Royal Air Force Air Cadets



ULTILEARN PISTON ENGINE PROPULSION QUESTIONSPISTON ENGINESEngine layoutsABCD1. Which of the above engine layouts is an inline 4 layout?ABCD2. What type of layout is the above piston engine?V TwinInline 4Vee 8Vee 43. The piston engine layout above is known as?Inline 3Inline 4Inline 5V-Twin4. The illustration above is what type of layout for a piston engine?V TwinInline 4Vee 4Flat 45. This illustration shows the typical layout for a light aircraft engine. What is this layout called?Inline 4Vee 4Staggered 4Flat 4Operation6. In a two stroke piston engine, how many times does the crankshaft rotate to complete one cycle?3 4 2 17. In a Wankel engine, for every rotation of the triangular piston, how many times does the crankshaft rotate?OnceTwiceThree timesFour times8. In a four stroke engine, at what nominal crankshaft angle does the spark initiate combustion?30 degrees after BDC30 degrees after TDC30 degrees before BDC30 degrees before TDC9. What is the firing order in a four cylinder piston engine?1, 3, 2, 41, 3, 4, 21, 4, 3, 21, 2, 3, 410. In a four stroke piston engine, what speed does the cam shaft rotate at in relation to the crankshaft?Twice crankshaft speedCrankshaft speedHalf crankshaft speedA quarter Crankshaft speed11. In a 4-stroke piston engine, what is the force which closes the exhaust and inlet valves?SuctionGravityA springA pushrod12. In a piston engine, ineffective crank angle occurs in the region of:BDC onlyNeither BDC or TDCTDC onlyBoth BDC and TDC13. What is the correct sequence for the operating cycle of a four stroke piston engine?Induction, compression, power, exhaustInduction, power, compression, exhaustPower, induction, compression, exhaustInduction, compression, exhaust, power14. In a piston engine, what forces the inlet and exhaust valves closed?A springGravityA pushrodSuction15. In a four stroke piston engine, how many times does the crankshaft rotate to complete one cycle3 4 2 116. In the modified 4-stroke cycle, which of these is valve lead?Inlet and exhaust valves are open togetherExhaust valve opening before the piston reaches BDCInlet valve closing after the piston has passed BDCExhaust valve closing after the piston has passed TDC17. In order for compression to occur in a piston engine which of the inlet valves and exhaust valves need to be closed?The inlet valvesNoneThe exhaust valvesAll the inlet and exhaust valvesComponents18. The purpose of gudgeon pins in a piston engine is to:Attach the pistons to their connecting rodsFasten together the two halves of the crankcaseHold the sparking plugs in placeRetain the valves in their guides19. A piston engine camshaft has a lobe for each valve, what is the difference in the low diameter and the high part of the lobe called?High spotValve liftPushrod bumpLift point20. In the illustration above, four parts are labelled. Which part is the gudgeon pin?W X Y Z21. In the illustration above, four parts are labelled. Which part is the crankshaft main bearing?W X Y Z22. In the illustration above, four parts are labelled. Which part is the connecting rod?W X Y Z23. The crankshaft is mounted in the engine on a series of mainline bearings. How many main line bearings are there in a four cylinder engine?3 4 5 624. In the illustration above, four parts are labelled. Which part is the valve?W X Y Z25. In the illustration above, four parts are labelled. Which part is the camshaft?W X Y Z26. In this diagram of a piston engine's valve mechanism, the arrow X points to:A scraperA camA pushrodA tappetSupercharging27. What is the primary function of a supercharger on a piston engine?To increase the pressure in the induction manifoldTo ensure the battery is charged throughout the full range of engine speedsTo speed up the extraction of exhaust gasesTo make use of unburnt fuel in the exhaust gases28. How is the air compressor driven in a position engine turbocharger?By belt of gears from the engine crankshaftBy an electric motorBy the exhaust gasesBy ram air pressure29. What is the main function of a supercharger when fitted to a piston engine?It delivers a stronger spark to the sparking plugsIt increases the amount of lubricating oil delivered to the bearingsIt increases the amount of air and fuel delivered to the cylindersIt ensures that the batteries are always fully charged30. How is the air compressor driven in a piston engine supercharger?By the engine crankshaftBy an electric motorBy the exhaust gasesBy ram air pressure31. Which of these statements, about an exhaust-driven turbocharger, is true?It operates best at high engine speedsIt operates as soon as the throttle is openedIt operates best at low engine speedsIt is more effective than an engine-driven supercharger at increasing the power outputIgnition32. The distributor includes two mechanisms, centrifugal weights and a pressure diaphragm, to advance the spark timing. What are these mechanisms for respectively?To advance the timing for engine speed and engine intake manifold pressureTo advance the timing for engine speed and air pressureTo advance the timing for engine temperature and air pressureTo advance the timing for engine pressure and exhaust temperature33. In electrical terms, what is meant by EMF?Electro Motive ForceEasy Motive ForceEnd Motive ForceExceptional Motive Force34. Which of the following describes a magneto as used in an aircraft's piston engine?A secondary compass systemA mechanical pump for circulating fuelAn instrument for metering the fuel flowA dynamo to produce the spark for the spark plugs35. In a magneto, what is one purpose of the condenser (or capacitor)?Make the primary current flow evenlyMake the secondary current flow evenlyReduce erosion at the spark plug gapsReduce pitting of the contact breaker points36 Which of the following accurately describes the purpose of a magneto in an ignition system?To produce the energy for the spark at the spark plugsTo circulate fuelTo sense fuel flowTo circulate oil37. In the modified 4-stroke cycle, ignition takes place:At TDC on the compression strokeAt TDC on the power strokeJust before TDC on the compression strokeJust before TDC on the power stroke38. In a breakerless electronic ignition system, what components indicate the position of the crankshaft to the ignition control unit?The coil packsThe alternatorThe distributor timing disc and sensorThe valve timing belt39. In a petrol engine, what basic maintenance is required to maintain healthy operation of the spark plugs?Clean the electrodes and bodySet the electrode gapCheck the plug ceramic insulator for cracksAll of the above40. In a magneto system, where is the power for the spark generated?In the contact breaker pointsIn the coil secondary windingsIn the condenserIn the coil primary windings41. In a piston aero engine, the purpose of the distributor is to distribute?High voltage electrical impulses to the cylindersOil to all parts of the engineCooling air to all external partsThe correct mixture of air and fuel to the cylinders42. In a magneto system, the primary and secondary windings are incorporated within the magneto. Where are the primary and secondary winding in a dynamo/alternator system?In the distributorIn the dynamo In the alternatorFuel System43. In a simple 4-stroke piston engine, which of these air-to-fuel ratios (by weight) would be the normal mixture?15:0109:0106:0112:0144. What ratio (by weight) of fuel to air should the carburettor normally supply in a piston engine?02:0101:0215:0101:1545. In a fuel injection system, how is the fuel atomised?Fuel pressure through small spray nozzleFuel pressure through fuel mixerFuel temperature through small jet orificeFuel pressure through a needle valve46. In a two stroke piston engine, how is the fuel air mixture supplied to the combustion chamber?By an electrical pumpBy a mechanically driven pumpBy atmospheric pressureBy the piston moving down the cylinder47. Where are the fuel tanks located in a freight or passenger type aircraft?In the fuselageIn the tailthe wings In In the fin and underwing tanksLubrication48. There are two basic types of oil system, a wet sump system and a dry sump system. In which type of engine application is a dry sump system typically used?Aircraft and high performance carsTractors and construction vehiclesRoad carsMilitary transport vehicles49. Oil specifications include the property of viscosity. What does high viscosity mean?Synthetic type oilA thinner consistencyMineral type oilA thicker consistency50. What is the purpose of the scavenge pump in the dry-sump lubrication system of a piston engine?To direct oil into the pressure chamberTo ensure that all engine components are lubricatedTo scavenge contaminants from the oilTo transfer oil from the crankcase to the oil tank51. In a piston engine, far more oil is circulated than is needed to reduce friction alone. Why?To lubricate the pressure pumpTo cool the engine internallyTo produce a full splash effectTo ensure the scavenge pump is always fed52. Oil is used for lubricating engine parts to reduce friction. What other function does the oil system provide?Ensures the fuel pump runs smoothlyRemoves friction generated heatProvides the engine cooling system fluidMixes with the fuel to assists in efficient combustion53. The mainline bearings in a piston engine are shell type bearings, how is the oil delivered to these bearings?By direct jetAs the crankshaft rotates, the big ends splash through the oil in the sumpBy pressure feed through internal drillings and pipesBy jet and splashCooling54. The 2 main methods of cooling piston aero engines are liquid cooling and air cooling. Which of the following is an advantage that air cooling has over liquid cooling?Much cheaper to makePromotes longer life between engine overhaulsCan hold the engine at a more even temperatureEngine can be more easily streamlined55. In a liquid cooled engine, what is the purpose of the thermostatic valve?It prevents cooling in the radiator until the driver/pilot selects it openIt prevents cooling in the radiator until the engine has warmed upIt prevents heating in the vehicle interior until the engine has warmed upIt allows the coolant to be cooled until the engine is hot, they it closes56. What is the main benefit of using liquid (as opposed to air) to cool an aircraft piston engine?The engine will be simplerThe engine will be less costly to produceA steady operating temperature will be more easily maintainedThe engine will be lighter57. What is the purpose of the fins which are arranged about the cylinder and cylinder head of an air-cooled engine?To direct air through the engine compartmentTo allow heat to dissipate rapidlyTo reduce the weight of the engineTo support the engine cowlings58. The two methods of cooling piston engines are liquid cooling and air-cooling. Which of the following is an advantage that air-cooling has over liquid cooling?Air cooled engines are much cheaper to makeAir cooling can hold the engine at a more even temperatureAir cooling promotes longer life between overhaulsAir cooled engines are more powerful59. The two methods of cooling piston engines are liquid cooling and air cooling. Which of the following is an advantage that liquid cooling has over air cooling?Liquid cooled engines are much cheaper to makeLiquid cooling can hold the engine at a more even temperatureLiquid cooled engines do not need overhaulingLiquid cooled engines are more powerful60. The main 2 methods of cooling piston aero engines are liquid cooling and air cooling. Which of the following is an advantage that air cooling has over liquid cooling?Can hold the engine at a more even temperaturePromotes longer life between engine overhaulsEngine can be more easily streamlinedMuch cheaper to make61. What/How is the thermostatic valve operated?Closed by heat, opened by a springManually closed, opened by a springOpened by heat, closed manuallyOpened by heat, closed by a springCarburation62. When a piston engine is accelerating, the purpose of an accelerator pump when fitted to the carburettor is:Prevent the mixture from becoming weakDecrease the air pressure in the float chamberIncrease the air pressure in the float chamberPrevent the mixture from becoming rich63. What is the purpose of the accelerator pump fitted to the carburettor of a piston engine? When the engine is accelerating it:Increase the air pressure in the choke tubeDecrease the air pressure in the choke tubePrevents the mixture from becoming too richPrevents the mixture from becoming too weak64. In this diagram of a simple carburettor, what does the arrow point to?FloatThrottle valveMain jetChoke tube65. In this diagram of a simple carburettor, which arrow (W, X, Y or Z) points to the main jet?X Z Y W66. Direct fuel injection is often used in aero piston engines, in preference to float chamber carburettors. Which of these statements applies to the direct fuel injection system?There is no choke on the intakeIt cannot operate invertedThe fuel does not have to be vaporisedA throttle butterfly is unnecessary67. The arrow X points to a device which is often incorporated into the carburettor of a piston aero engine. What is its function?Prevents the fuel/air mixture from becoming richer as the aircraft climbsEncourages good atomisation of the fuelPrevents the fuel/air ratio from becoming richer as the throttle valve is openedSupplies extra fuel when needed for acceleration68. In normal running conditions, what component in a carburettor controls engine speed?The throttle valveThe accelerator pumpThe choke valveThe float chamber69. In an electronic common rail fuel injection system, how is the fuel flow to the engine controlled?By varying the fuel pressureBy varying the jet orifice sizeBy varying the jet orifice size and fuel pressureBy varying the time the fuel injector valves are openPROPELLORS70. Propeller braking involves:Turning the blades beyond fine pitchFeathering the propellerThe selection of coarse pitchThe selection of fine pitch71. What is another term for coarse pitch?FairedFeatheredFoldedFlayed72. The blade angle on a propeller is varied from a coarse angle at the tip. This is called:Blade translationAdjustable pitchVariable pitchBlade twist73. Why were constant speeding variable pitch propellers developed?To reduce the work load of a pilotTo prevent the engine developing too much powerTo increase engine powerTo cool the engine more efficiently74. In an aircraft propeller system the function of the constant speed unit (CSU) is to?Retard the ignition timingFeather the propellerMaintain a selected engine speed within the power availableIncrease the mixture strength75. When a propeller rotates, what two motions produce the helix angle?Forward speed and blade angleForward speed and climb rateForward speed and descent rateForward speed and engine RPM76. A variable-pitch propeller is said to be feathered when:The leading edges are at 90 degrees to the direction of flightIt is in fully coarse pitchThe leading edges face forward in the direction of flightIt is in fully fine pitch77. In the propeller control unit, how is engine speed and propeller pitch controlled?By a spring balanced with bob weight centrifugal forceBy a spring balanced with bob weight spring forceBy a spring balanced with bob weight hydraulic forceBy a spring balanced with bob weight electrical force78. Blade twist in a propeller helps to?Make the blade stronger and lighterReduce noise levelsMake feathering possibleEven out the thrust along the length of the blade79. How does the propeller governor know the rotational speed of the propeller?The governor receives an electrical speed signalThe governor receives a hydraulic speed signalThe governor receives an air speed signalThe governor receives a mechanical speed signal80. On a variable-pitch propeller, the largest obtainable pitch angle is known as:Coarse pitchTake-off pitchOptimum pitchFine pitch81. In this diagram of a propeller, what is angle 'b'Pitch angleFine angleProp angleBlade angle ................
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