King Air C90GTi, Руководство по подготовке пилотов

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ITT AND TORQUEMETERS
Power management is relatively simple, with
two primar y operating limitations. The en-
gines are temperature and torque limited.
During operation requiring maximum en-
gine perfor mance, engine torque and ITT
operating parameters are affected by ambi-
ent temperature and altitude: at cold tem-
perature or low altitude, torque limits power;
at hot temperature or high altitude, ITT lim-
its power. Whichever limit is reached f irst,
deter mines the power available. These in-
d i c a t i o n s c a n b e s e e n o n t h e E n g i n e
Indicating System (EIS) (Figure 7-21).
ITT GAGE
The ITT gage (Figure 7-21), monitors the in-
terstage turbine temperature at station 5. ITT
is a prime limiting indicator of the amount of
power available from the engine under vary-
ing ambient temperature and altitude condi-
tions. The normal operating range, is 400 to
805°C. These limits also apply to maximum
continuous power. The maximum star ting
temperature of 1,090°C is indicated by the
secondary red line on the instrument. This
star ting limit of 1,090°C is limited to two
seconds. The engines will be damaged if lim-
iting temperatures indicated on the ITT gage
are exceeded.
TORQUEMETER
The torquemeter, (Figure 7-21), which is in-
dicated in ft-lb, constantly measures rota-
tional force applied to the propeller shaft .
The maximum permissible sustained torque
is 1,520 ft-lb, the red radial on the instr u-
ment. A transient torque limit of 1,626 ft-lb
is time-limited to twenty seconds. Cr uise
torques vary with altitude and temperature.
Torque is measured by a hydromechanical
t o r q u e m e t e r i n t h e f i r s t s t a g e o f t h e r e -
duction gearcase. Rotational force on the
f irst-stage ring gear allows oil pressure to
c h a n g e i n t h e t o rq u e m e t e r c h a m b e r. T h e
difference between the torquemeter cham-
b e r p r e s s u r e a n d r e d u c t i o n g e a r i n t e r n a l
p r e s s u r e a c c u r a t e ly i n d i c a t e s t h e t o rq u e
being produced at the propeller shaft. The
torque transmitter measures this torque and
sends a signal to the instr ument on the in-
str ument panel.
GAS GENERATOR
TACHOMETER (N
1
)
The N
1
gas generator tachometer (Figure 7-
21), measures the rotational speed of the
compressor shaft, in percent of r pm, based
on 37,500 r pm at 100%.
KING AIR C90GTi/C90GTx PILOT TRAINING MANUAL
7-21
FOR TRAINING PURPOSES ONLY
7
POWERPLANT
Figure 7-21. Engine Indicating System