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What are some reasons for using an inverted inline engine?
- if the a/c has short landing gear
- more aerodynamic due to its size
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What does GTISO stand for?
gear reduction, supercharger, fuel injection
(in notes, doesn't seem right, if you know for sure please edit this question)
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What is the identifier for an air cooled engine?
There isn't one
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What do the following designate on a Recip engine?
O
R
I
V
- horz opposed
- radial
- fuel injection
- V type
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What do the following designate on a Recip engine?
T
S
G
L
- Turbo
- Supercharged
- Gear reduction propeller drive
- Left hand rotation
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What do the following designate on a Recip engine?
H
A
- Horz mounted
- Aerobatic modified engine
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Can you still operate a engine if the data plate has been removed?
- No, according to CAR 201.05
- (data plate should be in accessible area)
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What are the 4 events of the four stroke cycle?
- Intake
- compression
- power
- exhaust
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How can you define stroke?
distance from TDC to BDC
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What is the period of time called when both valves are open?
valve overlap
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'the ratio of the amount of air entering the cylinder to the amount of air in an equivant volume in the atmosphere' is the definition of what term?
Volumetric efficiency
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How can you define Mean Effictive Pressure?
Ave. pressure on power stroke
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What is one way that max volumetric efficency achieved?
Scavenging
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What does the PLANK stand for?
- P MEP
- L Length
- A Area
- N Number of power strokes per minute
- K Number of cylinders
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It takes a certin amount of indicated horse power to overcome friction, the formula IHP-FHP is used.
What does FHP stand for?
IHP-FHP=?
- FHP=friction horse power
- IHP-FHP=Brake Horse Power
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What is the formula for indicated hp?
PLANK/33000
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What is the formula for mechanical efficency
IHP-BHP=FHP
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Define BHP?
Power to engine output shaft
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What does the dynometer measure?
- measures torque
- indicates BHP
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When will the MAP be the lowest?
idle
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What are 4 factor effective VE?
- superchargers/turbos
- intercoolers
- intake ducting (less restricting)
- Water meth injestion
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Mechanical Efficiency is mainly effected by what? how can it be improved?
mainly effected by internal friction, improved by luberication and low friction bearings
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what is the typical thermal efficicency of a recip engine expressed as a percent?
25-30%
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Where are the thermal efficiencies lost on a recip engine?
- exhaust (majority)
- prop
- friction
- cooling
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What prevents the oil from leaking out around the engine split line on a horz opposed?
silk thread
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What does BSFC stand for
Brake specific fuel consumption-overall effienciency
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What engine configuration uses a master and articulating rods?
Radial
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What engine config uses a fork and blade?
V type
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What design features are incorperated into pistons to reduce wear?
pins allowed to move side to side
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Why are cam ground pistons used?
allows for thermal expansion when engine is at operating temperature
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How do you measure the gap on piston rings?
feeler gauge
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what are the three styles of piston ring joints
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if you have chrome cylinders, what type of rings can piston rings could you use?
Cast iron rings
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What info is on the engine data plate?
Model, power rating, type cert, manuf name, serial #
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Where does the majority of power loss go?
exhaust
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What is the purpose of choked cylinders?
allows for thermal expansion
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What does the blue or orange marks on the cylinder walls indicate?
- blue-nitride
- orange-chrome
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What are the four different valve shapes?
- Tulip
- Semi tulip
- mushroom
- flat head
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Why do valves have 2 springs
to avoid resination frequency
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How are valves held in place?
with a split key (sping loaded closed)
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What will the valve do if you have to much clearence between the valve and rocker arm?
valve will open late and close early
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What is the purpose of prop reduction gearing?
reduces the speed of the prop so you can have high RPM (more power strokes)
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What are the three different styles of prop attachments?
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List five factors that affect power?
- Detnotation/pre ignition
- fuel octane rating
- compression ratio
- ignition timing
- fuel/air ratio
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whats the most efficient air/fuel mixture by weight?
15:1
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What mixture setting would you be at during take off?
Full rich
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What is defined as a square engine?
Bore and stroke are equal
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What is an over square engine?
undersquare?
- bore wider than stroke
- stroke longer than bore
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How does a constant speed engine increase power?
vary pitch angle
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What is the best indication of engine power output on a constant speed engines?
MAP
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in a constant speed engine what controls the
MAP
RPM
Air/Fuel
- Throttle
- Pitch Control
- Mixture
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What are some design features used by the engine baffles?
- Baffles forces air to flow past the cylinders
- uses venturi to create a low pressure system under the engine
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On a constant speed engine, if RPM goes up,What will happen to MAP?
MAP will drop because the throttle plate stays in the same position
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What is the formula for BSFC?
Fuel Burned in lbs/hr / BHP
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What is the purpose of dynamic balance?
Reduce torsional viberations
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What is another name for a plain bearing?
babbit
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What happens with to much piston ring gap?
to little
- blow by
- heats up and breaks
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What would you do if detonation occours during a climb?
increase RPM
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What is the function of dynamic dampers?
used on crankshafts to dampen torsional viberation
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How does luberication get from the hydraulic lifters to the rocker arm shafts?
inside push rod tubes
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What are the two types of overhauls ?
- Serviceable Limits
- Manufacturers limits
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If your engine is on condition, what are you required to do to ensure that the engine is serviceable?
100 hours you must go through an inspection
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What does SMOH
STOH stand for
- since major overhaul
- since top overhaul
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What are some of the reasons for a top overhaul?
- cylinder compression to low
- excessive oil consumption
- engine run with incorrect fuel
- exposure to volcanic ash
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What are some of the factors to determine the health of the engine at a 100 hour inspection?
- compression
- bore scope
- spark plug-one of the main indicators
- oil pressure
- oil consumption
- viberation
- fuel consuption
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When doing a compression test, what is the max difference between cylinders?
- 5psi
- less than 65 psi is unacceptable
- or greater than 60 psi but all cylinders must be with in 5psi of each other
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Why are recip cylinders required to be within 5 psi of each other?
reduce viberation
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What are 3 causes of low compression?
- intake/exhaust valve leakage
- piston rings
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What are the two different ways to measure compression?
differential and direct
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What does differential pressure measure?
- the leakage in the cylinders
- one gauge indicates the pressure going into the cylinder, the other indicates pressure how much pressure remains
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what does direct testing measure cylinder pressure?
measures the actual pressure in the cylinder
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With Valve clearence, what happens when the valves have excessive clearence? too little clearence?
- excessive-reduces valve opening duration and overlap
- too little clearence-period of valve overlap is lenghtened
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When would hydraulic lock occour?
when oil or liquid fuel accumulates or pools in the lower cylinders ex Radials
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How can you tell if the engine has hydraulic lock?
abnormail amount of effort required to rotate prop
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How can hydraulic lock be overcome?
remove spark plug and rotate engine in the direction of rotation
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