What is the powerplant?
Engine and propeller
What provides the power to turn the propeller?
Accessories mounted on the engine generate what?
- Electrical power
- Creates a vacuum source
- provide heat
What is the firewall?
- Protects occupants in case of fire
- Serves as a mounting point for the engine
What does the propeller do?
Translates the rotating force of the engine into a forward acting force called thrust
What are the two type of engines?
What are the 4 cycles of the reciprocating engine?
What is the purpose of the induction system?
To bring outside air into the engine, mix it with the fuel, and deliver it to the cylinders where combustion occurs
What does the throttle control?
Fuel and air mixture that flows into the cylinder
What does the Mixture control?
- Fuel/Air ratio
- (Full rich means max fuel being added, lean means less fuel being added)
What does outside air enter the induction system through?
Intake port at the front of the engine compartment.
Where does alternate air for the engine come from? What is the purpose?
- Comes from inside the engine cowling.
- It bypasses the air filter in case it is clogged.
What does the carburetor do?
Mixes the incoming air with fuel and delivers it to the combustion chamber.
Describe how the carburetor works.
- Air enters the carburetor and passes through a venture (velocity increase, pressure decreases).
- Fuel enters from a float chamber to a discharge nozzle that is located in the area of low pressure in the venturi.
- Fuel is forced through the nozzle by the higher atmospheric pressure in the float chamber.
What allows the float chamber to push the fuel through the discharge nozzle in the carburetor?
The float chamber is vented and pressure remains equal to atmospheric pressure. The pressure of the air in the venturi is lower than the float, forcing the fuel out of the nozzle.
How are carburetors calibrated?
At sea level in FULL RICH establishes the correct fuel-to-air misture ratio
Why would a mixture need to be lean?
to decrease the fuel flow to compensate for decreased air density (higher altitude).
What is carb icing?
- Water vapor my condense and form ice in the vernturi.
- Fuel vaporization and decreasing air pressure in the venturi causes a sharp temp drop to allow this.
- Apply carb heat
What will carb heat cause?
Slight decrease in engine power due to the less dense air entering the engine
Describe a fuel injection system.
- 4 basic components
- - fuel pump
- - fuel control unit
- - fuel manifold valve
- - fuel discharge nozles
- Fuel pump moves fuel from tank to FCU.
- FCU measures fuel based on mixture setting and sends it to fuel manifold valve at the rate set by throttle
- Fuel manifold distributes fuel to individual fuel discharge nozzles.
- Nozzles introduce air into the fuel and injects the mixture into the cylinder
Describe the ignition system
- Made up of:
- - magnetos
- - spark plugs
- - interconnecting wires
- - ignition switch
- Operation of magnetos controlled by ignition switch in cockpit.
- Magnetos send electrical current via interconnecting wires to spark plugs to ignite fuel in cylinder
What is a magneto?
- self-contained, engine driven unit that supplies electrical current to the spark plugs.
- Uses a permanent magnet to generate an electrical current completely independent of the electrical system.
What is a duel ignition system? Why is it used?
- Has two individual magnetos and systems.
- Enhances safety and increase reliability of the ignition system
Explain how the engine is started.
The starter come out to wind the crankshaft, turning the magnetos to make it self contained.
What is detonation?
- an uncontrolled, explosive ignition within the cylinder's combustion chamber.
- Causes excessive temperatures and pressures.
- Engine overheating, roughness, or loss of power can be expected.
What causes detonation?
Engine overheating or lower grade fuel
What is preignition?
Fuel/air mixture is ignited in advance of the normal timed ignition
What causes preignition?
A residual hot spot in the cylinder, such as a small carbon deposit on a spark plug
What are the two general fuel systems?
- Gravity fed
- Fuel pump system
Describe a fuel pump system
- engine driven pump provides fuel under pressure from the fuel tank to the engine.
- Electric boost pump w/ switch in cockpit for start up and back up.
- Primer helps pump fuel directly into the intake system prior to start up
What hazards is present during refueling?
- Possible combustion from a spark that causes fumes to ignite.
- Likely caused by static electricity.
- Attach ground wire before removing the fuel cap
Describe the landing gear
- air-oil shock
- oleo strut
- uses a piston enclosed in a cylinder with oil and compressed air to absorb the bumps
Describe the electrical system
- supplied by a 14 or 28 volt DC system
- usually powered by an engine-driven alternator
- Alternator produces AC first, the converts it to DC for the system.
- DC is delivered to a bus bar, and then to the components.
- Circuit breakers protects bus bar
What does the storage battery do?
- Provides means to start the engine
- Allows limited operations of electrical components without starting the engine
- Can be used in alternator malfunction
What is an ammeter?
monitors the electrical current in amperes
What is the master switch?
- Controls the entire electrical system
- Does not control ignition system
- Master must be on in order for the starter to operate