Aircraft Systems

Introduction

• Covers primary systems in aircraft:
  • Engine, propeller, induction
  • Ignition, fuel, lubrication
  • Cooling, electrical, landing gear
  • Environmental control systems

Powerplant

• Purpose: Produces thrust to propel an aircraft
• Types of engines:
  • Reciprocating and turboprop engines (thrust via propeller)
  • Turbojet and turbofan engines (increase air velocity)
  • All engines support aircraft operation systems

Reciprocating Engines

• Common in small aircraft
• Convert chemical energy (fuel) to mechanical energy
• Types:
  • Spark ignition (traditional, uses spark plug)
  • Compression ignition (uses diesel/jet fuel)

Engine Designs

1. Cylinder arrangement: radial, in-line, v-type, opposed
2. Operating cycle: two or four-stroke
3. Cooling method: liquid or air

• Radial Engines:

  • Circular arrangement, favorable power-to-weight ratio
  • Used in WWII, some still in service

• Horizontally-opposed Engines:

  • Compact, high power-to-weight ratios
  • Popular in smaller aircraft

Propeller

• Rotating airfoil generating thrust
• Depends on:
  • Airfoil shape, angle of attack, engine RPM
  • Twisted blade design for uniform lift

Types of Propellers

• Fixed-Pitch Propeller: Blade angles fixed, optimal at specific speeds
• Adjustable-Pitch Propeller: Changes pitch on the ground or in-flight
• Constant-Speed Propeller: Maintains constant RPM via governor

Propeller Overspeed

• Avoid overspeed situations; consult FAA guidelines

Induction Systems

• Purpose: Mix air and fuel, deliver to cylinders for combustion
• Types:
  • Carburetor system (mixes before intake)
  • Fuel injection system (mixes at cylinder entry)

Carburetor Systems

• Float-type: Common, uses venturi to draw fuel
• Pressure-type: Not typical in small aircraft
• Carburetor Icing: Progressive issue requiring carburetor heat

Ignition System

• Provides spark for fuel-air mixture ignition
• Components: Magnetos, spark plugs, high-tension leads
• Dual ignition systems for reliability

Oil Systems

• Lubricates, cools, cleans, and seals engine components
• Types: Wet-sump and dry-sump systems
• Use oil temperature and pressure gauges to monitor

Engine Cooling Systems

• Essential to prevent overheating
• Methods:
  • Air cooling
  • Liquid cooling
  • Use of engine cowlings to direct airflow

Exhaust Systems

• Manages expulsion of combustion gases
• Provides cabin heat and defrosting

Superchargers and Turbosuperchargers

• Increase engine power by compressing intake air
• Supercharger: Engine-driven, boosts manifold pressure
• Turbocharger: Exhaust-driven, maintains power at altitude

Electrical System

• Provides electrical power
• Components:
  • Alternator/generator, battery, master switch
  • Bus bars, circuit breakers, voltage regulator
  • Monitored by ammeter/loadmeter

Airframe Systems

Fuel Systems

• Ensure fuel supply during flight
• Types:
  • Gravity-feed
  • Fuel-pump

Hydraulic Systems

• Operate brakes, landing gear, flight controls
• Components: Reservoir, pump, valves, actuators

Landing Gear

• Supports aircraft on the ground
• Types:
  • Tricycle gear
  • Tailwheel gear

Pressurized Aircraft

• Maintains cabin pressure for high-altitude flights
• Avoids hypoxia
• Terms: Cabin altitude, differential pressure

Oxygen Systems

• Prevent hypoxia during flight
• Terms:
  • Oxygen masks, cannulas
  • Diluter-demand systems
  • Pressure-demand systems

Decompression

• Types: Explosive and rapid decompression
• Requires quick use of oxygen

Heating Systems

• Types: Fuel fired, exhaust, combustion heaters
• Essential for cabin and equipment heating

Anti-Ice and Deice Systems

• Prevents and removes ice formation
• Methods:
  • Deicing boots, thermal systems, weeping wings
  • Pitot and static ports heaters

Conclusion

• Understanding aircraft systems is crucial for safety and maintenance
• Refer to AFM/POH for specific information