SM Special (final stage revision) Flashcards
(194 cards)
Thrust is produced by the…..
force required to accelerate the mass of air through the engine
Gas TURBINES convert kinetic energy into mechanical energy, while combustion chambers…
convert chemical energy into kinetic energy
What is the effect of RAM effect on thrust?
Total recovery as forward speed increases
Is the average cruise EPR independent of TAT?
yes
What are the advantages of the free power turbine?
Lower starting torque, variable prop speed, high torque at low rpm, instant response (compared to turbofan)
What is the purpose of the NTS?
Increases blade angle to stop the propeller driving the engine
What is the purpose of the TSS?
Automatically feathers the propeller in the event of an engine failure
What does the safety coupling do?
Disengages the reduction gear from the engine (it is a backup to the NTS)
What are the advantages of a centrifugal flow compressor?
Simple and cheap
What are the advantages of an axial flow compressor?
Axial thrust, higher compression ratios, better power to weight ratio
What is the purpose of the bleed valve for engine operation?
Increases mass airflow over early compressor stages at low RPM
On startup, what indications will indicate a successful light-up?
Increasing EGT, TOT, or ITT.
During subsonic flow through a duct, what happens to density?
Remains constant
What is the difference in airflow through a duct between sonic and subsonic flow
Everything supersonic is backward, and density changes.
Why is air slowed down in the combustion chamber>
To prevent flameout
In the engine compressor, which blades experience the highest air loads?
Rear compressor
What is the purpose of the Variable Inlet Guide Vanes?
Reduce AoA on the front compressor blades at low RPM
In the combustion chamber, is the hottest temperature at the front or back of the primary zone?
Back
In turbojet aircraft, does range increase or decrease with an increase in altitude?
Increase with an increase in altitude
What is the issue with water in the fuel system? (CIM)
Corrosion, Icing, Microbial growth (C I M)
Compare AVTUR to AVGAS.
Higher SG, lower volatility, higher flashpoint, higher calorific value (by volume).
What is the purpose of a spring loaded relief valve in a fuel system?
Provides fuel supply in the event of a filter blockage
If a FMC detects a difference between the FMC calculated fuel and the fuel gauge indication, what happens?
The pilots are alerted with a fuel quantity error message, and the pilots then have to decide which quantity to use.
What happens to the range of an aircraft at the SG reduces?
Reduces