Bakers Oral Powerplant Exam Questions and Answers (Graded A+)

How are reciprocating engines classified? - ANSWER-1) Cylinder Arrangement w/ respect to crankshaft (in-line, V-type, radial and opposed) 2) Method of cooling (liquid cooled, or air cooled) what are the different types of piston rings - ANSWER-compression rings, oil control rings and scraper rings what are the main causes of a cylinder having low compression - ANSWER-broken piston rings, rings that are not seated properly, burnt valves and poorly seating valves what is the purpose of the oil control rings? - ANSWER-they are used to control the thickness of the oil film on the cylinder walls what may be the result of installing piston rings incorrectly - ANSWER-excessive oil consumption what type of piston rods are commonly found in radial engines - ANSWER-a master and articulating rod assembly what type of bearings are in general use in reciprocating engines - ANSWER-plain, roller and ball bearings what is the indication of valve blowby - ANSWER-a hissing or whistle when pulling the propeller through by hand what is the purpose of using more than one spring for valve closing - ANSWER-valve springs will resonate (or surge) at certain engine speeds. what is the purpose of valve overlap - ANSWER-better volumetric efficiency and lowers the cylinder operating temperatures describe the inspection you would give the valve springs during engine overhaul - ANSWER-they should be cleaned thoroughly, then visually inspected for evidence of overheating, cracks, broken ends, and compression strengh what is the purpose of using valves with sodium filled stems - ANSWER-because it is an excellent heat conductor what causes engine sudden stoppage - ANSWER-Striking an object or engine seizure due to internal damage. What type inspection must be made after sudden stoppage of an engine? - ANSWER-a complete engine tear down and inspection what is the purpose of the crankshaft dynamic dampers used in aircraft engines - ANSWER-to overcome forces which cause deflection of the crankshaft and torsional vibration How would you make a "runout" check on a crankshaft that is still installed in the engine? - ANSWER-remove the propeller from the crankshaft and attach a dial indicator gauge to the front of the crankcase. adjust the position of the gauge needle so that it is touching the shaft. rotate the crankshaft and check for misalignment what