Chapter 3 Engines Flashcards
Most general aviation airplane engines are of the ___ opposed variety.
Horizontally
Horizontally opposed cylinder arrangements pack a lot of engine into a ___ amount of space. Less space used by the engine means less overall ___.
Small, Drag
Name the four cycles of an airplane engine:
Intake, compression, power, exhaust
While the piston is in its downward journey, the ___ valve opens, and a mixture of fuel and air rushes in.
Intake
The ___ cycle occurs when the intake valve closes and the piston rises.
Compression
Just before the cylinder hits the top of its return journey, the ___ ___ fire.
Spark Plugs
The burning mixture pushes the piston downward. This is the ___ stroke.
Power
One purpose of the dual ignition system on an aircraft engine is to provide for …
improved engine performance
Magnetos contain spinnable magnets, housed in metal cases. When the internal magnets are spun, they generate electricity for the ___ ___.
Spark Plugs
What’s particularly interesting about magnetos is that they are self-contained spark generators and require no outside source of electrical energy to work other than the ___ motion of the airplane engine.
Turning
What is the purpose of the magneto’s impulse coupling?
To provide extra spin energy for the magneto’s internal magnets
Normally, airplanes are operated with the magneto switch in the ___ position.
Both
Is it permissible to operate the engine on one magneto?
yes. If one magneto goes bad, it’s permissible to switch to a single magneto
In many cases we’re concerned not only with the RPM drop on each magneto, but with the ___ in RPM between each mag drop.
Difference
Selecting the right or left magneto ___ the other mag by grounding it to the air frame.
Deactivates
The mag is grounded to the air frame via a wire called the …
P-lead
Mechanics (and flight instructors) sometimes recommend doing a P-lead security check just before shutting down. With the engine idling, quickly turn the mag switch from ___ to off, then immediately back to ___ again.
both, both
Exhaust gases sometimes have an afterlife. They can be put to use spinning a ___ or indirectly heating the ___ or cabin.
Turbocharger, carburetor
The ___, ___ and ___ manifold (pipes connected to each cylinder) make up the induction system on carburetor equipped airplanes.
air filter, carburetor, intake
Airplane carburetors located underneath the engine are called ___ type carburetors because air and fuel must be drawn upward toward each cylinder.
Updraft
The operating principle of float-type carburetors is based on the…
difference in air pressure at the venturi throat and the air inlet
The ___ jet is that portion of the carburetor that allows the engine to run when the throttle is pulled full aft.
Idling
Why doesn’t the engine quit or falter when the throttle is opened abruptly?
The accelerator pump supplies a shot of fuel into the throat of the carburetor along with the inrushing air.
Assuming the airplane has an updraft carburetor with an accelerator pump, what happens when the engine isn’t running and the throttle is pumped?
Fuel may fall to the bottom of the carburetor and soak the air filter, creating an opportunity for an engine fire.
Fuel-air ratios of approximately ___ part(s) fuel to ___ parts of air are the most efficient for combustion
one, 13
Temperature drops of as much as ___ within the carburetor’s throat are not uncommon.
70 degrees
your carburetor is a fine ice maker. because of the considerable drop in temp caused by the atomization and evaporation of fuel, any ___ present can and will freeze
moisture
be prepared for carburetor ice to form at almost any outside air temp, though it’s most likely to occur between outside temps of ___
20 degree F to 70 degrees F
Impact ice occurs when ___ ___ is present and the outside air temp (OAT) is at or below freezing
visible moisture
When is it possible to have an air filter freeze over while nowhere near a cloud?
If the air is moist and temps are low, water can accumulate and the air filter’s membrane can freeze.
Another occasion where impact ice is likely is during ___
freezing rain
if your air filter ever becomes clogged by impact ice, you have a remedy at hand. It’s called the ___ control
Carb Heat
Fuel ice forms ___ of the main discharge nozzle.
Downstream
Which condition is most favorable for the development of carb icing?
Temps between 20 degrees F and 70 degrees F and High humidity
Fuel ice can occur at outside air temps as high as ___ and at humidities as low as ___
85°F and 50% Humidity
Throttle ice forms on the ___ side of the throttle valve.It is more likely to occur when the throttle is in a ___ position.
rear, partially closed
Pulling the carb heat lever allows heated air to enter the carburetor, raising the air temp within its throat as much as ___
90°F
If an aircraft is equipped with a fixed pitch propeller and a float-type carburetor, the first indication of carb ice would most likely be ___
Loss of RPM
The presence of carb ice in an aircraft equipped with a fixed pitch propeller can be verified by applying car heat and noting…
a further decrease in RPM and then a gradual increase in RPM
Generally speaking, the use of carb heat tends to
decrease engine performance
Applying carb heat will
enrich the fuel/air mixture
What change occurs in the fuel/air mixture when carb heat is applied?
The fuel/air mixture becomes richer
A carburetor air temp gauge allows you to identify the ___ temp range where carburetor ice is most likely to occur.
Critical
All engines ___ have the same carb icing potential
DO NOT
Pulling out (toward you) on the mixture control ___ the amount of fuel for a given amount of air entering the engine
decreases
with an increase in altitude the air becomes thinner and doesn’t ___ as much for a given volume
Weigh
The basic purpose of adjusting the fuel/air mixture at altitude is to…
decrease the fuel flow in order to compensate for decreased air density.
Most engine manufacturers recommend leaning the mixture whenever you’re operating at or below ___ of the engine’s maximum power output.
75%
How might you estimate that you’re operating at power levels greater than 75% in a non-turbocharged engine?
If the airplane is operating with full throttle at less than 5,000 feet MSL
Remember, failure to lean appropriately means you’ll use up ___ portion of fuel unnecessarily
an extra
Airplanes with fixed pitch propellers (propellers having one pitch that can’t be changed in flight) and float-type carburetors can be leaned by reference to the ___
Tachometer
While leaning with reference to the tachometer, the RPM peaks. this means that you are at the fuel-air ratio that produces maximum ___ for a given air density and throttle setting.
power
A mixture that is too rich causes engine ___
roughness
A fouled spark plus in flight can sometimes be detected by ___
an increase in EGT
An excessively rich mixture contributes to ___,___,___, and ___.
A rough running engine, high fuel consumption, less range, smaller fuel reserves
During the run-up at a high elevation airport, a pilot notes a slight engine roughness that is not affected by the magneto check but grows worse during the carburetor heat check. Under these circumstances, what would be the most logical initial action?
Check the results obtained with a leaner setting of the mixture
The biggest danger with an excessively lean mixture is that it ___
burns hot
What is one procedure to aid in cooling an engine that is overheating?
Enrichen the fuel mixture
High cylinder head temps also lead to something known as ___
detonation
While cruising at 9,500 feet MSL, the fuel/air mixture is properly adjusted. What will occur if a descent to 4,500 feet MSL is made without readjusting the mixture?
The fuel/air mixture may become excessively lean.
For best power (most usable power per unit of air), enrich the mixture until the temperature ___. (check your POH to ensure the proper procedure for your aircraft.)
Decreases 125°F from peak EGT
Water is the most frequent contaminant found in fuel. Water, weighing approximately ___ pounds per gallon, ___ ___ than fuel, which weighs approximately ___ pounds per gallon
8, is heavier, 6
If it’s present, water rests on the ___ of the fuel tanks, where it’s often the first thing to go to the engine.
Bottom
Filling the fuel tanks after the last flight of the day is considered a good operating procedure because this will…
prevent moisture condensation by eliminating airspace in the tanks
Fuel tanks have sump drains found at the ___ part of the tank. The sumps should be drained after every ___
lowest, refueling
Different grades of aviation fuel (called AVGAS) are dyed for easy identification. Red colored fuel is of the ___ octane variety (very hard to find nowadays). ___ Fuel is of the 100LL or low lead variety and is one of the most common aviation fuels in use today. ___ fuel is 100 octane and is also very hard to find.
80, blue, green
What type fuel can be substituted for an aircraft if the recommended octane is not available?
The next higher octane aviation gas
As the fuel pump sucks from the tank, air must replace the departing fuel or a ___ forms
Vacuum
Boost pumps are often used during ___ to pressurized the fuel system. This helps purge air trapped within the fuel lines. After the engine starts, the electric boost pump is ___ to see if the ___ pump is operational and is pressurizing the system.
Engine start, turned off, mechanical
On aircraft equipped with fuel pumps, the practice of running a fuel tank dry before switching tanks is considered unwise because…
the engine-driven fuel pump or electric fuel boost pump may draw air into the fuel system and cause vapor lock.
The primer usually squirts fuel in the ___ portions of the induction system, ___ the carburetor completely.
Upper, bypassing
The regulations require fuel gauges to be accurate in only two conditions: when the tank is ___ and then it’s ___
Full, empty (no usable fuel on board)
Remember Rod Machado’s fuel axiom No. 13: If you smell fuel on take off, go back and land. You probably left the cap off your ___
Tank
If an airplane’s oil cap is left off or comes loose during flight, oil may be ___ ___ the engine
expelled from
For internal cooling, reciprocating aircraft engines are especially dependent on …
the circulation of lubricating oil
What should be the first action after starting an aircraft engine?
Adjust for proper RPM and check for desired indications on the engine gauges
Engines are generally preheated in extreme cold. Lycoming, for example, recommends the engine be preheated at temps below ___ to prevent engine damage during startup. Continental says ___.
10°F, 20°F
An abnormally high engine oil temp indication may be caused by…
the oil level being too low
Excessively high engine temps will…
cause loss of power, excessive oil consumption, and possible permanent internal engine damage
If the engine oil temp and cylinder head temp gauges have exceeded their normal operating range, the pilot may have been operating with…
too much power and the with the mixture set too lean
What action can a pilot take to aid in cooling an engine that is overheating during a climb?
Reduce rate of clime and increase airspeed
Inside most airplane engines is something known as an ___. This valve provides an alternate path for the flow of oil if the pressure within the system becomes dangerously ___
Oil pressure relief valve, high
Most modern airplane engines are ___ cooled. Water cooling may be more efficient, but it would mean carrying considerably more ___
Air, weight
In order to avoid shock-cooling a high performance engine during a cruise descent, make small power changes. A good rule of thumb is to make no more than a ___ RPM per minute reduction in engine speed on small engines and no more than ___ of manifold pressure per minute on high performance airplanes. Always leave enough power on so as not to cool the cylinder head temps below allowable limits.
100, 1 inch
Keep in mind that engine cooling is least effective at ___ power settings and ___ airspeeds, where a limited amount of air enters the engine cowling.
high, low
Keeping the ___ flaps closed helps maintain engine temps during the descent.
Cowl
During a descent, your job is to maintain stable cylinder head temps (CHT) and oil tmeps. On some airplanes, ___ entensoin or even ___ extension at high speeds can be used in lieu of large power reductions to start a descent (check your POH)
gear, partial flap
In an airplane with a fixed pitch prop, one lever, the ___ controls both power and propeller blade RPM.
Throttle
As you move up into higher performance airplanes you encounter constant speed (controllable pitch) propellers. Airplanes with these propellers usually have both a ___ and a/an ___ control, so you manage engine power and propeller RPM separately.
throttle, propeller
What is an advantage of a constant speed propeller?
It permits the pilot to select the blade angle for the most efficient performance
On airplanes with constant speed propellers, movement of the ___ determines the amount of fuel and air reaching the cylinders.
throttle
Simply stated, the ___ determines how much power the engine can develop.
throttle
Movement of the propeller control changes the propeller’s…
pitch
On an airplane with a constant speed propeller, the ___ determines engine power while the ___ determines how efficiently that power is used
throttle, propeller’s pitch
Forward movement of the propeller control causes both havlves of the propeller to rotate about their axes and attack the wind at a ___ angle
smaller
Pulling the propeller control rearward causes the propeller to attack the wind at a ___ angle of attack
larger
On an airplane with a constant speed propeller, the ___ tells you how fast the propeller spins (its RPM), and the manifold pressure gauge gives you an approximate measure of engine ___
tachometer, power
Opening the throttle slightly causes an increase in ___ pressure. More air and fuel are drawn inside the engine, and power ___. Eventually, as the throttle is fully opened, the pressure downstream of the throttle valve approaches that of the ___
Manifold, increases, atmostphere
Under normal conditions ( assuming a non-turbocharged engine), the engine’s manifold pressure can’t rise above ___ pressure
atmospheric
As a non-turbocharged airplane climbs, you’ll notice the manifold pressure gauge shows ___ even though the throttle is fulled opened
a decrease
Why have a propeller that can change its pitch in flight in the first place?
Airplanes with controllable pitch propellers can select the optimum angle of attack for climb and cruise.
Engine power is dependent on RPM. For an engine to develop its maximum power, it must be operated at its ___ allowable RPM. At any lower RPM the engine develops only a fraction of its total horsepower. That’s why on takeoff we want the propeller set to its ___ pitch (highest RPM) position.
Highest, Lowest
During cruise flight, is it necessary to always fly with maximum power and maximum RPM?
NO!!
Controllable pitch propellers on GA airplanes are of the constant speed variety. Once the RPM is established, changes in manifold pressure (by moving the throttle) ___ affect engine speed.
won’t
When you want to increase both the manifold pressure and RPM, change the ___ first, then increase the ___.
RPM, manifold pressure
A precaution for the operation of an engine equipped with a constant speed propeller is to…
avoid high manifold pressure setting with low RPM
Follow the same philosophy when decreasing manifold pressure and RPM. Pull the ___ back first, followed by the ___.
Throttle, propeller contorl
Be aware that the propeller governor starts working only when the engine is operating above a specific ___ and not below
RPM
Detonation occurs in a reciprocating aircraft engine when…
the unburned charge in the cylinders explodes instead of burning normally
Which would most likely cause the cylinder head temp and engine oil temp gauges to exceed their normal operating ranges?
Using fuel that has a lower-than-specified fuel rating
If a pilot suspects that an airplane engine with a fixed-pitch propeller is detonating during climbout after takeoff, the initial corrective action to take would be to …
lower the nose slightly to increase airspeed
If the grade of fuel used ina n aircraft engine is lower than specified for the engine, it will most likely cause…
detonation
The uncontrolled firing of the fuel/air charge in advance of normal spark ignition is known as …
preignition
Preignition causes peak pressures within the cylinder to occur before the beginning of the ___ cycle.
power
Fuel injection is a process in which fuel is directly ___ and ___ to each cylinder without the use of a carburetor.
metered, distributed
The FCU (fuel control unit) regulates botht he volume of the ___ entering the engine and the quantity of ___ delivered to the FMU (fuel manifold unit).
air, fuel
You can’t get carb ice in a fuel injection system for one very important reason: there is ___
no carburetor associated with this system
With regard to carb ice, float-type caruretor systems in comparison to fuel injection systems are generally considered to be …
more susceptible to icing
A major advantage of fuel injection is…
improved control of fuel-air ratio
A major disadvantage of Fuel Injection is
contamination of dirt and water can more easily affect fuel injected engines due to the small orifices of injector nozzles.
Airplanes with turbochargers are able to produce___ power at high altitudes
sea level
Turbocharging compresses air into the intake manifold by utilizing the normally unused ___ exiting the engine.
exhaust gases
The ___ valve closes (either automatically or manually, depending on your airplane) allowing more ___ to flow over the turbine. This spins the ___, allowing compressed air to be pumped into the induction system.
Wastegate, exhaust, compressor
Pressurizing an airplane allows you to fly at very high altitudes while remaining in a cabin environment with near ___ pressures. This is accomplished by directing ___ air from the ___ (or from an auxiliary compressor) into the cabin.
Sea-level, compressed, turbocharger
Temps drop as much as ___ within the carburetor’s throat are not uncommon.
70 degrees
Your carburetor is a fine ice maker. Because of the considerable drop in temp caused by the atomization and evaporation of fuel, any ___ present can and will freeze.
Moisture
Be prepared for carburetor ice to form at almost any outside air temp, though it’s most likely to occur between outside temps of ___.
20 degrees to 70 degrees.
Impact ice occurs when ___ ___ is present and. The tide air temp (OAT) is at or below freezing
Visible moisture
When is it possible to have an air filter freeze o
Ver while nowhere near a cloud?
If the air is moist and temps are low, water can accumulate on the air filter’s membrane and freeze.
Another occasion where impact ice is likely is during ___.
Freezing rain
If your air filter ever becomes clogged by impact ice, you have a remedy at hand. It’s called the ___ control.
Carb heat
Fuel ice forms ___ of the main discharge nozzle.
Downstream
Which condition is post favorable for the development of carb icing?
Temps between 29 degrees and 70 degrees and high humidity
Fuel ice can occur at outside air temps as high as ___ and at humidities as low as ___.
85 degrees F, 50%
Throttle ice forms on the ___ side if
The throttle valve. It is more likely to occur when the throttle is in a ___ position.
Rear, partially open
Pulling the carburetor heat lever allows heated air to enter the carburetor, raising the air temperature within it’s throat as much as ___
90 degrees
If an aircraft is equipped with a fixed pitch propeller and a float-type carburetor, the first indication of carburetor ice wo uld most likely be ___
Loss of RPM
THe presence of carb ice in an aircraft equipped with a fixed pitch propeller can be verified by applying carb heat and noting ___
A further decrease in RPM and then a gradual increase in RPM
Generally speaking, the use of carb heat tends to …
Decrease engine performance
Applying carb heat will …
Enrich the fuel/air mixture
What change occurs in the fuel/air mixture when carb heat is applied?
The fuel/air mixture becomes richer
A carburetor air temperature gauge allows you to identify the ___ temperature range where carb ice is most likely to occur.
Critical
All engines ___ have the same carb icing potential.
Do not
Pulling out (toward you) on the mixture control ___ the amount of fuel given amount of air entering the engine.
Decreases
With an increase in altitude the air becomes t hinder and doesn’t ___ as much for a given volume.
Weigh
The basic purpose of adjusting the fuel/air moisture at altitude is to …
Decrease the fuel flow in order to compensate for decreased air density
Most engine manufacturers recommend leaning the mixture whenever you’re operating at or below ___ of the engine’s maximum power output (check your POH to be sure)
75%
How might you estimate that you’re operating at power levels greater than 75% in a non-turbocharged engine?
If the airplane is operating with full throttle at less than 5000 feet MSL.
Remember, failure to lean appropriately means you’ll use up ___ portion of fuel unnecessarily.
An extra
Airplanes with fixed pitch propellers (propellers having one pitch that can’t be changed in flight) and float-type carburetor a can be leaned by reference to the …
Tachometer
While leaning with reference to the tachometer, the RPM peaks. This means that you are at the fuel-air ratio that produces maximum ___ for a given air density and throttle setting.
Power
A mixture that is too rich causes engine …
Roughness
A fouled spark plug in flight can sometimes be detected by …
An increase in Exhaust Gas Temp (EGT)
An excessively rich mixture contributes to ___,___,___and ___.
A rough running engine, high fuel consumption, less range, smaller fuel reserves
During the run-up at a high elevation airport, a pilot notes a slight engine roughness that is not affected by the magneto check but grows worse during the carburetor heat check. Under these circumstances, what would be the most logical initial action?
Check the results obtained with a leaner setting of the mixture.
The biggest danger with an excessively lean mixture is that it …
Burns hot
Want is one procedure to aid in cooling an engine that is overheating?
Enriched the fuel mixture
High cylinder head temperatures also lead to something known as …
Detonation
Wile cruising at 9,500 feet MSL the fuel/air mixture is properly adjusted. What will occur if a descent to 4,500 feet MSL is made without readjusting the mixture?
The fuel/air intrude may become excessively lean.
For best power (most useable power per unit of air), enrich the mixture until the temp ___. (Check your POH to ensure the proper procedure for your aircraft.)
Decreases 125 degrees F from peak EGT
Water is the most frequent contaminant found in fuel. Water, weighing approximately ___ pounds per gallon, ___ than fuel which weighs approximately ___ pounds per gallon.
8, is heavier, 6
