Module 15.17 Turboshaft engines Flashcards
What is the purpose of a turboshaft engine?
Produce shaft power to drive machinery instead of producing thrust
Where are turboshaft engines most common?
Helicopters and APU’s
How is the turboshaft engines out measured?
Shaft horsepower instead of thrust
A turboshaft engine can be made up of what two major part assemblies?
- The gas generator
- Power section
What does the power section consist of?
- Additional turbine stages
- Gear reduction system
- Shaft output
What does the power section consist of in the Ariel 2C engine?
Reduction and main gearbox
Turboshaft engine power shafts can be connected to what depending on their function?
Heli - Drive system
APU - Electrical generator
To prevent one engine driving the other in a twin engine system with a common gearbox, what is fitted?
Freewheel unit which automatically disconnects the slower engine
What form is the freewheel unit in?
A sprag clutch
What is the purpose of the universal joint?
To ensure alignment between the engine and main rotor gearbox, absorbs low amplitude oscillations produced in flight and opposes the engines torque reaction
The drive shaft must not carry what?
Tension or compression loads
What is the flexibility provided by in the shaft?
Coupling made up of CRES discs bolted to the shafts
How are the couplings failsafe?
Provide visual and gradual deterioration
What are the FADEC switch control positions?
Off, idle and flight
