Engine Exhaust and Reverser Systems Flashcards
How does a leak appear in an engine exhaust system?
It normally looks like a gray or black streak coming from a crack or from a location where components are not in perfect alignment
How can you check a reciprocating engine exhaust system for leaks?
Pressurize the exhaust system and wipe a soap solution over all joints and suspect areas. A leak will cause bubbles to form
Pressurize the exhaust system with the discharge from a vacuum cleaner and wipe a soap soliton over all joints and suspect areas. A leak will cause bubbles to form
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?
Bellows and ball joints prevent leakage while allowing contraction and expansion
Should a turbocharged engine be started with the waste gate open or closed?
Open, so as much exhaust as possible will bypass the turbine
What is the primary function of a reciprocating engine exhaust system
Its main function is to dispose of the gases safely with complete safety to the airframe and the occupants of the aircraft. The exhaust system can perform many useful function, but its first duty is to provide protection against the potentially destructive action of the exhaust gases
What is a short stack exhaust system?
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
What is the purpose of the exhaust system?
To remove high temperature noxious gases.
Name two types of reciprocating engine exhaust systems.
- Short stack
- Collector
What draw back in using collector type exhaust system is more than offset when used on turbocharged engines?
The loss of horsepower due to exhaust system back pressure.
What could result if the internal baffles or diffusers in an exhaust system fail?
The flow of the exhaust gases could be restricted, resulting in a loss of engine power.
What type of exhaust system is used on turbocharged engines?
Collector system
What kind of material is normally used to make the muffler shrouds found in the exhaust system?
Stainless steel
How do you inspect internal baffles and diffusers of an exhaust system?
By disassembling the exhaust system and visually inspecting the components.
Why is an exhaust system failure considered a severe hazard?
It can result in carbon monoxide poisoning, loss of engine power, or fire.
What could happen if lead, zinc, or galvanized marks are made on the exhaust system?
Can cause cracks when heated.
What happens if the heat exchanger leaks exhaust gasses into the induction system?
There is a loss in engine power.
What is an indication of an exhaust gas leak?
Flat gray or sooty black deposit in the area of the leak.
Where are the most common places to find cracks in an exhaust system?
At welded or clamped areas and at the flanges.
What are the most common causes of turbocharger waste gate sticking?
Coke deposits or carbon buildup
Why are turbocharged exhaust system leaks very damaging at high altitudes?
Pressure differential will cause the leak to escape with torch-like intensity.
What are exhaust system coke deposits?
Excessive carbon build up
What is the result of changing the exhaust nozzle area of a turbine engine?
The engine’s performance and exhaust gas temperature change.
Name the components of a typical turbine exhaust nozzle.
- Tail cone
- Exhaust ducts
- Support struts
What is the purpose of thrust reversers?
They decelerate an aircraft after landing.
How does a noise suppressor found on older turbojet engines work?
It converts frequency sound into high frequency sound, reducing the sound footprint
It converts frequency sound which is audible over great distance, into high frequency sound, thus reducing the sound footprint
What are the two most commonly used types of thrust reversers?
- Clamshell
- Cascade
How much thrust do the thrust reversers produce compared to the engines full forward thrust
Substantially less. (Up to 50% of the forward thrust)
What are the hazards of operating some thrust reversers at low ground speeds?
Ingestion of foreign objects (FOD)stirred up by the exhaust gasses and reingestion of hot exhaust gasses.
