5-5 Turboprop and Turboshaft Engines SQ

Describe the basic construction of a turboprop engine.

Gas generator with a reduction gearbox, torquemeter assembly, and a propeller assembly.
What component produces the majority of thrust in a turboprop?

Prop (90% of total thrust)
Why are reduction gears required in a turboprop?
- To keep the blade tips subsonic.
- Converts high RPM/low torque to low RPM/high torque.
How much thrust is produced from the exhaust gases of a turboprop?

10%
What are the advantages and disadvantages of a turboprop in comparison with a turbojet?
- Advantages:
- Low TSFC
- high thrust at low airspeed
- able to carry more load requiring short runways.
- Disadvantages:
- Heavier and more complicated
- limited to 450 knots.
How is a turboshaft constructed?

Gas generator with a free air/power turbine.
What is a free turbine?

A turbine that is not mechanically connected to the compressor and aft of the gas generator turbines.
Describe the sections of a turboshaft and its function.
- Gas generator:
- Provides exhaust gas to drive the free/power turbine.
- Free/power turbine:
- Connected to the main transmission, it converts the heat energy to mechanical energy to drive the rotors.
What percentage of a turboshaft's thrust comes from the exhaust?

Negligible

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dundane

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5-5 Turboprop and Turboshaft Engines SQ

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Updated

2016-06-16T14:45:31Z

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