#2 Reciprocating Engines Question and Answer

#2 Prepware

c

Which of the following is a characteristic of a thrust bearing used in most radial engines?
a. Tapered roller
b. Double-row ball
c. Deep groove ball
d. Cylindrical roller

b

if the hot clearances is used to set the valves when the engine is cold, what will occur during the operation of the engine?
a. The valves will open early and close early
b. The valves will open late and close early
c. The valves will open early and close late
d. The valves will open late and close late

b

If the oil pressure of a cold engine is higher than at normal operating temperatures, the
a. oil system relief valve should be adjusted
b. engine’s lubrication system, is probably operating normally
c. oil dilution should be turned on immediately
d. the engine needs topping up of oil

d

Four stroke cycle engines in the order of their occurrence are
a. exhaust, power, compression, intake
b. intake, compression, exhaust, power
c. intake, power, compression, exhaust
d. intake, compression, power, exhaust

c

When is the fuel/air mixture ignited in a conventional reciprocating engine?
a. When the piston has reached the top dead center of the compression stroke
b. When the piston has reached the top dead center of the intake stroke
c. Shortly before the piston reaches the top of the compression stroke
d. When the piston reaches the top dead center on the compression stroke

b

To what altitude will a turbo-charged engine maintain sea-level pressure?
a. Maximum Altitude
b. Critical Altitude
c. Service Ceiling
d. Pressure altitude

d

If the ignition switch is moved from BOTH to either LEFT or RIGHT during a magneto check, a normal operation is usually indicated by
a. increase RPM
b. no change in RPM
c. momentary interruption of both ignition systems
d. slight drop in RPM

a

What is the best indication of worn valve guides?
a. High oil consumption
b. Low compression
c. Low oil pressure
d. No change in oil consumption

d

If air is heard coming from the crankcase breather or oil filler during a differential compression check, what is this an indication of?
a. Head gasket leakage
b. Exhaust valve leakage
c. Intake valve leakage
d. Piston ring leakage

d

If the fuel/air ratio is proper and ignition timing is correct, the combustion process should be completed
a. when the piston reaches the bottom dead center during the power stroke
b. 20 to 30 degrees before the top center at the end of the compression stroke
c. when the exhaust valve opens at the end of the power stroke
d. just after the top center at the beginning of the power stroke

c

Which of the following conditions would most likely lead to detonation?
a. Late ignition timing
b. use of fuel with too high an octane rating
c. Use of fuel with too low an octane rating
d. None of the above

a

When does valve overlap occur in the operation of an aircraft reciprocating engine?
a. At the end of the exhaust stroke and the beginning of the intake stroke
b. At the end of the power stroke and the beginning of the exhaust stroke
c. At the end of the compression stroke and the beginning of the power stroke
d. At the end of the intake stroke and the beginning of the compression stroke

b

Which statement is correct regarding a four stroke cycle aircraft engine?
a. The intake valve opens on the power stroke
b. The intake valve closes on the compression stroke
c. The exhaust valve opens on the exhaust stroke
d. the intake valve closes on the intake stroke

c

Full-floating piston pins are those that allow motion between the pin and
a. the piston
b. both the piston and the large end of the connecting rod
c. both the piston and the small end of the connecting rod
d. the small end of the connecting rod

b

Ignition occurs at 28 degrees BTDC on a certain four-stroke cycle engine, and the intake valve opens at 15 degrees BTDC. How many degrees of crankshaft travel after ignition does the intake valve open? (Consider one cylinder only)
a. 707 degrees
b. 373 degrees
c. 347 degrees
d. 277 degrees

b

A hissing sound from the exhaust stacks when the propeller is being pulled through manually indicates
a. a cracked exhaust stack
b. exhaust valve blow by
c. worn piston rings
d. worn out exhaust stack

b

If the oil pressure gauge fluctuates over a wide range from zero to normal operating pressure, the most likely cause is
a. excess oil supply
b. low oil supply
c. broken or weak pressure relief valve spring
d. air lock in the scavenge pump intake

c

Excessive valve clearance in a piston engine
a. increases valve overlap
b. increases valve opening time
c. decreases valve overlap
d. decreases valve opening time

c

Which of these conditions will cause an engine to have an increased tendency to detonate?
1. High manifold pressure
2. High intake air temperature
3. Engine overheated
d4. late ignition timing

a. 2,3,4
b. 1,4
c. 1,2,3
d. 1,2,3,4

d

Which of the following would most likely cause a reciprocating engine to backfire through the induction system at low RPM operation?
a. Broken intake valve
b. Idle mixture too rich
c. Clogged enrichment valve
d. Lean mixture

c

If an engine with a stroke of 6 inches is operated at 2,000 RPM, the piston movement within the cylinder will be
a. at maximum velocity around TDC
b. constant during the entire 360 degrees of crankshaft travel
c. at maximum velocity 90 degrees after TDC
d. at maximum velocity around TDC

c

What is the basic operational sequence for reducing the power output of an engine equipped with a constant-speed propeller?
a. Reduce the RPM, then the manifold pressure
b. Reduce the manifold pressure, then retard the throttle to obtain the correct RPM
c. Reduce the manifold pressure, then the RPM
d. None of the above

b

The horsepower developed in the cylinders of a reciprocating engine is known as the
a. shaft horsepower
b. indicated horsepower
c. brake horsepower
d. torque

b

When is the fuel/air mixture ignited in a conventional reciprocating engine?
a. When the piston has reached the top dead center of the intake stroke
b. Shortly before the piston reaches the top of the compression stroke
c. When the piston reaches the top dead center on the compression stroke
d. Shortly after the piston reaches the top of the compression stroke

b

What is the advantage of using metallic-sodium-filled exhaust valves in aircraft reciprocating engines?
a. Increased strength and resistance to cracking
b. reduced valve operating temperatures
c. Greater resistance to deterioration at high valve temperatures
d. Lighter exhaust valves

a

Reduced air density at high altitudes has a decided effect on carburetion, resulting in a reduction of engine power by
a. excessively enriching the fuel/air mixture
b. excessively leaning the fuel/air mixture
c. reducing fuel vaporization
d. None of the above

c

One of the best indicators of reciprocating engine combustion chamber problems is
a. excessive engine vibration
b. starting difficulties
c. spark plug condition
d. unable to reach high RPM’s

b

The purpose of two or more valve springs in aircraft engines is to
a. equalize side pressure on the valve stems
b. eliminate valve spring surge
c. equalize valve face loading
d. system redundancy

b

The primary concern in establishing the firing order for an opposed engine is to
a. permit continuous power strokes
b. provide for balance and eliminate vibration to the greatest extent possible
c. keep power impulses on adjacent cylinders as far apart as possible in order to obtain the greatest mechanical efficiency
d. keep the power impulses on adjacent cylinders as close as possible in order to obtain the greatest mechanical efficiency

c

If air is heard coming from the crankcase breather or oil filler during a differential compression check, what is this an indication of?
a. Exhaust valve leakage
b. Intake valve leakage
c. Piston ring leakage
d. head gasket leakage

a

What is likely to occur if a reciprocating engine is operated at high power settings before it is properly warmed up?
a. Oil starvation of bearings and other parts
b. Excessive thinning of the engine oil
c. Accelerated oil breakdown and oxidation
d. No premature damages

3

How many of the following are factors in establishing the maximum compression ratio limitations of an aircraft engine?
1. Detonation characteristics of the fuel used
2. Design limitations of the engine
3. Degree of supercharging
4. Spark plug reach

a. Four
b. Two
c. Three
d. One

a

Which statement pertaining to fuel/air ratios is true?
a. The mixture ratio which gives the best power is richer than the mixture ratio which gives maximum economy
b. A rich mixture is faster burning than a normal mixture
c. The mixture ratio that gives maximum economy may also be designated as the best power mixture
d. a rich mixture gives the best fuel economy

c

Analog or mechanical fuel system used in reciprocating engines
a. Electric Pump System
b. Fuel injection system
c. Carburetor System
d. Gravity Fed fuel System

b

Commonly, how many numbers of sparkplugs per cylinder are used in a horizontally opposed engine
a. one
b. two
c. three
d. four

c

What ignites the fuel mixture in a common otto cycle engine
a. Pressure
b. Volume
c. Spark plugs
d. Entropy

a

What causes combustion in a diesel engine?
a. Pressure
b. Volume
c. Spark plugs
d. Entropy