Reciprocating engines Flashcards
How are conventional reciprocating engines classified
According to cylinder arrangement with respect to the crankshaft
In line, V-type, radio, and opposed
Method of cooling is liquid cooled, or air cooled
What are the different types of piston rings
Compression rings, oil control rings, and scraper rings
What are the main causes of a cylinder having low compression
Broken piston ring, rings that are not sealing properly, burnt valves, and poorly seating valves
What is the purpose of the oil control rings
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
Excessive oil consumption
What type of piston rod are commonly found in radial engines
Master and articulating rod assembly’s
What type of bearings are in general use in reciprocating engines
Plane, roller, and ball bearings
Plane bearings are generally used for crankshaft, camshaft and connecting rods
Roller bearings are used primarily as crankshaft main bearings
And ball bearings are used for supercharger impeller shaft bearings and crankshaft Russ bearings on large radial engines
What is the indication of valve blow by
Indicated by hissing or whistling when pulling the propeller through by hand.
Hey cylinder compression check should be completed to identify the faulty cylinder
What is the purpose of using more than one spring for valve closing
Valve springs will resonate at certain energy speeds. If only one spring is used, the valve will float as a spring surges. To illuminate this problem, two springs are installed on each valve
What is the purpose of valve overlap
Valve overlap permits better volumetric efficiency And lowers the cylinder operating temperatures
Describe the inspection you would give the valve springs during engine overhaul
Clean thoroughly, visually inspect for evidence of overheating, cracks, broken ends, and compression strength
What is the purpose of using valves with sodium filled stems
Sodium is used because it is an excellent he conductor
The sodium melts at a relatively low temperature, and as the valve moves up and down the sodium is circulated, carrying the heat from the valve head to the stem. Then the heat is dissipated to the cylinder head
What causes engine sudden stoppage
Striking an object or engine seizure Due to internal damage
What type inspection must be made after sudden stoppage of an engine
Most manufacturers require a complete engine tear down and inspection
What is the purpose of crankshaft dynamic dampers used an aircraft engine
Dampers are used to overcome forces which caused the flexion of the crankshaft and torsional vibration.
Crankshaft vibrations are reduced by placing floating dampeners weights in a counterweight assembly, particularly in a single throw type crankshaft
How would you make a run out check on the crankshaft that is still installed on an engine
Remove the propeller from the crankshaft and attach a dial indicator gauge to the front of the crankshaft. Adjust the piston of the gauge needle so that is touching the shaft. Rotate the crankshaft and check for misalignment
What is detonation
All fuels have a critical limit of temperature and compression, beyond this limit they will ignite spontaneously and burn with excessive violence
What cylinder is engine to magneto timing based on
The number one cylinder
It is usually set for around 30° before top dead center on the compression stroke
What is the engine sudden speed reduction
This occurs when a propeller strokes and object but continues to run
What can be learned about the condition of an engine by studying the result of a compression check
You can determine if the valves, piston rings, and Pistons are adequately sealing the combustion chamber
How can cold cylinder be located on a double row radial engine
Magic wand or a more modern infrared laser thermometer
What instrument can be used to check bore for out of roundness
A dial indicator, telescopic gauge and outside micrometer or inside micrometer
What would a cold cylinder indicate
No combustion inside the cylinder, normally do to know ignition or clogged fuel nozzle
Where is a crack most likely to occur in 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 of the airplane
