M15.3 Inlets Flashcards
What type of duct is a air inlet
Divergent
What does a divergent duct do
Increase air pressure
Parts of the inlet
Inlet duct
Inlet nose
What causes if disturbances in a air intake
- Damage
- Ice
- Crosswind
When is there no ram air effect
Aircraft is not moving
What happens when there is no ram air into an engine
Air gets pulled from the sides
What indicates the danger zone on a running engine
Red stripe
What is the ideal airspeed for air hitting the compressor
0.4-0.7 Mach
How is the risk of air separation in the inlet reduced
The lip is rounded
Which speeds is a pitot type intake designed to take
Up to 1.5 Mach
What is the inlet critical condition
Max airflow at rates Mach altitude
Supersonic shock wave types
- Normal
- Oblique
- Bow
When and how do normal shockwaves form
- Low supersonic speeds perpendicular to the airflow
What happens to airspeed in a normal shock wave
Supersonic to subsonic
What determines the angle of an oblique shock wave
The upstream velocity
Main difference between bow wave and oblique wave
Bow wave is detached
In supersonic ducts how is the buzz effect overcome
Variable geometry air intake
When can a normal shock diffuser inlet be used
Low supersonic speeds
How many shock waves are employed in a variable geometry air inlet duct
Three oblique, one normal
In a variable geometry air inlet, what is used at high speeds to prevent intake buzz
Bleed door
What type of valve is used in thermal engine anti-ice systems
Solenoid controlled pressure regulated valves
What closes the solenoid controlled valves
Spring force
What monitors the pressure regulating valves
Two pressure switches
What are the pressure switches found in thermal anti-icing
Downstream of the valve
Ice protection cyclic sequence - typical cycles
Fast - 2 minutes - OAT -6 to 10c
Slow - 6 minutes - OAT Below -6c
