Chapter 2: 2.1 & 2.2 Engines & Rotors Flashcards
-Name the parts of the engine
Inlet, Compressor, Combustion, Turbine, Exhaust
“Suck, Squeeze, Bang, Power, Blow”
Inlet Section Description
-Inlet Cowling: air first passes. Heated by inlet anti-ice
-Swirl Frame / Swirl Vane: Imparts rotation for FOD removal. Heated by Anti-Ice
-Inertial Particle Separator: collects FOD and removes it from the engine
-Deswirl Frame: removes rotation and passes clean, smooth air to the compressor
Compressor components
5 stage, single axial centrifugal rotor/stator assembly
Combustion components
12 injectors, 2 igniters, flow through annular combustion chamber
Describe the Turbines
Ng
Np
Where is TGT sensed
-Ng Turbine: gas-generator. Drives the compressor and AGB
-Np Turbine: connects to the input module.
-TGT is sensed between the Ng and Np turbines
Exhaust percentages
70% for cooling, 30% for pressurization, T2 and P3
AGB components
Front: Alternator and Engine Driven Fuel Boost Pump
Back: HMU, ODV, Engine Starters, IPS
PCL positions
PCL OFF: power available spindle is mechanically off
PCL IDLE: starter sequence is commenced. HMU controls the start sequence until self-sustaining combustion
PCL FLY: max power that could be supplied, if demanded (FAIL-HIGH)
PCL Lockout: manually control Np and Ng. TGT, Np governing, Ng governing and load sharing are deactivated but Np overspeed protection is retained.
Function of the Engine-Driven Fuel Boost Pump
(1) provide reliable suction feed to fuel tank/minimize vulnerability if damaged lines
(2) provide minimum pressure for HMU/high pressure pump
HMU Provides? (RANFAN)
Rapid engine transient response through collective compensation
Automatic Fuel Scheduling
Ng governing: receives inputs from T2, P3, Ng to adjust metering valve flow
Flameout and Compressor Stall protection via the variable geometry vanes and anti-ice start/bleed valve
Acceleration Limiting
Ng overspeed protection: 110+/- 2%
ODV Controls
Prevents coking by purging fuel overboard
Provides fuel to the 12 injectors
Traps fuel upstream so priming is NOT required
Returns fuel back to the HMU if Np overspeed is energized or if hot start preventer is activated
EDECU Functions 4N 3CHEF TASTED
4N
- Ng decay relight feature: if Ng drops below 62%, auto-ignition will attempt to re-ignite for 5 seconds
2 .Np governing: based on actual vs reference Np - Np Overspeed Protection: 120%, sends signal to ODV to divert fuel back to HMU and cause flameout
- Np Overspeed Test: re-references protection from 120% to 96%. When depressing A, system is testing B
EDECU Functions 4N 3CHEF TASTED
3C
- Manual Contingency Power: flipping the switch will increase the TGT limit to 891+/-10
- Auto Contingency Power: enabled in OEI conditions. Torque less than 50%, opposite engine will auto reset TGT from 866+/-10% to 891+/-10%
- Dual-Engine Auto Contingency Power: allows EDECU to limit at 891 +/- 10% but requires 1 of the following to occur:
a. Np drops below 96%
b. ≥3% droop between Np and reference Np
c. ≥5%/second Np droop rate with Np ≤ reference Np
EDECU Functions 4N 3CHEF TASTED
HEF
-Hot Start Prevention: TGT exceeds 900* C with Ng < 60% and Np < 50% and stops fuel flow by tripping ODV
-Engine Speed Trim: 96-101
-Fault Diagnostic System: EDECU Table
EDECU Functions 4N 3CHEF TASTED
TASTED
-TGT Limiting: actual vs reference. When approaching 878* C
-Auto Ignition System: after an overspeed and flameout, auto ignition closes the overspeed valve and turns on the igniters for 5 seconds. Will continue to cycle until Np is under control
Signals: EDECU faults codes
-Transient Droop Improvement based on collective position
-EDECU Lockout