Week 5

Question 1

What is a compressor stall?

Answer 1

Air not moving at desired rate through the compressor

Question 2

What is a compressor surge?

Answer 2

Stall of entire compressor

Question 3

_______ __________ work more efficiently at lower RPM”s than centrifugal compressors

Answer 3

Axial Compressors

Question 4

When can the centrifugal compressor handle all the air that the axial compressor is producing in a C+A compressor engine configuration?

Answer 4

At rated RPM

Question 5

Amount of air entering the centrifugal compressor has to be __________

Answer 5

Regulated

Question 6

What are the conditions required for a compressor stall?

Answer 6

High compressor RPM and Low inlet air density

Question 7

What are some symptoms of compressor stall?

Answer 7

• Loud Popping sounds
• Sudden shudder/movement of engine within the mount
• Possible flames shooting out the exhaust
• Rise in ITT or EGT
• Fluctuations in compressor RPM

Question 8

How do you control airflow going into the compressor?

Answer 8

Variable Inlet Guide Vanes, Variable Stator Vanes, Variable Bleed Valves

Question 9

When are compressors most likely to stall?

Answer 9

Startup and Accel/Decel conditions

Question 10

How do compressor anti-stall systems prevent compressor stall?

Answer 10

Match Axial Airflow Velocity to the Compressor RPM

Question 11

How are Variable Stator Vanes used?

Answer 11

Automatically regulated in pitch angle by means of the FCU

Question 12

In the case of the Variable stator Vanes, what is used as hydraulic fluid?

Answer 12

Fuel