Flashcards on Jet Engine and APU Systems

Jet Engine and APU Systems: A Comprehensive Guide for Students

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What are two methods of relieving thermal stress on a turbine disk?

Bleed air and grooves that allow cooling air onto the face of the disk.

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Aircraft Gas Turbine Engines

23 cards

Card 1

Question: What are two methods of relieving thermal stress on a turbine disk?

Answer: Bleed air and grooves that allow cooling air onto the face of the disk.

Card 2

Question: What may indicate a turbojet engine is out of trim during takeoff?

Answer: A high exhaust gas temperature (EGT) at the target engine pressure ratio (EPR).

Card 3

Question: What prevents burning of the combustion chamber liners?

Answer: Cooling air along the inside of the liner, often directed by louvers along the axial length of the liners.

Card 4

Question: Name one advantage of a turbofan over a turbojet.

Answer: Provides additional thrust without increasing fuel flow (more thrust same fuel flow).

Card 5

Question: What does trimming a turbojet engine mean?

Answer: Adjusting the fuel control to obtain the correct idling and maximum-thrust RPM.

Card 6

Question: Where are most APUs located in modern jet aircraft?

Answer: In the tail cone of the fuselage.

Card 7

Question: What is the primary function of an APU?

Answer: To provide electric power and compressed air when the main engines are not operating.

Card 8

Question: What are two sources of compressed air from an APU?

Answer: Bleed air from the APU turbine compressor, or compressed air from a load compressor driven by a free turbine.

Card 9

Question: How is most troubleshooting done for a modern APU?

Answer: By reading the fault codes generated by the FADEC.

Card 10

Question: What type of engine is an APU?

Answer: A turboshaft engine.