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Flashcards in Exam 2 Deck (245)
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The internal combustion engine used in our modern aircraft is a form of?

Heat engine


The mixture ratio of fifteen pounds of air to one pound of gasoline



What provides low pressure at the discharge nozzle of a float carburetor?

Carburetor Venturi


Why are float carburetors more susceptible to icing (at least two reasons)?

Fuel evaporation Decrease in air pressure in the venturi


Under what conditions should partial carburetor heat not be used?

CAT temperatures above 0*C


Under what conditions would the use of carburetor heat be detrimental?

In unimproved surfaces, such dirt, because the carburetor heat is unfiltered contaminants picked up from the ground could damage the engine


When should carburetor heat be used on the ground?

Engine starting in very cold temperatures Shutting off the engine w/ mixture control to prevent cold air from passing through the engine after combustion stops, but the engine has not yet stop turning Under conditions in extremes of high humidity and very high or low temperatures


Does application of carburetor heat richen or lean the mixture? How and why?

Richens the mixture Hot air further richens the mixture then decreases the RPM


What are the advantages of the pressure carburetor over the float carburetor?

Fuel distributed by mass Better metering system Allows for auto-mixture


What are the functions of the spider?

Distributes the fuel evenly to all the cylinders Provides a positive shut-off when the mixture is placed in the idle-cut position


What are the advantages of a fuel injection system, as a fuel metering system?

Provision is made in the pump to remove all vapor from the fuel and return it to the tank A by-pass check valve around the pump so fuel from the boost pump may flow to the fuel control for the starting


Why is it important for the pilot to know an engines exhaust gas temperature?

There is a relationship between the temperature of the exhaust gas temperature and the mixture ration being burned


(pounds of fuel burned per hour)/(brake horsepower)

specific fuel consumption


What is the importance of a fuels critical pressure and temperature?

Once it reaches a certain pressure and temperature, it will explode rather than burn evenly (otherwise known as detonation)


Why is tetrathyl lead sometimes added to aviation fuel?

For anti-detonation in larger aircraft


Why are two numbers used for identifying aircraft fuel octane (i.e. 100/130)?

Recognizes octane or performance number and the amount of tetrathyl


What does a carburetor air temperature gauge permit a pilot to do?

Helps indicate potential icing conditions Indicates whether or not a carburetor heat is necessary


Where are the fuel injection nozzles located on a typical light aircraft engine?

Screws into the cylinder head near the intake port


What is the difference between detonation and pre-ignition?

Pre-ignition: engine misfire prior to ignition Detonation: Engine misfire after ignition


What is critical altitude?

Term used to describe altitude where the throttle is fully open in order to achieve the desired power setting


Why does the MAP increase when RPM is decreased when there is no change of throttle position?

Less exhaust at back pressure; atmospheric pressure decreases Less force below piston; atmospheric pressure in crankcase is less Colder air is at higher altitudes; cold air is more dense


Which hass the higher operating speed and temperature, a turbocharger or a supercharger?



An indication of unregulated power change that results in the continual drift of manifold pressure

boot strapping


Excessive MAP (Manifold pressure)



Which cockpit control will change the MAP on an engine?

The throttle changes the MAP on an engine with constant speed prop


Which cockpit control will change the RPM on an engine?

Propeller control changes the RPM on an engine with constant speed propeller


Engine that requires MAP in excess of sea level pressure to produce its rater power

ground boosted engine.


Internal combustion engine in which air intake depends solely on atmospheric pressure and which does not rely on forced induction through a turbo or supercharger

normally aspirated engine.


Equipped with a turbo or supercharger (or both) to give improved engine performance

normalize engine.


Driven by the hot, high velocity exhaust gases that are being expelled from the engine.