Powerplant Flashcards
Describe the Propeller
- Dowty R408
- six bladed, constant speed, variable pitch, fully feathering
Describe the engines.
- PW150A
- NTOP 4580 shp / MTOP 5071shp
- Low Pressure Axial and High Pressure Centrifugal compressor stages each spin independent shafts and turbines.
- The Power Turbine has two stages, is positioned behind the compressor and associated turbine, and spins the propeller by a third shaft, via a reduction gearbox.
- Control achieved by Power and Condition Levers, Engine Control Panel, FADEC, and a PEC.
Describe the Engine Accessory Gear Box
- Located on top of the turbo-machinery
- Driven by the High Pressure Compressor Rotor
- FMU
- Oil Pump
- DC Starter-Gen
- PMU
What engines does the Q400 have?
Pratt and Whitney (PW) 150A
NTOP shp? MTOP shp?
4,580 and 5071 shp
What propellers does the Q400 have?
Dowty R408
How does the pilot control the powerplant?
Powerplant control is acheived through the Power and Condition Levers, and the Engine Control Panel.
- In the forward range, The Power Levers Control the engine through a FADEC, and in the Beta Range, they also control the Propeller Blade Angle.
- The Condition Levers, through a PEC Unit, control Propeller RPM, select engine power ratings, manually feather the prop, and provide fuel on/off control for start and shutdown.
Describe airflow through the engine.
Air first encounters an axial low pressure compressor, followed by a centrifugal high pressure compressor. It then enters internal ducts, is directed to the combustion chamber, fuel is introduced, and boom. The high energy air then inpacts the high and low pressure compressor tubines. The Engine Accesory Gearbox is connected to the High Pressure Compressor Shaft. The air then flows through a two stage, single unit Power Turbine that turns the propeller through a reduction gearbox.
What does the Engine Accessory Gearbox opperate?
- Fuel Metering Unit
- Oil Pump
- DC Starter - Generator
- Permanent Magnet Alternator (PMU)
What components are mounted to and driven by the Propeller Reduction Gearbox.
- Hydraulic Pump (Main EDP)
- AC Gen
- Propeller Control Unit (PCU)
- Propeller Overspeed Governor (POG)
Describe the FMU
The FMU is an electro-mechanical devise mounted to the Engine Accessory Gearbox and meters fuel in response to Power and Condition Lever Position, Engine Rating Selection, and FADEC commands. It incorperates a Low Pressure Pump, heater/filter element, High Pressure Pump, and a metering valve.
Describe the FADEC system.
The Full Authority Digital Control (FADEC) is mounted on the Left Side of the Engine and controls fuel flow based on inputs from the airplane, engine, and propeller control system. Its functions are FUEL SCHEDULING and
- the control of various engine bleed valves to prevent surges and stalls
- to prevent engine overspeed (108% NH)
- to control the start and shutdown sequence
- to provide voltage to the PEC
- and to detect powerplant faults.
FADEC is powered by the PMA, above 20% NH, and the Essential DC Bus.
Describe the Propeller.
- Dowry Aerospace R408
- Six-bladed, manufactured with carbon- and glass-fiber reinforced plastic and lightweight foam filler
- Fully Feathering
- Reversible
- Counter-weighted
- Constant Speed
- Electric Heater Elements are bonded to the inner leading edge of each blade.
Of what does the Propeller System consist?
- PEC
- PCU- Pitch Control Unit
- POG
- Auxiliary Feathering Pump
- Automatic Propeller Synchrophase System
Describe the PEC.
The PEC is a dual channel microprocessor controller which uses inputs from the airplane, prop sensors, and the engine control system to control prop pitch and speed. It is soft-mounted aft of the reduction gearbox. Safety functions include Autofeather and Automatic Underspeed Control, and UPTRIM command to the other FADEC in case of engine failure.
