producer or gas generator tachometers, turbine and rotor tachometers,
and N1 and N2 tachometers are some of the tachometer systems used.
The system may consist of dual indicators, registering rpm for
multiengine aircraft, registering engine and rotor rpm for rotary
wing aircraft, or engine and propeller rpm for fixedwing aircraft.
b. Torquemeter indicating system. Sometimes called a torque
pressure indicating system, the typical torquemeter indicating system
is a pressure indicator for continuous readings of engine output
the engine inlet section.
c. Engine oil pressure indicating system. A typical engine
oil pressure indicating system gives continuous readings of engine
oil pump pressure in psi to the indicator, by means of an electrical
transmitter mounted on the engine inlet section. The transmitter is
connected to the 28volt ac electrical system, and by a hose to a
pressure tap on the engine oil filter housing.
d. Engine oil temperature indicating system. In a typical
engine oil temperature indicating system, the indicator is
electrically connected to the 28volt dc system. An electrical
resistance type thermobulb installed in the engine oil pump housing
measures temperatures of the oil entering that unit. The temperature
readings are transmitted to the indicator in degrees centigrade.
e. Exhaust gas temperature indicating system. The indicator
in a typical exhaust gas temperature indicating system operates on
electrical potential from an engine thermocouple harness with probes
mounted in the aft section of the engine exhaust diffuser. The
thermocouple is a device which converts heat into electricity. The
exhaust gas temperature indicator (thermocouple thermometer
indicator) is actually a sensitive millivoltmeter, calibrated in
degrees centigrade. Its D'Arsonval movement is activated by an
electrical force generated by its related thermocouple. The
indicator circuit is entirely independent of any other electrical
power source, and includes a coil resistor which provides a means of
f. Fuel pressure indicating system. A typical fuel pressure
indicating system gives continuous readings of fuel pressure(psi) in
the main fuel supply line from the boost pumps in the tanks,