Chapter 6 - Engine Exhaust

Question 1

What is the purpose of the exhaust system?

Answer 1

To remove high temperature noxious gases

Question 2

Name two types of reciprocating engine exhaust systems?

Answer 2

The short stack and the collector systems

Question 3

What drawback in using collector-type exhaust systems is more than offset when used on turbocharged engines?

Answer 3

The loss of horsepower due to exhaust system back pressure

Question 4

What could result if the internal baffles or diffusers in a exhaust system fail?

Answer 4

The flow of the exhaust gasses could be restricted, resulting in a loss of engine power

Question 5

What type of exhaust system is used on turbocharged engines?

Answer 5

The collector system

Question 6

What kind of material is normally used to make the muffler shrouds found in the exhaust system?

Answer 6

Stainless steel

Question 7

How do you inspect the internal baffles and diffusers of an exhaust system?

Answer 7

By disassembling the exhaust system as necessary and visually inspecting the components

Question 8

Why is an exhaust system failure considered a severe hazard?

Answer 8

It can result in carbon monoxide poisoning, loss of engine power, or fire

Question 9

What could happen if lead, zinc, or galvanized marks are made on an exhaust system?

Answer 9

They cause a change in molecular structure, which could result in cracks when heated

Question 10

What happens if the heat exchanger leaks exhaust gasses into the induction system?

Answer 10

There is a loss of engine power

Question 11

What is an indication of an exhaust gas leak?

Answer 11

A flat gray or sooty black deposit in the area of the leak

Question 12

Where are the most common places to find cracks in an exhaust system?

Answer 12

At welded or clamped areas and at the flanges

Question 13

What is a common cause of turbocharger waste gate sticking?

Answer 13

Coke deposit or carbon buildup

Question 14

Why are turbocharged exhaust system leaks very damaging at high altitudes?

Answer 14

Pressure differential will cause the leak to escape with torch-like intensity

Question 15

What are exhaust system coke deposits?

Answer 15

Excessive carbon buildup

Question 16

What is the result of changing the exhaust nozzle area of a turbine engine?

Answer 16

The engine’s performance and exhaust gas temperature change

Question 17

Name the components of a typical turbine exhaust nozzle?

Answer 17

The tail cone, exhaust ducts and support struts

Question 18

What is the purpose of thrust reversers?

Answer 18

They help decelerate an aircraft after landing

Question 19

How does a noise suppressor found on older turbojet engines work?

Answer 19

It converts low frequency sound, which is audible over great distance, into high frequency sound, thus reducing the sound footprint

Question 20

What are two most commonly used types of thrust reversers?

Answer 20

The clamshell (or mechanically blocked) and the Cascade (or areodynamically blocked)

Question 21

How much thrust do the thrust reversers produce compared to the engine’s full forward thrust?

Answer 21

Substantially less

Question 22

What are the hazards of operating some thrust reverser at low ground speeds?

Answer 22

Ingestion of foreign objects stirred up by the exhaust gasses and re-ingestion of hot exhaust gasses