Results
Q1. The temperature of the gases within the cylinder of a four-stroke engine during the power stroke will:
Correct answer is – decrease
Q2. The number of revolutions of the crankshaft required to complete a full cycle in a four-stroke engine is:
Correct answer is – 2
Q3. The inlet valve opens before TDC in the exhaust stroke to:
Correct answer is – induce a greater amount of mixture into the cylinder
Q4. The correct working cycle of a four-stroke engine is:
Correct answer is – compression, power, exhaust, induction
Q5. Valve overlap is incorporated in the valve timing of a piston engine to:
Correct answer is – improve volumetric efficiency
Q6. With an increase in the rotational speed of a four-stroke engine, the valve overlap:
Correct answer is – remains constant
Q7. In a normally aspirated engine, exhaust back pressure:
Correct answer is – decreases as an aircraft climbs and thereby reduces the rate of decline of the engine power output
Q8. When the spark ignites the mixture:
Correct answer is – temperature and pressure increase within the cylinder
Q9. If the volume of a quantity of gas is halved during compression:
Correct answer is – its pressure is approximately doubled
Q10. The term Indicated Mean Effective Pressure refers to:
Correct answer is – the average pressure within the cylinder during the four cycles
Q11. The degrees of rotation to complete a full cycle on a nine cylinder engine will be:
Correct answer is – 720
Q12. The firing interval of a six cylinder horizontally opposed engine will be:
Correct answer is – 120
Q13. Which of the following statements would be correct for a double banked radial engine?
Correct answer is – The linear distance from TDC to BDC will accommodate two throws
Q14. On a four cylinder engine with a total volume of 9600 cc, bore area of 100 cm² and a crank throw of 10 cm, what would the Compression Ratio be?
Correct answer is – 6:1
Q15. With an increase in outside air temperature, specific fuel consumption will:
Correct answer is – increase
Q16. Combustion, in a four-stroke engine, theoretically occurs at:
Correct answer is – a constant volume
Q17. In a convergent duct:
Correct answer is – the pressure and temperature decrease, the velocity increases
Q18. During the compression stroke:
Correct answer is – the mass of the mixture remains constant
Q19. From Top Dead Centre (TDC) to Bottom Dead Centre (BDC) on the practical power stroke:
Correct answer is – the temperature of the gases rises for a short time then decreases
Q20. In a divergent duct:
Correct answer is – the temperature and pressure increase, the velocity decreases
Q21. During the induction stroke:
Correct answer is – the temperature of the gases reduces
Q22. Ideally, maximum pressure is attained within the cylinder:
Correct answer is – when combustion is complete
Q23. The power output of an internal combustion engine:
Correct answer is – is proportional to the weight of the mixture induced into the cylinder
Q24. During the period of valve overlap:
Correct answer is – the action of the exhaust gases flowing out past the exhaust valve tends to reduce the pressure in the cylinder
Q25. The power output of an internal combustion engine can be increased by:
Correct answer is – all of the above
Q26. Valve Overlap is:
Correct answer is – the number of degrees of crankshaft movement during which the inlet and exhaust valves are open at the same time
Q27. The purpose of a valve spring is to:
Correct answer is – close the valve
Q28. Excessive blue smoke from the exhaust of an engine that has been warmed up to normal operating temperature may indicate that:
Correct answer is – the piston rings are worn or stuck in their grooves
Q29. The camshaft of a horizontally opposed four-stroke engine rotates at:
Correct answer is – half engine speed
Q30. A reduction gear is fitted:
Correct answer is – between the crankshaft and propeller
Q31. Prolonged use of low rpm could cause contamination of the:
Correct answer is – spark plug
Q32. If the Starter Engaged Light remains on after engine start, you should:
Correct answer is – shut the engine down immediately
Q33. The crankshaft of typical in-line four cylinder aircraft engine:
Correct answer is – allows a firing order of 1-3-4-2
Q34. Two valve springs are fitted to each valve:
Correct answer is – to reduce valve bounce
Q35. Excessive valve clearance:
Correct answer is – will cause the valve to open late and close early
Q36. Valve lead occurs when:
Correct answer is – the inlet valve opens before top dead centre and the exhaust valve opens before bottom dead centre
Q37. Insufficient tappet clearance at the inlet valve would cause:
Correct answer is – the valve to open early and close late
Q38. The length of the stroke is:
Correct answer is – equivalent to twice the crank throw
Q39. Tappet clearance is measured between the:
Correct answer is – valve tip and the rocker pad
Q40. The number of revolutions required to complete the induction and compression stroke in a six cylinder four-stroke engine is:
Correct answer is – 1
Q41. The purpose of a crankcase breather is to:
Correct answer is – prevent pressure building up inside the crankcase
Q42. Tappet clearance is provided in a piston engine to:
Correct answer is – allow for expansion of the valve gear as the engine warms up
Q43. Piston rings are manufactured from cast iron:
Correct answer is – to take advantage of its extreme malleability
Q44. The exhaust valves:
Correct answer is – sometimes have their stems partly filled with sodium to assist cooling
Q45. Hydraulic valve tappets are used on some engines to:
Correct answer is – eliminate constant valve adjustment and checks
Q46. The swept volume of a cylinder is:
Correct answer is – the area of the bore x the stroke
Q47. The thermal efficiency of a piston engine can be increased by:
Correct answer is – increasing the compression ratio
Q48. A normally aspirated engine is one which:
Correct answer is – is not supercharged
Q49. The Compression Ratio of an engine may be defined as the:
Correct answer is – swept volume + clearance volume clearance volume
Q50. An engine has a total volume of 2100 cm³ and a swept volume of 1800 cm³. Its compression ratio is:
Correct answer is – 7:1
Q51. Volumetric efficiency may be defined as:
Correct answer is – the ratio of the volume of the mixture drawn into the cylinder during normal engine working, to the volume of the mixture which would be required to fill the cylinder under normal temperatures and pressures
Q52. The ratio of the power produced by an engine to the power available in the fuel is known as the:
Correct answer is – thermal efficiency
Q53. Specific Fuel Consumption (SFC)
Correct answer is – is the weight of fuel used by an engine per unit horsepower per unit time
Q54. Brake Horsepower is:
Correct answer is – useful power at the propeller
Q55. A method of improving Volumetric Efficiency is:
Correct answer is – valve overlap
