Engine Cooling Systems

Question 1

The primary purpose of baffles and deflectors installed around cylinders of air-cooled aircraft engines is to what?

Answer 1

force cooling air into close contact with all parts of the cylinders.

Question 2

What is the purpose of an augmenter used in some reciprocating engine exhaust systems?

Answer 2

To aid in cooling the engine.

Question 3

Aircraft reciprocating engine cylinder baffles and deflectors should be repaired as required to prevent loss of what?

Answer 3

cooling.

Question 4

Which of the following should a mechanic consult to determine the maximum amount of cylinder cooling fin that could be removed when cracks are found?

Answer 4

Engine manufacturer’s service or overhaul manual.

Question 5

Cracks in cooling fins that do not extend into the cylinder head…

Answer 5

may be repaired by removing the affected area and contour filing within limits.

Question 6

A bent cooling fin on an aluminum cylinder head should be what?

Answer 6

left alone if no crack has formed.

Question 7

Where are cooling fins usually located on air-cooled engines?

Answer 7

Cylinder head, cylinder barrel, and inside the piston.

Question 8

How do cowl flaps aid in cooling a horizontally opposed aircraft engine?

Answer 8

Controls the amount of air flowing around the cylinders.

Question 9

The position of the cowl flaps during normal cruise flight conditions is what?

Answer 9

closed.

Question 10

Generally, a small crack just started in a cylinder baffle…

Answer 10

may be stop drilled.

Question 11

Which of the following assists in removing heat from the metal walls and fins of an air-cooled cylinder assembly?

Answer 11

A baffle and cowl arrangement.

Question 12

During ground operation of an engine, the cowl flaps should be in what position?

Answer 12

Fully open.

Question 13

The component(s) in a turbine engine that operate(s) at the highest temperatures is/are the what?

Answer 13

first stage turbine nozzle guide vanes.

Question 14

During an operational check of an electrically powered aircraft engine cowl flaps system, the motor fails to operate. Which of the following is the first to be checked?

Answer 14

Flap actuator motor circuit breaker.

Question 15

(1) Some aircraft exhaust systems include an augmenter system to draw additional air over the engine for cooling.

(2) Augmenter systems are used to create a low pressure area at the lower rear of the aircraft engine cowling.

Answer 15

Both 1 and 2 are true.

Question 16

Which of the following defects would likely cause a hot spot on a reciprocating engine cylinder?

Answer 16

Too much cooling fin area broken off.

Question 17

What part of an air-cooled cylinder assembly has the greatest fin area per square inch?

Answer 17

Cylinder barrel.

Question 18

Reciprocating engines used in helicopters are cooled by what?

Answer 18

a fan mounted on the engine.

Question 19

The greatest portion of heat generated by combustion in a typical aircraft reciprocating engine is what?

Answer 19

carried out with the exhaust gases.

Question 20

A broken cooling fin on a cylinder head…

Answer 20

may be filed to smooth contours if damage and/or repair limits are not exceeded.

Question 21

An engine becomes overheated due to excessive taxiing or improper ground runup. Prior to shutdown, operation must continue until cylinders have cooled, by running engine at…

Answer 21

idle RPM.

Question 22

Cylinder head temperatures are measured by means of an indicator and a what?

Answer 22

thermocouple sensing device.

Question 23

High cylinder head temperatures are likely to result from what?

Answer 23

a very lean mixture at high power settings.

Question 24

The purpose of an intercooler when used with a turbocharger is to cool the what?

Answer 24

air entering the carburetor from the turbocharger.

Question 25

Prolonged idling of an engine will usually result in what?

Answer 25

Foreign material buildup on spark plugs.

Question 26

The most common method and generally the best conduction of heat from the inside of a cylinder barrel to the cooling air is accomplished by what?

Answer 26

machining fins directly on the outside of the barrel.

Question 27

What is the function of a blast tube as found on aircraft engines?

Answer 27

a device to cool an engine accessory.

Question 28

Which statement is true regarding the air passing through the combustion section of a jet engine?

Answer 28

Most is used for engine cooling.

Question 29

Which of the following results in a decrease in volumetric efficiency?

Answer 29

Part-throttle operation.

Question 30

The undersides of pistons are frequently finned. The principle reason is to what?

Answer 30

provide for greater heat transfer to the engine oil.

Question 31

What is the position of the cowl flaps during engine starting and warmup operations under normal conditions?

Answer 31

Full open at all times.

Question 32

Increased engine heat will cause volumetric efficiency to what?

Answer 32

decrease.