15.13 Start & Ignition Flashcards
(35 cards)
What are the 3 types of engine starters?
Cartridge starter, Air starter and Electric starter
What is the most common starter used on jet engines?
Air starter
What is the minimum psi required for a complete start?
30psi
How are GTEs started?
By rotating the HP compressor
When must the starter stay on until?
Until engine reaches self sustaining speed
What must you ensure before the fuel/air mixture is ignited?
Enough airflow is going through the engine to support combustion
What is a cartridge starter? Driven by?
A small impulse type turbine driven by high velocity gases from a burning cartridge
What 3 places can an air starter get its air supply from?
APU, GCU or the other engine (if running)
How does an air starter work?
- bleed valve and start valve open
- air turns starter turbine
- starter turbine turns gear train to move inboard clutch to outboard clutch
- when engaged, output shaft drives turbine
What do you do if an air starter valve fails to open?
Use manual valve override to allow engine start
What are 2 types of electric starting systems?
Direct cranking electrical system and starter generator system
Which electric starting system is most used?
Starter generator system
What type of electric starting system is used on APUs?
Direct cranking electrical system
What is the difference between a starter generator system and a direct cranking electrical system?
A starter generator system can be turned into a generator once self sustaining speed is reached
What source of voltage and current is required for starting a starter generator system?
24volts and 1500amps
What are the 4 field windings used on starter generators?
C (series) field, shunt field, compensating field and commutating winding
What type of field winding is used only for starting in a starter generator system?
C (series) field
What is the function of an undercurrent controller on a starter generator system?
Assures positive action of the starter and keeps it operating until self sustaining speed is reached
What 3 relays close when the battery and start switch turn ON in a starter generator system?
Motor relay, ignition relay and battery cut out relay
What switch is used if engine can’t reach self sustaining speed?
Stop switch
When does the undercurrent relay open? Why?
When current is less than 200amps. To switch to relay coils so engine can be self sustaining
When is continuous ignition used?
Possibility of engine flame out
What 3 parameters of flight is continuous ignition used on?
Take off, landing and emergencies
Do GTEs need special ignition at high altitudes? Why?
Yes. Require high heat intensity spark due to the low temperatures
