Recip Engines Bottom Half Flashcards
What are the major components on the bottom end?
-Connecting rods
-Crankshaft
-Crankcase
-Camshaft and lifters
-accessory pads and drives
How are the body of the connecting rod and cap identified?
They will have the cylinder no. on them
How are connecting rods held in place?
Two bearing inserts are installed in the big end and held in place by tangs on the inserts
What do connecting rods do?
They carry the forces produced by the pistons into the crankshaft
What is critical about connecting rods?
The torque on the nuts of the connecting rod bolts
How do you determine the stroke of the engine?
The length of the crankshaft throw
2xcrank cheek = stroke
What is the purpose of sludge plugs?
Any sludge in oil is going to be trapped and held by he sludge plugs until the next overhaul
What is the function of dynamic dampers in the crankshaft?
The floating counterweights absorb torsional vibrations by changing the resonant frequency
What are the types of propeller attachments?
Tapered-small low powered engines
Splined-larger high powered engines
Flanged-most common
What is the purpose of a bearing?
To permit the other surface to move with a minimum of friction and wear
What are the three types of bearings used?
Plain
Ball
Roller
What are the three types of bearing loads?
Thrust
Radial
Combination
What types of bearings are on the crankcase?
plain bearings
What are the crankcase halves sealed with?
A thin gasket compound and a fine silk thread to provide an efficient oil seal
What is the valve operating mechanism also referred to as?
The valve train
What closes the valve?
Spring pressure
What are valve lifters also called?
Tappets
What is the function of a hydraulic valve lifter?
It automatically maintains zero clearance using oil pressure int the valve train unlike solid lifters
What is the purpose of the small hole on the pushrod?
To allow oil to pass through them to lubricate the rocker arm assembly
What is TBO?
Time between overhaul-the recommended max no. of hours that an engine can run between overhauls without endangering safe normal operation
What is the reliability of a part?
The ability of a component to perform and maintain its functions in routine conditions, as well as hostile or unexpected conditions
What were most common recip engine configurations?
-In line
-V-engine
-Radial engines
-Horizontally opposed engines
Pro’s of a horizontally opposed engine
-The operate at higher RPM
-Require a shorter prop
-Better visibility in front of the aircraft
What is the difference between TCM and Lycoming engine numbering?
-TCM cylinder 1 is the right rear cylinder
-Lycoming cylinder 1 is the right front cylinder
What is the function of lubrication systems?
Reduces internal friction, cushions the impact, removes heat
What are the two basic types of lubrication systems?
Wet sump
Dry sump
What does a crankshaft do?
With the help of the connecting rods transforms the back and forth movement of the pistons into rotary motion.
How are the crankshaft bearings and connecting rod bearing journals hardened?
By nitriding
What is crankcase?
The foundation of the engine and attaches the engine to the airframe
What is a bearing?
Is any surface which supports, or is supported by, another surface
What is a thrust load?
Are exerted on the bearing on a plane parallel to the center of the shaft (also called axial loads)
What is a radial load?
Are exerted on the bearing on a plane perpendicular to the shaft
Where are plain bearings used?
Crankshaft, camshaft, connecting rods, and accessory drive shafts
Mostly subjected to radial loads
Where are ball bearings used?
Some supercharger impeller shaft bearings and rocker arm bearings
Where are roller bearings used?
Straight roller bearings used where the bearing is subjected to radial loads only
Tapered roller bearings used where bearing is subjected to both radial and thrust loads
What is the crankcase breather line?
Prevents the pressure inside the crankcase from becoming excessive
