Engines Flashcards
The engine is divided into four modules:
cold section, hot section, power turbine section, and accessory section
Cold section
(a) Cleans
(b) Directs
(c) Then compress the air
(Suck/Squeeze)
Hot Section
mixing of fuel and air for combustion
Power Turbine section
Extracts energy from hot expanding gases and converts it to mechanical energy (shaft horsepower)
Accessory Section
provides for engine-driven accessories and engine starting.
accessory section module is driven by the radial driveshaft
ATS
- Rotates the compressor until self-sustaining (52% Ng)
- PRSOV regulates air from IPAS to ATS (Pressure regulating shutoff valve)
Engine Fuel Boost Pump
Engine-driven, non-self-priming suction and pressure pump
Suction ensures that fuel supply system is under negative pressure, reducing danger of fire in case of fuel system damage
Common Hydromechanical Unit (CHMU)
The CHMU provides metered fuel, fuel pumping, flow computation, pressurization, fuel shutoff
Ng overspeed protection (mechanical) at 110±2% Ng, results in flameout
ODV
In normal operation it Provides fuel to the 12 fuel injectors
Np overspeed protection (electrical) at 118.1±1% Np from EDECU (activates the overspeed solenoid valve on the ODV, shutting off fuel from the ODV to the injectors and re-routing it to the CHMU, causing flame out)
fuel injector draining upon shutdown
Ignition System
Each engine has an ignition exciter unit with two igniter plugs. The exciter unit re-ceives power from its engine alternator.
3 windings of the alternator
(1) The engine-driven alternator supplies 115 Vac for the engine electrical system.
three windings providing power for:
(a) Engine ignition
(b) Ng speed indication
(c) EDECU
2 overspeed protections
NG mechanical (CHMU 110 +/- 3)
NP digital (ODV 118.1 +/- 3)
Enhanced Digital Electronic Control Unit (EDECU)
The EDECU controls the engine and transmits information to the crew.
MTRA
OVERSPEED PROTECTION
Transient droop improvement
TGT LIMITING
TQ MATCHING
HOT START PREVENTION
FAULT CODES
Maximum Torque Rate Attenuator (MTRA)
Reduces the risk of exceeding DE torque limits during uncompensated maneuvers.
These are any maneuvers where pedal or cyclic inputs are made but no collective control input occurs.
Engine Chip Detector
The chip detector attracts metal particles that may be present in the Engine Oil System.
The chip detector consists of an outer shell with internal magnet, electrical connector, removable screen and has no fuzz suppression (burning-off) capabilities.
Yellow wire
Yellow harness supplies power and control system trim signals
Blue Wires
overspeed and torque signals
Green Wires
Green harness conducts engine condition monitoring (crewstation instrumentation)
The engine alternator has three windings providing power for:
(a) Engine ignition
(b) Ng speed indication
(c) EDECU
Engine Chop Control
The guarded Chop (CHOP) button on the flight grip of the collective provides a means to immediately and simultaneously reduce both engines electronically to idle.
After pressing you must reduce power levers to idle or engines will go back to fly due to generators.
PAS
Power available spindle: The PAS is mechanically connected to the pilot’s power levers
converts push-pull motion at the POWER levers to rotary motion at the CHMU input shaft.
LDS
Converts push-pull motion at the collective lever to rotary motion at the CHMU input shaft.
Load demand spindle is connected to a bellcrank attached to the collective servo.
Black cable
Ignition
Air Turbine Starter:
- Rotates the compressor until self-sustaining (52% Ng)
- PRSOV regulates air from IPAS to ATS
