week 10 (Start Systems) Flashcards
2 types of start system
Electric and pneumatic
During normal Turbine Engine running, what drives (rotates) the AGB??
HIGH PRESSURE ROTOR
When the starter on AGB is engaged, what engine part will rotate first?
ACCESSORY GEARBOX
when the starter on AGB is engaged to start, what else (besides the AGB) will the starter motor Rotate?
HIGH PRESSURE ROTOR
What kind of starter do you find on modern small gas turbine engines?
Starter-Generator
What is the function of a Starter-Generator
When they are not being used to start the engine, they are being driven by the engine to produce electricity for aircraft system use
PURPOSE of Turbine EngineAIR Starting Systems
provides the initial rotor rotationto start the turbineengine.
3 TYPICAL SOURCES FOR STARTER PNEUMATIC AIR PRESSURE
APU (Auxiliary Power Unit)
GPU(Ground Power Unit)
Other Engine’s Pneumatic system
a low pressure, axial flowair motor that has a very high power to weight ratio.
Pneumatic Starter
What other component “drives” the AGB?
The AGB’s “Engine Hand-Turn Access”.Often referred to as the “maintenance hand-crank”
Pneumatic starters will incorporate a ___ ____ on their output shafts which will break at a predetermined gear train induced torque force to prevent damage to the engine.
Shear Point
The STARTER drive shaft always ____ with the engine’s AGB.
Rotates
what is the purpose of having choked (Convergent) nozzles before the turbine?
to speed up the airflow so that it impinges greater kinetic energy on the turbine wheel.
Pneumatic Starter Valve is _____ Controlled and ____ Operated
Electrically Controlled and Pneumatically Operated
In absence of air pressure Start Valve will spring load to?
Closed position
Typically most pneumatic valves have an arrow engraved on the body to indicate?
Correct Airflow
What ATA chapter is Starting?
ATA Chapter 80
This starter may be operated using conventional low pressure air from an APU, ground cart or running engine
High – Low Pressure pneumatic starter
This starter uses gas that is produced by the rapid burning of an explosive charge, the gases then impinge on the starter’s turbine.
Cartridge Pneumatic Starter
To bring an engine and its compressor/turbine up to idle speed requires a combined effort between ?
the starter and the turbine that drives the compressor.
If the engine fails to accelerate during a start, this is known as?
Hung Start
If the starter were to be disengaged following light-off, a ‘__ ___’ would be the result, causing significant damage to the engine.
Hot Start
What would happen if you supply more fuel to the engine in a hung start?
Over-temp
Engines that use a FADEC / EEC system to manage powerplant operations will most likely use the ____ to start the engines.
Computer
