Recip Engines Flashcards
What is the purpose of dynamics dampers on crankshafts?
They reduce engine vibration
What types of bearings are generally found in reciprocating engines?
Plain, Ball and Roller bearings.
Are the connecting rods used in each cylinder of a radial engine the same? Explain:
NO… Radial engines use master and articulating rod assemblies.
Name the different types of piston rings:
Oil control, Compression and oil Scrapper.
Where should piston rings gaps be installed relative to each other, and why?
Compression ring gaps should be staggered so that they do not aling. This prevents excessive blow-by (blow-by - also caused by worn or bore compression rings).
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.
Hydraulic
When troubleshooting a running engine malfunction, what does a cold cylinder indicate?
No combustion in that cylinder.
Name at least one part of an inspection that should be made after a propeller strike (not sudden stoppage)?
(1) Inspect the engine mounts, cranckcase, and nose section for damage
rings
(2) Inspect the oil screens/filters for metal particles
Oil control ring
Piston pin boss
(3) Inspect the propeller drive or crankshaft for misalignment.
What is the fuel pressure range on Float-Type carburators?
3 - 5 PSI
What publication is used to check an engine for normal operation?
The manufacturer’s maintenance manual.
What should be done to repair a loose stud in an engine crackcase?
Remove the loose stud, inspect the hole for size and condition of the threads.
It may be necessary to use a suitable oversize stud or Heli-Coil insert.
What is an indication that a primer is leaking or is 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 on a reciprocating engine when pulling the propeller through?
Perform a cylinder compression test to indentify the faulty cylinder.
What factors about the condition of an engine can be learned by studying the results of a compression test?
The results of a compression test determine if the valves, pistons rings and pistons are adequately sealing.
What is meant when it is said that an engine PART is within “serviceable limits”?
A part that is within the manufacture’s serviceable limits and can be used in an engine, will not likely wear to the point of causing engine failure within 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 its operating history affected?
OVERHAULED - The total time on the engine must be continued and the time since major overhaul is entered into the logbook.
REBUILT - If the manufacturer rebuilds the engine it is granted a ZERO-TIME status 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 and if necessary install a tail stand.
When inspecting a piston, where are cracks most likely to be found?
Highly stressed areas, base of piston bosses, inside at the junction of the bore and the walls and ring lands.
How is a cylinder barrel inspected for out of roundness?
You must measure with a (cylinder bore gage or a telescopic gauge and micrometer, or an inside micrometer) the top of the cylinder and the skirt.
This 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 electrical source.
What are the possible indications of an oil pressure transmitter or indicator malfunction?
A severe or sudden drop in oil pressure while the oil temperature remains normal and the oil supply remains full.
What are some indications of induction system leakage?
Low power and Uneven running.
