Aeronautics is the science or art involved
with the study, design, and manufacturing
of air flight capable machines, and the techniques
of operating aircraft and rockets within the
atmosphere.
The British Royal Aeronautical Society identifies
the aspects of "aeronautical Art, Science
and Engineering" and "the profession of Aeronautics
(which expression includes Astronautics)."
While the term originally referred solely
to operating the aircraft, it has since been
expanded to include technology, business,
and other aspects related to aircraft.
The term "aviation" is sometimes used interchangeably
with aeronautics, although "aeronautics" includes
lighter-than-air craft such as airships, and
includes ballistic vehicles while "aviation"
technically does not.A significant part of
aeronautical science is a branch of dynamics
called aerodynamics, which deals with the
motion of air and the way that it interacts
with objects in motion, such as an aircraft.
== History ==
=== 
Early ideas ===
Attempts to fly without any real aeronautical
understanding have been made from the earliest
times, typically by constructing wings and
jumping from a tower with crippling or lethal
results.Wiser investigators sought to gain
some rational understanding through the study
of bird flight.
An early example appears in ancient Egyptian
texts.
Later medieval Islamic scientists also made
such studies.
The founders of modern aeronautics, Leonardo
da Vinci in the Renaissance and Cayley in
1799, both began their investigations with
studies of bird flight.
Man-carrying kites are believed to have been
used extensively in ancient China.
In 1282 the European explorer Marco Polo described
the Chinese techniques then current.
The Chinese also constructed small hot air
balloons, or lanterns, and rotary-wing toys.
An early European to provide any scientific
discussion of flight was Roger Bacon, who
described principles of operation for the
lighter-than-air balloon and the flapping-wing
ornithopter, which he envisaged would be constructed
in the future.
The lifting medium for his balloon would be
an "aether" whose composition he did not know.In
the late fifteenth century, Leonardo da Vinci
followed up his study of birds with designs
for some of the earliest flying machines,
including the flapping-wing ornithopter and
the rotating-wing helicopter.
Although his designs were rational, they were
not based on particularly good science.
Many of his designs, such as a four-person
screw-type helicopter, have severe flaws.
He did at least understand that "An object
offers as much resistance to the air as the
air does to the object."
(Newton would not publish the Third law of
motion until 1687.)
His analysis led to the realisation that manpower
alone was not sufficient for sustained flight,
and his later designs included a mechanical
power source such as a spring.
Da Vinci's work was lost after his death and
did not reappear until it had been overtaken
by the work of George Cayley.
=== Balloon flight ===
The modern era of lighter-than-air flight
began early in the 17th century with Galileo's
experiments in which he showed that air has
weight.
Around 1650 Cyrano de Bergerac wrote some
fantasy novels in which he described the principle
of ascent using a substance (dew) he supposed
to be lighter than air, and descending by
releasing a controlled amount of the substance.
Francesco Lana de Terzi measured the pressure
of air at sea level and in 1670 proposed the
first scientifically credible lifting medium
in the form of hollow metal spheres from which
all the air had been pumped out.
These would be lighter than the displaced
air and able to lift an airship.
His proposed methods of controlling height
are still in use today; by carrying ballast
which may be dropped overboard to gain height,
and by venting the lifting containers to lose
height.
In practice de Terzi's spheres would have
collapsed under air pressure, and further
developments had to wait for more practicable
lifting gases.
From the mid-18th century the Montgolfier
brothers in France began experimenting with
balloons.
Their balloons were made of paper, and early
experiments using steam as the lifting gas
were short-lived due to its effect on the
paper as it condensed.
Mistaking smoke for a kind of steam, they
began filling their balloons with hot smoky
air which they called "electric smoke" and,
despite not fully understanding the principles
at work, made some successful launches and
in 1783 were invited to give a demonstration
to the French Académie des Sciences.
Meanwhile, the discovery of hydrogen led Joseph
Black in c. 1780 to propose its use as a lifting
gas, though practical demonstration awaited
a gas tight balloon material.
On hearing of the Montgolfier Brothers' invitation,
the French Academy member Jacques Charles
offered a similar demonstration of a hydrogen
balloon.
Charles and two craftsmen, the Robert brothers,
developed a gas tight material of rubberised
silk for the envelope.
The hydrogen gas was to be generated by chemical
reaction during the filling process.
The Montgolfier designs had several shortcomings,
not least the need for dry weather and a tendency
for sparks from the fire to set light to the
paper balloon.
The manned design had a gallery around the
base of the balloon rather than the hanging
basket of the first, unmanned design, which
brought the paper closer to the fire.
On their free flight, De Rozier and d'Arlandes
took buckets of water and sponges to douse
these fires as they arose.
On the other hand, the manned design of Charles
was essentially modern.
As a result of these exploits, the hot-air
balloon became known as the Montgolfière
type and the hydrogen balloon the Charlière.
Charles and the Robert brothers' next balloon,
La Caroline, was a Charlière that followed
Jean Baptiste Meusnier's proposals for an
elongated dirigible balloon, and was notable
for having an outer envelope with the gas
contained in a second, inner ballonet.
On 19 September 1784, it completed the first
flight of over 100 km, between Paris and Beuvry,
despite the man-powered propulsive devices
proving useless.
In an attempt the next year to provide both
endurance and controllability, de Rozier developed
a balloon having both hot air and hydrogen
gas bags, a design which was soon named after
him as the Rozière.
The principle was to use the hydrogen section
for constant lift and to navigate vertically
by heating and allowing to cool the hot air
section, in order to catch the most favourable
wind at whatever altitude it was blowing.
The balloon envelope was made of goldbeater's
skin.
The first flight ended in disaster and the
approach has seldom been used since.
=== Cayley and the foundation of modern aeronautics
===
Sir George Cayley (1773-1857) is widely acknowledged
as the founder of modern aeronautics.
He was first called the "father of the aeroplane"
in 1846 and Henson called him the "father
of aerial navigation."
He was the first true scientific aerial investigator
to publish his work, which included for the
first time the underlying principles and forces
of flight.In 1809 he began the publication
of a landmark three-part treatise titled "On
Aerial Navigation" (1809–1810).
In it he wrote the first scientific statement
of the problem, "The whole problem is confined
within these limits, viz. to make a surface
support a given weight by the application
of power to the resistance of air."
He identified the four vector forces that
influence an aircraft: thrust, lift, drag
and weight and distinguished stability and
control in his designs.
He developed the modern conventional form
of the fixed-wing aeroplane having a stabilising
tail with both horizontal and vertical surfaces,
flying gliders both unmanned and manned.
He introduced the use of the whirling arm
test rig to investigate the aerodynamics of
flight, using it to discover the benefits
of the curved or cambered aerofoil over the
flat wing he had used for his first glider.
He also identified and described the importance
of dihedral, diagonal bracing and drag reduction,
and contributed to the understanding and design
of ornithopters and parachutes.Another significant
invention was the tension-spoked wheel, which
he devised in order to create a light, strong
wheel for aircraft undercarriage.
=== The 19th century ===
During the 19th century Cayley's ideas were
refined, proved and expanded on.
Important investigators included Otto Lilienthal
and Horatio Phillips.
=== The 20th century ===
Pedro Paulet, scientist born in the city of
Arequipa, Peru in the year of 1874, was one
of the first to experiment with propulsion
rockets being considered the «Father of Modern
Rocket» and by others as the «Father of
Aeronautics Modern ». He developed plans
for a "torpedo plane", which is why he is
considered ahead of his time.
When the internal explosion engines were invented,
small enough to be able to propel a flying
device with them, a race started between two
flight possibilities: the lighter than the
air (dirigibles) and the heavier than the
air (aeroplanes) .
== Branches ==
Aeronautics may be divided into three main
branches comprising Aviation, Aeronautical
science and Aeronautical engineering.
=== Aviation ===
Aviation is the art or practice of aeronautics.
Historically aviation meant only heavier-than-air
flight, but nowadays it includes flying in
balloons and airships.
=== Aeronautical science ===
Aeronautical science covers the practical
theory of aeronautics and aviation, including
operations, navigation, air safety and human
factors.
A candidate pilot is likely to study for a
qualification in aeronautical science.
=== Aeronautical engineering ===
Aeronautical engineering covers the design
and construction of aircraft, including how
they are powered, how they are used and how
they are controlled for safe operation.A major
part of aeronautical engineering is aerodynamics,
the science of passing through the air.
With the increasing activity in space flight,
nowadays aeronautics and astronautics are
often combined as aerospace engineering.
==== Aerodynamics ====
The science of aerodynamics deals with the
motion of air and the way that it interacts
with objects in motion, such as an aircraft.
The study of aerodynamics falls broadly into
three areas:
Incompressible flow occurs where the air simply
moves to avoid objects, typically at subsonic
speeds below that of sound (Mach 1).
Compressible flow occurs where shock waves
appear at points where the air becomes compressed,
typically at speeds above Mach 1.
Transonic flow occurs in the intermediate
speed range around Mach 1, where the airflow
over an object may be locally subsonic at
one point and locally supersonic at another.
=== Rocketry ===
A rocket or rocket vehicle is a missile, spacecraft,
aircraft or other vehicle which obtains thrust
from a rocket engine.
In all rockets, the exhaust is formed entirely
from propellants carried within the rocket
before use.
Rocket engines work by action and reaction.
Rocket engines push rockets forwards simply
by throwing their exhaust backwards extremely
fast.
Rockets for military and recreational uses
date back to at least 13th-century China.
Significant scientific, interplanetary and
industrial use did not occur until the 20th
century, when rocketry was the enabling technology
of the Space Age, including setting foot on
the moon.
Rockets are used for fireworks, weaponry,
ejection seats, launch vehicles for artificial
satellites, human spaceflight and exploration
of other planets.
While comparatively inefficient for low speed
use, they are very lightweight and powerful,
capable of generating large accelerations
and of attaining extremely high speeds with
reasonable efficiency.
Chemical rockets are the most common type
of rocket and they typically create their
exhaust by the combustion of rocket propellant.
Chemical rockets store a large amount of energy
in an easily released form, and can be very
dangerous.
However, careful design, testing, construction
and use minimizes risks.
== See also
