Exhaust Systems

Question 1

What is the purpose of the exhaust system?

Answer 1

Capture the exhaust gases and direct it out of the engine.

Question 2

What is exhaust back pressure?

Answer 2

Opposes the flow of exhaust gases as they are forced out of the cylinders when the exhaust valve is open

Question 3

What are the different types of exhaust stacks?

Answer 3

Short stacks
Bayonet stacks

Question 4

What is a collector system?

Answer 4

Am exhaust system that collects gases from all cylinders and discharges them from one location

Question 5

What is a crossover system?

Answer 5

The left and right exhaust systems are connected together

Question 6

What are some uses of exhaust heat energy?

Answer 6

Cabin heat
Carb heat

Question 7

What are some purposes of a muffler?

Answer 7

Absorbs the sound
Directs the gases out of the tail pipe
Can provide provisions for carb and cabin heat

Question 8

What is the purpose of augmentor tubes?

Answer 8

Uses some of the velocity energy of the exhaust gases to increase the cooling airflow through the engine, decreases exhaust back pressure

Question 9

How does an augmentor tube work?

Answer 9

Its a convergent shape
creates low pressure
draws cooling air into the cowling and through cylinder fins
Reduces the exhaust back pressure

Question 10

What are two ways to recover some power?

Answer 10

Turbochargers
Power recovery turbines

Question 11

What material are exhaust systems normally made out of?

Answer 11

Stainless steel
Inconel

Question 12

Why are cracks common in exhaust systems?

Answer 12

Vibrations and sudden temperature changes

Question 13

Why are CO detectors required on aircraft?

Answer 13

CO could leak into the the cabin or flight deck

Question 14

What should not be used to mark on exhaust systems?

Answer 14

Pencils

Question 15

What should be done with exhaust systems prior to inspection?

Answer 15

Remove all heater muffs and shrouds

Question 16

Pure turbo jets work on _____ rather than ______?

Answer 16

Reaction
Aerodynamics

Question 17

What is the purpose of the exhaust on a turbine engine?

Answer 17

To straightening and accelerate the airflow

Question 18

What shape of the tail pipe on a subsonic aircraft?

Answer 18

Convergent duct

Question 19

What is the purpose of the exhaust cone?

Answer 19

To straighten and collect the exhaust gases into a solid high velocity exhaust jet

Question 20

What is a choked exhaust nozzle?

Answer 20

If the convergent exhaust nozzle increases the velocity of the exhaust gases to Mach 1 they cannot be accelerated any further.

Question 21

Purpose of a CD exhaust nozzle?

Answer 21

To increase the thrust produced by an engine by accelerating the exhaust gases to a high supersonic speed.

Question 22

How do noise suppressors work?

Answer 22

They increase the frequency which reduces the distance the noise travels

Question 23

Why do turbofan engines not normally require noise suppressors?

Answer 23

Extract more energy to drive the fan from the exhaust gases compared to turbojets
Exhaust velocities are lower
By-pass air provides a seal around the high velocity gases to reduce the sound

Question 24

How do propeller planes slow down?

Answer 24

Reverse pitch

Question 25

How does a thrust reverser work?

Answer 25

Deflects the exhaust and/or fan air in the forward direction

Question 26

How can a TR be operated?

Answer 26

Hydraulic power
Pneumatic power
Electrical power

Question 27

What are the two kinds of TR?

Answer 27

Clamshell doors
Cascade vanes

Question 28

What are clamshell TR also referred to as?

Answer 28

Mechanical blockage reverser, mechanical doors block the exhaust gas deflecting it in the forward direction

Question 29

When performing maintenance on a TR what must be done?

Answer 29

Must be mechanically locked out from deploying