Turbine Engine Indicating and Instumentation

Question 1

What are the instruments (gauges) which indicate the thrust output of a turbine engine? 3

Answer 1

1. Engine Pressure Ratio (EPR) gauge - turbojet/turbofan
2. Fan speed (N1) gauge - turbojet/turbofan
3. Torque gauge - turboprop.

Question 2

What is the primary engine power gauge in a turboprop?

Answer 2

The torque gauge

Question 3

What is the function of the torque gauge (torquemeter) in a turboprop engined aircraft?

Answer 3

To measure the power shaft output.

Question 4

Does a turbofan engine have a torque gauge?

Answer 4

No

Question 5

What is the Engine Pressure Ratio (EPR)?

Answer 5

The ratio of exhaust gas pressure (P7) to compressor intake/inlet pressure (P1 or P2).

Question 6

In a multi-spool engine, what does N1 refer to?

Answer 6

The rpm of the low pressure compressor and /or fan.

Question 7

What is N1 on a turbofan?

Answer 7

Fan rpm.

Question 8

How is a turbine engine’s rpm typically measured?

Answer 8

A generator, driven off the accessory gearbox, which drives an independent three phase AC electrical system and a synchronous motor.

Question 9

What is the basic operating principle of an Exhaust Gas Temperature (EGT) indicating system?

Answer 9

A set of thermocouples arranged in parallel.

Question 10

What is ITT?

Answer 10

Interstage turbine temperature.

Question 11

What is EGT?

Answer 11

Exhaust gas temperature.