AVN 2100 Airplane Powerplants and Related Systems Flashcards
The 2 most common types of powerplants are:
Reciprocating piston engine with propeller and gas turbine engine
The three main types of gas turbine engines are:
Turboprop, turbojet, turbofan
What and where is the firewall?
The firewall is a barrier between the engine and cockpit located behind the engine. It protects the cockpit from fire.
What is does the cowling do?
Covers the engine compartment and helps streamline the airplane and helps cool the engine by ducting air around the cylinders.
What creates thrust to move the airplane through the air?
The propeller
What is the difference between Aviation Gasoline and automobile gasoline?
It has a higher octane rating and has lead added.
What is the reciprocating engine mounted to?
The firewall
In addition to turning the propeller, what does the engine power?
Alternator, vacuum pump, heat
What is the most common cylinder layout for light aircraft?
Horizontally opposed
When the crankshaft is directly connected to the prop it is called:
Direct drive
Name the four strokes:
Intake (suck), compression (squeeze), power (bang), exhaust (blow)
How is power output of the engine increased?
Increasing the amount of fuel/air mixture entering the cylinder
What pulls the cylinder down on the intake stroke?
Inertia of the rotating crankshaft
When do the spark plugs ignite the fuel/air mix?
As the piston reaches the top of the cylinder
On the power stroke, what forces the piston down?
The burning of the fuel/air mix
What happens just prior tot he end of the power stroke?
The exhaust valve opens
Regardless of whether it is a 4 or 6 cylinder engine, each cylinder provides one power stroke per ___ revolutions of the crankshaft
2
What is the purpose of the shroud and where is it located?
Is is located around the muffler and exchanged heat from the exhaust into heated air for cabin hear, defrost, and carb heat
What regulated the timing of the valves?
The camshaft
How is the camshaft driven?
It is geared to the crankshaft
The camshaft rotates once for every ___ rotations of the crankshaft?
2
Normal power output during cruise flight for a C-172 is?
2300 RPM
Camshaft RPM at normal cruise in a C-172 is?
1150 RPM
The intake/exhaust valves open and close ____ per complete cylinder cycle.
One time
The intake/exhaust valves open and close once per ____ crankshaft revolutions and ____ camshaft revolutions.
Two. One.
What is the purpose of the ignition system?
Provides electric current to the spark plugs
Why do most aircraft have a dual ignition system?
Redundancy and more even combustion to provide more power and efficiency
A duel ignition system has __ spark plugs per cylinder and two _______.
Two. Magnetos
Each ______ send current to one ______ in each _________.
Magneto. Spark plug. Cylinder.
The magneto consists of:
a magnet that is rotated near a conductor which has a coil of wire around it
What drives the magneto?
The engine.
How is electric current generated by the magneto?
The rotation of the magnet induces and electric current in the coil of surrounding wire
What times the spark coming out of the magneto?
The distributor
What is the distributor geared to?
The crankshaft
The distributor turns ____ for every two turns of the crankshaft
Once
The magnetos are ______ of all other electrical systems
Independent
When the started is engages it rotates the ____
Crankshaft
The ____ is actuated by a small current from the ignition switch and allows a large current to flow from the battery to the starter.
Starter solenoid
The started is powered by the _______
Battery
On startup, only the ____ magneto provides spark to each cylinder
Left
What are the two forms of abnormal combustion?
Detonation and pre-ignition
What is detonation?
Temperature and pressure in the cylinder rises too high causing the fuel/air mix to explode rather than burn evenly
What can detonation cause?
Damage to the pistons, valves, spark plugs, and cause loss of power and engine failure.
An excessively high cylinder head temperature can indicate:
Detonation
Four causes of detonation are:
Lower grade fuel, old fuel, too lean mixture, over heated engine, excessive intake air temp.
Three ways to correct detonation:
Richen mixture, reduce power, increase airspeed
What is pre-ignition?
Ignition of fuel/air mix ahead of time
Four results of pre-ignition:
Rough running engine, sudden rise in cylinder head temp, backfiring of the engine, engine damage
Three causes of pre-ignition:
Hot spots from carbon and lead deposits, using high power with too lean fuel/air mix, overheated spark plugs
The carburetor ______
Mixes the fuel and air mixture prior to sending it to the cylinders
What is the correct ratio of fuel to air by weight?
1 part fuel to 12 parts air
A rich mixture means that:
The fuel/air mixture is larger
The maximum rich mixture ratio of fuel to air is:
1:8
The minimum lean mix fuel to air ratio is:
1:20
The carburetor works on _______ principle because the throat of the carb is a _______
Bernoulli, venturi
With a rich mix, there will be _____ fuel after combustion.
Excess
Five results of too rich mixture:
Excess fuel consumption, loss of power, rough running engine, fouling of spark plugs and lead deposits
With a lean mixture, the will be excess _____ left over after combustion.
Oxygen
Too lean a mixture causes ______ and can lead to __________
Excessive engine temperature, abnormal combustion, loss of power, and engine failure
A too ____ mixture is preferable to a too _____ mixture.
Rich, lean
The airflow is metered by the ______ and controlled from the cockpit by the ______
Throttle plate, throttle
Another name for the throttle plate is the ________
Butterfly valve
Carb ice is most likely to occur between ___ and ____ degrees F in high ______, but it can occur at ____ temp.
20, 70, relative humidity, higher
Temperature drops in the carburetor because of two things:
Pressure drop in the venturi and latent heat of fuel vaporization
Carburetor ice will cause _____ and eventually _____
RPM drop, engine failure
The carburetor heat should be used at _____ RPM setting
Lower
The carburetor heat is used to _____ by directing heated air from the shroud into the carburetor instead of cold air.
Melt carb ice
Should carb heat be used on the ground and why?
No, carb heat air is unfiltered and debris could be sucked into the engine
Why does carb heat lower engine performance?
Warmer air is less dense, and the lower amount of oxygen in the fuel/air mix results in a richer mixture using the same settings
The typical fuel system in a small high wing aircraft is ______ because it is _______
Gravity fed, simple
Low wing aircraft require a _____ to lift the fuel to the carburetor
Fuel pump
The C-152 has two ____ gal wing tanks with ____ usable gallons. The total fuel is ___ and the total usable fuel is ____
13, 12.25, 26, 24.5
The C-152 are vented in two spots:
Under the left wing and the right filler cap
Fuel tank venting prevents ____ and allows _____.
Vacuum, expansion
Why should fuel tanks be stored full?
To prevent water build up
_____ under each wing allow for checking the fuel for _____
Sumps, contamination
The fuel strainer is located at the _______
Lowest point in the fuel system
The color of 100LL is:
Blue
The color of 100/130 is:
Green
The color of 80/87 is:
Red
The color of jet fuel is:
Clear
Clear fuel can be cause by what two things:
Mixing fuel or using jet fuel
A drawback to carbureted engines is the the ____ mixture is distributed to ______
Same, all cylinders
With fuel injection, fuel is _____ into an ______ and then into _______
directly injected, induction manifold, each cylinder
An advantage of fuel injection is that _____ because each cylinder has its own ______
each cylinder receives the proper fuel/air mix, fuel line
Four advantages of fuel injection are:
No carb ice, improve control of fuel/air mixture to each cylinder, instant acceleration after idling, increased engine efficiency
Three disadvantages of fuel injection:
Vapor lock in fuel lines creates hard hot starts, more susceptible to contamination in fuel, surplus fuel may only be routed to one tank making uneven fuel loading or fuel vented overboard possible
The purpose of oil is to ____ and ______ and ______
lubricate the engine and reduce friction, sealing between piston and cylinder for better compression, carry away contaminants to the oil filter.
The oil pressure gauge indicates the oil pressure provided by the _____ .
Oil pump
What removes dirt from the oil?
The oil filter and screens
What is the purpose of the oil filter bypass valve?
Permits oil to bypass a clogged filter because dirty oil is better than no oil
If already cool enough, can oil in the sump bypass the oil cooler?
Yes
The oil temperature gauge displays the temperature of oil ______
After passing through the oil cooler
______ on each cylinder increase the surface area for better cooling.
Cooling fins
How are most light aircraft engine cooled?
Exposing the cylinders to air flow
______ help to evenly distribute air around the cylinders
Baffles
What is the purpose of cowl flaps?
To increase/decrease air flow over the engine.
Do cowl flaps increase parasite drag when extended?
Yes
The C-172 has a ___ volt electrical system with a ___ volt battery and a ___ amp alternator
28, 24, 60
The current from the alternator is ___
AC
The ________ provides energy for electrical system and charges the battery
Alternator
A ______ converts the AC current to DC
Rectifier
Alternators are driven by the ______
Engine
Once running, can the electrical system operate without the battery?
Yes
The electrical master switch is divided into two switches: the left side controls the ______ and the right controls the ________.
Alternator, battery
Normally, are both the alternator and battery used?
Yes
Most circuits are protected by ______. A few are protected by ______.
Circuit breakers, fuses
_____ are used to reduce wiring and act like _____
Bus bars, surge protectors.
The ______ displays the charging/discharging rate of the battery
Ammeter
The low voltage light illuminates when:
electrical energy is being supplied by the battery.
Seven electrically powered items are:
Turn coordinator, fuel quantity indicator, starter, oil temp gauge, oil pressure gauge, lights, avionics.
