Reciprocating Engines Flashcards
Define the term “operating flexibility” in regards to aircraft engines.
The ability of an engine to run smoothly and give desired performance at all speeds from idling to full-power output.
How are conventional reciprocating engines classified?
According to cylinder arrangement with respect to the crankshaft or method of cooling.
What are the different types of piston rings?
Compression
Oil Control
Scraper
What are the main causes of a cylinder having low compression?
Broken piston rings
Rings not seating properly
Burnt valves
Poorly seating valves
What is the purpose of the oil control rings?
To control the thickness of the oil film on the cylinder walls.
What may be the result of installing piston rings incorrectly?
Excessive oil consumption.
What type of piston rods are commonly found in radial engines?
Master and Articulating Rod Assembly.
What type of bearings are in general use in reciprocating engines?
Plain
Roller
Ball
What is the indication of valve blow-by?
Hissing or whistling when pulling the propeller through by hand.
What is the purpose of using more than one spring for valve closing?
Each spring, installed one inside the other, will resonate at a different engine speed, eliminating valve float.
What is the purpose of valve overlap?
Better volumetric efficiency and lower cylinder operating temperature.
Describe the inspection you would give the valve springs during engine overhaul.
Cleaned thoroughly, then visually inspected for evidence of overheating, cracks, broken ends, and compression strength.
What is the purpose of using valves with sodium filled stems?
The sodium is an excellent heat conductor which dissipates heat.
What causes engine sudden stoppage?
Striking an object or engine seizure due to internal damage.
What type of inspection must be made after sudden stoppage of an engine?
A complete engine tear down and inspection.
What is the purpose of the crankshaft dynamic dampers used in aircraft engines?
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?
Remove Prop. from crankshaft.
Attach dial indicator to front of crankcase.
Adjust gauge needle so it touches shaft.
Rotate crankshaft to check for misalignment.
What is detonation?
The instantaneous explosive burning of the last portion of the charge across the combustion chamber.
What cylinder is engine to magneto timing based on?
The number one cylinder.
What is engine sudden speed reduction?
When the propeller strikes an object but continues to run.
What can be learned about the condition of an engine by studying the results of a compression check?
If the valves, piston rings, and pistons are adequately sealing the combustion chamber.
How can a cold cylinder be located on a double row radial engine?
Infrared laser thermometer.
What instrument can be used to check bore for out of round?
Inside Micrometer.
What would a cold cylinder indicate?
That there has been no combustion inside the cylinder.
Where is a crack most likely to occur on a piston?
Where the piston pin/wrist pin connects.
What should be done to a nose wheel airplane before removing the engine?
Support the tail.
What is the running valve clearance on engines equipped with hydraulic lifters?
Zero
What lever is used to adjust the manifold pressure in a reciprocating engine?
Throttle
On an engine with a fixed pitch propeller, what is the relationship between manifold pressure and RPM?
As RPM increases, MAP increases.
What should be done to repair a loose stud in an engine crankcase?
Remove the loose stud and inspect the hole for size and thread condition. It may be necessary to use a suitable oversized stud.
What is meant by an engine part being within serviceable limits?
The part will not likely wear to the point of causing engine failure within the next time between overhaul.
What is an indication that primer is leaking or is open during engine operation?
The engine will not idle properly.
What are the main parts of a reciprocating engine accessories section?
Case and gear drivetrain.
What is stoichiometric ratio?
15:1
What type of ignition systems are used on modern reciprocating engines?
Electronic ignition systems.
