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Hang glider launching from Mount Tamalpais

Unpowered aircraft can remain airborne for a significant period of time without onboard propulsion. They can be classified as gliders, lighter-than-air balloons and tethered kites. In the case of kites, lift is obtained by tethering to a fixed or moving object, perhaps another kite, to obtain a flow of wind over the lifting surfaces.^[1] In the case of balloons, lift is obtained through inherent buoyancy and the balloon may or may not be tethered. Free balloon flight has little directional control. Gliding aircraft include sailplanes, hang gliders, and paragliders that have full directional control in free flight.

History

The first manned aircraft were kites, balloons and gliders. Man-lifting kites were used in ancient China and Japan, often as a punishment for prisoners. Unmanned hot-air balloons and toy "bamboo-copters" are also recorded in Chinese history.

The first manned free flight was in a hot-air balloon built by the brothers Joseph-Michel and Jacques-Etienne Montgolfier in Annonay, France in 1783. The hydrogen balloon appeared at about the same time and proved more practical.

The first practical, controllable glider was designed and built by the British scientist and pioneer George Cayley who many recognise as the first aeronautical engineer.^[2] It flew in 1849.

Tethered balloons and, to a lesser extent, kites were developed for military and meteorological observation, however the use of kites has remained largely recreational. Free-flying ballooning using coal gas (which has about half the lifting effect of hydrogen) became a popular sport. Gliders were used mainly for aerodynamic research until their sporting use was developed in the 1920s.

During the two World Wars, tethered barrage balloons were made and deployed in large numbers. Military assault gliders were also developed during World War II, while the rotor kite was used by the German Navy for seaborne observation.

Modern applications include experimental high altitude wind power generation.

Gliders

Sailplanes, hang gliders and paragliders are all types of glider aircraft.

For a glider to generate lift, it must first gain and then maintain sufficient forward air speed.

Launching a glider gives it the initial forward airspeed to start flying. This is often done by towing the aircraft into the air on a long line, using either a ground-based winch or vehicle, or a powered "tug" aircraft. A small foot-launched glider is launched by running downhill or stepping off a high location.

Forward speed is then maintained by a gradual descent through the surrounding air, with the wings angled slightly down so that their lift also provides a small forward thrust to counter the drag of the wing.

If the air is rising faster than the aircraft is descending through it, the glider will gain height and additional potential energy. Sources of such rising air include warm thermals and hill ridges.

In the past, unpowered military gliders have been used for military applications.

Today, the majority of use of all types of glider aircraft is recreational.

Balloons

Free-flying Balloons drift with the wind. The pilot controls the altitude either by heating the air more or by releasing ballast weight. The wind direction usually changes with altitude, so crude directional control can be obtained by changing altitude.

A round tethered balloon is unstable in any significant wind. A kite balloon is streamlined to make it stable in strong winds.

Today, the majority of manned balloon flights are recreational, whereas unmanned and usually free-flying balloons are widely used for meteorological measurement.

Kites

Kites are aircraft^[3] that are tethered to some other object (fixed or mobile) or other means that maintain tension in the kite line; and rely on virtual or real wind blowing over and under them to generate lift and drag. Kytoons are balloon kites that are shaped and tethered to obtain kiting deflections, and can be lighter-than-air, neutrally buoyant, or heavier-than air. Kites have been developed for commercial applications using kite control systems, including the airborne wind energy systems of high altitude wind power.

References

^ System and method for wind-powered flight Dale C. Kramer
^ Dee, Richard (2007). The Man who Discovered Flight: George Cayley and the First Airplane. Toronto: McClelland and Stewart. ISBN 978-0-7710-2971-4.
^ "Kites". NASA. Retrieved 2009-03-18.

External links

Fédération Aéronautique Internationale This is the world organisation for air sports such as gliding, hang gliding and paragliding

[1] System and method for wind-powered flight Dale C. Kramer

[2] Dee, Richard (2007). The Man who Discovered Flight: George Cayley and the First Airplane. Toronto: McClelland and Stewart. ISBN 978-0-7710-2971-4.

[3] "Kites". NASA. Retrieved 2009-03-18.

[1]

[2]

[3]

@@ Line 1: / Line 1: @@
+{{Short description|Aerial vehicle capable of sustaining flight without onboard propulsion}}
+{{More citations needed|date=December 2022}}
 [[File:Hanggliding03042006.JPG|thumb|300px|Hang glider launching from [[Mount Tamalpais]]]]
-'''Unpowered aircraft''' are a group of aerial vehicles that can fly without onboard propulsion. They can be classified as [[Glider aircraft]], [[balloon]]s and [[kite]]s. In this instance, 'flight' means a trajectory that is not merely a vertical descent such as a [[parachute]]. In the case of kites, the flight is obtained by tethering to a fixed or moving object, perhaps another kite.<ref>[http://www.google.com/patents/about?id=tayHAAAAEBAJ System and method for wind-powered flight Dale C. Kramer]</ref> In the case of balloons, the flight is free but there is little directional control.  The remainder of this group are the heavier-than-air craft such as [[Glider (sailplane)]], [[hang glider]]s. and [[paraglider]]s that have complete directional control and so can fly freely.
+'''Unpowered aircraft''' can remain airborne for a significant period of time without onboard propulsion. They can be classified as [[Glider aircraft|gliders]], lighter-than-air [[balloon (aeronautics)|balloon]]s and tethered [[kite]]s. In the case of kites, lift is obtained by tethering to a fixed or moving object, perhaps another kite, to obtain a flow of wind over the lifting surfaces.<ref>[https://patents.google.com/patent/US20010025900 System and method for wind-powered flight Dale C. Kramer]</ref> In the case of balloons, lift is obtained through inherent [[buoyancy]] and the balloon may or may not be tethered. Free balloon flight has little directional control. Gliding aircraft include [[Glider (sailplane)|sailplanes]], [[hang glider]]s, and [[paraglider]]s that have full directional control in free flight.
 ==History==
+{{main|History of aviation}}
-* ''For history of gliders, see [[Glider_aircraft#History_of_gliders|Glider aircraft]]
+The first manned aircraft were kites, balloons and gliders. Man-lifting kites were used in ancient China and Japan, often as a punishment for prisoners. Unmanned hot-air balloons and toy "bamboo-copters" are also recorded in Chinese history.
-* ''For history of glider/sailplanes, see [[Glider (sailplane)]]
-* ''For history of hang gliders, see [[History of hang gliding]]
-* ''For history of paragliders, see [[Paragliding#History|Paragliding]]
-* ''For history of balloons, see [[Balloon (aircraft)#History|Balloon]]
-* ''For history of kites, see [[Kite#History|Kite]]
-* ''For history of airborne wind energy aircraft, see [[High altitude wind power]]
-The first manned aircraft were kites, balloons and gliders. Kites are recorded in ancient Chinese history as being used for lifting men. Unmanned hot air balloons are also recorded in Chinese history. However the first free flight (i.e., untethered) by manned craft was by balloon built by the brothers Joseph-Michel and Jacques-Etienne [[Montgolfier brothers|Montgolfier]] in Annonay, France in 1783. The first practical, controllable glider was designed and built by the British scientist and pioneer [[George Cayley]] who many recognise as the first aeronautical engineer.<ref>{{cite book |last= Dee |first= Richard |coauthors= |title= The Man who Discovered Flight: George Cayley and the First Airplane |year= 2007|publisher= McClelland and Stewart|location= Toronto |isbn= 978-0-7710-2971-4 }}</ref> It flew in 1849. Thereafter gliders were used for aerodynamic research, until their sporting use was developed in the 1920s.
+The first manned free flight was in a hot-air balloon built by the brothers Joseph-Michel and Jacques-Etienne [[Montgolfier brothers|Montgolfier]] in Annonay, France in 1783. The hydrogen balloon appeared at about the same time and proved more practical.
-==Glider aircraft==
-[[Glider (sailplane)|Sailplanes]], [[Hang gliding|hang glider]]s and paragliders can gain some initial energy from a launch process, but can then gain additional [[potential energy]] from [[lift (soaring)|rising air]] such as [[thermal]]s and ridge lift. The launch may be by pulling the aircraft into the air with a tow-line, with a ground-based winch or vehicle, or with a powered "tug" aircraft. For foot-launched aircraft, there is also the option of merely stepping off a high location.
+The first practical, controllable glider was designed and built by the British scientist and pioneer [[George Cayley]] who many recognise as the first aeronautical engineer.<ref>{{cite book |last= Dee |first= Richard |title= The Man who Discovered Flight: George Cayley and the First Airplane |year= 2007|publisher= McClelland and Stewart|location= Toronto |isbn= 978-0-7710-2971-4 }}</ref> It flew in 1849.
-For glider aircraft to generate lift, they must maintain sufficient forward air speed. This is achieved by a gradual descent, though if the air is rising faster than the aircraft is descending, it will also ascend. Today, the majority of the use of all types of glider aircraft is recreational.
+Tethered balloons and, to a lesser extent, kites were developed for military and meteorological observation, however the use of kites has remained largely recreational. Free-flying ballooning using coal gas (which has about half the lifting effect of hydrogen) became a popular sport. Gliders were used mainly for aerodynamic research until their sporting use was developed in the 1920s.
+During the two World Wars, tethered [[barrage balloon]]s were made and deployed in large numbers. Military assault gliders were also developed during World War II, while the [[rotor kite]] was used by the [[German Navy]] for seaborne observation.
+Modern applications include experimental [[high altitude wind power]] generation.
+==Gliders==
+[[Glider (sailplane)|Sailplanes]], [[Hang gliding|hang glider]]s and [[Paragliding|paraglider]]s are all types of glider aircraft.
+For a glider to generate lift, it must first gain and then maintain sufficient forward air speed.
+Launching a glider gives it the initial forward airspeed to start flying. This is often done by towing the aircraft into the air on a long line, using either a ground-based winch or vehicle, or a powered "tug" aircraft. A small foot-launched glider is launched by running downhill or stepping off a high location.
+Forward speed is then maintained by a gradual descent through the surrounding air, with the wings angled slightly down so that their lift also provides a small forward thrust to counter the drag of the wing.
+If the air is rising faster than the aircraft is descending through it, the glider will gain height and additional [[potential energy]]. Sources of such [[lift (soaring)|rising air]] include warm [[thermal]]s and hill ridges.
 In the past, unpowered [[military glider]]s have been used for military applications.
+Today, the majority of use of all types of glider aircraft is recreational.
 ==Balloons==
-[[Balloon (aircraft)|Balloons]] drift with the wind, though normally the pilot can control the altitude either by heating the air or by releasing ballast, giving some directional control (since the wind direction changes with altitude). A tethered wing-shaped balloon has been tested <ref>[http://adsabs.harvard.edu/abs/2008AGUFMGC43B0734N Winged balloon]</ref> which has greater directional control. Today, the majority of the use of manned balloons is recreational, whereas unmanned balloons are widely used for meteorological measurement.
+Free-flying [[Balloon (aircraft)|Balloons]] drift with the wind. The pilot controls the altitude either by heating the air more or by releasing ballast weight. The wind direction usually changes with altitude, so crude directional control can be obtained by changing altitude.
+A round tethered balloon is unstable in any significant wind. A [[kite balloon]] is streamlined to make it stable in strong winds.
+Today, the majority of manned balloon flights are recreational, whereas unmanned and usually free-flying balloons are widely used for meteorological measurement.
 ==Kites==
@@ Line 29: / Line 47: @@
   | publisher = [[NASA]]
   | url = http://www.grc.nasa.gov/WWW/K-12/airplane/kite1.html
-  | accessdate = 2009-03-18}}</ref> that are tethered to some other object (fixed or mobile) or other means that maintain tension in the [[kite line]]; and rely on virtual or real wind blowing over and under them to generate lift and drag. [[Kytoon]]s are balloon kites that are shaped and tethered to obtain kiting deflections, and can be lighter-than-air, neutrally buoyant, or heavier-than air. Kites have been developed for commercial applications using [[kite control systems]], including the airborne wind energy systems of [[high altitude wind power]].
+  | access-date = 2009-03-18}}</ref> that are tethered to some other object (fixed or mobile) or other means that maintain tension in the [[kite line]]; and rely on virtual or real wind blowing over and under them to generate lift and drag. [[Kytoon]]s are balloon kites that are shaped and tethered to obtain kiting deflections, and can be lighter-than-air, neutrally buoyant, or heavier-than air. Kites have been developed for commercial applications using [[kite control systems]], including the airborne wind energy systems of [[high altitude wind power]].
 ==See also==
-{{div col|colwidth=20em}}
 *[[Kite types]]
 *[[Gliding]]
 *[[Gliding competitions]]
-*[[Gimli Glider]] - a passenger jet aircraft that ran out of fuel
+*[[Gimli Glider]], a passenger jet aircraft that ran out of fuel
 *[[Gyroglider]]
-*[[Colditz Cock]] - a glider built to escape from [[Colditz]]
+*[[Colditz Cock]], a glider built to escape from [[Colditz]]
-{{div col end}}
 ==References==
@@ Line 49: / Line 65: @@
 {{Aircraft types (by method of thrust and lift)}}
+{{Authority control}}
 {{DEFAULTSORT:Unpowered Aircraft}}
-[[Category:Unpowered aircraft]]
+[[Category:Unpowered aircraft| ]]
-[[Category:Unpowered flight]]
+[[Category:Unpowered flight|Aircraft]]
-[[ar:طائرة دون محرك]]