Cooling Systems

Question 1

The types of systems used to remove heat from aircraft engines:

Answer 1

1) Air

2) Liquid

Question 2

_______ increase the area from which cylinder heat can be dissipated.

Answer 2

Fins

Question 3

The components that must work together for the most efficient cooling are:

Answer 3

1) Fins
2) Cowling
3) Baffles

Question 4

Cylinder heads of most air cooled engines are made of _______.

Answer 4

Cast aluminum

Question 5

Types of cowlings for radial engines:

Answer 5

1) Townend ring

2) NACA cowling

Question 6

Most popular type of radial engine cowling:

Answer 6

NACA

Question 7

_________ control the amount of air flowing through NACA cowlings.

Answer 7

Adjustable cowl flaps

Question 8

The most common type of air cooling for modern horizontally opposed engines is __________.

Answer 8

Pressure cooling

Question 9

_______ are used in horizontally opposed engines to divide the cowling into two compartments.

Answer 9

Baffles

Question 10

Types of baffles:

Answer 10

1) Horizontal
2) Vertical
3) Inter-cylinder

Question 11

Air is prevented from leaking past the baffles by a __________.

Answer 11

Flexible rubber seal

Question 12

In a pressure cowling, the _________ control the pressure of the air below the engine.

Answer 12

Cowl flaps

Question 13

Along with close fitting shrouds, ________ force air to flow through the cylinder fins.

Answer 13

Inter-cylinder baffles

Question 14

What uses the high velocity of the exhaust gases to increase the flow of air through the cylinder fins?

Answer 14

Augmentor tube

Question 15

Modern liquid cooled engines use what as a coolant?

Answer 15

Ethylene glycol

Question 16

A sign of preignition when inspecting cylinders:

Answer 16

Burned paint

Question 17

T\F

Bent cast aluminum cylinder head fins should not be straightened.

Answer 17

True

Question 18

Common causes of preignition:

Answer 18

1) Broken fins
2) Missing baffles
3) Missing seals

Question 19

What percentage of air passing through a gas turbine is used for cooling?

Answer 19

75%

Question 20

A film of ______ prevents burning gases from contacting the metal inside the combustors.

Answer 20

Air

Question 21

________ is used to cool turbine blades.

Answer 21

Compressor bleed air

Question 22

Factors that greatly affect cylinder heat in an air cooled engine:

Answer 22

1) Surface area of the cylinders.

2) Ambient air temperature.

Question 23

An advantage of air cooled engines over liquid cooled:

Answer 23

Lighter weight

Question 24

Disadvantages of air cooled engines:

Answer 24

1) Uneven cooling

2) Risk of thermal shock

Question 25

Caused by rapid cooling of engine components during altitude changes:

Answer 25

Thermal shock

Question 26

A liquid cooled system is what type of system?

Answer 26

Pressurized system

Question 27

Disadvantages of liquid cooled systems:

Answer 27

1) Heavier (due to hoses, pumps, water and radiator)
2) More components that can fail.
3) Icing and corrosion

Question 28

Benefits of liquid cooled systems:

Answer 28

1) Even cooling
2) No thermal shock
3) No need for fuel enrichment system.

Question 29

_______ are used to provide cooling to the accessory end of the engine through the baffles.

Answer 29

Blast tubes

Question 30

Extra components required for a liquid cooled engine:

Answer 30

1) Radiator
2) Hoses
3) Pump
4) Water