Private Pilot Ground School モドキ

F. AIRPLANE ENGINE and SUBSYSTEM

1. Engine
• produce power to turn propellers
• pulls airplane forward
2. Principle of Operations
   • 4-strokes & 5-events
   • Stroke: Intake, compression, combustion, exhaust
   • Event: Intake, compression, Ignition, power, exhaust
3. Dual Ignition System
   • better performance
   • safety
4. Mixture Control & Altitude
   • needs of mixture control:
   • thinner air at high altitude = enriches
   • needs of precautions in descending flight: get too lean
5. Heat -problems in any engine-
   1. system prevent over heating
      • engine oil
        • to lubricates
        • to cool by circulations
        • to seal
        • to clean up (brings dirt to an oil filter)
        • to prevent corrosion and rust
      • fins (to dissipate heat into air)
      • baffle (circulate air)
      • curl flap (more air as needed)
   2. Overheating
      • loss of power
      • high oil consumption
      • excessive wear on Internal parts
   3. Cause of Overheating
      • climbing too steeply -too slow-
      • too much power
      • too lean mixture
      • not enough oil
      • wrong fuel (lower-than-specified)
   4. Corrective Action
      • increase airspeed (decent or level-off)
      • reduce power
      • enrich mixture
      • check oil level during a preflight
      • fill with correct aviation gasoline (avgas). If not available, use higher AVGAS
   5. Abnormal Combustion
      1. mostly caused by overheating
      2. detonation
         1. mixture explodes instead of burning normally
         2. loss of power, vibration, internal damage
      3. pre ignition
         1. uncontrolled combustion of fuel/air mixture
         2. in advance of normal ignition
         3. hot spot (carbon deposits, cracks....)
      4. in other cases, they are usually caused by pilot mistakes.
   6. Check Oil and Fuel,
      • use correct grade and type of fuel
      • oil level
      • engine room for any blockage,
      • aware of high temperature
6. Carburetor (float type)
   1. to mix fuel with air at proper amount
   2. principle of a float-type carburetor
      • metering air pressure difference at Venturi throat near air-inlet.
   3. carburetor icing
      1. loss of power
      2. 20 to 70 degrees in F with high humidity
   4. use of carb heat
   5. hot air from exhaust muffler (heated, but not mixed)
      1. melts carb ice and prevents carb icing
      2. enriches mixture -loss of slight power-
   6. used in many training fleet, but being replaced in newer airplanes
7. Fuel Injection (instead of a carburetor)
   1. better distribution of fuel = better performance
   2. less nor no carb ice (induction icing, blocked air inlet by ice)
8. Constant-Speed Propeller
   1. a pilot can choose most efficient blade angle of propeller
      • not pith angle, but angle of attack on prop
   2. propeller control - blade angle - RPM
   3. throttle control - engine output - manifold pressure
   4. power change
      • to increase (mixture, prop, then throttle)
      • to decrease (throttle, prop, then mixture)
9. Good Operating Procedure
   1. Don't let tank dry before switching tank
      • vapor lock
      • air can clog fuel line (fluid)
   2. fill the tank after the flight
      • prevent moisture
   3. After starting an engine,
      • check engine oil pressure, adjust RPM
   4. Hand prop
      • have a competent pilot in the cockpit
      • you don't know what is going to happen
   5. Do walk around inspection for preflight
   6. MUST use a written checklist
      • all items in logical sequence
      • eliminates any omitting an important step.
   7. After long shortage
      • check damage and obstructions by insects and animals