ENGINE COOLING SYSTEMS Flashcards
What is the most common means of regulating the cooling air flow through a radial engine?
By the use of cowl flaps.
What is the purpose of the fins on engine cylinders?
To increase the effective size of the cylinder for cooling
What other engine characteristics are designed to aid in engine cooling besides cooling fins?
The engine cowling and fables are designed to force air over the cylinder cooling fins.
Why is the ―open and close‖ adjustment during installation of cowl flaps important?
For each engine installation, the cowl flaps are set for tolerance that will permit them to open
and close the correct amount to keep the cylinder head temperature within allowable limits.
What should be done to cylinders when too much of the cooling fin area is broken off?
The cylinder should be replaced because it cannot cool properly and a hotspot will develop
When should cowl flaps be kept in the fully open position?
Normally during all ground operations
What publication should be referred to before reprofiling cylinder cooling fins?
The manufacturer’s service or overhaul manual should be used to obtain the allowable limits.
What power sources are used to operate the cowl flaps?
Cowl flaps may be operated by electrical power, hydraulic power, or manually
What is the purpose of blast tubes that are built into the baffles on a reciprocating engine?
To direct jets of cooling air onto the rear spark plug elbows of each cylinder to prevent
overheating of the ignition leads
What are the main reasons that excessive heat in a reciprocating engine is undesirable?
Excessive heat shortens the life of the engine parts, impairs lubrication, and affects
combustion.
Describe the augmentor system
Augmentors consist of two pairs of tubes running from the engine compartment to the rear of
the nacelle. The exhaust gas collector feeds exhaust gases into the inner augmentor tubes. Air
that has passed over the engine is fed into the outer tubes where it is heated by the exhaust
tubes and then expelled to mix with the exhaust gases. The heating of the air causes it to form a
high temperature, low pressure, jet-like exhaust which draws additional cooling air over the
engine. The heated air is sometimes used for cabin heating, defrosting, and anti-icing.
What is the source of air that is directed to engine bearings for cooling?
It is to bleed air from the compressor section of the engine.
What is the purpose of installation on the exhaust duct of a turbine engine?
What is the purpose of installation on the exhaust duct of a turbine engine?
What types of materials are used to make insulation blankets for turbine engines?
They are made of stainless steel, with layers of aluminum foil, fiberglass, and silver foil.
What areas of a turbine engine are cooled by the secondary air passing through the engine?
The combustion chambers and the turbines
