The Beginner's Guide to Aeronautics (BGA) was created
as a Web-based "textbook." The creation of the BGA is a research project
to explore the use of the personal computer and the Internet to present educational
materials to students, teachers, and lifelong learners in a more interactive
way than a printed, bound textbook.
As a general rule, the Web consists of many individual pages that are
connected, or related, to one another through hyperlinks. The Web is,
therefore, much less structured than a bound book, in which one page follows
another in a definite, numbered sequence. We have intentionally organized the
BGA to mirror this unstructured approach. Users can navigate the pages
of the BGA through hyperlinks based on their own interest and inquiry.
For those who prefer more structure to the information available at the BGA,
we have organized an alternative to the unstructured approach--a number of guided
tours through the site. Each tour is organized around a single topic, and
users move from page to page through the tour by using special buttons at the
bottom of each page.
Click to move back to the previous page.
Click to move to the next page.
Click to return to this page at the end of each tour.
(Some pages will be "crossed" by more than one tour, so it is important
to remember which tour you are on. If you click on a hyperlink you will leave
the tour; you can rejoin the tour by using the browser's "Back" command.
If you wish to abort a tour and return here, just click on the "Guided Tours" label
located above the buttons.
)
All of the tours begin and end on this page unless otherwise noted.
Descriptions of each tour are given below--just click on the
name of the tour to start you on your way. Have fun!
Fundamentals
- Newton's Laws of Motion The motion of aircraft
can be accurately described by the classical Laws of Motion developed by Sir
Isaac Newton in the late 1600's.
- Forces, Torques, and Motion As an object
moves through space it translates and rotates. The translations are in direct
response to forces on the object. The rotations are in response to torques
on the object.
- Thermodynamics Thermodynamics is the study
of the effects of work, heat and energy on a system. There are three laws of
thermodynamics based on large scale observations.
- Combustion Modern aircraft are powered
by jet engines which produce thrust by burning a fuel. Combustion is the
chemical process which combines fuel, oxygen, and a source of heat to
produce heat and exhaust products.
- Basic Fluid Dynamics Equations The motion of any fluid
can be described by the conservation of mass, momentum, and energy.
- Compressible Aerodynamics
Additional forces are present when an object travels through a gas at
speeds near or faster than the speed of sound for the gas.
Shock waves may also be present in the flow field.
- Aircraft Weight Weight is a major design
consideration for all aircraft. Equations have been developed to compute the
aircraft's weight and center of gravity during design.
Gases
- Standard Atmosphere Model The atmosphere
is a thin layer of gas that separates the surface of the planet from outer
space. The properties of the gas change with altitude through the atmosphere.
- Gas Statics The properties of a gas
are related to one another. You can learn about the properties of a gas by
considering a static volume of gas.
- Speed of Sound Small disturbances in a
gas are transmitted at the speed of sound which depends on the temperature of the gas.
The Mach number is the ratio of an object's speed to the speed of sound.
- Sound Waves Small disturbances in a
gas are transmitted through the gas as spherical waves. If the source of the disturbance
is moving the waves are distorted.
- Shock Waves and Expansions A large disturbance in a
supersonic flow generates shock waves or expansion fans. Shock waves are small regions
where the pressure, temperature and density increase. Expansions are regions where
the pressure, temperature, and density decrease.
- Pitot-Static Tube A Pitot-Static Tube is a device for measuring
the speed of an aircraft through the air. It depends on an application of Bernoulli's
equation for a moving fluid.
- Wind Tunnels Wind Tunnels are large devices
used to test models of proposed aircraft. (This tour does not return to this page)
Powered Aircraft
- Forces on an Airplane There are four forces
that act on an airplane. The motion of an aircraft depends on the relative
magnitude of the forces. So you must first understand what the forces are,
how they are directed, the nature of the forces, and how they are related.
- Cruising Aircraft
If the four forces on an aircraft are perfectly balanced, the aircraft
flies in a straight line at a constant speed. Equations have been developed
which describe cruising flight.
- Into the Wind The aerodynamic forces on an
airplane depend on the difference in velocity between the airplane and the air.
Determining the forces and resulting motion is complicated by the wind.
- Parts of an Airplane Airplanes are composed
of many parts with many different functions. Learn to recognize and identify
the different parts of an airplane.
- Fuselage The fuselage (or body) of the
airplane holds all of the parts together and carries the passengers or cargo.
- Jet Engines Most modern aircraft are powered
by gas turbine, or jet engines.
- Wings The wings generate most of the
lift necessary for flight.
- Ailerons Ailerons are parts of the wing
which are used to roll the aircraft.
- Spoilers Spoilers are parts of the wing
which are used to roll the aircraft and to decrease lift and increase drag during landings.
- Flaps and Slats Flaps and Slats are parts of the wing
which are used during take off and landing to increase lift and drag.
- Elevators Elevators are control surfaces connected
to the horizontal stabilizer and are used to pitch the aircraft.
- Stabilators Stabilators are control surfaces
which provide both horizontal stability and pitch control for the aircraft.
- Rudder A Rudder is a control surface connected
to the vertical stabilizer and used to yaw the aircraft.
- Control Surfaces On a modern aircraft, there are several
moving parts which are used to control the motion of the aircraft. This tour examines these
parts and the resulting motion.
Gliders
- Forces on a Glider Gliders are unpowered aircraft.
The forces on gliders and the response to external forces is quite similar
to powered aircraft. Examples: paper airplanes and the Space
Shuttle
- Gliding Flight Gliders are unpowered aircraft.
The flight of a glider is a little easier to analyze than the flight of a powered aircraft
Kites
- Forces on a Kite Kites are unpowered aircraft.
They are very similar to gliders except that, instead of moving through air,
a kite is held still and the blowing air moves past the kite.
- Kite Flying You can learn a great deal about
aerodynamics by flying a kite.
- KiteModeler - Kite Simulator KiteModeler is an
interactive computer program that lets you design and flight test a kite.
Model Rockets
Other Flying Objects
- Falling Objects An object falling through
the atmosphere is subjected to two forces, weight and drag, and attains a
constant terminal velocity. If the object were falling in a vacuum, only gravity
would act on the object.
- Objects that Generate Lift Many objects
generate lift as they move through a fluid.
- CurveBall - Baseball Simulation A big
league baseball player can throw a curveball because of aerodynamic forces
on the ball. Investigate the forces on the ball by using this simulation program.
Aircraft Lift
- Theories of Lift Lift is the force that
keeps an aircraft flying. Many theories for the generation of lift have been
proposed.
- Factors that Affect Lift Lift is the force
that keeps an aircraft flying. There are many factors that affect the amount
of lift generated by a body.
- Lift Equation Lift is the force that
keeps an aircraft flying. There is a simple algebraic equation to relate
the factors that affect lift.
- FoilSim - Lift Simulator FoilSim is an
interactive computer program that lets you design a wing on-line and determine
the theoretical lift of the wing.
Aircraft Drag
- Sources of Drag Drag is the force that
opposes the motion of an object through the air. There are several different
sources of aircraft drag.
- Factors that Affect Drag Drag is the force that opposes
an aircraft's motion. There are many factors that affect the amount of drag
generated by a body.
- Drag Equation Drag is the force that opposes the
aircraft's motion . There is a simple algebraic equation to relate
the factors that affect drag.
Aircraft Thrust
- Propulsion Systems Thrust is the force that
pushes an airplane through the air.
There are many different types of propulsion systems which generate thrust.
- Propellers For the forty years following
the Wright Brothers first flight, aircraft used propellers to produce thrust.
Modern general aviation aircraft still use propellers.
- Jet Engines Most modern aircraft are powered
by gas turbine, or jet engines.
There are several different types of jet engines which are used for different missions.
- Turbojets The turbojet is the
most basic type of gas turbine engine.
- Afterburning Turbojets To develop the
extra thrust needed for supersonic flight, an afterburner is often connected
to the exit of a turbojet or turbofan engine.
- Turbofans Most modern airliners are
powered by highly efficient turbofan engines.
- Turboprops Many small commuter airliners
use highly efficient turboprop engines. The turboprop uses a gas turbine
engine to turn a propeller.
- Ramjets A ramjet engine produces thrust by
burning a fuel at high pressure and exhausting the gas through a nozzle.
The high pressure is produced by the forward speed of the vehicle.
- Rockets A rocket engine produces thrust by
burning a fuel at high pressure and exhausting the gas through a nozzle.
The oxygen for combustion is carried with the propulsion system.
- Parts of a Jet Engine Jet Engines are composed
of many parts with many different functions. Learn to recognize and identify
the different parts of a jet engine.
- Inlet The inlet sits upstream of the compressor and
brings air into the engine.
- Compressor The compressor increases the pressure
of the air while delivering it to the burner.
- Combustor or Burner Combustion of the fuel takes
place in the burner. Fuel is mixed with high pressure air from the compressor and burned.
- Power Turbine The power turbine sits downstream
of the burner and extracts some energy from the hot exhaust to power the compressor.
- Nozzle The nozzle is a specially shaped tube
which accelerates the hot exhaust gas to produce thrust.
- Thrust Equation Mathematical
equations have been developed which describe the generation of aircraft thrust.
- Calculating Fuel Flow Rate Mathematical
equations have been developed which describe the fuel usage of a jet engine.
- EngineSim - Engine Simulator EngineSim is an
interactive computer program that lets you design a turbine engine on-line and determine
the theoretical thrust, fuel flow, and weight of your engine.
Aircraft Motion
- Basic Aircraft Motion The motion of an
airplane through the air can be described as a combination of translation and
rotation.
- Cruising Flight
If the four forces on an aircraft are perfectly balanced, the aircraft
flies in a straight line at a constant speed.
- Aircraft Roll Motion A roll motion
is caused by deflecting the ailerons which causes the wings tips to move up and down.
- Aircraft Pitch Motion A pitch motion
is caused by deflecting the elevators which causes the aircraft nose to move up and down.
- Aircraft Yaw Motion A yaw motion
is caused by deflecting the rudder which causes the aircraft nose to move side to side.
- Banking Turns An airplane changes direction
by rolling in the direction of the turn and producing a gradual curved flight path.
- Gradual Climb An airplane climbs whenever the
lift is greater than the weight. The rate of climb is increased by high excess thrust.
Simulation Programs
- FoilSim - Lift Simulator FoilSim is an
interactive computer program that lets you design a wing on-line and determine
the theoretical lift of the wing.
- EngineSim - Engine Simulator EngineSim is an
interactive computer program that lets you design a turbine engine on-line and determine
the theoretical thrust, fuel flow, and weight of your engine.
- CurveBall - Baseball Simulation A big
league baseball player can throw a curveball because of aerodynamic forces
on the ball. Investigate the forces on the ball by using this simulation program.
- RangeGames RangeGames is an
interactive computer program that presents problems for you to solve. The problems
involve aspects of cruising flight and aircraft take-off.
- RocketModeler - Model Rocket Simulator RocketModeler is an
interactive computer program that lets you design and flight test a
model rocket.
- KiteModeler - Kite Simulator KiteModeler is an
interactive computer program that lets you design and flight test a kite.
- Atmosphere Model Simulator This interactive
computer program lets you study how the
properties of the atmosphere change with altitude.
- Mach and Speed of Sound Calculator This interactive
computer program computes speed of sound and the Mach number for a given
vehicle speed and altitude using the standard atmosphere model.
- Sound Wave Simulator This
interactive computer program lets you study how the doppler shift occurs and how
Mach waves are formed.
- Single Shock Wave Simulator This interactive
computer program lets you study a shock wave generated by supersonic flow
passing a wedge.
- Multiple Shock Wave Simulator This interactive
computer program lets you study shock wave interactions and the generation of
centered expansion fans.
- Isentropic Flow Calculator This interactive
computer program solves the isentropic flow equations for a variety of inputs.
It also calculates the Mach angle, Prandtl-Meyer angle and corrected airflow.
- Nozzle Simulator This interactive
computer program lets you study how rocket and turbine engine nozzles operate.
Presentations
Navigation ..
- Beginner's Guide Home Page
- NASA Glenn Learning Technologies Home Page
- http://www.grc.nasa.gov/WWW/K-12
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