Transcript Cadet Phase I & II Aerospace Dimensions Introduction to

Cadet Phase I & II
Aerospace Dimensions
Aircraft Systems and Airports (Module 2)

Session 1:
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
Chapter 1 ‘Airplane Systems’
Activity
Additional material for Cadet Officers only
Session 2:
Chapter 2 ‘Airports’
Activity
 Chapter 3 ‘Aeronautical Charts’
Activity

(ONLY for all Cadets that have not yet passed corresponding AE test, and Cadet Mentors)
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
1
Airplane Systems

Important Terms (Quiz):
 Powerplant
 Compression
 Reciprocating
 Stoichiometric
 Cycle
 Rich
Mixture
 Combustion
 Lean
Mixture
 Combustion
 Stroke
Chamber
 Fuel
 Meter
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
/ Metering
2
Airplane Systems

Chemistry of Power
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A Heat Engine is one that uses Combustion to create Heat
Energy, which it then converts into Mechanical Energy
The Combustion occurs when a compressed Fuel/Air mixture
is ignited by a spark
 The Fuel, Aviation Gasoline (Petroleum Spirit, a Fossil Fuel), is
mixed with Air in the Carburetor, then injected into the cylinder
and compressed
 The ‘ideal’ Fuel/Air mixture is 1/15, called Stoichiometric
– More Fuel = Rich Mixture, More Air = Lean Mixture
– Normally Rich at start-up, then reduced to typically 1/12
 Compression begins the chemical combination process, and
makes the combustion more efficient
– When ignited, the mixture Oxidizes, releasing Energy BANG!
– After ignition, waste gases such as Carbon Dioxide, and Carbon
Monoxide, plus water are expelled through the exhaust system
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
3
Airplane Systems

What’s inside a reciprocating engine, and how does it
work?
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Intake Valve - fuel/air mixture enters here
The Cylinder - fuel is compressed and burned inside
Exhaust Valve - Exhaust gasses out here
Piston - Forced down by explosion,
then pushes up and forces exhaust
gasses out of the cylinder
Connecting Rod (Con-Rod) connects piston to crankshaft
Crankshaft - translates piston
up/down into shaft rotation,
complex shape allows all pistons
to work together in sequence
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
4
Airplane Systems

Converting Chemical to Mechanical Energy
4 stroke reciprocating engine (5 event):
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
5

Airplane Systems
Cylinder Arrangements:
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In-Line
 Cylinders in a straight line, all facing same way
Horizontally Opposed In-Line
 Cylinders in a straight line, facing each other in pairs,
con-rods not joined

V In-Line
 Two rows of cylinders,
matched in pairs
angled to form a V
when viewed along
the crankshaft,
con-rods joined

Radial
 Complex ‘Star’ cylinder
arrangement,
con-rods joined
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
6
Airplane Systems

Major Parts of an Aircraft Reciprocating Engine
(Horizontally Opposed In-Line - External view)
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What Cylinder Arrangement do you see?
What does the Starter do?
What does the
Carburetor do?
What does the
Magneto do?
What is the
Crankcase for?
Do all the Cylinders
operate the same
cycle at the
same time?
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
7

Airplane Systems
Fuel Systems: Aircraft Carburetor
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Air is drawn into the engine through the carburetor (due to piston
suction), and flows through a Venturi
The Venturi causes the air to accelerate, and thus, due to
Bernoulli's principle, the pressure drops
The pressure drop sucks gasoline into the airflow
Mixture Control ensures that the mixture which enters the cylinder is
the correct mix of fuel and air
Nozzle ‘Atomizes’ the mixture
(very fine mist), which makes
combustion much more efficient
Throttle opens/closes a valve to
control the amount of mixture
which can enter the cylinders
When necessary, the Carburetor
Heat function uses Hot Exhaust
gasses to melt any ice in the Venturi
Throttle and Mixture can be controlled from the cockpit
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
8
Airplane Systems

Jet Engines

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Air drawn in and compressed by Compressor fans
 mixed with fuel and ignited in Combustion Chamber
 Hot Exhaust exits Combustion Chamber
as high speed and drives Turbine,
which via Shaft drives compressor
 In Exhaust Nozzle thrust transfers
to aircraft via Thrust Cone
Rocket Engines (Liquid type)

Pumps draw liquid Oxidizer and Fuel
into the Combustion Chamber via the Injectors
 The Mixture is ignited, expands extremely rapidly,
exiting through the
‘Bell’ Nozzle
 The nozzle transfers the
exhausts thrust to the
rocket body
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
9
Airplane Systems

Electrical Systems
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An aircraft engine typically generates electrical power, as well as
driving the propeller, and so is called a Powerplant
Electric power for the spark plugs is generated by the Magnetos,
which work like a motor in reverse, by generating an electric current
when their internal components are rotated
 Modern aircraft have a battery to get this started, but it is possible
to have a working electrical system for the combustion spark with
NO battery at all!
Electrical power for the aircraft’s equipment (radio, lights etc.) is
supplied by the Alternator, which works just like the magneto, but
supplies a much lower AC voltage (14-28 volts), and also recharges
the battery (needed for starting & electrical power when engine off)
Electrical Current Flow is monitored by the Ammeter
The Master Switch can cut off/turn on the electrical system
Electric current is distributed through the Bus, and individual
accessories/systems can be isolated by a series of Circuit Breakers
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
10
Airplane Systems
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Engine Instruments
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The pilot needs to know if a problem develops in the engine,
BEFORE it stops working
Since the engine contains oil it is possible to identify leaks
and heating problems by measuring
Oil Pressure and Oil Temperature
These are shown on a Gauge in the cockpit:
Without gears, Engine Speed = Propeller Speed,
so it is extremely important to know what the
engine speed is
This is shown in the cockpit by the
Tachometer in Revolutions per Minute:
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
11
Airplane Systems
 Flight Instruments

The Pitot-Static System (Pressure Differential)
 Altimeter - Since the pressure at different
altitudes is known, by measuring the actual
outside pressure, the altimeter is calibrated to
show high high up you are
 Vertical Velocity Indicator - The rate at which
the pressure changes is used to indicate how
quickly you are going up or down
 Airspeed Indicator Measures the difference in
speed between still air and
the Relative Wind, thus
showing your Airspeed,
Note: this is NOT True
Airspeed or Ground Speed
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
12
Airplane Systems

Flight Instruments
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Gyro Power: A Gyro is a spinning rotor mounted on an axle and
allowed to move in 3-Dimensions by a gimbal system
 Due to a principal called ‘Rigidity in Space’, once spinning the Gyro
will strongly resist any attempt to change its orientation
 By comparing the difference between what the aircraft is doing, and
the orientation of the gyro, you can measure and display several
useful flight characteristics:

Attitude Indicator shows a stable
‘Artificial Horizon’

Turn Coordinator - shows  Heading Indicator Roll and Yaw indication.
shows any change of
Inclinometer (Ball in Liquid
‘compass heading’
filled tube) shows ‘slip’
Dr. R.A. Bartholomew - Civil Air Patrol, New
Jersey Wing
13