Powerplant Conceptual Questions (Mock Exams)

The measurement of efficiency of a rocket engine-propellant combination is known as _____.

a. propulsive efficiency

b. rocket efficiency

c. specific thrust

d. specific impulse

D

The force exerted per unit area on the earth's surface due to the weight of the air.

a. Energy

b. Density

c. Atmospheric pressure

d. Surroundings

C

A capacity of a given body to produce physical effects external to the body.

a. Weight

b. Energy

c. Specific weight

d. Work

B

The one that separates the substance from its surroundings is called the _____.

a. border

b. boundary

c. system

d. wall

B

It is the sum of the gage pressure and atmospheric pressure.

a. Absolute pressure

b. Gage pressure

c. Vacuum pressure

d. Plenum pressure

A

It refers to the quantities that describe and define the thermodynamic substance.

a. Weight

b. Volume

c. Properties

d. Mass

C

On an Otto cycle process, it represents the area enclosed by the relation of entropy and temperature.

a. Heat

b. Work

c. Net Heat

d. Net Work

D

Engine ignition system belongs to ATA Chapter _____.

a. 73

b. 74

c. 75

d. 76

B

Newton's third law of motion generally termed the as "Law of Inertia" states that ____.

a. "To every action, there is an equal and opposite reaction."

b. "Force is proportional to the product of mass and acceleration."

c. "Every body persists in its state of rest, or of motion in a straight line, unless acted upon by some outside force."

d. "Two thermodynamic systems are each in thermal equilibrium with a third, then they are in thermal equilibrium with each other."

C

At what stage in a turbine engine is gas pressure the greatest?

a. Compressor inlet

b. Compressor outlet

c. Turbine outlet

d. Exhaust Cone

B

The actual power delivered to the propeller of an aircraft engine is called _____.

a. friction horsepower

b. indicated horsepower

c. brake horsepower

d. torque

C

To what altitude will a turbocharged engine maintain sea level pressure?

a. Critical altitude

b. Service ceiling

c. Pressure altitude

d. Absolute altitude

A

The purpose of two or more valve springs in aircraft engines is to _____.

a. equalize side pressure on the on the valve stems

b. eliminate valve spring surge

c. equalize valve face loading

d. induce valve spring vibration

B

Backfiring through the carburetor generally results from the use of _____.

a. an excessively lean mixture

b. excessively atomized fuel

c. an excessively rich mixture

d. equal amount of fuel and air

A

Some cylinder barrels are hardened by _____.

a. nitriding

b. shot peening

c. tempering

d. welding

A

One cause of afterburning in an aircraft engine is _____.

a. a sticking intake valve

b. an excessively lean mixture

c. an excessively rich mixture

d. a sticking exhaust valve

C

What publication is used for guidance to determine whether a powerplant repair is major or minor?

a. Federal Aviation Regulations, Part 43, appendix A

b. Airworthiness Directives

c. Technical Standard Orders

d. Service Bulletins

A

A severe condition of chafing or fretting in which a transfer of metal from one part to another is called _____.

a. scoring

b. galling

c. burning

d. waxing

B

Straightening nitride crankshaft is _____.

a. recommended

b. approved by the manufacturer

c. not recommended

d. imposed by the all engine repair manuals

C

Which of the following conditions is usually not acceptable to any extent in turbine

blades?

a. Cracks

b. Dents

c. Pits

d. Holes

A

When must an AD be complied with after it becomes effective?

a. As specified in the AD

b. During the next scheduled inspection

c. At the next scheduled overhaul

d. Every after A check or B check

A

What publication contains the mandatory replacement time for parts of a turbine engine?

a. Engine Manufacturer's Service Instructions.

b. Federal Aviation Regulation Part 43.

c. Engine Manufacturer's Maintenance Manual.

d. Federal Aviation Regulation Part 49

A

The two types of centrifugal compressor impellers are _____.

a. single-entry and double-entry

b. rotor and stator

c. impeller and diffuser

d. steady and dynamic

A

An advantage of the centrifugal-flow compressor is its _____.

a. pressure rise per stage

b. ram efficiency

c. peak efficiency

d. steady temperature

A

Standard sea level pressure is _____.

a. 101.325 Bars

b. 29.29 in. Hg

c. 760 Torr

d. 14.7 psf

C

The Brayton cycle is known as the constant _____.

a. pressure cycle

c. mass cycle

b. temperature cycle

d. polytrophic cycle

A

Universal gas constant is equal to __________.

a. 287.08 J/kg-K

b. 286.9 J/kg-K

c. 8,314 J/kg-K

d. 53.342 J/kg-K

A

A weak fuel to air mixture along with normal airflow through a turbine engine may result in _____.

a. a rich flameout

b. a lean die-out

c. high EGT

d. very low fuel supply

B

What is the primary function of an exhaust cone of a turbine engine?

a. Align the exhaust gases to develop an efficient power

b. Collect and convert exhaust gasses into a solid high-velocity exhaust jet

c. Collect and convert exhaust gasses into a solid low-velocity exhaust vapor

d. Straighten the swirling exhaust gasses.

B

An adiabatic surface is best described as _____.

a. impervious to heat

b. an implication of perfect insulation

c. cannot be penetrated by heat

d. all of the above

D

Entropy is also defined as that function of the working substance which remains constant during _____.

a. an isochore process

b. an isentropic process

c. a polytropic process

d. an adiabatic process

B

Aircraft piston is commonly made of _____.

a. cast iron

b. silicone steel

c. aluminum bronze

d. aluminum alloy

A

Kinetic energy is the energy of a substance due to its _____.

a. motion

b. potential force

c. mass

d. molecular movement

A

In an irreversible adiabatic process, entropy always _____.

a. decreases

b. increases

c. remains zero

d. have a constant n value

C

A rocket engine is a powerplant, self-contained, which depends _____.

a. on the oxidizer and fuel for operation

b. on atmospheric air for operation

c. on the ignition system installed, as necessary, for operation

d. on air thrust for operation

A

In a ramjet or "flying stovepipe," compression is obtained by utilizing the forward motion of the aircraft to produce _____.

a. dynamic pressure

b. intake air

c. equivalent turbo-charged air

d. thrust forces

C

The first law of thermodynamics states that during any cycle a system undergoes, the cyclic integral of the heat is _____.

a. equal to the work required

b. directly proportional to the temperature and volume

c. proportional to the cyclic integral of the work

d. proportional to the cyclic integral of the pressure and volume

C

Matter is composed of an aggregation of molecules that are moving continuously _____.

a. hazardly

b. in rotational motion

c. in translational motion

d. in vibratory motion

D

The following are the major components of a normally aspirated engine except _____.

a. air intake

b. induction filter

c. fuel delivery system

d. ice removal system

D

A fuel ratio of 11:1 normally refers to _____.

a. a stoichiometric mixture

b. 1 part of air, 11 parts fuel

c. 1 part of fue, 11 parts of air

d. 1.1 part of fuel, 1 part of air

C

For what primary purpose is a turbine engine fuel control unit trimmed?

a. To obtain maximum thrust output when desired

b. To properly position the power levers

c. To adjust the idle RPM

d. Eliminate vibration in the compression section

A

Reciprocating engine power will be decreased at all altitudes if _____.

a. air density is increased

b. humidity is increased

c. manifold pressure is increased

d. altitude is maintained

B

The device that controls the volume of the fuel/air mixture to the cylinders is called a _____.

a. mixture control

b. metering jet

c. tachometer

d. throttle valve

D

Which of the following is not under bulk property?

a. Temperature

b. Refractive Index

c. Degree of Hardness

d. Volume

D

The two types of compressor commonly used on jet engines are?

(a) Turboprop and turbofan

(b) high pressure and low pressure

(c) centrifugal and axial flow

(d) rotor and stator

C

A system in which there is no exchange of matter with the surrounding and does not cross it boundaries is called a?

(a) isolated system

(b) open system

(c) variable system

(d) closed system

D

Intensive properties are?

(a) dependent of the mass

(b) independent of the mass

(c) remains the same

(d) expanded properties of mass

B

Basically the power is the function of force time and?

(a) velocity

(b) a constant

(c) drag

(d) distance

D

If an aircraft turbine engine uses only the thrust developed within the engine to produce its propulsive force, such engine is

known as?

(a) turbojet

(b) turbofan

(c) propjet

(d) ramjet

A

A thermodynamic cycle is a sequence of processes that eventually returns the working substance to its?

(a) original pressure

(b) original state

(c) original temperature

(d) original volume

B

The first law of thermodynamics states that one form of energy may be?

(a) created

(b) destroyed

(c) created and destroyed

(d) converted into another

D

The detonation properties of gasoline are measured by an octane number, the higher the number,

(a) the higher the tendency to detonate

(c) may detonate due to roughened surface

(b) may detonate if the chamber is not of right size

(d) the less tendency of gasoline to detonate

D

The Four Stroke Five Events Engine Cycle in proper order of occurrence.

(a) Intake, Compression, Power, Ignition, Exhaust

(b) Intake, Power, Compression, Ignition, Exhaust

(c) Intake, Ignition, Power, Compression, Exhaust

(d) Intake, Compression, Ignition, Power, Exhaust

D

A pulse jet engine is a modification of the

(a) ramjet

(b) rocket

(c) pure jet

(d) turbine

A

A turbojet engine operates on a?

(a) Carnot Cycle

(b) Diesel Cycle

(c) Brayton Cycle

(d) Otto Cycle

C

What type of turbine blade is most commonly used in aircraft jet engines?

(a) impulse

(b) reaction

(c) impulse-reaction

(d) stator

C

Where is the highest gas pressure in the turbojet engine?

(a) at the entrance of the turbine section

(b) at the entrance of the burner section

(c) at the outlet of tailplane

(d) at the outlet of the burner section

B

The operating principle of the turbojet engine is the application of?

(a) Newton's First Law

(b) Newton's Second Law

(c) Newton's Third Law

(d) Zeroth Law

C

Which is the main advantage of an APU's centrifugal flow compressor

(a) low starting power requirements

(b) shorter than axial

(c) high pressure rise per stage

(d) cheaper

B

Where is the diffuser section located in the turbine engine?

(a) between N1 and N2

(b) between burner and turbine

(c) between compressor and burner

(d) at the intake

C

In a dual axial flow compressor system the first stage turbine drives the?

(a) N2 compressor

(b) N1 compressor

(c) both N1 and N2

(d) Fan

A

The primary purpose of an oil-fuel heat exchanger is to?

(a) decrease viscosity

(b) heat the fuel

(c) cool the oil

(d) cool the fuel

C

Which is the most critical parameter for a turbine engine during starting?

(a) starter engagement time

(b) oil pressure

(c) EGT

(d) RPM

C

On most engines ram recovery occurs at?

(a) 60 knots

(b) 80 knots

(c) 100 knots

(d) 140 knots

D

In a reciprocating engine with the name of IO-365-H2, 365 stands for?

(a) Engine power

(b) total displacement in m³

(c) total displacement in in³

(d) individual cylinder displacement in in³

C

In a turbofan engine the primary source of thrust is the?

(a) exhaust

(b) high velocity jet

(c) fan

(d) afterburner

C

An engine driven air pump that increases manifold pressure and forces the fuel/air mixture into the cylinders which has the effect of increasing the power output of the engine.

(a) Compressor

(b) Supercharger

(c) Diffuser

(d) Turbocharger

B

The ratio of turbine discharge pressure to compressor inlet pressure.

(a) EPR

(b) EGT

(c) tachometer

(d) Torque meter

A

An internal viewing device which allows you to visually inspect areas inside a turbine engine without disassembling the engine.

(a) camera

(b) borescope

(c) electronic imaging

(d) engine endoscopy

B

It is considered the most efficient cycle?

(a) Otto

(b) Brayton

(c) Diesel

(d) Carnot

D

A self-contained unit, which enables the aircraft to be independent of external pneumatic and electrical power sources.

(a) accessory section

(b) gearbox

(c) auxiliary power unit

(d) integrated drive generator

C

In a dual axial-flow compressor, the first stage turbine drives__________.

(a) N1 compressor

(b) N2 compressor

(c) N3 compressor

(d) N4 compressor

B

A parameter used to describe the performance of reciprocating piston engines which is the theoretical constant pressure that, if it acted on the piston during the power stroke, would produce the same network as actually developed in one cycle.

(a) brake effective pressure

(b) thermal effective pressure

(c) combustion pressure

(d) mean effective pressure

D

In a refrigeration cycle the heat inside is absorbed by?

(a) condenser coils

(b) evaporator coils

(c) expansion valve

(d) compressor

B

It is a reversible adiabatic thermodynamic process.

(a) isobaric

(b) isentropic

(c) isothermal

(d) polytrophic

B

The following are parts of a refrigerator except?

(a) evaporator

(b) expansion valve

(c) Compressor

(d) condenser coils

A

How is anti-icing fluid ejected from the slinger ring on a propeller?

(a) pressure pump

(b) centripetal force

(c) centrifugal force

(d) bourdon tubes

C

Geometric pitch of a propeller is defined as the

(a) effective pitch minus slippage

(b) effective pitch plus slippage

(c) angle between blade chord and axis of rotation

(d) effective pitch plus distance travelled

B

What operational force tends to bend the propeller blades forward at the tip?

(a) centrifugal twisting force

(b) torque

(c) aerodynamic twisting force

(d) thrust bending force

D

Which bearing is least likely to be a roller or ball bearing?

(a) rocker arm bearing

(b) master rod bearing

(c) crankshaft

(d) all of the above

B

The actual power delivered to the propeller of an engine is called?

(a) friction horsepower

(b) indicated horsepower

(c) shaft horsepower

(d) break horsepower

D

When is the fuel/air mixture ignited in a conventional reciprocating engine?

(a) after Top Dead Center

(b) Shortly before Top Dead Center

(c) After Bottom Dead Center

(d) shortly before Top Dead Center

B

What is the purpose of having piston ring gaps?

a. So that oil can freely enter the system.

b. So that the piston rings will have allowance in the event of thermal expansion.

c. So that the temperature from the piston can be easily transferred to the cylinder walls.

d. For easier overhaul procedures.

B

How do cooling fins help in dissipating heat from the cylinder assembly?

a. It increases the surface area of the cylinder for convection.

b.They provide an outlet for hot air.

c. They make the cylinder assembly become lighter.

d. Their shape helps cool air flow smoothly against the outer walls of the cylinder.

A

If a four-stroke, five-event engine uses a carburetor, during what stroke is fuel introduced into the combustion chamber?

a. Intake

b. Compression

c. Power

d. Exhaust

A

A crankshaft completes one rotation in order to:

a. Complete one stroke

b. Complete three strokes

c. Complete one cycle

d. Complete two strokes

D

At what position does the piston start at during the intake stroke?

a. Top dead center

b. Bottom down center

c. Bottom dead center

d. Top down center

A

The engine cycle that does not require an outside source of ignition.

a. Otto Cycle

b. Diesel Cycle

c. Brayton Cycle

d. Carnot Cycle

B

This is also known as a "mechanical plunger."

a. Crankshaft

b. Cyclinder Assembly

c. Piston

d. Connecting Rod

C

Dictates that pressure equates to the force applied by a fluid is proportional to the surface area.

a. Pascal's Law

b. Euler's Equation

c. Boyle's Law

d. Bernoulli's Equation

A

The _____ type engine has two banks of cylinders directly opposite each other with a crankshaft in the middle.

a. Radial

b. In-line

c. V-type

d. Opposed

D

A crankshaft is checked for ___ by placing it on knife edges and observing any tendency to rotate.

a. Dynamic Balance

b. Static Balance

c. Centrifugal Balance

d. Damage and Cracks

B

The _____ is the link which transmits forces between the piston and the crankshaft.

a. Camshaft

b. Compression Stroke

c. Connecting Rod

d. Power Stroke

C

The _____ type connecting rod is used on horizontally opposed engines.

a. Master-and-articulated

b. Fork and blade

c. Plain

d. Normal

C

Why is it important for bearings to be made of non-ferrous materials?

a. To withstand high temperatures during engine operation.

b. To minimize friction between two moving parts.

c. Because these materials are less likely to develop corrosion.

d. Because these materials are cheaper

C

The actual amount of power produced by an engine.

a. Actual Horsepower

b. Friction Horsepower

c. Brake Horsepower

d. Indicated Horsepower

C

Defined as the distance traveled by a piston inside the cylinder assembly.

a. Stroke

b. Bore

c. Event

d. Cycle

A

What type of energy is produced by burning the fuel and air mixture?

a. Thermal

b. Electrical

c. Chemical

d. Mechanical

C

Energy can neither be created nor destroyed is stated by:

a. The zeroth law of thermodynamics

b. The first law of thermodynamics

c. The second law of thermodynamics

d. The third law of thermodynamics

B

Which of the following statements describe the brayton engine cycle?

a. A repeating cycle in which the events happen one after another.

b. A linear cycle in which the events happen simultaneously

c. A linear cycle in which the events happen one at a time.

d. A repeating cycle in which the events happen two at a time.

B