POWERPLANT 1 Flashcards
A ________________ is a type of heat engine that derives its name from the back-and-forth, or reciprocating movement of its pistons.
reciprocating engine
The ________________ is also known as an internal-combustion engine. This name is used because the fuel mixture is burned within the engine.
reciprocating engine
The two primary reciprocating engine designs are the ___________ and _______________.
spark ignition and the compression ignition
what is the ratio of fuel air mixture?
weight of fuel to the weight of air in the mixture to be burned
the ____________ also called a centrifugal compressor drew air through an inlet.
super charger
Fuels for aviation also demanded
attention. When engine designers tried to
build motors with greater power, they ran
into the problem of ______
“knock.”
_________ fuels avoided knock but
produced little power.
Poor-grade
During _____________, the best piston engines
used a turbocharger.
World War II
types of reciprocating engine
- radial engine
- in-line engine
- v- type engine
- opposed or flat type engine
A _________ consists of a row, or
rows of cylinders arranged radially
about a central crankcase.
radial engine
two types of radial engine
single row and double row
__________ radial engine has an odd number of cylinders attached radially to a crankcase. A typical configuration consists of five to nine
cylinders evenly spaced on the same circular plane with all pistons connected to a single crankshaft.
Single-row
____________ radial engines consisted of two single row engines in line with each other connected to a single crankshaft. This type of engine is sometimes referred to as a double row radial engine and typically has a total of 14 or 18 cylinders.
Multiple-row
An ______________ engine generally has an even number of cylinders that are aligned in a single row parallel with the crankshaft. This engine can be either liq-uid-cooled or air cooled and the pistons can be located either upright above the crankshaft or inverted below the crankshaft.
in-line
The cylinders of a __________ are arranged around a single crankshaft in two in-line banks that are 45, 60, or 90 degrees apart.
V-type engine
Since __________ had two rows of cylinders, they were typically capable of producing more horsepower than an in-line engine
V-type engines
Most ____________ had 8 or 12 cylinders and were either liquid-cooled or air cooled.
V-type engines
_______________ are the most popular reciprocating engines used on light aircraft.
Opposed-type engines
A typical _______________ can
produce as little as 36 horsepower to
as much as 400 horsepower.
opposed engine
_____________ have high power-to-weight ratios because they have a comparatively small, lightweight crankcase.
Opposed-type engines
Most efficient, dependable, and
economical type available for light
aircraft.
Opposed-type engines
The Four Basic Power Delivering Parts
cylinder
pistol
connecting Rod
crankshaft
The __________ provides a combustion
chamber where the burning and
expansion of gases takes place to
produce power.
cylinder
A _____________ houses the piston and
connecting rod assembly as well as
the valves and spark plugs.
cylinder
Transmits power through pistons,
connecting rods and rotate the
crankshaft
cylinder
The _______ in a reciprocating engine is
a cylindrical plunger that moves up
and down, back and forth within a
cylinder.
piston
Piston speed is maximum during the
_______ and _______ quarters of crankshaft
rotation.
first and fourth
The _____________ is the link which
transmits the force exerted on a
piston to a crankshaft.
connecting rod
One end of a connecting rod
connects to the crankshaft and is
called the ____________
crankpin end
The other end connects to the piston
and is called the ______________.
piston end
The ___________ is the backbone of a
reciprocating engine.
crankshaft
Its main purpose is to transform the
reciprocating motion of the pistons
and connecting rods into rotary
motion to turn a propeller.
crankshaft
Since __________ must withstand high
stress, they are generally forged from
a strong alloy such as chromiumnickel molybdenum steel.
crankshafts
The vast majority of certified aircraft reciprocating engines operate on the four stroke cycle, sometimes called the _________ after its originator, a German physicist.
Otto cycle
Two complete revolutions of the crankshaft
(720°) are required for the four strokes; thus,
each cylinder in an engine of this type fires
once in every _________ of the
crankshaft.
two revolutions
4 Strokes:
- Intake
- Compression
- Power
- Exhaust
5 Events:
- Intake
- Compression
- Ignition
- Power or Expansion
- Exhaust or Scavenging
“Fuel and air enters inside the
combustion chamber.”
intake
The intake valve is opened
considerably before the piston reaches ____
on the exhaust stroke,
TDC
The intake valve is timed to close
about ____ to _____ past BDC on the
compression stroke, depending upon the
specific engine, to allow the momentum of
the incoming gases to charge the cylinder
more completely.
50° to 75°
During the ____________, the
crankshaft continues to rotate, the piston is
forced upward in the cylinder, and both
intake and exhaust valves are closed. The
movement of the piston upward
compresses the fuel-air mixture.
compression stroke
Fuel and air compression”
compression stroke
The charge is fired by means
of an ____________ as the piston
approaches TDC.
electric spark
The time of ignition varies
from ____to ____ before TDC, depending
upon the requirements of the specific
engine to ensure complete combustion of
the charge by the time the piston is slightly
past the TDC position.
20° to 35°
“Fuel and air burned”
power
The temperature of these burning gases in power stroke may be between _______and _____
3,000° and 4,000 °F.
“Fuel and air or carbon deposits
moves outside the cylinder”
exhaust stroke
firing order of V type engine with four cylinders
1 3 4 2
firing order of v type engine with six cylinders
1 6 5 4 3 2
firing order of v type engine with 8 cylinders
1 3 7 2 6 5 4 8
firing order of in line engine with three cylinders
1 2 3
firing order of in line engine with four cylinders
1 3 4 2
firing order of in line engine with six cylinders
1 5 3 6 2 4
______________ engines
require only one upstroke and one down
stroke of the piston to complete the
required series of events in the cylinder.
two-stroke cycle
The intake and exhaust functions are
accomplished during the same stroke.
two stroke cycle
Most _______ engines are of the
crankcase compression type.
two-stroke
The earliest two-strokes were of the
________ type.
uniflow
The _______ cycle has a three-sided rotor that
turns inside an elliptical housing, completing
three of the four cycles for each revolution.
rotary
The ______ cycle depends on high
compression pressures to provide for the
ignition of the fuel/air charge in the cylinder.
diesel
there are ___ magnetos, left and right
two
Types of Magnetos:
Slick Magneto
Bendix Dual Magneto
Bendix Single Magneto.
It is the job of the __________ to
measure the amount of incoming intake air
and meter out the proper fuel/air ratio to
the cylinder intakes.
carburetor
___________________ help provide electrical power in an aircraft.
Aircraft generators
Most ______________ starters are the direct
cranking electric type.
reciprocating engine
Aircraft reciprocating engine pressure lubrication systems can be divided into two basic classifications:
wet sump and dry sump.
_____________ stores oil in a reservoir inside the engine. After the oil is circulated through the engine, it is returned to this crankcase-based reservoir.
wet sump system
A ____________ pumps the oil from the
engine’s crankcase to an external tank that
stores the oil.
dry sump engine
The _______________ uses a scavenge pump, some external tubing, and an external tank to store the oil.
dry sump system
___________ radial engine, cylinder No. 1 is the top cylinder.
Single-row
__________ radial engine, all odd-numbered cylinders are in the front, and all even numbered cylinders are in the rear.
Double-row
Cylinder Numbering (Opposed Engine)
___________ starts from rear
Continental
Cylinder Numbering (Opposed Engine)
___________ starts from front.
Lycoming
The Sequence in which the power event occurs in the different cylinders. Designed to provide for balance and to eliminate vibration.
Firing Order
The __________ acts as a lid on the
cylinder barrel to provide an
enclosed chamber for combustion.
cylinder head
__________ contain intake and exhaust valve ports, spark plugs, valve actuating mechanisms, and
serve to conduct heat away from the cylinder barrels.
Cylinder heads
The ___________ in a reciprocating engine is a cylindrical plunger that moves up and down, back, and forth within a cylinder.
piston
2 Types of Piston Rings
Compression rings and oil rings
_______________prevent gas from escaping past the piston during engine operation and are placed in
the ring grooves immediately below the piston head.
Compression rings
_________ control the amount of oil that is applied to the cylinder walls as well as prevent oil from entering the combustion chamber.
Oil rings
A _________ joins the piston to the
connecting rod.
piston pin
__________ are sometimes called wrist
pins
Piston pins
Engine __________ regulate the flow of gases into and out of a cylinder by opening and closing at
predetermined times in the combustion process.
valves
The ___________ controls the amount of fuel/air mixture that enters a cylinder through the intake port,
intake valve
The ____________ allows the exhaust gases to exit the cylinder through the exhaust port.
exhaust valve
– a device for actuating the valve lifting mechanism.
Camshaft
A circular piece of steel with a series of raised cam lobes on its outer edge.
Cam ring
– a mechanism to transmit the force of the cam to the push rod
Valve lifter or tappet
– a steel or aluminum alloy rod or tube situated
between the valve lifter and the rocker arm to transmit the motion of the valve lifter
Push Rod
– a pivoted arm mounted
on the bearings of the cylinder head
to open and close the valves.
Rocker Arm
4 Parts of a Crankshaft
Main Bearing Journal/Main Journal
Crankpin
Crank cheek or crank arm
Counterweights and dampers
Represent the centerline of a crankshaft and support the crankshaft as it rotates in the main
bearings. Center of rotation of the crankshaft.
Main Bearing Journal/Main Journal
Or connecting-rod bearing journals or throws, serve as attachment points for the connecting rods.
Crankpin
Its function is to relieve the whip and vibration
caused by rotation of the crankshaft.
Counterweights and dampers
2 Types of Overhaul
top overhaul and major overhaul
__________________ consists of the
complete reconditioning of the power
plant.
Major overhaul
This means an overhaul of those parts on top of
the crankcase, without completely dismantling the engine.
top overhaul
At _____________, an engine should be completely dismantled, thoroughly cleaned, and inspected.
regular intervals
A ____________________ can perform or supervise a
major overhaul of an engine if it is not equipped with an internal supercharger, or has a propeller reduction system other than spur-type gears.
certified power plant-rated
technician
The primary function is to provide
space for the mounting of accessories
necessary for operation and control of the
engine.
Accessory Section
Aircraft carburetors are separated
into two categories:
float type carburetors
and pressure-type carburetors
complete with idling, accelerating, mixture control, idle cutoff, and power enrichment systems, are the most common of the two carburetor types.
Float-type carburetors
The _______________ delivers fuel under pressure by a fuel pump.
pressure-type carburetor
The basic difference between a float-type and a pressure-type carburetor is the _________________.
delivery of fuel
Carburetors are normally calibrated at sea-level air pressure where the correct fuel-air mixture ratio is established with the mixture control set in the ____________ position.
FULL RICH
