Reciprocating Engine Theory 2 Flashcards
The recommended maximum number of hours that an engine can run between overhauls.
Time between overhauls.
TBO
The ratio of the weight of an aircraft engine to the brake horsepower it develops.
Specific weight.
NASA
National Aeronautics and space administration.
NACA
National advisory committee for aeronautics.
This assures a good flow of cooling air over the engine cylinders and produces a forward aerodynamic force.
NACA cowling
T/F
NACA cowlings actually produce a forward aerodynamic force.
True
The ability of an engine to perform as the manufacturer has promised is known as the _______ of an engine.
Reliability.
The durability of an aircraft engine may be indicated by the manufacturer’s recommended _______.
TBO
A reciprocating engine with all the cylinders arranged in a straight line.
In-line engine.
A form of reciprocating engine in which the cylinders are arranged in two banks which are separated by an angle between 45 and 90 degrees.
V-engine
An in-line or v-engine in which the cylinders are mounted below the crankshaft.
Inverted engine.
A radial engine in which the propeller, crankcase and cylinders revolve as a unit.
Rotary radial engine.
The end of a reciprocating engine on which many of the accessories are mounted.
Accessory end.
The end of a reciprocating engine to which the propeller mounts.
Propeller end.
The end of a reciprocating engine that does not attach to the propeller.
Antipropeller end.
T/F
All radial engines number the cylinders with the bottom cylinder as 1.
False.
Top cylinder is 1
T/F
Radial engine cylinder numbering progresses consecutively around the engine in a counterclockwise direction.
False.
Direction of the crankshaft
A reciprocating engine in which the cylinders are arranged like the spokes of a wheel radiating out from a small central crankcase
Radial engine.
The firing order of a nine-cylinder radial engine is _______.
1-3-5-7-9-2-4-6-8
The smoothness with which a reciprocating engine runs is determined by the ______.
Spacing and timing of the firing impulses.
T/F
All cylinders fire in two revolutions of crankshaft rotation.
True.
The reservoir on an aircraft engine that holds the lubrication oil.
Sump.
Two basic types of lubrication systems used on aircraft reciprocating engines.
Wet sump.
Dry sump.
________ lubrication systems are normally used by radial engines and inverted in-line and V-engines.
Dry-sump
_______ engines carry all the lubricating oil in an integral sump that is part of the crankcase.
Wet-sump
R =
Radial
O =
Opposed
A=
Aerobatic
G=
Geared nose section
H=
Horizontal, for helicopter
I=
Fuel injected
L (At beginning of sequence) =
Left hand engine rotation
L (At end of sequence)
Liquid cooled
S=
Supercharged
T or TS =
Turbocharged
V=
Vertical for helicopter
F=
FADEC controlled
The middle number in a reciprocating engine ID represents _________.
Piston displacement in cubic inches.
Cylinder walls are hardened by either _______ or _______.
Chrome plating,
The process of nitriding.
_______ have a surface with a spiderweb of tiny stress cracks.
Channel-chromed cylinders
A method of case hardening steel using heat and ammonia gases.
Nitriding.
Used to restore or reinforce threads of a bolt hole.
Heli-coil insert
The internally threaded, cast aluminum top that is screwed onto the steel cylinder barrel.
Cylinder head.
T-shaped valve with a circular head, used to cover the intake and exhaust openings in the cylinder head
Poppet valve
Pivoted arm that forces poppet valves off their seats.
Rocker arm.
Take more punishment than any other component in an engine.
Exhaust valves.
Two or more springs are used on each valve to prevent _____.
Valve surge/float.
Multiple springs are used in valves to prevent valve float caused by _______.
Resonant frequency of the spring.
______maintain zero clearance in the valve operating train
Hydraulic valve lifters
5 reciprocating engine traits:
Reliability, Operating flexibility, Durability, Specific weight, Streamline-ability
Cylinder finish type identified by blue paint.
Nitride
Cylinder finish type identified by orange paint.
Chrome plated
T/F
The intake valve head is bigger than that of the exhaust valve.
True.
T/F
The intake valve stem is bigger than that of the exhaust.
False
Some valve stems are filled with sodium to _______.
Dissipate heat.
4 types of reciprocating engines:
Radial,
Horizontally opposed,
V-engine,
In-line
Two types of cooling:
Air and liquid
The purpose of the cylinders’ firing order is to ______.
Reduce vibration.
Two companies that produce 4 and 6 cylinder horizontally opposed engines:
Continental,
Textron-Lycoming
Cooling systems use a mix of water and ______.
Ethylene glycol.
_______ is welded to the face of many exhaust valves that operate at high temps.
Stellite
An assembly fit in which the hole is smaller than the part that fits into it.
Interference fit.
A reciprocating engine piston that is not round.
Cam-ground piston
4 types of piston heads:
Recessed.
Truncated cone.
Domed.
Cupped.
3 types of piston rings:
Compression.
Oil control.
Oil scraper/wiper.
Almost all piston rings are made of _______.
Cast iron.
T/F
Piston rings used in chrome plated cylinders must not be plated.
True
The wear between the cylinder ring and cylinder wall produces a seal and allows the rings to ______.
Seat.
3 methods of heat transfer:
Conduction.
Radiation.
Convection.
A four cylinder crankshaft in a continental engine has 3 ______ and 4 _____.
Main journal bearings.
Throws.
Component of a crankshaft that traps debris by centrifugal force.
Sludge plug.
3 different methods of attaching props to engine crankshafts:
Splined shaft.
Tapered shaft.
Flanged shaft.
Part of crankshaft that absorbs torsional vibrations.
Dynamic counterweights.
Serves as the foundation of the engine and attaches the engine to the airframe.
Crankcase
Horizontally opposed engine crankcases are cast of _____.
Aluminum alloy
Crankshafts are supported in the crankcase by ______.
Plain bearings.
T/F
Crankshafts do not use any type of ball bearing insert or bushing.
True.
Parts of the valve train:
Camshaft, Cam lobe, Hydraulic valve lifter, Pushrod, Rocket arm, Valve springs, Poppet valve.
Used to maintain zero clearance in the valve train:
Hydraulic valve lifter
Zero lash valve lifter
T/F
Most radial engines use hydraulic valve lifters.
False.
The valve clearance when the engine is hot is ________ than the clearance when it is cold.
Greater.
The cylinder barrel of a modern reciprocating engine is made of _______ or _______.
Chrome moly.
Chrome nickel moly.
The part of the cylinder that fits into the crankcase.
Skirt.
A type of cylinder in which the diameter at the top is smaller than the diameter at the middle.
Choke-ground/bored
T/F
The diameter of a cam-ground piston perpendicular to the wrist pin is smallest.
False.
A pin that is not clamped to either the connecting rod nor the piston is called ______
Full floating wrist pin
The bearing on the small end of a connecting rod is a ______.
Bronze bushing
The throws on a crankshaft of a 4 cylinder HO engine are ______ degrees apart.
180
The camshaft of a HO engine turns at _______ the speed of the crankshaft.
One half
The bearing used in most rocker arms is a _____
Bronze bushing
