engine cooling systems

Question 1

what are the three main reasons that excessive heat is undesirable in any reciprocating engine

Answer 1

1. it affects the behavior of combustion
2. it weakens and shortens the life of engine parts
3. it impairs lubrication

Question 2

what is used to provide sufficient cooling surface area for air cooled reciprocation engines

Answer 2

cooling fins

Question 3

what happens to waste engine heat after it is transferred to cylinder cooling fins

Answer 3

it is further transferred from the engine cylinders to the air

Question 4

what should be done to a cylinder with excessive cooling fin area broken off

Answer 4

replace the cylinder

Question 5

what is the principle function of engine cowling and baffles

Answer 5

to direct airflow over the cylinders for cooling

Question 6

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

Answer 6

cowl flaps

Question 7

what is an augmentor cooling system

Answer 7

it is an exhaust system incorporating inner and outer tubes that uses exiting exhaust gas velocity to produce a venturi effect to draw more airflow over the engine

Question 8

what type power is used to operate cowl flaps

Answer 8

manual, electrical, hydraulic

Question 9

why do some aircraft use augmentors

Answer 9

to provide additional cooling airflow

Question 10

where should cowl flaps be positioned during ground operations

Answer 10

fully open

Question 11

what information must be consulted prior to re-profiling a cooling fin

Answer 11

the manufacturer’s maintenance manual

Question 12

what are the functions of engine cowling

Answer 12

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

Question 13

what is the purpose of cowl seals

Answer 13

they force air to circulate around and through the baffle system

Question 14

why is cowl flap adjustment important

Answer 14

the movement must be within tolerances to keep cylinder head temperatures within allowable limits

Question 15

where must most cooling airflow to cool a turbine engine

Answer 15

through the inside of the engine

Question 16

what areas of a turbine engine are cooled by air passing through the engine

Answer 16

the combustion chamber and turbine

Question 17

what is the source of bleed air vented to turbine engine bearings and other parts in some engines

Answer 17

the engine compressor

Question 18

what is the approximate percentage of air passing through a turbine engine that is used for cooling rather than combustion

Answer 18

75%

Question 19

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

Answer 19

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

Question 20

how is compressor bleed air used to effectively allow higher gas temperatures in the turbine section of some engines

Answer 20

bleed air from the compressor is ducted through hollow turbine section inlet guide vanes and hollow first stage rotor blades, keeping them cool enough to prevent damage