15.07 Flashcards
What unit is commonly used to express noise
Effective Perceived Noise deciBel (EPNdB)
When replacing the cascade segment,what must you make sure
It is the correct cascade arrangement for the engine position
What are the 2 methods used in order to reduce the noise level of an engine
- Design
2. dampen external and internal noise sources
What is the main task of the exhaust system on jet engine
To accelerate the airflow
What type of nozzle is used for pressure ratios of more than 2:1
Convergent-divergent nozzle
pneumatic reverser actuation systems are only used on what type of thrust reverser
Cascade type with translating sleeves
What do thrust reverser do?
Produce the breaking force by deflecting the exhaust gas stream to the opposite direction
What is the subsystem inside the thrust reverse control system
Thrust reverser interlock System
With a faulty reverser can the aircraft be released for service
Yes
What is the role of a muffler in the exhaust duct
Reduce noise in APU
What is the role of the control system
To activate the thrust reverser and to increase the engine power
How are the two exhaust systems exhausted on modern high-bypass turbofan engine
Separately
What is the role of the reverser actuation system
Either pneumatic or hydraulics component. It moves the airflow deflection mechanism by signals from the reverser control system
What does the green reverse light indicate
Fully deployed and throttle interlock released (engine power can be increased)
What are the three subsystem for a reverser System
Control system
actuation system
Airflow deflection system
What is the main task of the exhaust system in a turboprop engine
Safely guide the exhaust gases overboard
What guides the exhaust gases from the rear of the turbine into the atmosphere
Exhaust system guide
What is a disadvantage of of a thrust reverser
The compressor can stall
Why should high gas velocity must be avoided
Because they decree the propulsion efficiency
What is the angle of the gas stream when deflected
45-60 degrees
What is an advantage of a common exhaust nozzles
It reduces the very high gas velocity by mixing the two gas flow
How is the exhaust airflow caused
By the pressure ratio between the turbine discharge and ambient pressure
What does a reverse unlock message indicate
That the reverser is not safe in its stowed position
When can you use thrust reversers
On on ground due to safety
