Aircraft Engine Exam Study Guide PDF

Chapter 2 Name Date REVIEW EXAM I. Which of the following statements is true regarding 6. The clearance between the rocker arm and the valve tip...

Chapter 2 Name Date REVIEW EXAM I. Which of the following statements is true regarding 6. The clearance between the rocker arm and the valve tip bearings used in high-powered reciprocating aircraft affects how many of the following? engines? (1) Point at which valve opens a. The outer race of a single-row, self-aligning ball (2) Height of valve opening bearing will always have a radius equal to the radius (3) Duration of valve opening of the balls. a. One b. There is less rolling friction when ball bearings are b. Two used than when roller bearings are employed. c. Three c. Crankshaft bearings are generally of the ball type d. None because of their ability to withstand extreme loads without overheating. 7. Which of the following statements regarding engine d. Crankshaft bearings are generally of the ball type crankshafts is true? because of their ability to withstand loads. How­ a. Counterweights reduce torsional vibration. ever, some manufacturers object to the use of ball b. Counterweights provide static balance. bearings because they require a positive high-pres­ c. A six-throw crankshaft utilizes three dynamic sure oil supply. dampers. d. Dynamic dampers are designed to resonate at the 2. Which propeller reduction-gear ratio will cause the natural frequency of the crankshaft. highest propeller rpm? (Assume the same engine rpm in each case.) 8. Cam-ground pistons are installed in some aircraft a. 16:7 engines to b. 16:9 a. provide a better fit at operating temperature. c. 20:9 b. cause the master rod piston to wear at the same rate d. 3:2 as those installed on the articulating rods. c. act as a compensating feature so that a compensated 3. Which of the following is the principal advantage of magneto is not required. using propeller reduction gears? d. equalize the wear on pistons that do not operate in a a. They enable the propeller rpm to be increased with­ vertical plane. out an accompanying increase in engine rpm. b. They allow the diameter and blade area of the pro­ 9. Some aircraft engine manufacturers equip their prod­ peller to be increased. ucts with choked or taper-ground cylinders. Choke­ c. They permit the engine rpm to be increased with an type cylinders are used because they accompanying increase in power and allow the pro­ a. provide a straight cylinder bore at operating peller to remain at a lower, more efficient rpm. temperatures. d. They enable the engine rpm to be increased with an b. reduce the possibility of piston rings sticking in the accompanying increase in propeller rpm. ring grooves. c. compensate for normal cylinder barrel wear. 4. Which of the following is the type of thrust bearing d. increase the compression pressure for starting used in most radial engines? purposes. a. Tapered roller b. Double-row ball 10. An overhead valve engine using zero-lash hydraulic c. Double-row straight roller valve lifters is observed to have no clearance in its d. Deep-groove ball valve operating mechanism after the minimum inlet-oil and cylinder-head temperatures for takeoff have been 5. Which of the following bearings is least likely to be a roller or ball bearing? reached. This condition can be expected a. during normal operation. a. Rocker-arm bearing (overhead valve engine) b. when the lifters become deflated. b. Master rod bearing (radial engine) c. Crankshaft main bearing (radial engine) c. as a result of carbon and sludge becoming trapped d. Generator armature bearing in the lifter and restricting its motion. d. as a result of inverting the tappet valve during the assembly of the lifter. Chapter 2 I REVIEW EXAM 13 11. The insides of some cylinder barrels are hardened by 16. Excessive valve clearance causes the valves to a. nitriding. a. open early and close early. b. shot peening. b. open late and close early. c. nickel plating. c. open early and close late. d. cadmium plating. d. open late and close late. 12. The operating valve clearance of an engine using 17. An advantage of using metallic sodium-filled exhaust hydraulic tappets (zero-lash lifters) should not exceed valves in aircraft reciprocating engines is a. 0.15 to 0.18 in. a. increased resistance to corrosive gases. b. 0.00 in. b. increased strength and resistance to fatigue. C. 0.25 to 0.32 in. c. reduced valve operating temperatures. d. 0.30 to 1.10 in. d. greater resistance 10 detonation at high valve tem­ peratures. 13. Full floating piston pins are those which allow motion between the pin and 18. Valve clearance changes on opposed-type engines a. the connecting rod. using hydraulic lifters are accomplished by b. the piston. a. rocker-arm adjustment. c. both the piston and the large end of the connecting b. rocker-arm replacement. rod. c. adding or removing valve-stem shims. d. both the piston and the small end of the connecting d. pushrod replacement. rod. 19. The source of most of the heat that is absorbed by the 14. The purpose of two or more valve springs in an air­ lubricating oil in a reciprocating engine is the craft engine is to a. connecting-rod bearings. a. reduce valve stretch. b. crankshaft main bearings. b. equalize side pressure on the valve stems. c. exhaust valves. c. eliminate valve-spring surge. d. pistons and cylinder walls. d. eliminate valve-stem breakage. 20. The way in which the oil collected by the piston ring is 15. Consider the following statements: returned to the crankcase is (I) Only cast-iron piston rings can be used in nitrided a. down vertical slots cut in the piston wall between or chromium-plated cylinders. the piston oil ring groove and the piston skirt. (2) Chromium-plated piston rings inay be used in plain b. through hollow piston pins. steel cylinders. c. through holes drilled in the piston oil ring groove. Of these two statements, d. through holes drilled in the piston-pin recess. a. only No. l is true. b. only No. 2 is true. c. neither No. I nor No. 2 is true. d. both No. 1 and No. 2 are true. 14 Student Study Guide / Aircraft Powerplants