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POWERPLANT CHAPTER#6
EXHAUST SYSTEMS:
| Question | Answer |
|---|---|
| What is the purpose of the exhaust system? | To remove high temperature noxious gases. |
| Name two types of reciprocating engine exhaust systems. | The short stack and collector systems. |
| What drawback in using collector-type exhaust systems 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 gasses could be restricted, resulting in a loss of engine power. |
| What type of exhaust system is used on turbocharged engines? | The 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 the internal baffles and diffusers on an exhaust system? | By disassembling the exhaust system as necessory and visually inspecting the components. |
| Why is an exhaust system failure considered a severe hazard? | It can result in carbon monoxide poisoing, loss of engine power, or fire. |
| What could happen if lead, zine, or galvanized marks are made on an exhaust system? | They cause a change in molecular structure, which could result in cracks when heated. |
| What happens if the heat exchanger leaks exhaust gases into the induction system? | There is a loss of engine power. |
| What is an indication of an exhaust gas leak? | Flat gray or sooty black deposits in the area of the leak. |
| Where are the most common places to find cracks in an exhaust system? | Welded or clamped areas and the flanges. |
| What is a common cause 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 buildup. |
| 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, and support struts. |
| What is the purpose of thrust reversers? | They help decelerate an aircraft after landing. |
| How does a noise suppressor found on older turbojet engines work? | It converts low frequency sound, which is audible over great distance, into high frequency sound, thust reducing the sound footprint. |
| What are the two most commonly used types of thrust reversers? | The clamshell (mechanically blocked) and the cascade (aerodynamically blocked). |
| How much thrust do the thrust reverser produce compared to the engine's full for ward thrust? | substantially less. |
| What are the hazards of operating some turust reversers at low ground speeds? | Ingestion of foreign objects stirred up by the exhaust gasses and re-ingstion of hot exhaust gasses. |