King Air C90GTi, Pilot Training Manual

Page: 152 / 557

During nor mal operation, fuel is injected
into the combustion chamber liner through
14 simplex nozzles, which are supplied by
a dual manifold consisting of primar y and
s e c o n d a r y t r a n s f e r t u b e s a n d a d a p t e r s .
During star ting, the fuel/air mixture is ig-
nited by two spark igniters which protr ude
into the liner. After star ting, the igniters
are turned off, since combustion is self-sus-
taining. The resultant gases expand from
the liner, reverse direction in the exit duct
zone, and pass through the compressor tur-
bine inlet guide vanes to the single-stage
c o m p r e s s o r t u r b i n e . T h e g u i d e va n e s e n -
sure that the expanding gases impinge on
the turbine blades at the cor rect angle, with
m i n i m u m l o s s o f e n e rg y. T h e ex p a n d i n g
gases are then directed forward to drive the
power turbine section. The single-stage power turbine, consisting of
an inlet guide vane and turbine, drives the pro-
peller shaft through a reduction gearbox.
The compressor and power turbines are lo-
cated in the approximate center of the en-
gine, with their respective shafts extending
in opposite directions. This feature simpli-
f ies the installation and inspection proce-
d u r e s . T h e e x h a u s t g a s f r o m t h e p owe r
turbine is directed through an annular ex-
haust plenum to atmosphere through twin
o p p o s e d e x h a u s t p o r t s p r ov i d e d i n t h e
exhaust duct.
KING AIR C90GTi/C90GTx PILOT TRAINING MANUAL
7-7
FOR TRAINING PURPOSES ONLY
7
POWERPLANT
Figure 7-8. Power and Compressor Sections