Table of Contents
Advertisement
SECTION 7
CESSNA
AIRPLANE AND SYSTEMS DESCRIPTION
MODEL 208B 867 SHP
GARMIN G1000
INTERSTAGE
TURBINE
TEMPERATURE
SENSING
SYSTEM
The interturbine temperature sensing system is designed to provide the
operator with an accurate indication of engine operating temperatures
taken between the compressor and power turbines. The system
consists of twin leads, two bus bars, and eight individual
chromel-alumel thermocouple probes connected in parallel. Each
probe protrudes through a threaded boss on the power turbine stator
housing into an area adjacent to the leading edge of the power turbine
vanes. The probe is secured to the boss by means of a floating,
threaded fitting which is part of the thermocouple probe assembly.
Shielded leads connect each bus bar assembly to a terminal block
which provides a connecting point for external leads to the ITT indicator
in the airplane cabin.
PROPELLER GOVERNOR
The propeller governor is located in the 12 o'clock position on the front
case of the reduction gearbox. Under normal conditions, the governor
acts as a constant speed unit, maintaining the propeller speed selected
by the pilot by varying the propeller blade pitch to match the load to the
engine torque. The propeller governor also has a power turbine
governor section built into the unit. Its function is to protect the engine
against a possible power turbine overspeed in the event of a propeller
governor failure. If such an overspeed should occur, a governing orifice
in the propeller governor is opened by flyweight action to bleed off
compressor discharge pressure through the governor and computing
section of the fuel control unit. When this occurs, compressor discharge
pressure, acting on the fuel control unit governor bellows, decreases
and moves the metering valve in a closing direction, thus reducing fuel
flow to the flow divider.
7-70
208BPHCUS-00
U.S.
Advertisement
Chapters
Table of Contents
