Induction and Engine Cooling Systems

Question 1

What effect does excessive heat have on reciprocating engine?

Answer 1

shortens the life of the engine parts, changes behavior of the combustion and impairs lubrication

Question 2

What is the purpose of cooling fins?

Answer 2

They provide a larger cooling surface area for removing heat from cylinder heads of air cooled reciprocating engines. Airflow around the cooling fans transfers the heat from the cylinder heads to the air.

Question 3

What are the reasons for using engine cowlings, baffles and cowl air seals?

Answer 3

It streamlines the engine area to reduce drag and is used together with the baffles in Cowl air seals to direct flow over the cylinders for cooling.

Question 4

What is the purpose of cowl flaps and how are they operated?

Answer 4

There used to control the amount of airflow through the cowling. They’re either mechanically, electrically, or hydraulically operated.

Question 5

What is used to control the amount of airflow through the cooling area of a reciprocating engine?

Answer 5

Cowl flaps

Question 6

Where should Cowl flaps be positioned for ground operations?

Answer 6

Fully open

Question 7

What type of power is used to operate cowl flaps?

Answer 7

Mechanical, hydraulic or electrical

Question 8

What should be done when cooling fan damage is discovered

Answer 8

Depending on the scope of damage, some cooling fins may be repaired subject to the manufactures overhaul and repair limitations. If there’s an excessive amount of cooling fan broken off, the cylinder should be replaced.

Question 9

Why is cowl flap adjustment important?

Answer 9

The movement must be within tolerances to keep cylinder head temperatures with an allowable limits

Question 10

How are turbine engines cooled?

Answer 10

They are cooled by air passing through the engine about 75% of the air passing through the engine is used for cooling which leads 25% for combustion. This air is usually used to cool the combustion chamber and the turbine

Question 11

In the turbine engine, where does bleed air come from that is used to cool bearings in other parts?

Answer 11

The engine compressor

Question 12

What is the relationship between turbine engine upper temperature limits and power produced?

Answer 12

The higher combustion temperatures that an engine can withstand without damage, the more power it is capable of producing

Question 13

What is the approximate percentage of air passes through a turbine engine that is used for cooling rather than combustion?

Answer 13

75%

Question 14

What can be done effectively to allow higher gas temperatures in the turbine section of some engines?

Answer 14

Compressor bleed air ducted through the hollow sections and the turbine inlet guide vanes and first stage rotor blades can lower temperatures enough to preheat prevent heat damage

Question 15

What happens to waste engine heat after it is transfered to cylinder cooling fins?

Answer 15

It is further transferred from the engine cylinders to the air

Question 16

What is the function of engine cowling?

Answer 16

It streamlines the engine area to reduce drag, and it forms an envelope around the engine to aid in controlling cooling airflow

Question 17

What is the purpose of Cowl air seals?

Answer 17

They force air to circulate around and through the baffle system

Question 18

How does an augmenter cooling system work?

Answer 18

An outer tube placed over existing exhaust gas creates a Venturi affect that draws more airflow over the edge and does providing additional cooling

Question 19

What information must be consulted prior to re-profiling cooling fan?

Answer 19

The manufactures service or overhaul publications

Question 20

Where must cooling air flow to cool a turbine engine?

Answer 20

Through the inside of the engine

Question 21

What areas of turbine engine are cooled by air passing through the engine?

Answer 21

The combustion chamber and turbine