ul></ul><ul><ul><ul><li>Fixed Horizontal </li></ul></ul></ul><ul><ul><ul><ul><li>Creates download on tail to keep fuselage more level during high speed flight </li></ul></ul></ul></ul><ul><ul><ul><li>Synchronized Elevator </li></ul></ul></ul><ul><ul><ul><ul><li>Connected to Cyclic </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Changes pitch to change tail down load for various flight speeds </li></ul></ul></ul></ul><ul><ul><ul><li>Fixed Vertical </li></ul></ul></ul><ul><ul><ul><ul><li>For directional stability </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  95. 95. Helicopters Controls <ul><li>Miscellaneous </li></ul><ul><ul><li>Hydraulics </li></ul></ul><ul><ul><ul><li>For larger or heavier M/R systems </li></ul></ul></ul><ul><ul><ul><li>Mostly use Irreversible type systems to overcome flight loads and dampen vibrations in sticks </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  96. 96. Helicopters Controls <ul><li>Miscellaneous </li></ul><ul><ul><li>Example system: </li></ul></ul><ul><ul><ul><li>Bell 206 </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  97. 97. Helicopters Controls <ul><li>Stabilizer Controls </li></ul><ul><ul><li>Are inherently unstable </li></ul></ul><ul><ul><li>As rotor lift/thrust vector tilts away from vertical = creates vector to pull away from center </li></ul></ul><ul><ul><li>= negative stability </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  98. 98. Helicopters Controls <ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul><ul><ul><li>Compensations </li></ul></ul><ul><ul><ul><li>Bell Stabilizer Bar </li></ul></ul></ul><ul><ul><ul><ul><li>Bar below M/R @ 90 o to blade span </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Acts like gyroscope and uses Rigidity in Space characteristic to try and keep rotor and aircraft in one attitude </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Worked too well so needs hydraulic damper to limit it’s effectiveness and allow reasonable maneuverability </li></ul></ul></ul></ul>
  99. 99. Helicopters Controls <ul><li>Compensations </li></ul><ul><ul><li>Offset Flapping Hinge </li></ul></ul><ul><ul><ul><li>On fully-articulated rotor heads and on some tail rotors </li></ul></ul></ul><ul><ul><ul><li>Hinge moved a distance from rotor’s rotation axis = acts like lever to provide restoring force </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  100. 100. Helicopters Controls <ul><li>Compensations </li></ul><ul><ul><ul><li>Stabilization Augmentation System (SAS) </li></ul></ul></ul><ul><ul><ul><ul><li>Like simple autopilot </li></ul></ul></ul></ul><ul><ul><ul><ul><li>One- or two-axis </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Only to aid stability, not true autopilot </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  101. 101. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Large number of moving and rotating parts = susceptible to vibrations </li></ul></ul><ul><ul><li>Vibrations = abnormal wear, premature part failure, and uncomfortable ride for people </li></ul></ul><ul><ul><li>Must minimize vibes </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  102. 102. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Types </li></ul></ul><ul><ul><ul><li>Low Frequency </li></ul></ul></ul><ul><ul><ul><ul><li>Feel as “beat” in structure and may be able to almost count the beats </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Comes from Main Rotor </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  103. 103. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Types </li></ul></ul><ul><ul><ul><li>Low Frequency </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul><ul><ul><li>Vertical vibe </li></ul></ul><ul><ul><ul><li>Up & down motion </li></ul></ul></ul><ul><ul><ul><li>Caused by blades being Out-of-Track </li></ul></ul></ul>
  104. 104. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Types </li></ul></ul><ul><ul><ul><li>Low Frequency </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul><ul><ul><li>Lateral vibe </li></ul></ul><ul><ul><ul><li>Side-to-side motion </li></ul></ul></ul><ul><ul><ul><li>Comes from blades being out of balance or spaced unequally </li></ul></ul></ul>
  105. 105. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Types </li></ul></ul><ul><ul><ul><li>High Frequency </li></ul></ul></ul><ul><ul><ul><ul><li>Felt as “buzz” in structure </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Comes from cooling fan, engine and/or accessories, gearboxes, or (most commonly) Tail Rotor </li></ul></ul></ul></ul><ul><ul><ul><ul><li>May only notice if some part of body goes to sleep </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Feet = Tail Rotor (through pedals) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Butt = others </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  106. 106. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Measurement of vibes </li></ul></ul><ul><ul><ul><li>Feel </li></ul></ul></ul><ul><ul><ul><ul><li>Adjust until feels OK (at minimum level) </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  107. 107. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Measurement of vibes </li></ul></ul><ul><ul><ul><li>Electronic </li></ul></ul></ul><ul><ul><ul><ul><li>Use accelerometers to measure rate and strength accurately </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Use Strobe light or “Clock” to locate </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Use above as coordinates on chart to determine exactly where and how much weight to add or remove </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Can use to troubleshoot (narrow down vibe rate and look at those components operating at that rate) </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  108. 108. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Correction of vibes (M/R & T/R) </li></ul></ul><ul><ul><ul><li>If out of balance condition </li></ul></ul></ul><ul><ul><ul><ul><li>May require Static or Dynamic procedures (or both depending on helicopter) </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Some require Static balancing after assembly </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Put on balance stand and adjust until no movement when released </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>T/R done like propeller (knife-edge stand) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>M/R done on special stand with Bullseye level </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  109. 109. <ul><li>Vibrations </li></ul><ul><ul><li>Correction of vibes (M/R & T/R) </li></ul></ul><ul><ul><ul><li>If out of balance condition </li></ul></ul></ul><ul><ul><ul><ul><ul><li>M/R also may require Blade Sweep to be adjusted (for chordwise balance) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>= stretch string between blades and adjust until blades are exactly 180 o apart (adjust by “sweeping” blades forward or aft as necessary) </li></ul></ul></ul></ul></ul>Helicopters Controls <ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  110. 110. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Correction of vibes (M/R & T/R) </li></ul></ul><ul><ul><ul><li>If out of balance condition </li></ul></ul></ul><ul><ul><ul><ul><li>Dynamic balancing done during operations on ground and in air </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Uses Electronic gear to measure rate and strength and charts to show adjustments </li></ul></ul></ul></ul><ul><ul><ul><li>Some M/Rs don’t need dynamic after static but all T/Rs do </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  111. 111. Helicopters Controls <ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>Example: Chadwick-Helmuth Vibrex ® system
  112. 112. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Measurement of vibes </li></ul></ul><ul><ul><ul><li>Example chart: </li></ul></ul></ul><ul><ul><ul><ul><li>T/R balance </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  113. 113. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Measurement of vibes </li></ul></ul><ul><ul><ul><li>Example chart: </li></ul></ul></ul><ul><ul><ul><ul><li>T/R balance </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  114. 114. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Measurement of vibes </li></ul></ul><ul><ul><ul><li>Example chart: </li></ul></ul></ul><ul><ul><ul><ul><li>M/R balance </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  115. 115. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Measurement of vibes </li></ul></ul><ul><ul><ul><li>Example chart: </li></ul></ul></ul><ul><ul><ul><ul><li>M/R balance </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  116. 116. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Correction of vibes (M/R & T/R) </li></ul></ul><ul><ul><ul><li>If out of Track condition </li></ul></ul></ul><ul><ul><ul><ul><li>Track = path Blade tips follow during rotation </li></ul></ul></ul></ul><ul><ul><ul><ul><li>In-Track = all tips follow same path (or Cone the same amount) and = minimal vertical vibes </li></ul></ul></ul></ul><ul><ul><ul><ul><li>All M/Rs need to be checked and adjusted and some T/Rs </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  117. 117. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Correction of vibes (M/R & T/R) </li></ul></ul><ul><ul><ul><li>If out of Track condition </li></ul></ul></ul><ul><ul><ul><ul><li>Ground check </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Use marking stick or Flag </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Marking Stick uses crayon or grease pencil on end of long stick and carefully raise to bottom of blades to make mark on lowest one (adjust until marks all blades) </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  118. 118. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Correction of vibes (M/R & T/R) </li></ul></ul><ul><ul><ul><li>If out of Track condition </li></ul></ul></ul><ul><ul><ul><ul><li>Ground check </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Flag is strip of canvas suspended between F shaped pole + put crayon mark on blade tips (different color on each blade) then move Flag so just touches each blade to get a colored mark </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Use colors to determine which blade needs adjustment </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  119. 119. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Flag Tracking </li></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>Flag Tracking
  120. 120. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Correction of vibes (M/R & T/R) </li></ul></ul><ul><ul><ul><li>If out of Track condition </li></ul></ul></ul><ul><ul><ul><ul><li>Ground check </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>All are adjusted by changing the length of the Pitch Links (controls Angle of Incidence of blades) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Link between Swashplate and M/R blade </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Increase angle = more lift = blade flies higher </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Each manufacturer usually has standard adjustments (I.e. 1/6 turn = ½” blade movement) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Limitation: can’t check in flight </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  121. 121. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Correction of vibes (M/R & T/R) </li></ul></ul><ul><ul><ul><li>If out of Track condition </li></ul></ul></ul><ul><ul><ul><ul><li>Ground & Flight </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Use spotlight or strobe </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Spotlight uses colored reflectors attached to blade </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Light shows colored streaks and can see “altitude” difference between them </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  122. 122. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Correction of vibes (M/R & T/R) </li></ul></ul><ul><ul><ul><li>If out of Track condition </li></ul></ul></ul><ul><ul><ul><ul><li>Ground & Flight </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Strobe is keyed by pickup on swashplate </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Flashes once for each blade </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Has reflectors on each blade with different angled “Target” line </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Flashes ‘stop’ targets at one location and can easily see difference and which blade to adjust </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  123. 123. Helicopters Controls <ul><li>Vibrations </li></ul><ul><ul><li>Correction of vibes (M/R & T/R) </li></ul></ul><ul><ul><ul><li>If out of Track condition </li></ul></ul></ul><ul><ul><ul><ul><li>Ground & Flight </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>For ground and hover adjustment = use Pitch Links </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>For in-flight adjustment = most blades have trailing edge fixed trim tabs to allow limited bending </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  124. 124. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Powerplants </li></ul></ul><ul><ul><ul><li>Reciprocating </li></ul></ul></ul><ul><ul><ul><ul><li>See all types: Horizontal and Vertically mounted Opposed engines & some Radials </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  125. 125. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Powerplants </li></ul></ul><ul><ul><ul><li>Reciprocating </li></ul></ul></ul><ul><ul><ul><ul><li>Verticals and Radials usually are Dry-sump with M/R Transmission (GearBox) mounted on top and using same oil supply </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  126. 126. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Powerplants </li></ul></ul><ul><ul><ul><li>Reciprocating </li></ul></ul></ul><ul><ul><ul><ul><li>Verticals and Radials usually are Dry-sump with M/R Transmission (GearBox) mounted on top and using same oil supply </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>Bell 47
  127. 127. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Powerplants </li></ul></ul><ul><ul><ul><li>Reciprocating </li></ul></ul></ul><ul><ul><ul><ul><li>Horizontals usually use some form of Belt Drive </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Multiple V-belts or one wide “timing” belt </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  128. 128. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Powerplants </li></ul></ul><ul><ul><ul><li>Reciprocating </li></ul></ul></ul><ul><ul><ul><ul><li>None have propeller for cooling air blast and “fly wheel” for starting </li></ul></ul></ul></ul><ul><ul><ul><ul><li>All use some form of Cooling Fan driven by engine to blow air across cylinders </li></ul></ul></ul></ul><ul><ul><ul><ul><li>All are generally hard to start (no fly wheel to help process keep going) </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  129. 129. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Powerplants </li></ul></ul><ul><ul><ul><li>Reciprocating Instruments </li></ul></ul></ul><ul><ul><ul><ul><li>Since M/R is essentially a Variable-pitch Propeller = all use both Tachometer (RPM) and Manifold Pressure gauges for power measurement </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Engines must be operated at relatively constant RPM (to allow enough Lift & Thrust) and usually very near the manufacturer’s Overspeed limit </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  130. 130. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Powerplants </li></ul></ul><ul><ul><ul><li>Reciprocating </li></ul></ul></ul><ul><ul><ul><ul><li>Usually uses Correlated Throttle and Collective </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Pull up on collective = more blade pitch = more lift/thrust generated = more drag </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Need more engine power to keep RPM constant </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Correlation increases throttle automatically as Collective is pulled up (may not do entire job, though) </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  131. 131. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Powerplants </li></ul></ul><ul><ul><ul><li>Reciprocating </li></ul></ul></ul><ul><ul><ul><ul><li>Usually uses Correlated Throttle and Collective </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Pull up on collective = more blade pitch = more lift/thrust generated = more drag </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Need more engine power to keep RPM constant </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Correlation increases throttle automatically as Collective is pulled up (may not do entire job, though) </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>Bell 47
  132. 132. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Powerplants </li></ul></ul><ul><ul><ul><li>Turbines </li></ul></ul></ul><ul><ul><ul><ul><li>Are ideal powerplants as operate most efficiently at constant RPM and have very high power to weight ratio </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  133. 133. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Powerplants </li></ul></ul><ul><ul><ul><li>Turbines </li></ul></ul></ul><ul><ul><ul><ul><li>Are TurboShaft engines </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>All output power is converted to rotating shaft power (Torque) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Torque sent to Transmission to drive Main & Tail Rotors and other necessary components </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  134. 134. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Powerplants </li></ul></ul><ul><ul><ul><li>Turbines </li></ul></ul></ul><ul><ul><ul><ul><li>Are TurboShaft engines </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Two basic types: Direct Shaft & Free Turbine </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Direct Shaft has PTO shaft connected to all Compressor and Turbine section stages </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Are very hard to start as must turn all engine + Main and Tail rotors </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  135. 135. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Powerplants </li></ul></ul><ul><ul><ul><li>Turbines </li></ul></ul></ul><ul><ul><ul><ul><li>Are TurboShaft engines </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Two basic types: Direct Shaft & Free Turbine </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Free Turbine has some Turbine stages which only supply PTO power </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Easier to start as rotors not mechanically connected to main part of engine </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  136. 136. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Powerplants </li></ul></ul><ul><ul><ul><li>Turbines </li></ul></ul></ul><ul><ul><ul><ul><li>Are TurboShaft engines </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Measure power output with Tachometers, Torquemeters, and Turbine Temperature gauges </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Tachs measure RPM in % (due to high actual RPM) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Free Turbine versions need to measure both main engine (N 1 ) and Power Turbine (N 2 ) and usually have separate gauges </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  137. 137. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Powerplants </li></ul></ul><ul><ul><ul><li>Turbines </li></ul></ul></ul><ul><ul><ul><ul><li>Are TurboShaft engines </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Torquemeters measure power being absorbed by M/Rs </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Similar to MAP gauge on recips </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Measures in % or in Pounds of Torque </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  138. 138. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Powerplants </li></ul></ul><ul><ul><ul><li>Turbines </li></ul></ul></ul><ul><ul><ul><ul><li>Are TurboShaft engines </li></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>Turbine Temps very important as are directly proportional to how hard the engine’s working and critical during the start cycle </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>May be TIT, ITT, TOT, or EGT system (manufacturer’s choice) </li></ul></ul></ul></ul></ul><ul><ul><ul><ul><ul><li>CAN NOT exceed max. limit or will damage Turbine section components </li></ul></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  139. 139. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Transmissions </li></ul></ul><ul><ul><ul><li>For speed and/or directional change of rotating shaft(s) </li></ul></ul></ul><ul><ul><ul><li>May be Rack & Pinion or Planetary Gear systems </li></ul></ul></ul><ul><ul><ul><li>Uses engine oil or has own supply </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  140. 140. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Transmissions </li></ul></ul><ul><ul><ul><li>For speed and/or directional change of rotating shaft(s) </li></ul></ul></ul><ul><ul><ul><li>May be Rack & Pinion or Planetary Gear systems </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>Schweizer (Hughes) 269 Transmission: Rack (Ring Gear) and Pinion
  141. 141. Bell 47 Transmission: Planetary system
  142. 142. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Transmissions </li></ul></ul><ul><ul><ul><li>Engine drives M/R Transmission which in turn drives the T/R, Hydraulic pumps, Electrical Generator, Cooling Fans (if appropriate for the aircraft), and Rotor Tach sending unit connected to (usually) Dual Tach (Rotor and Engine RPM on same gauge) </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  143. 143. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Clutch </li></ul></ul><ul><ul><ul><li>USED TO RELIEVE THE ENGINE LOAD DURING STARTING </li></ul></ul></ul><ul><ul><ul><li>May be Manual, Electrical, or Centrifugal </li></ul></ul></ul><ul><ul><ul><li>Manual and Electrical pull Idler Pulley against Belt(s) to tighten them and connect engine with Transmission </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  144. 144. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Clutch </li></ul></ul><ul><ul><ul><li>Centrifugal uses hinged Shoes pushed against a Drum by Centrifugal Force </li></ul></ul></ul><ul><ul><ul><ul><li>Shoes on arms attached to engine crankshaft </li></ul></ul></ul></ul><ul><ul><ul><ul><li>Drum attached to Transmission </li></ul></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  145. 145. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Freewheeling Unit </li></ul></ul><ul><ul><ul><li>FOR AUTOROTATION PURPOSES </li></ul></ul></ul><ul><ul><ul><li>Disconnects M/R from engine if engine turns slower than M/R </li></ul></ul></ul><ul><ul><ul><li>Usually either Roller or Sprag style </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>
  146. 146. Helicopters Controls <ul><li>Power Systems & Other Components </li></ul><ul><ul><li>Freewheeling Unit </li></ul></ul><ul><ul><ul><li>FOR AUTOROTATION PURPOSES </li></ul></ul></ul><ul><ul><ul><li>Disconnects M/R from engine if engine turns slower than M/R </li></ul></ul></ul><ul><ul><ul><li>Usually either Roller or Sprag style </li></ul></ul></ul><ul><li>History </li></ul><ul><li>Configurations </li></ul><ul><li>Types of Rotor Systems </li></ul><ul><li>Forces Acting on the Rotor </li></ul><ul><li>Flight Conditions </li></ul><ul><li>Controls </li></ul><ul><li>Stabilizer Controls </li></ul><ul><li>Vibrations </li></ul><ul><li>Power Systems </li></ul>

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