Exhaust gas temperature harness. The chromel-alumel, thermoelectric measuring
system is independent of all other engine electrical wiring. The engine components are ten
thermocouple probes to the shielded harness. The aircraft wiring, spool resistor, and indicator complete
the system. The ten thermocouple probes protrude into the gas flow of the engine at station number 7.
The probes react to variations in power turbine entry temperature by developing a proportional
electromotive force across the chromel-alumel junction. This electromotive force results in meter
deflection of the cockpit indicator calibrated to read temperature in degrees centigrade.
The T55 series gas turbine engine is used to power the CH-47 Chinook helicopter. The CH-
47A and B are equipped with the T55-L-7 series engines, and the CH-47C is equipped with the T55-L-
7C or T55-L-l1. These are all basically the same except for shaft horsepower ratings and internal details.
The fuel system includes starting and main fuel components. The fuel control is a hydromechanical
device that automatically meters the proper amount of fuel under varying atmospheric conditions and
power requirements. The engine has its own lubrication system with the oil tank contained within the
inlet housing. It is equipped with an interstage bleed air system to facilitate acceleration and avoid
compressor stalls. The anti-icing system prevents icing by ducting hot air from the diffuser section to
the engine inlet. The engine has a starting and ignition system, and its performance is monitored by
instruments on the cockpit instrument panel.