Turbine Engine

Question 1

Defined the term thermal efficiency in regards to aircraft engine

Answer 1

The ratio of net work produced by engine to the chemical energy supply and forms of fuel

Question 2

what are the major component of a typical gas turbine engine?

Answer 2

Air inlet, compression section, combustion section, turbine section, exhaust section and accessory section

Question 3

Why are the two principal type of compressors used in turbo jet aircraft?

Answer 3

Axial flow, and centrifugal flow

Question 4

What are the four combustion chamber system?

Answer 4

Can-annular, annular, reverse flow annular type and can type

Question 5

what is the purpose of inter-connector tubes between can type combustion chamber?

Answer 5

To spread the flame to the combustion chambers that are not equipped with igniter plug during engine starting

Question 6

What prevents burning of the liner walls in can type combustion chamber

Answer 6

Louver provided along the axial length of the liners to direct a cooling layer of air along the inside wall of the liner

Question 7

What type of damage may be found when inspecting compressor blade?

Answer 7

Dent, scratches, gouges, galling, burns, bars, piting, and cracks

Question 8

What is the location and function of the diffusion section in a turbine engine?

Answer 8

The diffuser is the divergent section of the engine located between the compressor section and the burner can. The function is to change high velocity compress discharge air to static pressure.

Question 9

Where are stress ruptured crack most likely to occur on turbine Blade

Answer 9

Hairline cracks on or across the leading edge or trailing edge of the blade .cracks appears at right angle to the edge length

Question 10

How are compressor blade attached to disk type rotor?

Answer 10

fitted by bulb type ,fir tree, or dove trail type root that are lock by means of screws, peening,locking wires, pins or keys

Question 11

What is the purpose of nozzle diaphragm or turbine nozzle?

Answer 11

They change a portion of heat and pressure energy into velocity energy. They also deflect the gas so they strike the turbine at the most efficient angle for maximum turbine rotation.

Question 12

What is the major difference between turboprop and turbo jet engine?

Answer 12

Turbo prop engine has more turbine stages than turbojet engine. turbo prop turbine must also driven a propeller.

Question 13

What is a turbofan engine?

Answer 13

Same principle as the turbo prop, except the propeller is replaced by a duct-enclosed axial flow fan

Question 14

What is the effect of air density on the thrust of turbine engine

Answer 14

Air density determine the mass of it is used by the jet engine.the factor that affects are the temperature and the pressure of air. If density increases, thrust increase and vice versa. Increasing air temperature entering the engine, will cause a decrease in air density and thrust. An increase in air pressure entering the engine will cause an increasing air density and thrust. With a given throttle setting engine thrust vary if the temperature or the pressure to air entering the engine change.

Question 15

What are the two common most type of thrust reverser?

Answer 15

Mechanical blockage and aerodynamic blockage type

Question 16

What is a split compressor system in a turbine engine

Answer 16

Required to concentric shaft oining the turbine stages to their respective r compressor

Question 17

What is one method of relieving thermal stress on the turbine disk

Answer 17

To direct cool bleed air back on the face of the disk

Question 18

What may be the indication of a turbo jet engine is out of trim

Answer 18

Engine has high exhaust gas temperature for take off

Question 19

What does it mean when you have high EGT, high fuel flow , and low thrust or power

Answer 19

Pending engine failure or low compression

Question 20

What is a free turbine

Answer 20

Turbine wheel drives the propeller or helicopter transmission instead of compressor

Question 21

What is the main purpose of thrust reversers

Answer 21

To back off airplane or slowing the aircraft down to effective braking speed

Question 22

What are the advantage of turbofan engine over turbojet engines

Answer 22

Use a fan to bypass more air around engine core and provide thrust. This advantage is provides additional thrust without increasing fuel flow

Question 23

What methods are commonly used to accomplish turbine engine compressor field cleaning ?

Answer 23

Fluid wash and abrasive grits blast

Question 24

What would the possible cause be for a turbo jet or turbo engine having a high EGT, low rpm and high fuel at all engine pressure ratio sitting

Answer 24

Possible turbine damage or loss of turbine efficiency

Question 25

Defined term operating flexibility in regard to aircraft engine

Answer 25

Ability of an engine to run smoothly and give desired performance at all speed from idling to full power output

Question 26

How are conventional reciprocating engine classified

Answer 26

Cylinder arrangement and method of cooling

Question 27

What are the different types of piston rings?

Answer 27

Compression ring , oil control ring, scraper ring

Question 28

What are the main causes of a cylinder having low compression?

Answer 28

Broken piston ring, rings not seated properly ,burn valve ,valve not seated properly

Question 29

What is the purpose of the oil control rings? 

Answer 29

To control the thickness of the oil film on the cylinder wall

Question 30

What type of piston rod are commonly found in radial engine

Answer 30

Master and articulating

Question 31

Want may be the result of installing piston ring correctly

Answer 31

Excessive oil consumption

Question 32

What type of bearing are generally used in a reciprocating engine?

Answer 32

Plain ball roller type

Question 33

What is the indication of valve blow by

Answer 33

By hissing or a whistle when pulling the propeller true by hand

Question 34

What is the purpose of using more than one spring valve closing

Answer 34

To eliminate valve float caused by spring surge

Question 35

What is the purpose of valve overlapping?

Answer 35

Better volumetric efficiency and lower the cylinder operating temperature

Question 36

Describe the inspection,you would give to the valve spring during engine overhaul

Answer 36

Clean thoroughly and look for signs of overheating, cracks, broken end and compression strength

Question 37

What is the purpose of using Valve with sodium filled stem

Answer 37

Excellent heat conductor, and dissipate heat well

Question 38

What causes engine sudden stoppage?

Answer 38

Striking an object or engine seizure due to internal damage

Question 39

What type of inspection must be made after sudden stop picture of an engine?

Answer 39

Most manufacture require a complete engine tear down and inspection

Question 40

What is the purpose of crankshaft dynamic dampers use an aircraft engine?

Answer 40

To overcome to force which caused deflection of the crankshaft and torsional vibration. (to reduce the vibration caused by torsional load)

Question 41

How would you make a run out check on the crankshaft that is still installing the engine

Answer 41

Remove the propeller from the crankshaft ,placed dial indicator in front of the crank case, adjust the position of gauge needle, so that it’s touching the shaft rotate the crankshaft and check for misalignment.

Question 42

What is detonation?

Answer 42

When fuel reach beyond its limit temperature and compression that will ignite simultaneously and burn with explosive violence this explosion burning of the last portion of charge it’s called detonation

Question 43

What cylinder is engine magneto timing based on?

Answer 43

Number one cylinder at around 30° TDC of compression stroke

Question 44

What is a Engine sudden speed production?

Answer 44

Went to propeller, strike an object, but continues to run

Question 45

Why can’t be alone about the condition of the engine by studying the result of a compression check?

Answer 45

You can determine if the valve ,piston rings and Pistons adequately, sealing the combustion chamber

Question 46

How can a cold cylinder be located on a double roll radial engine?

Answer 46

Old tool called magic wand and modern infrared laser thermometer

Question 47

What instrument can be used to check for bore out of roundness?

Answer 47

Dial indicator, telescopic, scope, and micrometer

Question 48

What would a cold cylinder indicate?

Answer 48

No combustion inside the cylinder due to no ignition or clogged fuel nozzle

Question 49

Where is crack most likely to occur on a piston

Answer 49

Where the piston pin/wrist, pin connect

Question 50

What is the running valve clearance on a Engine equipped with hydraulic lifters?

Answer 50

Zero

Question 51

What level is used to adjust the manifold pressure in a reciprocating engine?

Answer 51

Throttle control

Question 52

On the engine to fix pitch propeller what is the relationship between the manifold pressure in the rpm

Answer 52

Rpm increase also manifold air pressure increase

Question 53

What should be done to repair a loose stud in an engine crank case

Answer 53

Removed the loose stud and inspect the whole for size and condition of the thread . It may require to use a oversize stud