T-45C TS, ADV & IUT ENG-27/ENG-28
Engineering Review
Sg 2, fr 85
(4) When engine start switch is momentarily
Dump Valve
set to START, the GTS accelerates, the
start valve is opened, the dump valve
Sg 2, fr 86
closes and the GTS supplies compressed
Engine Start Switch
air to the engine ATS
Sg 2, fr 87
(5) Shuts down after engine reaches 45% rpm
GTS Air to ATS
b.
ATS: air turbine starter output shaft drives
Sg 2, fr 88
Air Starter Motor
c.
Start control unit
Sg 2, fr 89
Start Control Unit
(1) Sequences start cycle by monitoring
speeds of GTS, air turbine starter, and
engine
(2) Electrically off-loads DC generator and
HYD 2 system until engine N2 rpm reaches
45% to ease strain on ATS
(3) Shuts down GTS and engine ignition when
engine N2 rpm reaches 45%
2.
Engine starting component function
Sg 2, fr 90
External Bleed Air
a.
Bleed air valve: relieves pressure from N2
compressor to ease engine starting and
prevent compressor stalls
b.
Igniters: two high-energy 12 joule igniter plugs
fitted to engine combustion chamber
(1) Powered by 28 VDC essential services bus,
produce approximately 80 sparks per
minute
(2) Controlled by IGNITION switch and starter
control unit during normal start
(3) Controlled by GTS start button during air
start--igniters energized while GTS start
button is pressed (+30 seconds when
airborne)
(9-98) Original
Page 27-29
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