unit 2

Question 1

A jet engine derives its name from its design in that it uses

Answer 1

an exhaust-gas driven turbine wheel to drive its compressor

Question 2

A turbo-supercharger is essentially a

Answer 2

high-capacity air pump

Question 3

The two forces that air is subjected to after it is drawn into the guide vanes of centrifugal compressor are

Answer 3

rotational and centrifugal

Question 4

A constructional feature of the centrifugal compressor is that the impeller

Answer 4

is forged as a single unit

Question 5

The jet engine compressor that is cheaper to manufacture is the

Answer 5

centrifugal type, because of its fewer parts

Question 6

Which is a constructional feature of an axial-flow compressor casing?

Answer 6

Split along the horizontal centerline

Question 7

The percentage of combustion efficiency of a gas turbine is usually between

Answer 7

95 and 100

Question 8

What is the most probable cause of flameout of a jet engine flying at 40,000 feet with a constant engine revolution per minute (rpm) of 50 percent?

Answer 8

the rpm is too low

Question 9

The excess airflow that is not burned in the combustion section is used to

Answer 9

mix with and cool the burned gases

Question 10

The inner and outer surfaces of an annular-type combustion chamber are formed by

Answer 10

interlocking stainless-steel bands

Question 11

Fuel that accumulates after a failed start is

Answer 11

drained overboard by a drain system

Question 12

The parts on a can-annular combustion section must be removed in a specific order because of the

Answer 12

combustion chamber crossover tubes

Question 13

What is the most common type of fuel nozzle system?

Answer 13

Pressure-atomizing

Question 14

Three types of turbine and van assemblies used in jet engines are impulse, reaction, and

Answer 14

reaction-impulse

Question 15

The “fir tree” method of attaching turbine blades (buckets) to the turbine rotor disc is preferred because

Answer 15

of the temperature differential between the turbine rotor disc and the blades.

Question 16

In an non-afterburning engine, the exhaust duct connects the turbine outlet and the

Answer 16

jet nozzle

Question 17

The purpose of the exhaust duct is to

Answer 17

straighten exhaust gas-flow

Question 18

What is one common type of variable-area orifice that is used on augmentors?

Answer 18

Segmented-flap

Question 19

The purpose of an augmentor (afterburner) in a jet engine is to

Answer 19

augment the maximum thrust capability of the basic engine

Question 20

How many different types of loads can be imposed on a jet engine bearing?

Answer 20

three

Question 21

When you handle jet engine bearings, you must change cotton gloves frequently because they

Answer 21

get soaked with sweat

Question 22

Before inspecting new jet engine bearings, you should

Answer 22

remove the preservative coating

Question 23

Next to contamination and improper lubrication, what is the greatest enemy of antifriction bearings?

Answer 23

Improper removal

Question 24

The most commonly used bearing removal tools include

Answer 24

arbor presses and bearing pullers

Question 25

Which type of defect appears on bearings as a result of bearing parts striking together

Answer 25

nicks

Question 26

Which type of defect appears on bearings as a result of small particles of foreign material becoming lodged between the rollers?

Answer 26

Grooves

Question 27

Excessive bearing wear can usually be detected by

Answer 27

roughness of the metal

Question 28

Before you install separable bearings, you must ensure the

Answer 28

bearings are a matched set

Question 29

Of the following, the recommended method of expanding a bearing race before installation is to use a

Answer 29

hot-oil bath

Question 30

The reduction gearbox on an F100-PW-220 engine reduces speed between the main fuel gear pump and the engine-driven main gearbox by

Answer 30

52 percent