Hang gliding: Difference between revisions

Hang gliding saw a stiffened flexible wing hang glider in 1904, when [[Jan Lavezzari]] flew a double lateen sail hang glider off [[Berck|Berck Beach]], [[France]]. In 1910 in [[Breslau]], the [[triangle control frame]] with hang glider pilot hung behind the triangle in a hang glider, was evident in a gliding club's activity.<ref>{{cite web|url=http://lh4.ggpht.com/_y21JroWG1xg/SG6MAf0c7KI/AAAAAAAAATk/CoCQ25QpLrM/1908StephanNitschCollection.jpg|title=1908 hang glider in Breslau territory with pilot hung by his left foot, a device used through 1900s (decade) up to today for natural bodily commute|access-date=30 April 2017|url-status=live|archive-url=https://web.archive.org/web/20160101030149/http://lh4.ggpht.com/_y21JroWG1xg/SG6MAf0c7KI/AAAAAAAAATk/CoCQ25QpLrM/1908StephanNitschCollection.jpg|archive-date=1 January 2016}}</ref>  The biplane hang glider was very widely publicized in public magazines with plans for building;<ref name="spicerweb">{{cite web|url=http://www.spicerweb.org/Chanute/Cha_index.aspx|publisher=spicerweb.org|title=Chanute Main Page|access-date=30 April 2017|url-status=live|archive-url=https://web.archive.org/web/20170607035110/http://www.spicerweb.org/chanute/Cha_index.aspx|archive-date=7 June 2017}}</ref> such biplane hang gliders were constructed and flown in several nations since [[Octave Chanute]] and his tailed biplane hang gliders were demonstrated. In April 1909, a how-to article by Carl S. Bates proved to be a seminal hang glider article that seemingly affected builders even of contemporary times. Many builders would have their first [[hang glider]] made by following the plan in his article.<ref name="comcast">{{cite web|url=http://mywebpages.comcast.net/JerryCY/PMGlider/|publisher=mywebpages.comcast.net|title=The Popular Mechanics Glider|access-date=30 April 2017|url-status=dead|archive-url=https://web.archive.org/web/20060207115532/http://mywebpages.comcast.net/JerryCY/PMGlider/|archive-date=7 February 2006}}</ref>  Volmer Jensen with a biplane hang glider in 1940 called VJ-11 allowed safe three-axis control of a foot-launched hang glider.<ref name="sailplanehomebuilders">{{cite web|url=http://www.sailplanehomebuilders.com/volmer_vj-11.htm|publisher=sailplanehomebuilders.com|title=Home Builders of the Future &#124; VJ-11 Information Page. The history of the VJ-11 hang glider.|access-date=30 April 2017|url-status=live|archive-url=https://web.archive.org/web/20090312062320/http://www.sailplanehomebuilders.com/volmer_vj-11.htm|archive-date=12 March 2009}}</ref>

On 23 November 1948, [[Francis Rogallo]] and [[Gertrude Rogallo]] applied for a [[kite]] patent<ref name="google">{{cite web|url=https://patents.google.com/patent/US2546078|title=Patent US2546078 - Flexible kite - Google Patents|access-date=30 April 2017}}</ref> for a fully flexible kited wing with approved claims for its stiffenings and gliding uses; the ''flexible wing'' or [[Rogallo wing]], which in 1957 the American space agency [[NASA]] began testing in various flexible and semi-rigid configurations in order to use it as a recovery system for the Gemini [[space capsule]]s. The various stiffening formats and the wing's simplicity of design and ease of construction, along with its capability of slow flight and its gentle landing characteristics, did not go unnoticed by hang glider enthusiasts. In 1960–1962 [[Barry Hill Palmer]] adapted the flexible wing concept to make foot-launched hang gliders with four different control arrangements.<ref name="earlyaviators">{{cite web|url=http://www.earlyaviators.com/ebates.htm|author=Ralph S. Cooper, D.V.M.|publisher=earlyaviators.com|title=Carl S. Bates|access-date=30 April 2017|url-status=live|archive-url=https://web.archive.org/web/20160305193020/http://earlyaviators.com/ebates.htm|archive-date=5 March 2016}}</ref> In 1963 Mike Burns adapted the flexible wing to build a towable kite-hang glider he called [[Skiplane]]. In 1963, [[John W. Dickenson]] adapted the flexible wing [[airfoil]] concept to make another water-ski kite glider; for this, the [[Fédération Aéronautique Internationale]] vested Dickenson with the Hang Gliding Diploma (2006) for the invention of the "modern" hang glider.<ref name="fai">{{cite web|url=http://www.fai.org/awards/award.asp?id=21|publisher=fai.org|title=FAI Award: The FAI Hang Gliding Diploma|access-date=30 April 2017|url-status=dead|archive-url=https://web.archive.org/web/20110518115844/http://www.fai.org/awards/award.asp?id=21|archive-date=18 May 2011}}</ref>  Since then, the Rogallo wing has been the most used [[airfoil]] of hang gliders.

Launch techniques include launching from a hill/cliff/mountain/sand dune/any raised terrain on foot, tow-launching from a ground-based tow system, aerotowing (behind a powered aircraft), [[powered hang glider|powered harnesses]], and being towed up by a boat. Modern winch tows typically utilize hydraulic systems designed to regulate line tension, this reduces scenarios for lock out as strong aerodynamic forces will result in additional rope spooling out rather than direct tension on the tow line. Other more exotic launch techniques have also been used successfully, such as [[hot air balloon]] drops from very high altitude. When weather conditions are unsuitable to sustain a soaring flight, this results in a top-to-bottom flight and is referred to as a "sled run". In addition to typical launch configurations, a hang glider may be so constructed for alternative launching modes other than being foot launched; one practical avenue for this is for people who physically cannot foot-launch.<ref name="cableairport">{{cite web|url=http://www.cableairport.com/airfair/Performers/Dan_Buchanan.html|publisher=cableairport.com|title=Dan Buchanan|access-date=30 April 2017|url-status=dead|archive-url=https://web.archive.org/web/20070928095243/http://www.cableairport.com/airfair/Performers/Dan_Buchanan.html|archive-date=28 September 2007}}</ref>

In 1986 Denis and 'Redtruck' took a group of international pilots to Alice Springs to take advantage of the massive thermals. Using the new system many world records were set. With the growing use of the system, other launch methods were incorporated, static winch and towing behind an [[ultralight trike]] or an [[Ultralight aircraft (United States)|ultralight airplane]].

A glider in flight is continuously descending, so to achieve an extended flight, the pilot must seek air currents rising faster than the sink rate of the glider. Selecting the sources of rising air currents is the skill that has to be mastered if the pilot wants to achieve flying long distances, known as [[Cross-country flying|cross-country]] (XC). Rising air masses derive from the following sources:<ref>{{cite book | last = Pagen | first = Dennis | title = Understanding the Sky - A Sport Pilot's Guide to Flying Conditions | publisher = Dennis Pagen | date = January 1992 | location = Mingoville, Pennsylvania, USA | pages = 280 | isbn =  978-0-936310-10-7  }}</ref>

; Ridge lift

: [[Ridge lift]] occurs when the wind encounters a mountain, cliff, hill, sand dune, or any other raised terrain. The air is pushed up the [[windward]] face of the mountain, creating lift. The area of lift extending from the ridge is called the lift band. Providing the air is rising faster than the gliders sink rate, gliders can soar and climb in the rising air by flying within the lift band parallel to the ridge. Ridge soaring is also known as [[slope soaring]].

; Mountain waves

: The third main type of lift used by glider pilots is the [[lee waves]] that occur near mountains. The obstruction to the airflow can generate [[standing wave]]s with alternating areas of lift and sink. The top of each wave peak is often marked by [[lenticular cloud]] formations.

; Convergence

: Another form of lift results from the [[Convergence zone|convergence]] of air masses, as with a [[Sea breeze|sea-breeze front]]. More exotic forms of lift are the polar vortices which the [[Perlan Project]] hopes to use to soar to great altitudes.<ref name="perlanproject">{{cite web|url=http://perlanproject.com|publisher=perlanproject.com|title=Home &#124; Perlan Project|access-date=30 April 2017}}</ref> A rare phenomenon known as [[Morning glory cloud|Morning Glory]] has also been used by glider pilots in Australia.<ref name="dropbears">{{cite web|url=http://www.dropbears.com/brough/index.html|publisher=dropbears.com|title=Morning Glory Clouds of the Gulf of Carpentaria &#124; A Guide to the Morning Glory|access-date=30 April 2017|url-status=live|archive-url=https://web.archive.org/web/20090720032625/http://www.dropbears.com/brough/index.html|archive-date=20 July 2009}}</ref>

; Roll

: Most flexible wings are set up with near neutral roll due to [[sideslip]] ([[Dihedral (aircraft)#Anhedral|anhedral]] effect). In the roll axis, the pilot shifts their body mass using the wing control bar, applying a rolling moment directly to the wing. The flexible wing is built to flex differentially across the span in response to the pilot applied roll moment. For example, if the pilot shifts their weight to the right, the right wing trailing edge flexes up more than the left, creating dissimilar lift that rolls the glider to the right.

; Yaw

; Pitch

: The pitch control response is direct and very efficient. It is partially stabilized by the [[Washout (aeronautics)|washout]] combined with the [[Swept wing|sweep]] of the wings, which results in a different angle of attack of the rear most lifting surfaces of the glider. The wing centre of gravity is close to the hang point and, at the trim speed, the wing will fly "hands off" and return to trim after being disturbed. The weight-shift control system only works when the wing is positively loaded (right side up). Positive pitching devices such as reflex lines or washout rods are employed to maintain a minimum safe amount of washout when the wing is unloaded or even negatively loaded (upside down). Flying faster than trim speed is accomplished by moving the pilot's weight forward in the control frame; flying slower by shifting the pilot's weight aft (pushing out).

The altitude records for balloon-launched hang gliders:

|-

| Wadi Rum, Jordan

| 25 October 1994

| <ref>{{Cite book|last=Leden |first=Judy |date=2003|title= Flying with Condors. New York: Orion Books.|publisher=Orion Publishing Group, Limited |isbn=0-7528-0874-5}}</ref>

|-

| Edmonton, Alberta, Canada

| 29 August 1982

| <ref>Edmonton Journal, 30 August 31, 1982; "Kerry Bissell, an official observer of the Soaring Association of Canada: It's 33,000 feet. If the reading is taken at the top of the trace mark, the record is 11,400 meters"</ref>

| California City, California, USA

| 9 September 1978

| <ref>Hang Gliding magazine, December 1978, p35.</ref>

|-

| Mojave Desert, California, USA

| 21 November 1976

| <ref>{{Cite book| title = The Guinness Book of Records, 1982 }}</ref>

| San Jose, California, USA

| 25 December 1974

| <ref>Sarasota Journal, 27 December 1974 p4D.</ref>

[[Category:Glider aircraft]]

[[Category:Individual sports]]