15.3* Flashcards
What type of duct does a conventional sub-sonic inlet duct form?
Divergent duct
What happens in the inlet duct when the engine is running but the aircraft is stationary?
A core depression forms causing air to be sucked in from around the intake
What effect will ram air have on thrust?
Engine thrust will increase
What will occur when total RAM recovery is obtained?
More air than engine can use, engine uses less energy, reduction in ram drag, nose suction
How is flow separation in the inlet prevented?
By the use of large radius intake lips
What is meant by Sub critical?
The demand from engine has dropped and the shock wave has been expelled to create a bow wave causing a reduction in pressure
What is meant by the term critical?
All conditions are correct. I.e speed airflow size of intake and all shockwaves are in the correct position
What is meant by the term super critical?
The diffuser pressure has dropped, the normal shock wave has been sucked further into the intake causing a stronger shock wave poor flow and an abrupt pressure rise
What happens to the air as it passes over an oblique shockwave?
Velocity decreases but remains super sonic, pressure and temperature increases
What generally dictates the type of engine icing system that is used?
The mass airflow of the engine
Engine anti ice valves are normally of what configuration?
Solenoid controlled, pneumatically operated
Where does the engine get its sir for icing protection from?
Itself (engine)
On an electrical anti ice/de ice system what is the purpose of the internally heated mats?
To carry out the de icing function
Apart from air what other methods can be used to de ice the spinner?
Hot oil tank or rubber spike
What effect will pneumatic engine anti icing have on the operation of an engine?
EGT will rise as air is bled away from anti icing
