Jet_engine DGCA Questions

Jet Engine: DGCA Questions 1. Blade is an angle formed by a line perpendicular to the propeller s haft and line formed by the (a) Relative wind (b) Apparent wind (c) Chord of the blade (d) Blade face 2. Thrust produced by a rotating propeller is a result of  (a) Propeller slippage (b) An area of low pressure behind the propeller  (c) An area of decreased pressure immediately in front of the pressure blades (d) The angle of relative wind and rotational velocity wind and rotational velocity of the  propeller  3. Propeller blade station number increase from (a) Huh to tip (b) Tip to hule (c) Leading edge to aft edge (d) Aft edge of leading edge 4. It should have high specific gravity (a) Low pan point 5. Velocity index should be high. High freezing point  – at  –  at a cold atm the water contents in the fuel in having tendency to form in a ice crystal 6. It should be filtered to jet engine (a) It should have low carbon content after burning the fuel 7. In twin spool engine, with constant N 2, compressor inlet temperature is decreasing then (a)  N2 changes (b) Fuel flow increases (c)  N1 decreases (d) The ratio N1 is maintained constant  N2 8. The thrust developed by high bypass ratio rat io engine is (a) Indicated by EGT (b) Indicated by N 2 (c) Proportional fan speed (d)  Not affected by ambient conditions

9. Perceived noise decibel (PNDB) level is low in case of  (a) Pure jets without noise suppressor  (b) Straight jet with noise suppressor  (c) Low by pass jets (d) High by pass jets with acoustic panel 10. Ignitor plug spark is due to

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Jet Engine: DGCA Questions (a) (b) (c) (d)

High frequency High input current Discharge (storage) capacitor  DC voltage

11. In a ‘hot tank’ oil system (a) Oil cooler is not provided (b) Oil is stored in a separate tank  (c) Oil is at high temp in the tank  (d) De-aerator effect is very slow 12. If jet velocity and mass flow is constant c onstant for a jet engine then thrust (a) Is maximum when aircraft speed is minimum (b) Is maximum when aircraft speed is maximum (c) Is more when jet velocity and inlet velocity are equal (d) Is always constant 13. Water injection systems are provides for the jet engine engine for the thrust augmentation the thrust augmentation for water injection can be caused and by two methods. (a) By adding or injecting water at the compressor inlet (b) By adding or injecting water at the differ section Fig shown that a water tank made up of aluminum or sheet metal allows the water flow a regulating It then panes to the pressure regulating V/o of the diffuse and compressor inlet thought which water injection in done by providing two manifolds at the diffuse and compressor manifold. A water heater is provided for the water to not formed ice in cold atm or cold weather condition A drain a/v provided to drain full water tank after are it is generally use of after getting sufficient thrust by water injection Water injection system used when aircraft an going to take off 

14. In a compressor space between surge line and working lines called (a) Safety margin on surge margin (b) Stable zone unstable zone (c) Unstable zone (d) Stagger zone 15. Hottest zone in turbine engine is (a) Compressor outlet (b) Turbine (c) 1st stage NGV (d) Exhaust nozzle 16. In a high by pass engine NGV’s are eliminated (a) To reduced noise (b) To reduce weight

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Jet Engine: DGCA Questions (c) To increase efficiency (d) To satisfy 1 and 2 above For maximum thrust The thrust augmentation is achieved a the compressor inlet by injecting water at the compressor inlet which increases mass airflow and their by thrust Thrust augmentation is achieved a the diffuser section by injecting water at the diffuser  section and which als the diffuser section and decreases the temperature of the diffuser section which gives high deme man airflow high affect to maximum 17. Brayton cycle is (a) Constant temperature cycle (b) Constant volume cycle (c) Constant pressure and constant temperature cycle 18. NGV’s of turbine are usually (a) Hollow (b) Solid (c) Air cooled (d) As per (1) & (2) above 19. Most common defects in combustion chamber is (a) Crack and burning (b) Scoring (c) Pitting (d) Blistering

20. Jet engine ignition system. Jet engine ignition system is a high intensity intensit y and dual capacitor discharge type are used The two system are used for the ignition system (a) Low voltage A.C or D.C type ignition s ystem (b) High voltage capacitor discharge type ignition system 21. High voltage capacitor discharge type ignition system FIGURE SHOWN HIGH VOLTAGE CAPACITOR DISHCARGE TYPE CUT (A.G) A 115 A.C is provided bu E.S.I. but to the primary coil of the transformer A to reduce the noise level a filter cut is provided at the primary After paning 115V at the primary a seen way coil induces a voltage of about 2000V approximately which paner through solid rectifier A through resistance to the dual capacitor or  storage capacitor which store the electrically charger  In the next cycle a 20000 is paned through rectifier B this resistance 22. Combustion chamber used in a modern jet engines are (a) Can annular type (b) Annular type (c) Can type (d) As stated in 1 and 2

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Jet Engine: DGCA Questions 23. Exhaust nozzle is (a)  No necessary for jet engines (b) Made up of titanium alloy (c) Made up of aluminum alloy (d) A must for jet engine 24. Internal energy of a perfect gas is (a) A function of temperature only (b) A function of pressure only (c) Always constant (d) A function of temperature and pressure 25. The turbo jet engines (a) Can be used in thermal power stations as prime stations as primer movers (b) Are more efficient at lower altitudes (c) Work on Newton’s third law of motion (d) (2) and (3) above are correct 26. Compression process in axial compressor is (a) Isothermal (b) Adiabatic (c) Isobaric (d) Isometric 27. Compressor pressure ratio of an engine compressor depends upon (a) Ambient pressure (b) Ambient temperature and ambient pressure (c) Speed and ambient pressure (d) Speed mass airflow and ambient temperature The energy stored in a dual capacitor and storage charger at a fule charge level and then tenses the tube this caused charger when fully developed it induces in the primary winding of the transformer  (TRIGGER), which is of up to app 2000 V This induces a appx of 20,000V to the secondary of the tram former winding and which gives high intensity current flow thr ignite plug which gives spark  A bleeder resistance are provided for troiger capacitor to give protection for excess voltage Two igniter plug are used for capacitor discharge t ype cht for alternate operations 28. The fuel nozzles used in modern gas turbine engines (a) Are always of dual type (b) Are identical for engine with same power rating (c) Are welded to the combustion chamber  (d) Is the last component in the fuel system 29. Anti –  Anti  – icing icing system used on jet aircrafts (a) Is fully automatic (b) Is to be used only to melt the ice formed (c)  Never makes use of electrical heaters (d) Need (d)  Need not be used thought thought the flight 30. How many igniters are usually used on a turbine engine having nine burner cans? (a) One

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Jet Engine: DGCA Questions (b) Two (c) Three (d) Nine (d)  Nine 31. The material used for jet engine is following foll owing main fine types (a) Titanium (b) Aluminum or Aluminum alloy (c)  Nickel bare alloy (d) Nickel (d)  Nickel chrome alloy (e) Steel or stainless steel Titanium are high resistant to 1000 & corrosion and are used for fan blades and sometime for  compressor vanes Aluminum or aluminum alloy are used for jet engine for its light weight characteristics it is high resistant to corrosion heat  Nickel- chrome alloy’s re used fore turbine blades, which stands for high temperature Steel or stainless steel alloy are used for rota vane or staten sta ten vane in an axial flow type t ype jet 32. In an axial flow turbine engine, compressor bled air is sometimes used to aid in the cooling of  (a) Oil (b) IGV (c) Fuel cooler  (d) Turbine 33. Which of the following turbine fuel filters has the greatest filtering action? (a) Micron (b) Wire mesh (c) Wafer screen (d) Stacked charcoal 34. For starting a turbine engine (a) D.C motor is never used (b) Very very low cranking speeds are required (c) Ignition is necessary (d) Statements 2 and 3 are correct 35. Mechanical integrity of the turbine as well as engine operating conditions of the engine can be checked by (a) Engine oil pressure (b) Exhaust gas temperature (c) Engine oil temperature (d) Engine pressure ratio 36. Which parameter will determine engine power? (a) EGT and vibration meter  (b) RPM and oil pressure (c) RPM and fuel pressure (d) EPR OR RPM

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Jet Engine: DGCA Questions 37. Mark the correct statement (a) Thrust reverse reduces landing roll (b) Oil pressure for jet engine is always regulated (c) VSV’ are not provided on modern jet engine (d) By providing fire wall in the engine cowl compartment engine fire detection element can be eliminated

Get more previous year DGCA question papers and AME study material at  www.rjworld.com or visit http://aviation.rjworld.com .

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