Engine, Exhaust And Reverser Systems

Question 1

How does a leak appear in an engine exhaust system?

Answer 1

It normally looks like a gray or black feather shaped streak, coming from a crack or from a location where components are not in perfect alignment

Question 2

How can you check a reciprocating engine exhaust system for leaks?

Answer 2

Pressurize the exhaust system with the discharge from a vacuum cleaner and wipe a soap solution joints, and suspect areas a will cause bubble to form

Question 3

How do the components in the exhaust system of a turbocharged engine allow for expansion and contraction due to heat and at the same time prevent leakage

Answer 3

Bellows and ball joints prevent leakage while allowing contraction and expansion

Question 4

Should a turbocharged engine be started with the waste gate open or closed

Answer 4

Open so as much exhaust as possible bypass the turbine

Question 5

What is the primary function of a reciprocating engine exhaust system?

Answer 5

Its main function is to dispose of the gases with complete safety to the airframe and the occupants of the aircraft. The exhaust system can perform many useful functions, but it’s first duty is to provide protection against the potential destructive action of the exhaust gases.

Question 6

What is a short stack exhaust system?

Answer 6

The short stack exhaust system utilizes open exhaust tubes with no mufflers. The short stack system is generally used on non-supercharged engines and low powered engines where the noise level is not too objectionable. 

Question 7

Why are thrust reversers not normally used when the airplane is moving below approximately 60 knots

Answer 7

There is a danger of recirculating, the exhaust gases, and of the engine ingestion foreign objects stirred up by the high velocity gases

Question 8

What is a mechanical blockage thrust reverser?

Answer 8

A thrust reverser that slides a pair of scoop shaped doors aft and opens them so they block the rear flow of gases and deflect the gases forward

Question 9

How does a cascade type thrust reverser operate

Answer 9

A portion of the fan cowl moves rear and a series of blocker doors deflect the fan discharge air through cascades that direct the discharge forward at the same time blocker doors shut off the flow of gases from the core engine and deflect it through cascades directed it forward