Rajesh M15 Important Notes UPDATED PDF

❌❌ — When fuel burns it produces pressure energy — During start observe EGT ( Not all ) — Amount of air flow going in engine depends upon RPM, aircraft speed, ambient density — Convergent Duct - Pressure decreases, velocity increase ,temperature decreases — convergent nozzle mostly produce m...

❌❌ — When fuel burns it produces pressure energy — During start observe EGT ( Not all ) — Amount of air flow going in engine depends upon RPM, aircraft speed, ambient density — Convergent Duct - Pressure decreases, velocity increase ,temperature decreases — convergent nozzle mostly produce momentum & pressure Thrust — Inlet Duct efficiency - high duct efficiency at all altitude — Bell Mouth Inlet- high Aerodynamic efficiency, Funnel Shape , zero duct loss, allow air intake without any restrictions , giving a bell type shaped & rounded to edge ???— Recess for inlet in fuselage - Nose Type — Inlet System - Rose Ram Pressure — Inlet duct produce both Profile & Parasite Drag , Induce Drag also — Ability of duct to convert kinetic or dynamic pressure energy at inlet of duct into static energy at inlet of compressor known as duct pressure efficiency ratio — Inlet duct efficiency should have high duct efficiency at all altitude — Disadvantage of divided type Intake Aircraft of Ram pressure occurs on one side of intake, uneven distribution of airflow into compressor — Divided entrance duct : Pilot sits lower in fuselage single engine — VIGV & VSV controlled by FCU — Inlet recessed in fuselage FLUSH Type — The length, shape and placement of the duct is determined to a great extent by location of engine in the aircraft — Choose a spike in variable geometry induction duct produce normal shock ( Bow Shock ) — variable geometry Duct : Convergent- Divergent Duct — Small jet engine where compressor ratio doesn’t matter Centrifugal compressor — Some engine use type of compressor where compressor ratio is not a factor Centrifugal Compressor — Compression in Centrifugal Compressor , perpendicular to longitudinal axis — Centrifugal compressor less prone to FOD — In Centrifugal compressor, compressor manifold used to divert air from diffuser to combustion chamber — MTCS 1) In centrifugal compressor the tip speed problem loose efficiency 2) Centrifugal Force provide high acceleration due to ejected high velocity & high kinetic ✅✅✅ energy 3) Both — In can type Combustion chamber the air enters through the front and directed inside the Liner. — Primary one task inlet duct during flight operation which convert Kinetic Energy into RAM pressure rise inside the duct — Good Inlet Duct : Ram aur pressure increase inside the duct — Intake of GTE designed to convert Kinetic Energy to Pressure Energy — Change radial direction of airflow to axial direction - Compressor Outlet Elbow/Air Outlet Duct/Conversion Chamber Inlet Duct — Loss in Centrifugal Compressor due to 1) Air expelled outward thought Centrifugal action ✅✅✅ 2) Loss of energy due to turn 3) All — Primary advantage of axial compressor over centrifugal compressor is Greater Pressure Ratio — advantage of centrifugal compressor peak efficiency — In compressor clearance between rotor and case is maintained by using knife edge add compressor blade that rub and make space for rotation ,By using abradable material in case — Adiabatic Compressor : Air compressed at 100% efficiency, since there is no loss in processes either by friction , conduction or turbulence.( 90% is good adiabatic efficiency for compressor & turbine) — Total pressure at outlet of compressor: P3 , T3 ( Athishay )— Jet Engine Thermal Efficiency limited by ability of Compressor — Thermal efficiency is ratio of amount of heat from burned combustion air to Fuel Burned — Advantage of forward fan engine, Reduce injection of FOD — Prevent dirt particles injection in the engine vorteX reducer installed bottom side of engine ( Vortex destroyer, Vortex Destroyer , Blow Away jet ) — Indication of compressor stalled, rumbling noise +compression ratio, EGT and cockpit indication fluctuation — Highest pressure in Compressor stagnation pressure — Stagnation Probe type used in Turbojet — The most efficient way to get out of a Compressed stall is IGV — Energy change that take place in Impellor of compressor are Pressure Increase , Velocity Increase, Temperature Increase — Ring fixed blade at intake of axial flow compressor called IGV — Axial Flow Compressor : High Ram Efficiency — Compressor Surge indicated by 1) Disturbance in instantaneous flow of air 2) Hot gas from combustion chamber expel to compressor with loud bang ✅ 3) Loss of thrust 4) All ****** — Labyrinth Seal used to protect stator in compressor — Impeller made of Forged Alluminium — — Burning of fuel in combustion chamber in the entry of combustion chamber — Location of drain valve in combustion chamber, 2 or more in bottom of combustion chamber — Fuel manifold drain valve only solenoid operated , closed by solenoid while engine starting , drain valve closed by fuel pressure — purpose of Can Combustion Chamber outer casing distribute proper cooling air — Air enters into combustion chamber Inner Casing — combustion chamber gas path marking : Layout Dye & Chalk — Swirl Vanes mix fuel & air in combustion chamber — Can type combustion chamber for centrifugal compressor — Maintenance Friendly : Can Type ??— Annual Combustor ( Basket ) used in both axial & centrifugal — Most commonly used Combustion Chamber is Annular — Complete combustion space used Annular — Susceptible to Warpage : Annular — Advantage of Can Annular Combustion Chamber greater structural stability ( & loser pressure loss than Can Type ) — Combustion Skirt : Liner — Air used for Combustion is 25% — Rotor Blade of compressor is Drum & Disk — Perforation liners of different size & shape — Max no. of can in Multiple can combustor 8-10 — Can Annular contains forward face : 6 Apertures — Combustor Design often referred as Black Art — Reducing Pressure loss in combustion chamber, Increase diameter or length of diameter — Louvers control flame pattern of combustion chamber — Combustor used in Axial & Centrifugal Compressor is Annular ( Basket ) — Inlet and outlet area of impulse turbine blade inlet and outlet areas are same — Velocity of hot gases through reaction turbine blades increases — Impulse turbine blade maintain velocity & Pressure , Change only direction of flow — Air enter Plenum chamber at 90° — Cascade vanes reduce pressure drop in manifold — Interconnected Tubes , outer tube around interconnecting tune not only afford airflow between chambers but also fulfill an insulating Function around hot flame tubes., Slightly longer tube inside than outside tube — In combustion chamber , interconnector tube to all cans is same size — Good Combustor = High Combustion emergency — Gases before entering turbine must be cooled to Half — turbine case cooling Active Clearance control ( ACC ) — ACC controlled by EEC — NGV position : forward to Turbine wheel — NGV - Nickel Alloy — Modern Turbine Blade in GTE : Impulse reaction — Bleed Air used for cooling wheel of turbine & IGV — Highest Temperature in GTE is Turbine Nozzle — Turbine Nozzle convert Heat Energy to Velocity( K.E. ) — Hot Spots in Tail Cone - Malfunction of Fuel Nozzle — Location on NGV in GTE immediate forward of Turbine Wheel — Turbine Creep is Over Temperature & Centrifugal Load — Turbine blade detoriation, bending , blowing occurred by Over Temperature — Turbine Stator vane , nozzle diaphragm welded to turbine disk — Turbine Stator Vane - point of highest velocity in turbine engine ??— Turbine disc made of Cobalt based Alloy — Turbine vanes & blades from nickel based alloy — Kinetic Energy extracted by Turbine — MTCS 1) Turbine inlet nozzle assembly consist of inner shroud and outer sound between which the nozzle vanes are fixed ✅✅✅ 2) Each vane fit into contoured slot into the Shroud to the airfoil shape 3) BOTH — Turbine blades are retained in their respective groups by peening, riveting , Welding , Lock Tabs — hottest component in GTE turbine inlet nozzle vane — critical factor of GTE is Turbine Inlet Temperature — Radial Strut Purpose : Straightening the swirling motion of exhaust gases, support the inner cone in the exhaust duct — Turbine Absorb KINETIC ENERGY — Bleed Air is ducted into vane & exit through porous material is Transpiration Cooling & used on stationary Vanes — Film Cooling fir Blades & Vanes — Free Turbine Position between engine & main Rotor shaft — Single Crystal Method used to prevent Turbine Blade from high temperature — Large Volume Expansion & Sharp Pressure Drop at Exhaust — Material of Exhaust Duct( Tailpipe )- Stainless Steel ( CRS ) — Jet Pipe material : Stainless Steel — Exhaust System : Nickel, Titanium — Tail Cone( Exhaust Cone ): closely fits with opposite of last stage turbine disk , reduce swirling motion of exhaust gases, increases the pressure — Parts of Exhaust cone : Tie Rods , Struts , Outer Duct , Inner Shell — Jet Nozzle convergent - Subsonic — In choked Nozzle Velocity remain constant ( Choked nozzle reach a speed of sound the sound cannot be further accelerated ) — Terminating Part of Jet Engine is exhaust cone — Terminating part of Airframe is Exhaust Nozzle — Variable Area Exhaust Duct operated Electrical ,Pneumatic, Hydraulic — During usage of variable area exhaust duct nozzle size is increased — EGT also called Turbine Outlet Temperature , Turbine Gas Temperature, Jet Pipe Temperature — Limiting Factor for GTE is EGT — Convergent Nozzle mostly produce Momentum & Pressure Thrust — Tail cone 1) Closely fitted with opposite of the last stage turbine disc 2) Reduce swiring motion of exhaust gases ✅✅ 3) Increase pressure 4) All — Exhaust gases pass to atmosphere through propelling nozzle , which is converging nozzle , increasing gas velocity , exit velocity is Subsonic at low thrust Condition only — 8 Thermocouples in Exhaust section — Loss of Turbine efficiency ( If one turbine blade is damaged ) , Causes Turbine absorb less power than designed , causing decrease in N2. For a given EPR , more energy is required therefore Fuel flow & EGT Increase. Change in N1 is usually insignificant — Exhaust Duct strengthen by Tail Cone — Temperature of Exhaust monitored to prevent overheating of turbine blades & other exhaust components — EGT monitored to prevent overheating of combustion chamber , Turbine Case , Turbine Blade — Kinetic Energy extract by Turbine — major components of turboshaft are 9 — major components in turboprop are 5 — Turbine Stages of Turboprop is 5 ??— Anti-icing on turboprop is Electrical — Hot gases possess to remove ice in the England on turboprop engine ice break is called Deicing — Turboprop engine constant speed is maintained by fuel flow and blade angle — Because of induced propeller loads turboprop engine develops higher torque loads , as a result engine mounts are proportionally heavier — Turboprop engine gas generator section compressor , combustion & compressor turbine — Turboprop: - Acceleration temperature too high during starting: Fuel control bypass valve sticking closed, acceleration cam of fuel control is incorrectly adjusted, defective fuel nozzle , fuel control thermostat failure - Acceleration temperature during starting too low : acceleration cam of fuel control is incorrectly adjusted — Turboprop Torque directly proportional to Horsepower — Torque pressure is usually read from Direct Reading Pressure Gauge — Torque transmitted through Propeller Reduction Gear — Characteristic of turboprop does not affect thrust when engine speed increase — Propulsive Efficiency : Amount of trust developed by jet nozzle compared with the energy supplied to it in usable form — Drive shaft of Turboshaft take NONE LOADS ( no tension & no compressor ) — Turboshaft Engine correct misalignment & provide transmission — Turboshaft: Engine gives power to shaft other than propeller — In Turboshaft Engine Both ends flexible( most appropriate) & shaft is short — Over running clutch of turbo shaft located between engine and main rotor — in turboshaft free wheeling unit and over running clutch prevent rotor speed exceed engine speed — In Turboshaft , overrunning clutch or free wheeling unit feature permit auto rotation in case of power loss — Position of free wheeling unit between engine and Main Rotor shaft — Advantage of Turboshaft engine High reliability, small Size , Light Weight — In Turboshaft engine both ends are Flexible — ⅔ rd energy - Gas Generator , 1/3rd - RGB — In turboshaft engine- 1) Output shaft maybe couple directly to the engine turbine ✅✅ 2) Shaft may be driven by free turbine located in the exhaust system 3) Both  ✅✅ — Power section of Jet Engine :- 1) Reduction Gear Box ( RGB ) 2) Torque Meter Assembly 3) compressor 4) All — Bearing used in Engine by size and weight/length Rotor — Carbon Seal - Spring Loaded against to provide bearing cavity , rest against surface , prevent oil leakage — Hydraulic Bearing work effectively with high oil lubrication — Hydromanic or Slipper type Bearing used on Turbine powerplants where operating Rotor speed approach 45,000 RPM & where excessive loads during flights are anticipated — High Heat Resistant : Ball Bearing In hydraulic bearing outside race surrounded by thin film oil ,this reduces vibration transmitted to engine — Thrust Ball Bearing take load in one one direction — Angular contact Bearing take Axial & Radial in one direction — Radial Bearing : Greater Radial load & limited axial — Duplex Bearing( Self Aligning ) Take axial Load in Either direction — To Prevent Bearing compressor damage due to clogged fuel nozzle , main filter check periodically in line maintenance — Exhaust Turbine Bearing most critical lubricating point in GTE due to high-temperature — Aviation Fuel high heat value per pound — JET B Blending of ATF and gasoline Jet B & JP4 are similarly alike — Low volatile fuel prevent vapour Lock ???— JET A is Low volatile Fuel — JET A1 Most commonly used commercial fuel — Jet A1 freezing point -52.6°F — BTU : British Thermal Unit ( More in JET A1 ) — API - American petroleum Institute — Fuel Inhibitor : prevents corrosion , Prevent microbiological growth, prevent oxidisation — Fuel Additive : Prevents bacterial & microbial growth ( even ice formation) — Anti Ice liquid : Iso Propyl — Anti Ice : Pilot ( If all aayega then both pilot & automatic ) — Amount of water in fuel checked by Litmus Paper — Calorific value of fuel is an expression of heat or energy content per pound or gallon that is released during combustion — Fuel control senses power lever position, engine RPM, either compressor Inlet pressure or temperature and burner pressure or compressor discharge pressure — Fuel control meters fuel by sensing Compressor Inlet Temperature — Fuel System Inhibition is Mineral Oil — Fuel flow pump size is determined by flow during Maximum speed — Starter : sprawl Clutch , Turboprop : Over Running Clutch ✅✅✅ — Electrical starter 1) Pawl & Rachet Mechanism 2) Automatic clutch release mechanism 3) Both — Full Flow System used for short distance- Total Loss — Oil foaming removed by Deaerator — Oil Temperature sensor - 1) bulb type cockpit light indication ✅✅✅✅ 2) thermocouple & Indicator 3) Both — Oil inlet temperature is also indicate the proper operation of Engine Oil Cooler — Capacity of scavenge Oil pump is greater than pressure oil pump — Spur Gear Type Pump : Constant displacement pump — High pressure Gauge instrument Bourdon Tube — Lubrication of starter & reciprocating engine: splash — Lubrication of Turbine Engine : Spray Type — Full flow lubrication system bigger pump used — Chip detector location downstream of scavenge Pump — Most common oil lubrication system in the modern engine Dry Sump — Aeroshell 500 - Type 2 — Aeroshell 560 - Type 3 — Lubrication System oil pressure from pump is proportional to engine RPM in relief valve system — Oil Tank : Welded sheet Aluminium or steel — Oil flow system used for short duration of flight is Total Loss — Major difference between full flow and total loss is oil scavenge system — Difference between fuel flow system and total loss system control of oil flow system to bearing — Lubricating Oil should be Low Viscous & High load carrying — GTE used Synthethic Oil — If synthetic oil fall at painted surface, painted surface should be white clean with petroleum solvent — Painted surface cleaned with Mineral Based Oil — Oil Inlet Temperature Indicator show temperature of oil as it enter oil pressure pump — Fuel cooled Oil cooled , Oil regulated to control heating — Engine oil classification based upon SAE — FCU in Engine driven accessory Mechanical, Hydraulic, Electric , pneumatic — FCU is typically an Engine driven accessory that meters fuel using Hydromechanical , Hydropneumatic , or electronic means — Fuel flow indicator measure flow between fuel pump and FCU — The basic parameter for describing the fuel economy of aircraft engine : Specific Fuel Consuption — EEC controlled Hydromechanical control ( Athishay )— Electrical Fuel Control unit - HYBRID — EEC powered by the generator , aircraft system , PMAf — Supervisory EEC dene signal to HMU / Fuel metering unit — EEC programming plug located on FADEC A channel — EEC : 1) Channel A - Blue 2) Channel B - Green 3) Thermocouple - Yellow 4) Non EEC circuit - Grey — EPR mode is Rated or Normal mode , N1 mode is alternate or Fault mode — In N1 mode , FADEC schedules fuel flow as a function of Thrust Lever Position — N1 is similar to that of Hydromechanical Fuel control system — And approximately 78° TRA maximum power available is calculated by FADEC. Altitude less than 14,100 ft FADEC calculate “T/O power Rating “. Altitude greater than 14,100 ft , FADEC calculate rating for maximum continuous power — If engine is started without EEC programming plug , FADEC goes to N1 mode. But nothing happens with FADEC operation when EEC programming disconnects in Flight — FADEC is BITE system — Fuel metering : throttle N1 -FADEC when EPR Setting not used — Fuel Inhibitor used for Anti Corrosion , Anti Oxide , Anti Microbe — Fuel additives Anti-microbe & Anti Freeze — Anti Ice & Anti Biological Mix is PRIST — Low pressure Filter installed between engine & fuel tank — Fuel Heater Prevents low filter icing — FCOC ke liye high filter icing — High-pressure filter between Fuel Pump & Fuel Control — Fine Mesh Filter ( Also called Last Chance Filter )use just before oil pass from the spray nozzle on to the bearing surface — FADEC starting : Either A or B automatically — After each engine change and fuel control change change control system from the pylon to engine must be rigging — Rigging of Airframe to Pylon is same component change — Power Lever control cables & Push pull rods in airframe system to the Pylon & nacelle not usually disturbed at engine change time & usually no rigging required , except when some component has changed — Rigging Done to ensure full throttle moment , free obstruction , if not do rigging of Airframe Control System checked & discrepancies repaired — Rigging of Fuel control both in normal range — Electronic control amplifier protects engine from over temperature condition when operating at Takeoff — Fuel control is engine drive accessory which can be operated by Mechanical Hydraulically , Electric & Pneumatically — Fuel Flow coordinator coordinate with Propeller , Electronic Temperature Datum Control , Fuel Control — Fuel filter may incorporate a silver strip indicator that detects any abnormal concentration of sulphur in the fuel — At what Position water is injected for Thrust Augmentation - at compressor inlet or Diffuser Case — Thrust augmentation depends on type of coolant, ingredient added to coolant, quantity of coolant — In Thrust Augmentation , After burner produce 50% Thrust Increase — After Burning = Hot Operation — As temperature of After burner increases , Burner flame is concentrated around axis of jet pipe — disadvantage of water injection system - high weight ratio system, compressor blade erosion, thermal shock, compressor stall — Methanol Added to water injection system, to increase freezing point of water — With use of water injection will increase thrust 10% to 30% — Using water injection will increase Thrust cycle 21% — Water Injection used in High Power — Engine power rating using water injection= Wet Thrust — Demineralised water used to prevent deposit buildup on compressor blade — Throttle advanced 86% RPM , microswitch activated , shutoff valve open , permit water reach engine driven pump — ⅓ rd water pass LP regulator into INLET SPRAY RING — ⅔ rd water pass HP regulator , into DIFFUSER CASE NOZZLE RING — To ensure proper drainage of Water Tank , 8 Amber Low pressure warning lights illuminated until drain switch moved to OPEN position — Water Injection location that is more suitable for Axial Flow Compressor Engine — Safety resistor connected ACROSS choke — Discharge Resistor Across reservoir capacitor — Bleed Resistor wired ACROSS output circuit — Bleeder Resistor provided to dissipate the energy in igniter plug in absence or fails to fire — Thermocouple voltage taken by difference between hot and cold junction — Thermocouple: temperature probe EMF generated from hot to cold junction — Thermocouple Probe is Hot or Measuring Junction , Indicator as Cold or Reference Junction — EGT measured by thermocouple average of all probe — GTE contain K type ( Fire Proof ) thermocouple — 8 Thermocouples present in Exhaust Section — In terminal block with ( TEMPERATURE )Thermocouple used has Chromel & alumel Alumel has larger diameter stud , Chromel has smaller Stud — Alumel : Green ( -ve polarity ) , Chromel : White ( +ve polarity ) — FIRE THERMOCOUPLE Chromel & Constantan — Thermocouple Junctions are connected in Parallel — Thermocouple have longer life at Discharge ( Exhaust ) — Fire Extinguished once should not attempt for start — Photoelectric : Visible light , Infra Red light ,Fire Detection System — Halon 1301 - FREON 13 Bromotrifluoromethana - Halon 1301 — Fire Detectors use in Engine are Overheat Detector , Rise Detector , Flame Detector — Thermal switch type : connected in parallel with each other & series with Indicator Light — Thermocouple : Series with Each other — Fenwall continuos system : connected in series to control unit — FenwalFire detection system can withstand 1 fault only and spot detections are wired in parallel — Kidde Continuous loop system wired in special ceramic core with Inconel Tune — Engine firewall bulkhead material Stainless Steel , Titanium — Cowling - removable, fix, access panels, upper half, lower half — Cowl Material : Al alloy — Oil temperature increase fault bearing ( Athishay ) — Started motor gives drive to RGB — Turbo prop engine SHP taken from output shaft — Turboprop Engine has more turbine stages ✅✅ — Turbo prop power delivered to propeller by gear train & shaft — Torquemeter assembly attached between air inlet housing & reduction gear assembly — TorqueMeter assembly transmits torque from engine to gearbox of reduction section — turboprop torquemeter fitted between RGB to propeller ??— Torquemeter connected Shaft to RGB ??— Centrifugal Compressor location - AGB & Combustion Chamber — Turboprop deliver power From Gas Generator to RGB , RGB to propeller — Removal of Hoses in Turboprop closed hydraulic line hoses — In Turboprop Engine constant RPM is Function - TIT or FUEL Flow — Torque pressure is read from direct Reading pressure gear — Hot gas propulsion : Catridge — Starter used only once: Catridge ??— Disadvantage of cartridge type starter is required external power — starter shaft shear when Torque to engine increase — When started speed is more than engine speed Pawl clutch ( also called spray clutch ) used to disconnect mechanism — Starter - Automatic Cutoff — Disadvantage of Airturbine Starter high volume airflow at 50 PSI — Air turbine starter converts energy from compressed air to shaft horsepower — Air Turbine Starter Consist of axial flow turbine that drive coupling through Reduction Gear Assembly and Starter clutch assembly — Air Turbine Starter compresses air used to shaft power — Air Turbine Starter consists of Axial flow turbine that drive coupling through Reduction Gear Train — Starter equipped with outputs spline shaft having shear section that permits shaft to shear if torque to engine during starting Cycle is excessive — Duplex Nozzle small orifice provides Low Pressure fuel — Which among the following is function of Centrifugal Switch in APU: 1) Start & Ignition circuit 2) Overspeed protection circuit 3) Governor speed indication Circuit 4) All ??— APU auto shutdown light : AMBER — APU - 115 V , 3 phase , 400 Hz — Air Inlet of APU located in On the Top — APU provide Pneumatic Power & Electrical Power — Starter motor connected to APU in to the gearbox — APU use Annular & Can type combustor depending on Turbine used — APU load Compressor produce BLEED AIR ( Bleed air load imparted on APU is greater than any load ) — N g tachometer indicate : Engine speed — N p tachometer indicate: propeller or free turbine speed — Tachometer - Electrical Type & Probe Type — APU starter coupled to Gearbox — Main difference between ground & Inflight APU are Ballistic Containment & Ram Air Intake — APU located at unpressurised section on empennage — In APU air enters through inlets it’s used for cooling — fire extinguisher should be positioned during operation of APU — Modern aircraft use Capacitor Type Ignition System — ignition used start & relight — H.E. Ignition unit receive Low voltage supply from aircraft electrical systems — Case of Igniter plug made of INCONEL — Transistor Ignition Unit consist of only Transistor Chopper ( Transistor chopper circuit has many advantages, no moving parts and longer operating life ) — Ignition system , Spark ignitions are generally located in 2 diametrically opposite combustion liners — Ability to relight vary accordingly to altitude & forward speed of aircraft — Spark Rate : 60 to 100 sparks / minute — Ignition Unit output varied according to requirement — Long Term preserves Engine : up to 6 months — Humidity indicator should be inspected after 24 hours(indicator has not turned pink) — Humidity Indicator on engine store in shipping case inspected every 30 days — Humidity indicator tester inside the container with an inspection window provided — Protective Envelope : 90 Days — Metal Container : 180 Days — More than 30% Relative humidity desiccants should be replaced — Humidity Blanket should not exceed 60 % — After Period of 3 yrs , uninstalled engine stored in envelope should be represerved — Relative Humidity not considered for T/O — Engine speed is measured by Calculating compressor RPM , Fan RPM , Turbine RPM — Noise suppresses are generally built of welded stainless steel sheets stock & are relatively simple construction — As distance doubled , noise level decrease 6dB — As distances halved , noise level increase 6dB — Cold Flow in Hose marking of debt due to clamp — Engine Mount Mounting bolt inspected by MPI Mounting frame inspected by DPI — If only Engine Mount then both MPI & DPI — Engine mounted by using Bolt , Nut & Vibration Dampening Pad !!!— Position of Engine Shutoff Valve is After Pump — Fuel shutoff valve either mechanically, electrically, or pneumatically —Propeller Beta Range not controlled by governor & controlled by power lever position — In pressure relief system relief valve spring loaded to close position — Pressure relief valve system control line to deliver to bearing — Where minimum loss permitted Rubbing seal ( Contact Seal ) is used — Ring Seal : Metal Ring Which is housed in a close fitting groove in a static housing — Rubbing or contact seals are use in application where a minimum amount of leakage and high degree of sealing required. Eg : Variable Stator Vane Assembly — Non Rubbing Clearance or Labyrinth Seal devices thought which specific amount of leakage can take place because there is no actual contact between rotating & stationary part of seal — Ram Ratio : Ambient pressure / Compressor Inlet pressure — SAE 201 W : W indicates Winter — Newton’s 2nd law : Acceleration ( Thrust of Engine calculated ) — Centrifugal Breather : Remove air from oil droplet — Vibration unit on engine is mounted on Pylon — Vibration Unit on engine is mounted perpendicular to engine — Vibration displayed in Non dimensional unit — Vibration Sensing unit is Peizo electric sensor — GTE produce Vibration it’s pattern is higher the velocity higher the vibration — Vibration Monitoring : Milliammeter — EGT ( Thermocouple ): Millivoltmeter — Aviation Fuel is High Heat / Pounds — Engine speed measured by Magnetic Indicator — Performance Indicator : EPR & fan speed ( N1 ) — Engine Condition Indicator : EGT , Fuel Flow , Compressor speed , Oil pressure , Temperature Guager —Thrust Reverser - Low RPM & low airspeed — Post Exit of Thrust Reverser obstruction in jet nozzle — Tachometer is Electric & Probe Type — Tachometer output signal is amplified to run servomotor type indicator — Dual Tachometer used in Helicopteron — EPR , EGT , fuel flow , Throttle position determine aerodynamic performance of engine — Vibration amplitude & oil consumption evaluate mechanical performance — Servo operated EGT Indicator warning arises Input voltage low — Variable Vane System exclude unwanted air during Low speed — Air fails out from intake where compressor rotate at very high speed Compressor stall — Prime action that tends to cause stall is Choking — Any action that increase airflow relative to engine speed will increase the angle of attack and increase the tendency to stall — Indication of compressor stall rapid EGT Increase or fluctuation or RPM fluctuation — severe compressor stall caused by fuel system malfunction or foreign object ingestion. — Angle of Attack will vary with Engine RPM , Compressor Inlet Temperature , Compressor Discharge or burner pressure — Stall prevented by Bleed Valve , VIGV & VGV , Variable Exhaust Nozzle — Compressor stalk more severe at Low altitude , Low speed , High RPM — High AOA = Stall , Low AOA = Choke 1) Low air velocity , Normal RPM , Stall 2) Normal Air velocity , High RPM , Stall 3) High air velocity , normal RPM , Choke 4) Normal air velocity , Low RPM , Choke — Rule of thumb when engine has operated above approximate 85% rpm for period exceeding 1 minute, during the last 5 minutes prior to shut down it is recommended , that the engine operated below 85% ( Preferably at idle )rpm for a period of five minutes to prevent possible seizure of rotor — To prevent seizure of case & Turbine : Active Tip clearance used — EPR used for Takeoff — Viscosity ( Jet A > Jet B > AVGAS ) — Volatility ( AVGAS > Jet B > Jet A > Jet A1 ) — Viscosity Measured by Saybolt Universal Viscosimeter. Oils are classified as 80,100,120. The number of second required for 60 Cubic Centimetres of heated oil to flow — Scalling corrosion caused by sodium in air & sulphur in fuel at high temperature — Corrosion preventive compound : Petroleum based — Motoring wash generally done by turning the engine by starter , engine run up by starter between 10-15% RPM ( 10-25% RPM ) — Factors effecting overhaul efficiency of engine is 1) Combustion Efficiency 2) Thermal efficiency ✅✅✅✅ 3) Overhaul efficiency 4) All — Air Fuel Ratio 60:1 — Vapour Lock due to Low Fuel pressure , High Temperature , High Turbulence — Trimming of Engine carry out due to Maximum speed Adjustment & Idle speed adjustment. Both adjustments are made in normal mode — MTCS 1) Fuel flow instrument indicate the fuel flow in pounds per hour from the engine fuel control  2) Fuel fuel flow is of interest in monitoring fuel consumption and checking engine ✅✅ performance 3) BOTH — Fuel flow indicator monitor fuel consumption and checking engine performance !! — in cold weather conditions fuel volatility is medium — Choke : Extend duration of discharge — Discharge Resistor : residual store energy in capacitor is dissipated within 1 min after shutdown of engine — Safety Resistor : Fitted to enable unit to operate safely , even when high tension lead is disconnected & Isolated — Bleeder Resistor : Provided in the discharge circuit to dissipate residual charge on trigger capacitor between completion of 1 discharge at spark igniter & beginning of new cycle — Bleed Resistor: Wired across output circuit to act as dummy load in the event ignition unit is energised while spark plug disconnected — Tank Capacitor : Discharge current from main ignition unit surges to spark plug electrodes , building potential between centre electrode & ground electrode — Storage Capacitor : Discharge accumulated energy across ionised igniter plug gap — Cooling air taken from HP compressor ( Athishay )— Compressor Surge due to Burner & RPM — Engine Installations with Cable hoist 1) Position the powerplant beneath the nacelle 2) Attach the engine sling to the engine ✅✅✅ 3) Carefully observe all the horse simultaneously to raise the engine 4) All — Upto ⅕ th Total Engine core mass airflow may be used for various function — EPR can be indicated by either Electromechanical or Electro transmitter — EPR measure Electrical Means ( Electro mechanical transmitter ) — Integrated EPR ( IEPR ) , this parameter is integrated average of Fan & Gas Generator Exhaust pressures divided by inlet Total Pressure — In bypass engine , fan Thrust produces 80% — Fan air of short duct exit separate from common nozzle — Stagger Angle greater at Tips than root — Engine vibrates throughout rpm range but indicated amplitude reduces as rpm reduced : Turbine Damage — Engine vibrate at high rpm and fuel flow when compared to constant EPR : Compressor Damage — Engine fire but will not accelerate to correct speed Insufficient Fuel Supply — Machine surface of rotor in GTE : LAND — Normal Shockwave , Flow direction no change , velocity decreased to subsonic , Great Increase in static pressure & Static temperature & density — Oblique Shockwave , Flow direction flow towards corner , velocity decreased by still supersonic , Increase in static pressure & Static temperature & density — Trust produced by turbojet 1) Changing momentum by air and fuel 2) Momentum of fuel ✅✅✅ 3) Force caused by difference in pressure across exhaust multiply area of nozzle 4) All of the above — Direction of Airflow controlled by VARIABLE IGV & VSV — Density of Fuel depends on Temperature — Centrifugal Breather remove air from oil — position of fuel shut off valve after Pump — Engine Hydraulic System : PTFE — MTICS , Trend Analysis 1) Monitoring engine performance and condition over a period of time provide a database for trend analysis 2) Data collected during initial operation establishes baseline to compare to all subsequent operation data 3) Significant changes in relationship between performance parametres may signal ✅✅✅ impending failure 4) Data collection automatically and manually same method — To prevent rich blowout compressor inlet pressure, burner pressure, RPM , Inlet temperature & pressure — Mach Speed related to local Speed of Sound — Amount of Thrust depends on ✅✅✅ 1) Fuel burned 2) Mass of airflow passed through 3) Air pushed behind it — When engine is running at Max Rating the velocity of exit gases would be 4 times the velocity of idle rating — OIL Pressure Trim Orifice : Help adjust oil pressure at low speeds — Modular construction of jet engine is major parts can be removed without disturbing other parts — Vapour Pressure measured by REID — Hotspots on Tailcone : malfunctioning of Fuel nozzle & faulty combustion chamber ?? — Positive Dispalcement : 40 to 100 PSI — Idea Air/ Fuel mixture - 15:1 — Total Airflow 60:1 — In test cell Thrust measured by Strain Gauge — High Tension ignition system check done by Micrometer — Seal used to protect Stator : Labyrinth Seal — Restricted Leakage Labyribth Seal — Buna N : Hydraulic line — sensitive relay closes then triggers Slave Relay , which permit current to warning light — Jetcal Analyser designed to functionally check & troubleshoot the temperature measuring system in GTE without running engine , saving fuel & engine life — Blade Cuff : Increase Flow of Cooling air into nozzle — Part Throttle Thrust : Rated Thrust obtained below Rated Throttle Rating — Commonly used electronically operated oil temperature gauge Wheatstone / Ratiometer — Information on exposure to oil : MSDS — HP nozzle guide vanes cooled with HP intermittent air — Fuel Nozzle cleaned insiter & detergent — Flame Stabilizer : Blunt nosed V section annular rings located downstream of Fuel Burners — While testing fire detection system in aircraft power the cockpit and held a test switch for 10 seconds — In FCOC , oil flow around tube — Starting sequence for Turbojet engine Starter , Ignition , Fuel — IGV : K E to PE — During Negative torque in flight to limit it Pitch Angle increased — Engine speed measured by Calculating compressor rpm,Turbine RPM , fan RPM — Fuel Flow Coordinater coordinate Propeller , Fuel Control , Electronic Temperature datum control — 2 Parameters recorded for calculating Thrust Horsepower of Turboprop is Thrust & Airplane Speed