Reciprocating Engines Flashcards
What is the purpose of dynamic dampers on a crankshaft?
They reduce engine vibration
What types of bearings are generally found in reciprocating engines?
Plain, ball and roller bearings
Are the connecting rods used for each cylinder of a radical engine the same? explain:
No. Radical engines use master and articulating rod assemblies.
Name the different types of piston rings:
Oil control
Compression
Oil scrapper
Where should piston rings gaps (splits) be installed relative to each other and why?
Gaps should be staggered, so they don’t align. This prevents excessive blow by.
What could result from incorrectly installed Piston rings?
Excessive oil consumption
What purpose do oil control rings serve?
They regulate the thickness of the oil film of the cylinder walls
What is used to help prevent valve surge or floating in an aircraft engine?
Two or more springs are used on each valve
On engines equipped with hydraulic valve lifters what should the running valve clearance be?
Zero
What is the purpose of valve overlap?
It allows better volumetric efficiency, and lowers cylinder operating temperatures
When troubleshooting a running engine malfunction, what does a cold cylinder indicate?
No combustion in that cylinder
Name at least one part of the inspection that should be made after a propeller strike:
Inspect the engine mounts, crankcase and nose section for damage
Inspect the oil screens/filters for metal particles
Inspect the propeller drive or crankshaft for misalignment
What is the fuel pressure range on float type carburetors?
3-5 PSI
What publication is used to check an engine for normal operation?
The manufacturers maintenance manual
What should be done to repair a loose stud in an engine crankcase?
Remove the loose stud and inspect the hole for proper size and condition of the threads. It might be necessary to use a suitable oversize stud or Heli coil insert
What is an indication that a primer is leaking or open during engine operation?
The engine will not idle properly
What procedure should be followed when valve blow-by is indicated by a hissing sound when pulling the propeller through its rotation?
Perform a cylinder compression test to identify the faulty cylinder
What factors about the condition of an engine can be learned by studying the results of a compression test?
The test can help determine if the valves, piston rings and pistons are adequately sealing
What is meant when an engine part is within “serviceable limits?”
The part is within the manufacturers serviceable limits and can be used in engine, and will not likely wear enough to cause engine failure before the next Time Between Overhaul (TBO) interval
When an engine is overhauled, how is its total time affected? When an engine is rebuilt, how is it operating history affected?
OVERHAULED- the total time on the engine is continued and the Time Since Major overhaul is entered into the logbook
REBUILT- the engine total time is reset to zero and is considered to have NO previous operating history
Name some of the precautions that should be performed prior engine replacement:
Disconnect the battery
Turn off the fuel valves
Chock the wheels
Install a tail stand (if necessary)
When inspecting a piston where are cracks most likely to be found?
Highly stressed areas
Based off piston bosses
Inside of the junction of the bore and the walls
Ring lands
How is a cylinder barrel inspected for out of roundness?
Measure the top of the cylinder and the skirt with a cylinder bore gauge and a micrometer, or an inside micrometer. Two readings should be taken, 90° to each other.
Is the aircraft electrical system required to power a cylinder head temperature gauge?
No. A thermocouple is used as the electric source.
What are the possible indications of an oil, pressure transmitter or indicator malfunction?
A severe or sudden drop in oil pressure when the oil temperature is normal, and the oil supply is full
What are some indications of induction system leakage?
Low power and uneven running
