View source for Glider (aircraft)

{{Short description|Aircraft designed for operation without an engine}}
{{Other uses|Glider (disambiguation)}}
{{More footnotes needed|date=November 2009}}
{{Use British English|date=October 2017}}
[[File:Dg800.jpg|thumb|300px|Single-seat high performance fiberglass [[Glaser-Dirks DG-808]] [[Glider (sailplane)|glider]]]]
[[File:Habicht (468040905).jpg|thumb|300px|Aerobatic glider with tip smoke, pictured on July 2, 2005, in [[Lappeenranta]], Finland]]
A '''glider''' is a [[fixed-wing aircraft]] that is supported in flight by the dynamic reaction of the air against its lifting surfaces, and whose [[gliding flight|free flight]] does not depend on an engine.<ref>[http://www.faa.gov/library/manuals/aircraft/glider_handbook/media/faa-h-8083-13.pdf FAA Glider handbook] {{webarchive|url=https://web.archive.org/web/20090206073836/http://www.faa.gov/library/manuals/aircraft/glider_handbook/media/faa-h-8083-13.pdf |date=2009-02-06 }}</ref> Most gliders do not have an engine, although [[motor-glider]]s have small engines for extending their flight when necessary by sustaining the altitude (normally a sailplane relies on rising air to maintain altitude) with some being powerful enough to take off by [[Motor glider|self-launch]].

There are a wide variety of types differing in the construction of their wings, aerodynamic efficiency, location of the pilot, controls and intended purpose. Most exploit [[lift (soaring)|meteorological phenomena]] to maintain or gain height. Gliders are principally used for the [[air sport]]s of [[gliding]], [[hang gliding]] and [[paragliding]]. However some [[spacecraft]] have been designed to descend as gliders and in the past [[military glider]]s have been used in warfare. Some simple and familiar types of glider are toys such as [[paper plane]]s and [[balsa wood]] gliders.

==Etymology==
''Glider'' is the [[agent noun]] form of the verb ''to glide''. It derives from Middle English ''gliden'', which in turn derived from Old English ''glīdan''. The oldest meaning of glide may have denoted a precipitous running or jumping, as opposed to a smooth motion. Scholars are uncertain as to its original derivation, with possible connections to "slide", and "light" having been advanced.<ref>Liberman, Anatoly. [http://userpage.fu-berlin.de/~alvismal/7etym.pdf "An Addendum to “Ten Scandinavian and North English Etymologies”"] {{Webarchive|url=https://web.archive.org/web/20160303195306/http://userpage.fu-berlin.de/~alvismal/7etym.pdf |date=2016-03-03 }}, from ''alvíssmál'' 7. 1997. 101–104.</ref>

==History==
{{Main|Early flying machines}}
Early pre-modern accounts of flight are in most cases difficult to verify and it is unclear whether each craft was a glider, kite or parachute and to what degree they were truly controllable. Often the event is only recorded  a long time  after it allegedly took place. A 17th-century account reports an attempt at flight by the 9th-century poet [[Abbas Ibn Firnas]] near [[Córdoba, Spain]] which ended in heavy back injuries.<ref>[[Lynn Townsend White Jr.]] (Spring, 1961) "Eilmer of Malmesbury, an Eleventh Century Aviator: A Case Study of Technological Innovation, Its Context and Tradition", ''Technology and Culture'' '''2''' (2), pp. 97–111 [100–101].</ref> The monk [[Eilmer of Malmesbury]] is reported by [[William of Malmesbury]] ({{Circa|1080|1143}}), a fellow monk and historian, to have flown off the roof of his [[Malmesbury Abbey|Abbey in Malmesbury]], England, sometime between 1000 and 1010 AD, gliding about {{convert|200|m|yd}} before crashing and breaking his legs.<ref>White, L. Jr., ''Eilmer of Malmesbury, an Eleventh Century Aviator''. Medieval Religion and Technology. Los Angeles: University of California Press, 1978, Chapter 4.</ref> According to these reports, both used a set of (feathery) wings, and both blamed their crash on the lack of a tail.<ref>[[Lynn Townsend White Jr.]] (Spring, 1961). "Eilmer of Malmesbury, an Eleventh Century Aviator: A Case Study of Technological Innovation, Its Context and Tradition", ''Technology and Culture'' '''2''' (2), pp. 97–111 [98 & 101].</ref> [[Hezârfen Ahmed Çelebi]] is alleged to have flown a glider with eagle-like wings over the [[Bosphorus]] strait from the [[Galata Tower]] to [[Üsküdar]] district in [[Istanbul]] around 1630–1632.<ref>[http://www.cmistanbulbogazici.com/who-is-hezarfen-ahmet-celebi/ Who is Hezarfen Ahmet Çelebi?] {{webarchive|url=https://web.archive.org/web/20160121173615/http://www.cmistanbulbogazici.com/who-is-hezarfen-ahmet-celebi/ |date=2016-01-21 }}</ref><ref>[http://www.privatetour.net/hezarfen-ahmet-celebi-the-first-man-to-fly Hezârfen Ahmed Çelebi "The First Man to Fly"] {{webarchive|url=https://web.archive.org/web/20160121173616/http://www.privatetour.net/hezarfen-ahmet-celebi-the-first-man-to-fly |date=2016-01-21 }}</ref><ref>Çelebi, Evliya (2003). Seyahatname. Istanbul: Yapı Kredi Kültür Sanat Yayıncılık, p. 318.</ref>

===19th century===
[[Image:Lilienthal in flight.jpg|thumb|225px|[[Otto Lilienthal]] in flight]]
{{Main|Early flying machines}}
The first heavier-than-air (i.e. non-balloon) man-carrying aircraft that were based on published scientific principles were Sir [[George Cayley]]'s series of gliders which achieved brief wing-borne hops from around 1849. Thereafter gliders were built by pioneers such as [[Jean Marie Le Bris]], [[John J. Montgomery]], [[Otto Lilienthal]], [[Percy Pilcher]], [[Octave Chanute]] and [[Augustus Moore Herring]] to develop [[aviation]]. Lilienthal was the first to make repeated successful flights (eventually totaling over 2,000) and was the first to use rising air to prolong his flight. Using a Montgomery tandem-wing glider, [[Daniel J. Maloney|Daniel Maloney]] was the first to demonstrate high-altitude controlled flight using a balloon-launched glider launched from 4,000 feet in 1905.<ref>Harwood, Craig S. and Fogel, Gary B. ''Quest for Flight: John J. Montgomery and the Dawn of Aviation in the West'', University of Oklahoma Press 2012.</ref>

The [[Wright Brothers]] developed a series of three manned [[Unpowered aircraft|glider]]s after preliminary tests with a [[kite]] as they worked towards achieving powered flight. They returned to glider testing in 1911 by removing the motor from one of their later designs.

===Development===
{{Main|Glider (sailplane)}}
In the inter-war years, [[glider (sailplane)|recreational gliding]] flourished in Germany under the auspices of [[Rhön-Rossitten Gesellschaft|Rhön-Rossitten]].  In the United States, the [[Schweizer brothers]] of Elmira, New York, manufactured sport sailplanes to meet the new demand. Sailplanes continued to evolve in the 1930s, and sport gliding has become the main application of gliders. As their performance improved, gliders began to be used to fly cross-country and now regularly fly hundreds or even over a thousand of kilometers in a day,<ref>{{cite web|url=https://www.fai.org/page/igc-1000km-badges|access-date=24 May 2019|title=FAI list of people with 1000km diplomas|date=5 October 2017|archive-date=8 May 2019|archive-url=https://web.archive.org/web/20190508043629/https://www.fai.org/page/igc-1000km-badges|url-status=live}}</ref> if the weather is suitable.

[[Military glider]]s were developed by during World War II by a number of countries for landing troops,. A glider – the [[Colditz Cock]] – was even built secretly by [[Prisoner of War|POWs]] as a potential escape method at [[Attempts to escape Oflag IV-C#The "Colditz Cock" glider|Oflag IV-C]] near the end of the war in 1944.

[[File:Lithuanian glider BrO-18 Boružė by Br.Oškinis, 1975.jpg|thumb|Smallest glider in the world – BrO-18 "Boružė" ([[Coccinellidae|Ladybird]]), constructed in [[Lithuania]] in 1975]]

===Development of flexible-wing hang gliders===
{{Main|Hang gliding}}
Foot-launched aircraft had been flown by Lilienthal and at the meetings at [[Wasserkuppe]] in the 1920s. However the innovation that led to modern hang gliders was in 1951 when [[Francis Rogallo]] and Gertrude Rogallo applied for a patent for a fully flexible wing with a stiffening structure.  The American space agency [[NASA]] began testing in various flexible and semi-rigid configurations of this [[Rogallo wing]] in 1957 in order to use it as a recovery system for the Gemini [[space capsule]]s. [[Charles Richards (NASA engineer)|Charles Richards]] and [[Paul Bikle]] developed the concept producing a wing that was simple to build which was capable of slow flight and as gentle landing. Between 1960 and 1962 [[Barry Hill Palmer]] used this concept to make foot-launched hang gliders, followed in 1963 by Mike Burns who built a kite-hang glider called [[Skiplane]]. In 1963, [[John W. Dickenson]] began commercial production.<ref>The [[Fédération Aéronautique Internationale]] Hang Gliding Diploma (2006) for the invention of the modern hang glider: [http://www.fai.org/awards/award.asp?id=21 FAI Award: The FAI Hang Gliding Diploma] {{webarchive|url=https://web.archive.org/web/20110518115844/http://www.fai.org/awards/award.asp?id=21 |date=2011-05-18 }}</ref>

===Development of paragliders===
{{Main|Paragliding}}
January 10, 1963 American [[Domina Jalbert]] filed a patent [https://patents.google.com/patent/US3131894 US Patent 3131894] on the [[Parafoil]] which had sectioned cells in an [[Airfoil|aerofoil]] shape; an open leading edge and a closed trailing edge, inflated by passage through the air – the ''ram-air'' design.<ref>{{Cite web |url=http://www.circlinghawk.com/history.html |title=History of Paragliding |access-date=2009-02-15 |archive-url=https://web.archive.org/web/20090913071154/http://www.circlinghawk.com/history.html |archive-date=2009-09-13 |url-status=dead }}</ref> The 'Sail Wing' was developed further for recovery of [[NASA]] space capsules by David Barish. Testing was done by using [[ridge lift]].<ref>{{Cite web |url=http://www.ushpa.aero/article.asp?id=29 |title=Pilot Profile: David Barish, the Probable Inventor of the Paraglider |access-date=2009-03-10 |archive-url=https://web.archive.org/web/20100608083256/http://www.ushpa.aero/article.asp?id=29 |archive-date=2010-06-08 |url-status=dead }}</ref> After tests on [[Hunter Mountain (New York)|Hunter Mountain]], [[New York (state)|New York]] in September 1965, he went on to promote "[[slope soaring]]" as a summer activity for [[ski resort]]s (apparently without great success).<ref>[http://www.flyaboveall.com/articles/davidbarish.htm David Barish, The Forgotten Father of Paragliding] {{webarchive|url=https://web.archive.org/web/20101029042939/http://www.flyaboveall.com/articles/davidbarish.htm |date=2010-10-29 }}</ref> NASA originated the term "paraglider" in the early 1960s, and ‘paragliding’ was first used in the early 1970s to describe foot-launching of gliding parachutes. Although their use is mainly recreational, unmanned paragliders have also been built for military applications e.g. [[Atair Insect]].

==Recreational types==
[[File:Glider2010-overgunma.ogv|thumb|325px|(video) A glider sails over [[Gunma prefecture|Gunma]], Japan.]] 
The main application today of glider aircraft is sport and recreation.

===Sailplane===
{{Main|Glider (sailplane)}}
Gliders were developed from the 1920s for recreational purposes. As pilots began to understand how to use rising air, gliders were developed with a high [[lift-to-drag ratio]].  These allowed longer glides to the next source of '[[lift (soaring)|lift]]', and so increase their chances of flying long distances. This gave rise to the popular sport known as [[gliding]] although the term can also be used to refer to merely descending flight. Such gliders designed for soaring are sometimes called sailplanes.

Gliders were mainly built of wood and metal but the majority now have composite materials using glass, carbon fibre and [[aramid]] fibers. To minimise [[drag (force)|drag]], these types have a [[fuselage]] and long narrow wings, i.e. a [[Wing configuration#Aspect ratio|high aspect ratio]]. In the beginning, there were huge differences in the appearance of early-sailplanes.  As technology and materials developed, the aspiration for the perfect balance between lift/drag, climbing ratio and gliding speed, made engineers from various producers create similar designs across the world. Both single-seat and two-seat gliders are available.

Initially training was done by short 'hops' in [[primary glider]]s which are very basic aircraft with no [[Cockpit (aviation)|cockpit]] and minimal instruments.<ref name="Schweizer">Schweizer, Paul A: ''Wings Like Eagles, The Story of Soaring in the United States'', pages 14–22. Smithsonian Institution Press, 1988. {{ISBN|0-87474-828-3}}</ref>  Since shortly after World War II training has always been done in two-seat dual control gliders, but  high performance two-seaters are also used to share the workload and the enjoyment of long flights. Originally skids were used for landing, but the majority now land on wheels, often retractable. Some gliders, known as [[motor glider]]s, are designed for unpowered flight, but can deploy [[Reciprocating engine|piston]], [[rotary engine|rotary]], [[jet engine|jet]] or [[electric motor|electric engines]].<ref name="definition">{{Cite web |url=http://www.fai.org/component/phocadownload/category/?download=5849:section-3-2012 |title=Definition of gliders used for sporting purposes in FAI Sporting Code |access-date=2013-01-01 |archive-url=https://web.archive.org/web/20140106224126/http://www.fai.org/component/phocadownload/category/?download=5849:section-3-2012 |archive-date=2014-01-06 |url-status=dead }}</ref> Gliders are classified by the [[Fédération Aéronautique Internationale|FAI]] for competitions into [[glider competition classes]] mainly on the basis of span and flaps.

[[Image:Goatglider.jpg|thumb|right|Ultralight "airchair" [[Sandlin Goat]] 1 glider]] A class of ultralight sailplanes, including some known as [[microlift glider]]s and some as 'airchairs', has been defined by the FAI based on a maximum weight. They are light enough to be transported easily, and can be flown without licensing in some countries. Ultralight gliders have performance similar to [[hang gliding|hang gliders]], but offer some additional crash safety as the pilot can be strapped in an upright seat within a deformable structure. Landing is usually on one or two wheels which distinguishes these craft from hang gliders. Several commercial ultralight gliders have come and gone, but most current development is done by individual designers and home builders.

===Hang gliders===
[[Image:Hg rheinebene aug2000.jpg|thumb|right|Modern 'flexible wing' hang glider.]]
{{Main|Hang gliding}}
Unlike a sailplane, a hang glider is capable of being carried, foot launched and landed solely by the use of the pilot's legs.<ref>{{Cite web |url=http://www.fai.org/hang_gliding/system/files/sc07a_2008.pdf |title=FAI Sporting Code Section 7 |access-date=2009-03-13 |archive-url=https://web.archive.org/web/20090319104911/http://www.fai.org/hang_gliding/system/files/sc07a_2008.pdf |archive-date=2009-03-19 |url-status=dead }}</ref>
* In the original and still most common designs, Class 1, the pilot is suspended from the center of the flexible wing and controls the aircraft by shifting their weight.
* Class 2 (designated by the [[Fédération Aéronautique Internationale|FAI]] as Sub-Class O-2) have a rigid primary structure with movable aerodynamic surfaces, such as [[spoiler (aeronautics)|spoiler]]s, as the primary method of control. The pilot is often enclosed by means of a [[Aircraft fairing|fairing]]. These offer the best performance and are the most expensive.
* Class 4 hang gliders are unable to demonstrate consistent ability to safely take-off and/or land in nil-wind conditions, but otherwise are capable of being launched and landed by the use of the pilot's legs.
* Class 5 hang gliders have a rigid primary structure with movable aerodynamic surfaces as the primary method of control and can safely take-off and land in nil-wind conditions. No pilot fairings are permitted.

In a hang glider the shape of the wing is determined by a structure, and it is this that distinguishes them from the other main type of foot-launched aircraft, [[paraglider]]s, technically Class 3. Some hang gliders have engines, and are known as [[powered hang glider]]s. Due to their commonality of parts, construction and design, they are usually considered by aviation authorities to be hang gliders, even though they may use the engine for the entire flight. Some flexible wing powered aircraft, [[Ultralight trike]]s, have a wheeled undercarriage, and so are not hang gliders.

===Paragliders===
[[Image:paraglidertakeoff.jpg|thumb|left|A paraglider taking off in Brazil]]
{{Main|Paragliding}}
A paraglider is a free-flying, foot-launched aircraft. The pilot sits in a harness suspended below a fabric wing. Unlike a hang glider whose wings have frames, the form of a paraglider wing is formed by the pressure of air entering vents or cells in the front of the wing. This is known as a ram-air wing (similar to the smaller parachute design).  The paraglider's light and simple design allows them to be packed and carried in large backpacks, and make them one of the simplest and economical modes of flight. Competition level wings can achieve glide ratios up to 1:10 and fly around speeds of {{convert|45|km/h|mph|abbr=on}}.

Like sailplanes and hang gliders, paragliders use rising air (thermals or ridge lift) to gain height. This process is the basis for most recreational flights and competitions, though aerobatics and 'spot landing competitions' also occur. Launching is often done by jogging down a slope, but winch launches behind a towing vehicle are also used. A [[Paramotor]] is a paraglider wing powered by a motor attached to the back of the pilot, and is also known as a [[Powered paragliding|powered paraglider]]. A variation of this is the [[paraplane]], which has a motor mounted on a wheeled frame rather than the pilot's back.

===Comparison of gliders, hang gliders and paragliders===
There can be confusion between gliders, hang gliders, and [[paragliding|paragliders]]. Paragliders and hang gliders are both foot-launched glider aircraft and in both cases the pilot is suspended ("hangs") below the lift surface. "Hang glider" is the term for those where the airframe contains rigid structures, whereas the primary structure of paragliders is supple, consisting mainly of woven material.

{{Comparison of sailplanes hang gliders and paragliders}}

==Military gliders==
{{Main|Military glider}}
[[Image:Waco CG-4A USAF.JPG|thumb|right|[[Waco CG-4]]A of the USAF]]
'''Military gliders''' were used mainly during the [[World War II|Second World War]] for carrying troops and heavy equipment (see [[Glider infantry]]) to a combat zone, including the British [[Airspeed Horsa]], Russian [[Polikarpov BDP S-1]], American [[Waco CG-3]], Japanese [[Kokusai Ku-8]], and German [[Junkers Ju 322]]. These aircraft were towed into the air and most of the way to their target by military transport planes, e.g. [[C-47 Skytrain|C-47 Dakota]], or by bombers that had been relegated to secondary activities, e.g. [[Short Stirling]]. Once released from the tow near the target, they landed as close to the target as possible. Advantages over paratroopers were that heavy equipment could be landed and that the troops were quickly assembled rather than being dispersed over a drop zone. The gliders were treated as disposable leading to construction from common and inexpensive materials such as wood, though a few were retrieved and re-used. By the time of the Korean War, transport aircraft had also become larger and more efficient so that even light tanks could be dropped by parachute, causing gliders to fall out of favor.

==Research aircraft==
{{Main|Experimental aircraft}}
[[Image:Horten H.IV.jpg|thumb|left|Horten Ho IV flying wing sailplane prone seating glider]]
Even after the development of powered aircraft, gliders have been built for research, where the lack of powerplant reduces complexity and construction costs and speeds development, particularly where new and poorly understood aerodynamic ideas are being tested that might require significant airframe changes. Examples have included delta wings, flying wings, lifting bodies and other unconventional lifting surfaces where existing theories were not sufficiently developed to estimate full scale characteristics.

Unpowered [[flying wing]]s built for aerodynamic research include the [[Horten brothers|Horten]] [[flying wing]]s, the scaled glider version of the [[Armstrong Whitworth A.W.52]] jet powered flying wing.

[[Lifting bodies]] were also developed using unpowered prototypes. Although the idea can be dated to [[Vincent Justus Burnelli]] in 1921, interest was nearly non-existent until it appeared to be a solution for returning spacecraft. Traditional space capsules have little directional control while conventionally winged craft cannot handle the stresses of re-entry, whereas a lifting body combines the benefits of both. The lifting bodies use the fuselage itself to generate [[lift (force)|lift]] without employing the usual thin and flat wing so as to minimize the drag and structure of a wing for very high [[supersonic]] or [[hypersonic]] flight as might be experienced during the [[re-entry]] of a [[spacecraft]]. Examples of type are the [[Northrop HL-10]] and [[Martin-Marietta X-24]].

The [[NASA Paresev|NASA Paresev Rogallo]] flexible wing glider was built to investigate alternative methods of recovering spacecraft. Although this application was abandoned, publicity inspired hobbyists to adapt the flexible wing airfoil for modern hang gliders.

==Rocket gliders==
[[Image:Messerschmitt Me 163B USAF.jpg|thumb|right|Me 163B on display at the National Museum of the USAF]]
{{Main|Rocket glider}}
Rocket-powered aircraft consume their fuel quickly and so most must land unpowered unless there is another power source. The first rocket plane was the [[Lippisch Ente]], and later examples include the [[Messerschmitt Me 163]] rocket-powered interceptor.<ref>The Me 163 was powered by an unstable fuel mix and landing with fuel left caused several accidents</ref> The American series of research aircraft starting with the [[Bell X-1]] in 1946 up to the [[North American X-15]] spent more time flying unpowered than under power. In the 1960s research was also done on unpowered [[lifting bodies]] and on the [[X-20 Dyna-Soar]] project, but although the X20 was cancelled, this research eventually led to the Space Shuttle.

[[NASA]]'s [[Space Shuttle orbiter|Space Shuttle]] first flew on April 12, 1981. The Shuttle re-entered at [[Mach number|Mach]] 25 at the end of each [[spaceflight]], landing entirely as a glider. The Space Shuttle and its [[Soviet]] equivalent, the [[Buran (spacecraft)|Buran shuttle]], were by far the fastest ever aircraft. Recent examples of rocket glider include the privately funded [[SpaceShipOne]] which is intended for sub-orbital flight and the [[XCOR EZ-Rocket]] which is being used to test engines.

==Rotary wing==
{{Main|Rotor kite}}
Most unpowered [[rotorcraft|rotary-wing aircraft]] are kites rather than gliders, i.e. they are usually towed behind a car or boat rather than being capable of free flight. These are known as  [[rotor kite]]s.  However rotary-winged gliders, 'gyrogliders',  were investigated that could descend like an [[autogyro]], using the [[lift (force)|lift]] from [[helicopter rotor|rotors]] to reduce the vertical speed. These were evaluated as a method of dropping people or equipment from other aircraft.

==Unmanned gliders==
===Paper airplane===
{{main|Paper airplane}}
A paper plane, paper aeroplane (UK), paper airplane (US), paper glider, paper dart or dart is a toy aircraft (usually a glider) made out of paper or paperboard; the practice of constructing paper planes is sometimes referred to as aerogami (Japanese: kamihikōki), after origami, the Japanese art of paper folding.<ref>{{cite web |title=Aerogami – Event Description |url=https://www.pragyan.org/16/home/events/chill_pill/aerogami/ |website=Pragyan |access-date=21 March 2019 |archive-date=21 March 2019 |archive-url=https://web.archive.org/web/20190321063409/https://www.pragyan.org/16/home/events/chill_pill/aerogami/ |url-status=live }}</ref>

===Model gliders===
{{main|Model glider}}
'''Model glider aircraft''' are flying or non-flying models of existing or imaginary gliders, often scaled-down versions of full size planes, using lightweight materials such as [[polystyrene]], [[Ochroma pyramidale|balsa]] [[wood]], [[foam]] and [[fibreglass]]. Designs range from simple glider aircraft, to accurate [[scale model]]s, some of which can be very large.

Larger outdoor models are usually [[radio-controlled glider]]s that are piloted remotely from the ground with a [[transmitter]]. These can remain airborne for extended periods by using the lift produced by [[slope soaring|slopes]] and [[thermal]]s. These can be winched into wind by a line attached to a hook under the fuselage with a ring, so that the line will drop when the model is overhead. Other methods of launching include towing aloft using a model powered aircraft, catapult-launching using an elastic [[bungee cord]] and hand-launching. When hand-launching the newer [[Discus Launch Glider|"discus" style]] of wing-tip hand-launching has largely supplanted the earlier "javelin" type of launch.

===Glide bombs===
{{Main|Glide bomb}}
A [[glide bomb]] is a bomb with aerodynamic surfaces to allow a gliding flightpath rather than a ballistic one. This allows the bomber aircraft to stand off from the target and launch the bomb from a safe distance. Most types have a remote control system which enables the aircraft to direct the bomb accurately to the target. Glide bombs were developed in Germany from as early as 1915. In World War II they were most successful as anti-shipping weapons. Some air forces today are equipped with gliding devices that can remotely attack airbases with a [[cluster bomb]] warhead.

==See also==
{{Portal|Aviation}}
*[[Flight]]
*[[Gliding flight]]
*[[Unpowered aircraft]]
*[[Underwater glider]]
*[[Boomerang]]

==References==
{{Reflist}}

{{Aircraft types (by method of thrust and lift)}}
{{Authority control}}

{{DEFAULTSORT:Glider Aircraft}}
[[Category:Aircraft by type]]
[[Category:Glider aircraft| ]]
[[Category:Articles containing video clips]]
[[Category:Aircraft categories]]