Exam 2 Flashcards
Ch. 6-?
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
Stoichiometric
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?
Turbocharger
An indication of unregulated power change that results in the continual drift of manifold pressure
boot strapping
Excessive MAP (Manifold pressure)
overboost.
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.
supercharger.
Applies to an engine system that has both a turbocharger that boosts air pressure before the carburetor and a supercharger that further boosts pressure of the fuel:air mixture
turbocharger
Controls the volume of the exhaust gas that is directed onto the turbine and thereby regulates the speed of the rotor and the output of the compressor
waste-gate
One side of the diaphragm in the differential pressure control senses air pressure upstream fro the throttle
deck pressure
Limits maximum MAP, thus preventing overboost by limiting the deck pressure
density controller
Regulates the position of the waste-gate valve to maintain a pre-set pressure differential across the throttle so that if the pilot opens the throttle, there will be a response
differential pressure controller
In an automatic turbo charger, what provides the force to open the waste gate? To close it?
Open: decrease oil pressure Close: increased oil pressure
What is the purpose of an alternate air valve and how does it work?
Valve in the induction system that directs air either from the air filter or from a point inside the engine nacelle into the carburetor or the fuel injection system
The altitude above which the turbocharging (or supercharging) system can no longer maintain seal level power
critical altitude
What is the purpose of the intercooler and how does it work?
Reduces the temperature before compressed air reaches the engine 1) Fresh outside air is collected and piped to the intercooler so that it flows over and cools the tubes 2) As the induction air charge flows through the tubes of the intercooler, heat is removed and that charge is cooled to a temperature the engine can tolerate without detonation occurring
A turbocharger compresses
Air only
A supercharger compresses?
Fuel/Air mixture
List three basic types of oxygen equipment and the altitude limitation of each.
Fixed: Large: and High performance aircraft OBOGS: On board oxygen generating system; reliable, safer, and requires less maintenance Portable: Smaller aircraft; less expensive than fixed system, but last shorter than fixed; Types: Diluter, Diluter demand, Pressure demand, Continuous flow
What is the color code for oxygen cylinders and other components?
Green
Regarding oxygen safety precautions, what material must not come into contact with oxygen?
Hydrocarbons
What is meant by ‘demand’ when discussing an oxygen ‘pressure-demand’ regulator?
Only uses it when oxygen is inhaled by the user
Defined as a change in cabin pressure faster than the lungs can decompress
explosive decompression
Defined as a change in cabin pressure where the lungs decompress faster than the cabin
rapid decompression
List five basic requirements needed to have a cabin pressurization system?
- Cabin Structure 2. Source of compressed air 3. Means of regulating the temperature of air flowing into the cabin 4. Means of regulating the pressure and rate of pressure change in the cabin 5. Means of controlling the rate of outflow of air from the cabin
What are the purposes of positive and negative cabin pressure relief valves?
To regulate cabin pressure by either releasing air in out and operates automatically. Safety
What is meant by ‘isobaric’ pressurization range?
Isobaric: crew has control
What is meant by ‘pressure differential’ range?
Pressure differential: Crew doesn’t have control over pressure
What component physically meters the flow of air from the cabin of a pressurized aircraft?
Outflow Valve
The flow of electrons or the presence of flowing electrons of the ability (potential) of electrons to flow
electricity
The smallest particle of any matter that is able to exhibit the properties and characteristics of that matter
atom
A very small, electrically charged particle that exists as a part of every atom
electron
An electrical force outside the atom can attract electrons away from the outer ring and leave the atom in an unbalanced condition
ion
Rate of one electron flow
current.
When electrons flow the opposite to their flow
resistance
The basic statement which says in effect that the current that flows in a circuit is directly proportional to the voltage (pressure) that causes it, and inversely proportional to the resistance (opposition) in the circuit
Ohm’s Law
Atoms with loosely held electrons
Conductor
Made up of materials which are composed of atoms which hold their outer electrons more tightly so that electrons can’t flow in response to an electromotive force
Insulator
When a coulomb flows past a point in one second One ampere is one amp
Ampere
The standard unit of resistance The resistance at a specific temperature of a column of mercury having a specified length and weight
Ohm
The unit of electrical pressure The amount of pressure required to force one amp of flow through one ohm of resistance
Volt.
The measure of the rate of energy conversion
Watt.
Sharp points on which static charges concentrate and will discharge into the air before they can build up on the smooth surface sufficiently high to jump across the hinges causing hinge bearing damage and radio interferences
Static Discharge Wick.
The charge in a circuit
Electricity
Briefly describe the two kinds of ‘electron flow.’
Direct Current: Unidirectional Alternating Current: Alternates direction
Which direction do electrons flow in an electrical circuit?
High to low
E is Voltage I is current R is resistance E=(I)(R)
formula for ‘Ohm’s Law
Name two types of electrical currents.
Direct Current (DC) Alternating Current (AC)
Cycles per seconds in AC
Hertz
What is meant by ‘flux’ or ‘lines of flux.’
Lines of magnetic force
Why/how are lines of flux important in the generation of electricity?
Lines of magnetic flux pass between the poles of a magnet, and if a conductor is moved through these lines of flux, they will transfer to the conductor and force electrons to flow through it
A ____ gyro combines a directional gyro with a direction sensing instrumentation.
slayed
A _____ instrument is typically used to measure high temperatures.
thermocouple
A _____ is an instrument that displays engine RPM.
tachometer
A _____ type instrument is used to measure high pressures.
bourdon
A rate gyro uses the gyroscopic characteristics of _____.
precession
A vertical speed indicator measures the rate of change of _____ pressure.
static
absolute altitude
The vertical height of an aircraft above ground level
Air-driven gyroscopic instruments require very _____ air.
clean
All elevations on aeronautical charts are measured from _____ _____ _____
mean sea level
Altimeters installed in aircraft that operate under instrument flight rules must have their accuracy checked every _____ calandar months.
24
An _____ gives the pilot an indication of the load imposed on the aircraft structure in terms of G’s.
accelerometer (g-meter)
An A&P maintenance technician _____ disassemble and repair an aircraft instrument.
cannot
An aneroid barometer measures _____ pressure.
absolute
An attitude gyro uses the gyroscopic characteristic of _____ _____ _____.
rigidity in space
An instrument that measures aircraft speed relative to the speed of sound is called a _____.
machmeter
ARING
Aeronautical Radio Inc
Because navigation charts are laid out according to the geographic poles and a magnetic compass points to the magnetic poles, the difference between the positions is called _____.
variation
Bourdon tube
gauges used to indicate lower pressures uses a flexible tube that uncoils and coils made from brass,bronze or copper.
Compass _____ is caused by the magnetic fields in the aircraft that interfere with those of the earth.
deviation
compass correction card
small card mounted near the magnetic compass to show the pilot the amount of deviation error for each heading
compensator magnet
used to correct distortion of the earths field from a nearby iron structure
CRT
Cathode Ray Tube
Density altitude _____ a direct measurement
is not
deviation
error in the indication of a magnetic compass caused by magnetic fields in the aircraft.