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49 Cards in this Set
- Front
- Back
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Name the 4 Types of Reaction Engines
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1. Rocket
2. Ram Jet 3. Pulse Jet 4. Gas Turbine |
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A blocked EPR Probe causes the gauge to what?
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Over Read.
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Thrust Output is a product of what?
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Mass Airflow x Acceleration
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A Gas Turbine can be categorized into what types?
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1. Pure Turbo Jet
2. High Bypass Jet (Turbo Fan) 3. Turboprop / Turboshaft |
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Engine Pressure Ratio (EPR) is a measurement of what?
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Exhaust Gas Pressure vs Inlet Air Pressure
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The Large Fan at the front of the Turbo Fan engine is N?
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1
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Bypass Ratio is a measure of what?
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Amount of air that bypasses the engine core compared to that which flows through the core.
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The Turboprop Engine can be further categorised into what types?
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1. Free Power Turbine
2. Direct Drive |
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The Gas Turbine working cycle is referred to as what?
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The Brayton Cycle
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In the Brayton Cycle, pressure is ____________during combustion.
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Constant.
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Name the two types of ducts used in a Gas Turbine.
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1. Convergent
2. Divergent |
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A Convergent Duct _______velocity and _______ pressure / temperature.
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Increases...........Decreases
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A Divergent Duct __________velocity and _______ pressure / temperature.
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Decreases........Increases
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Name the two compressor types used in a Gas Turbine.
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1. Centrifugal Flow
2. Axial Flow |
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To achieve a useful pressure rise, centrifugal compressors require a ______ frontal area.
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Large.
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One "Stage" of an axial compressor consists of a ______ blade followed by a ________vane.
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Rotor / Stator
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An axial compressor consumes more/less air and gives a smaller/larger pressure rise compared to a centrifugal compressor.
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More / Larger
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Stator Vanes give the correct Angle of Attack to the Rotor Blades over what %RPM Range?
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Design RPM (92% - 98%)
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A Compressor Stall, leading to a Compressor Surge, could be identified by what 3 cockpit gauges?
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Dropping RPM, Rise in Fuel Flow, Immediate Rise in EGT.
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Name the 3 Types of Airflow Control, to prevent Stall and Surge when operation 'Off Design RPM'.
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1. Variable Inlet Guide Vanes
2. Variable Stator Vanes 3. Bleed Air Valve (Surge Valve) |
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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.
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20%, 20%, 60%
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A Rich Flame-out is more likely to occur at what stage of flight?
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A High Power, Low Speed Climb.
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A Lean Flame-out is more likely to occur at what stage of flight?
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A Low Power, High Speed Descent.
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State the four types of Combustion Chambers.
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1. Single
2. Multiple 3. Tubo-Annular 4. Annular |
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In the turbine section, the Nozzle Guide Vanes (Stator Blades) come before or after the rotor blades?
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Before
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Name the two types of turbine rotor blades.
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1. Impulse
2. Impulse / Reaction |
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In respect to the turbine section, define 'Blade Creep'?
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The stretching of turbine blades over time due to heat stress and rotational forces.
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In a turbo-jet engine, how much energy does the turbine stage absorb?
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75%
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In a turbo-shaft engine, how much energy does the Gas Producer & free-power turbine extract?
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75% & 15%
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Name two types of short term 'Thrust Augmentation'.
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1. After-burning
2. Water / Methanol Injection |
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Reverse Thrust on turbo fan engines is achieved by what two primary methods?
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Directing some of the bypass airflow forwards through cascade vanes, OR, clam-shell doors re-directing some of the exhaust gasses.
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Fuel quantity is measure in tank by what type of system?
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Capacitance Type System.
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What other two features could be installed to cross check the capacitors?
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1. Drip Sticks
2. Magnastick |
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What are the three tank types employed in modern aircraft?
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1. Rigid
2. Bladder 3. Integral |
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When hot air is taken from the compressor, what happens to the thrust amount?
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Decreases
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Name the different starting methods for a turbine engine.
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1. Electric
2. Cartridge Starter 3. Air Turbine (Compressed Air) |
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Self Sustaining speed usually occurs at what %N2 range?
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35% - 50%
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Idle RPM is usually between what %N2?
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55% - 60%
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Specific Fuel Consumption is a measure of what?
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Engine Efficiency.
= FF (kg/hr) ⁘ Thrust (kg) Lower SFC = Better |
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What are three factors that would increase SFC?
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1. Increase in Ambient Temperature
2. Decrease in Compressor Pressure 3. Ops outside of Design RPM |
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Engine Performance depends on what 5 factors?
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1. RPM
2. Airspeed 3. Altitude 4. Density 5. Temperature |
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Engine RPM is directly related to Thrust Output. In a fixed geometry engine, the top ____% of RPM produces _____% of thrust
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25%........50%
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In a modern variable geometry engine, the top _____% or RPM produces _____% of thrust.
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13%.......50%
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As airspeed increases, prior to Ram Recovery Point, what happens to thrust?
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Decreases
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What is 'Ram Ratio'?
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Total Pressure compared to Static Intake Pressure.
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As altitude is increased, temperature and pressure both decrease. The net effect on thrust is a ________, as the ________drop has the greater effect.
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Decrease..........Pressure.
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As temperature increases, what happens to the thrust output?
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Decreases.
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What two factors mean a decrease in thrust due to increase in temperature?
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1. Higher temp = less dense air parcel
2. Higher temp = less fuel can be fed in until turbine temp limits are reached. |
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In general terms, up to 350kts, list the order of efficiency of the 4 engine types.
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1. Turboprop
2. Turbofan 3. Low Bypass Jet 4. Pure Turbojet |
