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14 Cards in this Set
- Front
- Back
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What effect does excessive heat have on reciprocating engines? |
It shortens the life of the engine parts, changes the behavior of combustion, and impairs lubrication. |
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What is the purpose of cooling fins? |
They provide a larger cooling surface area for removing heat from cylinder heads of aircooled reciprocating engines. Airflow around the cooling fins transfers the heat from the cylinder heads to air. |
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What are the reasons for using engine cowlings, baffles and cowl air seals? |
The cowling performs two main functions: it streamlines the engine area to reduce drag and is used together with the baffies and cowl air seals to direct airflow over the cylinder for cooling. |
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What is the purpose of cowl flaps and how are they operated? |
They are used to control the amount of airflow through the cowling. They are either mechanically, electrically or hydraulically operated. |
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Where should cowl flaps be positioned for ground operations? |
Fully open. |
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What type of power is used to operate cowl flaps? |
Manual, hydraulic, or electrical. |
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What should be done when cooling fin damage is discovered? |
Depending on the scope of damage, some cooling fins may be repaired subject to the manufncturer's overhaul and repair limitations. If an excessive amount of tho cooling fin is broken off, the cylinder should be replaced. |
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Why is cowl flap adjustment important? |
The movement must be within tolerances to keep cylinder head temperatures within allowable limits. |
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How doos an augmenter cooling system work? |
An outer tube placed over the exiting exhaust gas creates a venturi effect that draws more airflow over the engine, thus providing additional cooling. |
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How are turbine engines cooled? |
Thy are cooled by air passing through the engine. About 75% of the air passing through the engine is used for cooling which leaves only about 25% for combustion. This air is used to coolthe combustion chamber and turbine. |
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In a turbine engine, where does bleed air come from that is used to cool bearings and other parts? |
The engine comprossor. |
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What is the relationship between turbine engine upper temperature limits and power produced? |
The higher the combustion temperatures that an engine can withstand without damage, the more power it is capable of withstanding. |
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Whatt is the approximate percentage of air passing through a turbíne engine that is used for cooling rather than combustion? |
Approximately 75% |
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What can be done to effectively allow higher gas temperatures in the turbine of some engines? |
Compressor bleed air ducted through hollow sections in the turbine inlet guide vanes and first stage rotor blades can lower temperature enough to prevent heat damage. |
