ENGINE COOLING SYSTEMS
PRACTICE TEST EXAM
1. How does metallic sodium in an exhaust valve aid in transferring heat? - correct answer-The sodium
melts when the engine is running and it sloshes up and down as the valve operates. The sodium picks
up heat from the valve head and carries it into the stem so it can be transferred to the cylinder head
and dissipated into the air.
How is the structure around a turbine engine protected from excessive heat from the engine? -
correct answer-An insulating blanket protects the structure from excessive heat.
2. What is the function of blast tubes that are installed in a pressure cooling system of a reciprocating
engine? - correct answer-These blast tubes direct cooling air to the magnetos and the generator.
3. What is meant by pressure cooling of an aircraft engine? - correct answer-Air cooling in which air is
forced to flow through baffles and cylinder fins by a pressure differential across the engine.
4. What is the purpose of an augmentor tube in the cooling system of an aircraft reciprocating engine? -
correct answer-The augmentor tube uses the velocity of the exhaust gases to produce a low pressure
on one side of the engine that helps pull cooling air through it.
5. Where is the highest temperature located in a turbine engine? - correct answer-At the inlet to the
high-pressure turbine.
6. How are the turbine inlet guide vanes and the first-stage turbine blades in some turbine engines
cooled? - correct answer-High-pressure compressor bleed air flows through the hollow guide vanes
and hollow turbine blades.
PRACTICE TEST EXAM
1. How does metallic sodium in an exhaust valve aid in transferring heat? - correct answer-The sodium
melts when the engine is running and it sloshes up and down as the valve operates. The sodium picks
up heat from the valve head and carries it into the stem so it can be transferred to the cylinder head
and dissipated into the air.
How is the structure around a turbine engine protected from excessive heat from the engine? -
correct answer-An insulating blanket protects the structure from excessive heat.
2. What is the function of blast tubes that are installed in a pressure cooling system of a reciprocating
engine? - correct answer-These blast tubes direct cooling air to the magnetos and the generator.
3. What is meant by pressure cooling of an aircraft engine? - correct answer-Air cooling in which air is
forced to flow through baffles and cylinder fins by a pressure differential across the engine.
4. What is the purpose of an augmentor tube in the cooling system of an aircraft reciprocating engine? -
correct answer-The augmentor tube uses the velocity of the exhaust gases to produce a low pressure
on one side of the engine that helps pull cooling air through it.
5. Where is the highest temperature located in a turbine engine? - correct answer-At the inlet to the
high-pressure turbine.
6. How are the turbine inlet guide vanes and the first-stage turbine blades in some turbine engines
cooled? - correct answer-High-pressure compressor bleed air flows through the hollow guide vanes
and hollow turbine blades.
