M15.17 Turboshaft Engines Flashcards
What is a turboshaft engine?
A variant of a jet engine optimised to produce shaft power to drive machinery instead of producing thrust
What are common applications of turboshaft engines?
- Helicopters
- Auxiliary Power Units (APUs)
How is the output of a turboshaft engine measured?
In Shaft Horsepower (SHP) instead of thrust
What are the two major parts assemblies of a turboshaft engine?
- Gas generator
- Power section
What components make up the gas generator in a turboshaft engine?
- Compressor
- Combustion chambers with ignitors and fuel nozzles
- One or more stages of the turbine
What does the power section of a turboshaft engine consist of?
- Additional stages of turbines
- Gear reduction system
- Shaft output
What is the purpose of the gas generator in a turboshaft engine?
To create hot expanding gases to drive the power section
What is the primary function of a turboshaft engine?
To provide sustained high-power output
What is the role of the reduction gearbox in a turboshaft engine?
To reduce the engine output RPM before transmission to the main rotor gearbox
What is a free turbine in the context of turboshaft engines?
A turbine that rotates independently, often used in the design of turboshaft engines
What is the purpose of the drive system in turboshaft engines?
To transfer power produced within the engine to components it must drive
What is a typical example of a drive system in a turboshaft engine?
Pratt & Whitney Canada PT6 Twin PakTM
What is a universal joint’s function in a turboshaft engine’s drive system?
To ensure drive shaft alignment and absorb low amplitude oscillations
What must the drive shaft in a turboshaft engine’s coupling be provided with?
Flexibility for deflections caused by transmission movements
What type of control system is typically used in turboshaft engines?
FADEC-controlled engines
What does FADEC stand for?
Full Authority Digital Engine Control
What options are typically available on a control switch for a turboshaft engine?
- Off
- Idle
- Flight
What is the significance of the coupling in a turboshaft engine?
To provide a flexible joint that accommodates transmission movement without carrying tension or compression loads
What type of stresses does the drive shaft experience during operation?
Alternating fatigue stresses
What is the typical control mechanism for adjusting fuel flow in a turboshaft engine?
The fuel control receives a signal from the flight crew to adjust engine fuel flow based on power requirements
What is the main purpose of the reduction gearing in turboshaft engines?
To reduce the output drive speed for usable rotor speeds
What is a common feature of modern designs of turboshaft engine couplings?
They are fail-safe and show gradual deterioration
Fill in the blank: The Arriel 2C engine is widely used on a range of medium single and twin-engine __________.
helicopters
True or False: Turboshaft engines are exclusively used in aviation.
False
