adada
PISTON; LOSSES IN PISTON: -Cooling of cylinder body -Friction due to motion of piston -Energy carried out by exhaust gas -Radiation of heat -Improper valve timing. FACTORS AFFECTING POWER: -Thermal Eficiency -Volumetric Efficiency -Mechanical Efficienciy -Piston Displacement -Compression Ratio -lgnition Timing -Engine Speed -Specific Fuel Consumption. ADVANTAGES FUEL INJECTION: -Reduction in lcing -Better Fuel Flow -Faster Fuel Response -Precise mixture control -Better fuel distribution -Easier cold weather start up. CAUSES OF DETONATION: -Use of lower fuel Grade -High MAP with low RPM -High Power Setting with low mixture -Steep climb ( reduced cooling) AVOID DETONATION: -Proper Fuel Grade -Use cowl flaps for cooling -Rich mixture and shallow climb angle -Avid long, steep climbs at high power -Monitor gauges. LUBRICATION: -Lubrication of engine’s moving parts – Engine cooling by reducing friction -Removal of heat from cylinders -Sealing between pistons and cylinder walls -Carries contaminant away. DISADVANTAGES FUEL INJECTION: -Difficulty starting hot engine -Vapour lock on hot days -Difficulty starting engine due to fuel starvation. SUPERCHARGER: -Internally driven -Speed controlled RPM -Compresses Mixture -Compressor Pressure=MAP -LOW Exhaust back pressure climb. TURBOCHARGER: -Externally driven -Speed controller by waste gate -Compresses air -Compresses Pressure>MAP -HIGH Exhaust back pressure SYNCHRONYZING: -Reduce Noise -Reduce vibration -Optimize beat frequency. SYNCHROPHASING: Noisy interference between propeller tips so clearance is given.TURBINE: APU: -Electricity -Air conditioning -Pressurized Air for engine start -Hydraulic power in some cases RAT: Emergency hydraulic power -Variable pitch propeller -Deployment + operation in 3 sec. FADEC: (Controls parameters to obtain optimum range of engine) – Throttle position -Air pressure & temperature -Engine gas temperature. HOT START: -EGT increases and exceeds 1% of admitted -Engine to be shut down CAUSES: -Low air pressure to start -Strong pipe tailwind -Early HP cock opening -Excessive devices to engine WET START: Fail to light up in a certain time when fuel is introduced in the combustion chamber. No rise in EGT nor RPM. CAUSES: Faulty igniter plug -Faulty high-energy ignition unit -Start-Battery Voltage low. LUBRICATING OIL: -Low volatility -High flash point -High film strength -Wide temperature range -Low viscosity -High viscosity index HUNG START:Engine does not reach idle RPM CAUSES: -Excessive devices to engine -Not enough fuel to combustion chamber -Not enough pressured air from APU. NEED TO DRY COMBUSTION CHAMBER;
LUBRICATION: -Reduce friction -Keep engine clean -Minimize corrosion -Cold down the bearings -Act as hydraulic fluid on pitch mechanisms. USE OF BLEED AIR: -Air conditioning/Pressurization -Hydraulic reservoir pressurization -Fuel tank pressurization -Potable water tank presurization -Reverser actuator -Anti-ice of engine & surfaces -Fuel heater -Cooling of engine blades. SUBSONIC AIR INLET: -Divergent(baja P.d.) -Smooth and round lips -Ice protection using hot air -Short and circular CENTRIFUGAL COMPRESSOR: -Cheap and robust and small -Large frontal section AXIAL COMPRESSOR: -More power and efficiency -Complex and pricy -Susceptible to FOD and surge SECONDARY INLET DOORS: -Stationary -Low speed -High AoA. (Las 3 high power settings) CAUSES OF STALL/SURGE: Lor engine rpm -Strong ground x-wind -Inlet icing -Damaged blades and inlet INDICATIONS OF SURGE: -Thrust loss -Erratic rpm -Vibration -Rapid rise in EGT -Compressor banging -Burning gas out of inlet and exaust CONVERGENT-DIVERGENT NOZZLE: At throat, MACH 1 is reached, then still accelerates at divergent. THRUST PERFORMANCES: Max T/O thrust -Max G/A trst -Max continious trst – Max climb thrust. INCREASING THRUST: AFTERBURNING: -Short periods -Introduce fuel into gas after turbine step to use unburnt oxygen -Increase of up to 70% -Automatic nozzle shape modification. WATER/METHANOL INJECTION: -Increases airflow density to improve that thrust by adding sprayed water in the diffuser or combustion chamber methanol to avoid water temperature reduction REVERSE SAFEGUARDS: Reverser cant’ be selected until throttle idle -Reverser used only after aircraft has weight on the main wheel -Reverse RPM can’t be increased untilreverser doors are in the deployed position -If forward thrust is selected and reverse doors move to deployed, throttle automatically idle -If reverse thrust selected and doors move to stowed, reverse lever automatically to deploy. REVERSE RESTRICTIONS OF USE: -Minimum speed 60-80 kts -Minimize hot gas reingestion -Not used for ground manouvering -Restricted in spite of noise abatement.