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49 Cards in this Set

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  • Back
Name the 4 Types of Reaction Engines
1. Rocket
2. Ram Jet
3. Pulse Jet
4. Gas Turbine
A blocked EPR Probe causes the gauge to what?
Over Read.
Thrust Output is a product of what?
Mass Airflow x Acceleration
A Gas Turbine can be categorized into what types?
1. Pure Turbo Jet
2. High Bypass Jet (Turbo Fan)
3. Turboprop / Turboshaft
Engine Pressure Ratio (EPR) is a measurement of what?
Exhaust Gas Pressure vs Inlet Air Pressure
The Large Fan at the front of the Turbo Fan engine is N?
1
Bypass Ratio is a measure of what?
Amount of air that bypasses the engine core compared to that which flows through the core.
The Turboprop Engine can be further categorised into what types?
1. Free Power Turbine
2. Direct Drive
The Gas Turbine working cycle is referred to as what?
The Brayton Cycle
In the Brayton Cycle, pressure is ____________during combustion.
Constant.
Name the two types of ducts used in a Gas Turbine.
1. Convergent
2. Divergent
A Convergent Duct _______velocity and _______ pressure / temperature.
Increases...........Decreases
A Divergent Duct __________velocity and _______ pressure / temperature.
Decreases........Increases
Name the two compressor types used in a Gas Turbine.
1. Centrifugal Flow
2. Axial Flow
To achieve a useful pressure rise, centrifugal compressors require a ______ frontal area.
Large.
One "Stage" of an axial compressor consists of a ______ blade followed by a ________vane.
Rotor / Stator
An axial compressor consumes more/less air and gives a smaller/larger pressure rise compared to a centrifugal compressor.
More / Larger
Stator Vanes give the correct Angle of Attack to the Rotor Blades over what %RPM Range?
Design RPM (92% - 98%)
A Compressor Stall, leading to a Compressor Surge, could be identified by what 3 cockpit gauges?
Dropping RPM, Rise in Fuel Flow, Immediate Rise in EGT.
Name the 3 Types of Airflow Control, to prevent Stall and Surge when operation 'Off Design RPM'.
1. Variable Inlet Guide Vanes
2. Variable Stator Vanes
3. Bleed Air Valve (Surge Valve)
In the Combustion Chamber, _____% of Airflow enters through the front, ____% enters the primary zone through holes in the walls, and the remainder _____% is used for dilution and cooling.
20%, 20%, 60%
A Rich Flame-out is more likely to occur at what stage of flight?
A High Power, Low Speed Climb.
A Lean Flame-out is more likely to occur at what stage of flight?
A Low Power, High Speed Descent.
State the four types of Combustion Chambers.
1. Single
2. Multiple
3. Tubo-Annular
4. Annular
In the turbine section, the Nozzle Guide Vanes (Stator Blades) come before or after the rotor blades?
Before
Name the two types of turbine rotor blades.
1. Impulse
2. Impulse / Reaction
In respect to the turbine section, define 'Blade Creep'?
The stretching of turbine blades over time due to heat stress and rotational forces.
In a turbo-jet engine, how much energy does the turbine stage absorb?
75%
In a turbo-shaft engine, how much energy does the Gas Producer & free-power turbine extract?
75% & 15%
Name two types of short term 'Thrust Augmentation'.
1. After-burning
2. Water / Methanol Injection
Reverse Thrust on turbo fan engines is achieved by what two primary methods?
Directing some of the bypass airflow forwards through cascade vanes, OR, clam-shell doors re-directing some of the exhaust gasses.
Fuel quantity is measure in tank by what type of system?
Capacitance Type System.
What other two features could be installed to cross check the capacitors?
1. Drip Sticks
2. Magnastick
What are the three tank types employed in modern aircraft?
1. Rigid
2. Bladder
3. Integral
When hot air is taken from the compressor, what happens to the thrust amount?
Decreases
Name the different starting methods for a turbine engine.
1. Electric
2. Cartridge Starter
3. Air Turbine (Compressed Air)
Self Sustaining speed usually occurs at what %N2 range?
35% - 50%
Idle RPM is usually between what %N2?
55% - 60%
Specific Fuel Consumption is a measure of what?
Engine Efficiency.
= FF (kg/hr) ⁘ Thrust (kg)

Lower SFC = Better
What are three factors that would increase SFC?
1. Increase in Ambient Temperature
2. Decrease in Compressor Pressure
3. Ops outside of Design RPM
Engine Performance depends on what 5 factors?
1. RPM
2. Airspeed
3. Altitude
4. Density
5. Temperature
Engine RPM is directly related to Thrust Output. In a fixed geometry engine, the top ____% of RPM produces _____% of thrust
25%........50%
In a modern variable geometry engine, the top _____% or RPM produces _____% of thrust.
13%.......50%
As airspeed increases, prior to Ram Recovery Point, what happens to thrust?
Decreases
What is 'Ram Ratio'?
Total Pressure compared to Static Intake Pressure.
As altitude is increased, temperature and pressure both decrease. The net effect on thrust is a ________, as the ________drop has the greater effect.
Decrease..........Pressure.
As temperature increases, what happens to the thrust output?
Decreases.
What two factors mean a decrease in thrust due to increase in temperature?
1. Higher temp = less dense air parcel
2. Higher temp = less fuel can be fed in until turbine temp limits are reached.
In general terms, up to 350kts, list the order of efficiency of the 4 engine types.
1. Turboprop
2. Turbofan
3. Low Bypass Jet
4. Pure Turbojet