Cooling Systems Flashcards
The types of systems used to remove heat from aircraft engines:
1) Air
2) Liquid
_______ increase the area from which cylinder heat can be dissipated.
Fins
The components that must work together for the most efficient cooling are:
1) Fins
2) Cowling
3) Baffles
Cylinder heads of most air cooled engines are made of _______.
Cast aluminum
Types of cowlings for radial engines:
1) Townend ring
2) NACA cowling
Most popular type of radial engine cowling:
NACA
_________ control the amount of air flowing through NACA cowlings.
Adjustable cowl flaps
The most common type of air cooling for modern horizontally opposed engines is __________.
Pressure cooling
_______ are used in horizontally opposed engines to divide the cowling into two compartments.
Baffles
Types of baffles:
1) Horizontal
2) Vertical
3) Inter-cylinder
Air is prevented from leaking past the baffles by a __________.
Flexible rubber seal
In a pressure cowling, the _________ control the pressure of the air below the engine.
Cowl flaps
Along with close fitting shrouds, ________ force air to flow through the cylinder fins.
Inter-cylinder baffles
What uses the high velocity of the exhaust gases to increase the flow of air through the cylinder fins?
Augmentor tube
Modern liquid cooled engines use what as a coolant?
Ethylene glycol
A sign of preignition when inspecting cylinders:
Burned paint
T\F
Bent cast aluminum cylinder head fins should not be straightened.
True
Common causes of preignition:
1) Broken fins
2) Missing baffles
3) Missing seals
What percentage of air passing through a gas turbine is used for cooling?
75%
A film of ______ prevents burning gases from contacting the metal inside the combustors.
Air
________ is used to cool turbine blades.
Compressor bleed air
Factors that greatly affect cylinder heat in an air cooled engine:
1) Surface area of the cylinders.
2) Ambient air temperature.
An advantage of air cooled engines over liquid cooled:
Lighter weight
Disadvantages of air cooled engines:
1) Uneven cooling
2) Risk of thermal shock
Caused by rapid cooling of engine components during altitude changes:
Thermal shock
A liquid cooled system is what type of system?
Pressurized system
Disadvantages of liquid cooled systems:
1) Heavier (due to hoses, pumps, water and radiator)
2) More components that can fail.
3) Icing and corrosion
Benefits of liquid cooled systems:
1) Even cooling
2) No thermal shock
3) No need for fuel enrichment system.
_______ are used to provide cooling to the accessory end of the engine through the baffles.
Blast tubes
Extra components required for a liquid cooled engine:
1) Radiator
2) Hoses
3) Pump
4) Water
