Flight Power
Warm-Up Questions
CPS Questions 1-2
Chapter 1, Lesson 5
Lesson Overview
 The
principles of Boyle’s Law, Charles’s
Law, and Gay-Lussac’s Law
 The characteristics of internal
combustion engines
 The mechanical, cooling, and ignition
systems of reciprocating engines
Chapter 1, Lesson 5
Lesson Overview, cont.
 How
the different types of jet engines
work
 The role of reversers and suppressors
used in jet aircraft
 Reaction engines
 The development of new engine
technology
Chapter 1, Lesson 5
Quick Write
Which is the more significant achievement –
being the first to invent something, or the first
to make it practical? Or are both equally
important?
(Note to teacher: Use “Pick a Student” button in CPS)
Chapter 1, Lesson 5
© Laser143/Dreamstime.com
Boyle’s Law
Relationship between pressure and volume of a
confined gas at a constant temperature
 When pressure increased, the volume
decreased, when pressure decreased, the
volume increased

Chapter 1, Lesson 5
Reproduced from NASA/Glenn Research Center
Charles’s Law
The volume of a gas is directly proportional to
its temperature
 If temperature of a gas rises, its volume
increases; if temperature falls, the volume
decreases

Chapter 1, Lesson 5
Reproduced from NASA/Glen Research Center
Gay Lussac’s Law
Relationship between pressure of a gas, and
temperature, when the volume is constant
 Pressure rises when temperature rises, and
pressure falls when temperature falls

Chapter 1, Lesson 5
Reproduced from NASA/Glen Research Center
Activity 1:
Animated Gas Lab

View the Animated Gas Lab at the NASA
website

Use the lab to work through the questions
Chapter 1, Lesson 5
The Characteristics of Internal
Combustion Engines


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Internal combustion engines
turn propellers which
generate thrust
Combustion process—
chemical energy converts to
mechanical energy
The piston compresses fuel
and air before combustion;
then is forced back down the
cylinder following combustion
Chapter 1, Lesson 5
Reproduced from NASA/Glen Research Center
Learning Check Questions
CPS Questions 3-4
Chapter 1, Lesson 5
Activity 2:
Internal Combustion Engine Parts
 Observe
the four-stroke internal
combustion engine animation
 Label the engine parts and provide a
short description
Chapter 1, Lesson 5
Activity 2—Four Stroke
Internal Combustion Engine
Chapter 1, Lesson 5
Reproduced from NASA/Glen Research Center
Reciprocating Engines

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Internal combustion engine is a
reciprocating engine
Back-and-forth movement of the
pistons produces mechanical
energy
Most small aircraft have
reciprocating engines
Parts include cylinders, pistons,
connecting rods, a crankshaft,
crankcase, intake and exhaust
valves, and spark plugs
Chapter 1, Lesson 5
Reproduced from US Department of
Transportation/Federal Aviation Administration
Intake Stroke—First Stroke

Piston moves down, intake
valve opens, drawing air and
fuel in at constant pressure

Provides great deal of surface
area that reacts quickly with
the oxygen in the air
Chapter 1, Lesson 5
Reproduced from NASA/Johnson Space Center
Compression Stroke—
Second Stroke


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The piston reaches the bottom,
the intake valve closes, sealing
the cylinder
Volume decreases, the piston
compresses the fuel-air mixture,
raising temperature and
increasing pressure
Gas particles are close together,
can react quickly when ignited
Chapter 1, Lesson 5
Reproduced from NASA/Johnson Space Center
Power or Ignition Stroke—
Third Stroke





As the piston nears the top, a surge of
current is sent to spark plug
The Spark ignites the compressed fuelair mixture
Fuel rapidly combines with oxygen and
produces carbon dioxide gas and water
vapor
Hot gases force the piston down turning
the crankshaft
The crankshaft turns the aircraft
propeller
Chapter 1, Lesson 5
Reproduced from NASA/Johnson Space Center
Exhaust Stroke—
Fourth Stroke
Piston reaches the bottom and
starts back up the cylinder, the
exhaust stroke begins
 The exhaust valve opens,
residual heat is released, and
pressure returns to
atmospheric conditions
 The piston pushes waste gas
out of the cylinder

Chapter 1, Lesson 5
Reproduced from NASA/Johnson Space Center
Cooling
Air cooled system—air flows through
openings at the front of the engine
cowling into the engine compartment
 Hot air leaves the engine through
openings in lower, aft portion
of the cowling
 Liquid-cooled —requires the additional
weight of a radiator and liquid
 Radiators pump air-cooled liquid in pipes
around hot parts of an engine

Chapter 1, Lesson 5
Reproduced from US Department of
Transportation/Federal Aviation Administration
Ignition System
Provides the spark that ignites the fuel-air
mixture in cylinders
 Firing of two spark plugs improves combustion
and results in more power; if one magneto
fails, other can still work on its own

Chapter 1, Lesson 5
Reproduced from NASA/Glen Research Center
Learning Check Questions
CPS Questions 5-6
Chapter 1, Lesson 5
Turbojets
Engine is an open tube that burns fuel
continuously
 Main parts: compressor, combustion
chamber, turbine, inlet, shaft, and nozzle
 Large air mass enters the inlet and is drawn
into a rotating compressor

Chapter 1, Lesson 5
Reproduced from US Department of
Transportation/Federal Aviation Administration
Turbojets, cont.
Compressor raises air pressure and forces the
gas into smaller volumes, gas pressure
increases and heats up
 Fuel is injected into the combustion chamber,
where it ignites
 Heated gas passes over turbine blades causing
them to rotate shaft connected to compressor
 Nozzle’s purpose is to convert chemical energy
into mechanical energy, thus producing thrust

Chapter 1, Lesson 5
Turbofans

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Modified turbojet engine - has additional turbine to turn
a fan at front of the engine
Two-spool engine; one powers compressor, other turns
the large fan
Air from large fan enters the engine core, where fuel
burns to provide some thrust
90 percent of the air bypasses the engine core; as much
as 75 percent of the total thrust is from bypass air
Chapter 1, Lesson 5
Reproduced from US Department of
Transportation/Federal Aviation Administration
Turboprops
Hybrid of a turbojet and a propeller engine
 Has a turbojet core to produce power but with
two turbines
 First turbine powers the compressor; the second
turbine powers the propeller

Chapter 1, Lesson 5
Reproduced from US Department of
Transportation/Federal Aviation Administration
Ramjets
Ramjets work with another power source for
initial thrust, such as a rocket
 Operates by combusting fuel in a stream of air
compressed by aircraft’s forward motion
 Airflow is subsonic, less than the speed of sound

Chapter 1, Lesson 5
Reproduced from NASA/Johnson
Space Center
Scramjets
 Scramjets
overcome
the speed limitation
 It is a supersoniccombustion ramjet
 Needs another engine
or vehicle to accelerate
it to operating speed
Chapter 1, Lesson 5
Reproduced from NASA's Dryden Flight
Research Center
Thrust Reversers
Diverts thrust to the opposite
direction of the aircraft’s motion
 Clamshell reverser forms a
shield at the back of the nozzle,
deflects exhaust so it no longer
produces forward thrust
 Cascade reverser is a series of
airfoils with a high degree of
camber that opens, to change
the airflow’s direction

Courtesy of Dan Brownlee
Chapter 1, Lesson 5
Noise Suppressors
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Laws regulate how much noise an aircraft
can make
Flow of exhaust creates much of the racket
Chevron noise suppressor has teeth cut in
nozzle’s edge to reduce noise
Corrugated noise suppressor has ridged
nozzles; breaks noise in a large exhaust
flow
Ejector-type noise suppressor directs
surrounding air so it mixes with the highvelocity exhaust to reduce noise
Copyright © Boeing. All Rights Reserved
Chapter 1, Lesson 5
Learning Check Questions
CPS Questions 7-8
Chapter 1, Lesson 5
Activity 3:
Jet Engine Characteristics
 View
the various animations of a jet engine
to observe the parts and their functions
 Label
the parts and provide a short
description of characteristic
Chapter 1, Lesson 5
Activity 3: Engine
Chapter 1, Lesson 5
Reproduced from NASA/Glen Research
Center
Activity 3: Compressor
Chapter 1, Lesson 5
Reproduced from NASA/Glen Research
Center
Activity 3: Turbine
Chapter 1, Lesson 5
Reproduced from NASA/Glen Research
Center
Reaction Engines
Reaction engine
develops thrust by its
reaction to a substance
ejected from it
 Operates according to
Newton’s third law of
motion
 Rocket engines are also
reaction engines

Chapter 1, Lesson 5
Courtesy of NASA
The Development of
New Engine Technology


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Aerospace engineers are working on new engine
technologies that cut fuel use and reduce emissions
Geared turbofan engine reduces fuel consumption,
emissions, engine noise, and operating costs
Open rotor jet engine focuses on fuel efficiency,
reduced emissions, and noise reduction
Chapter 1, Lesson 5
Courtesy of NASA/Glenn Research Center
Thrust Vectoring
Thrust vector engine has nozzles that turn to
redirect thrust; lets aircraft maneuver with
greater precision
 The aim of this technology is maneuverability,
not fuel efficiency

Chapter 1, Lesson 5
Courtesy of NASA/Glenn Research Center
Learning Check Questions
CPS Questions 9-10
Chapter 1, Lesson 5
Activity 4: Flight Power

Create a presentation on a jet engine (current
model or one under development)

Research sources and describe how the
engine works, and why the engine is suited for
the aircraft’s purpose
Chapter 1, Lesson 5
Summary
 The
principles of Boyle’s Law, Charles’s
Law, and Gay-Lussac’s Law
 The characteristics of internal
combustion engines
 The mechanical, cooling, and ignition
systems of reciprocating engines
Chapter 1, Lesson 5
Summary, cont.
 How
the different types of jet engines
work
 The role of reversers and suppressors
used in jet aircraft
 Reaction engines
 The development of new engine
technology
Chapter 1, Lesson 5
Review Questions
CPS Questions 11-12
Chapter 1, Lesson 5
Next….

Done – flight power

Next – aviation innovation
Chapter 1, Lesson 5
Copyright © Boeing. All Rights Reserved