Principles of Gas
The relationship between pressure and velocity in a closed system
Together they make up total pressure.
The advantages of a single-entrance duct
Simplest and most effective at providing smooth airflow.
Other than mechanical malfunctions, what causes most stalls?
Airflow distortions.
Two ways the Fan can be driven in a turbofan engine?
Through the gas generator turbine or a free-power turbine.
The two types of electric current
AC and DC
The three sections of a gas generator
Compressor, burner, turbine
The components of an axial flow compressor
Rotors, stators
What should be done if a stall cannot be controlled?
Execute engine failure procedures.
"Bypass air" is .....
Airflow from the fan "bypassed around the gas generator."
What signals a system malfunction?
Warning Lights
Cycle that explains the movement of air through a gas generator
Brayton Cycle
What is creep?
Turbine blade elongation and deformation.
What should a pilot do to avoid compressor stalls?
Avoid rapid and unnecessary PCL movements. Maintain at least minimum
prescribed airspeeds.
What is a free turbine?
A turbine that is not mechanically connected to the compressor and aft of the gas
generator turbines.
What bus charges the battery?
DC Essential Bus
The optimum cruise altitude( and why).
Approximately 36,000
temperature remains isothermal
What is the shape of a subsonic inlet duct? Why?
What is the shape of a supersonic inlet duct? Why?
Divergent, decrease velocity I increase pressure.
Convergent/Divergent, decrease velocity I increase pressure.
List some flight conditions that could cause a compressor stall.
Abrupt attitude change or flight through turbulent air.
How much thrust is produced by the fan on a turbofan? Gas Generator?
30-60% from the fan.
40-70% from the gas generator exhaust gases.
With the main generator failure, what bus or busses will stay on the line?
DC and AC essential buses
How does subsonic airflow react through a convergent opening and a divergent opening? And For Supersonic?
Convergent: velocity increases and pressure decreases.
Divergent: velocity decreases and pressure increases.
Divergent: velocity increases and pressure decreases.
Convergent: velocity decreases and pressure increases
The components of a reciprocating engine
Crankcase, cylinders, pistons, connecting rods, valves, valve-operating mechanism, and the crankshaft
Indications of a compressor stall
Mild pulsations, engine vibration, loud bangs, drop in RPMs, and rise in turbine temperature.
Describe the sections of a turboshaft and its function.
Gas generator: Provides exhaust gas to drive the free/power turbine.
Free/power turbine: Connected to the main transmission, it converts the heat energy to mechanical energy to drive the rotors.
Name the four types of busses and the type of equipment that is supplied power.
Essential bus - safety of flight
Primary bus- mission equipment
Monitor/ Secondary bus- convenience
items
Starter bus - starting circuits