History of hang gliding

Hang gliding is an air sport employing a foot-launchable aircraft known as a hang glider. Typically, hang gliders are composed of an aluminium or composite framed fabric wing. The pilot is ensconced in a harness depending from the airframe, and exercises control by shifting body weight in opposition to a control frame.

Overview

Early glider designs did not reliably achieve safe flight, their builders lacking a comprehensive understanding of the underlying principles of flight. The first recorded "controlled" flights were by German engineer Otto Lilienthal, whose research, published in 1889, strongly influenced later designers. [cite book | last = Lilienthal | first = Otto | authorlink = Otto Lilienthal | coauthors = | title = The Flight of Birds as a Basis of Aviation | publisher = | date = 1889 | location = | pages = | url = | doi = | id = | isbn = 978-0938716587 ] [ [http://www.google.com/patents?id=10xzAAAAEBAJ&dq=544816 Flying-Machine, Otto Lilienthal's patent] ] The type of aircraft employed by Lilienthal is now referred to as a hang glider. Further hang glider research was undertaken during the 1920s in Europe, [ cite web|url=http://www.glider-pilot.co.uk/Wings%20of%20%20Wasserkuppe/Wings%20of%20%20Wasserkuppe.htm |title=The Wings of Wasserkuppe |accessdate=2008-08-14 |last=Griffitts |first=Glen |date=2004 ] Australia [cite web|url=http://grafton.nsw.free.fr/ski_wing |title=Grafton's Ski Wing |accessdate=2008-08-13 |last=Skyvington |first=William ] and the U.S.A, [ cite web|url=http://history.nasa.gov/SP-4308/ch11.htm#382 |title=Spacedcraft Revolution - In the Service of Apollo |accessdate=2008-08-14 |first=NASA |publisher=NASA ] [ cite web|url=http://members.aol.com/hiitec/kite/trike.html |title=Hang Gliding, 1960 Style |accessdate=2008-08-14 |last=Palmer |first=Barry H. ] where designers tested several wing concepts and the 'pendulum weight-shift control system'.

In 1957 the American space agency NASA began testing various formats of a new airfoil called the Rogallo wing with the intent of possibly implementing the design as a recovery system for the Gemini space capsules. A lateral project was to give some eight pilots free-flight hang gliding experience; to satisfy that Charles Richards and his team of engineers was directed by Paul Bikle to construct a quick and cheap Rogallo wing hung-pilot glider; the series of wings produced in 1961-2 formed the foundation of a decade of Rogallo winged hang gliders. The wing's simplicity of design and ease of construction, in combination with its slow flight characteristics, did not go unnoticed by hang glider enthusiasts; Rogallo's flexible wing airfoil was soon adapted to the purpose of recreational flight, launching a hang glider Renaissance. ["Low & Slow" magazine produced by Joe Faust (1971) was the most powerful publicity tool during the early years. He followed "Low & Slow" with "Hang Glider Weekly" to reach 23 nations through 1981 with 216 editions. Joe's publications were written by a staff of scores of correspondents worldwide. A monthly publication, "Ground Skimmer" was started in May of 1972 as a newsletter for club members in California. It soon grew to be a comprehensive magazine, recording the history of the hang gliding movement as it happened. By the end of 1973, the organization had become truly national in scope and in November of 1976, the name of the magazine was changed to "Hang Gliding". "Glider Rider" also appeared. In 2002, "Hang Gliding" and "Paragliding" magazines were combined and the resulting magazine was named "Hang Gliding & Paragliding" magazine.]

Early history

The sleek high performance jets, sailplanes and hang gliders of today have a heritage that dates back to man’s first attempts at flight.

The Chinese Daoist writer Ge Hong (284–364 AD) wrote that kite vehicles with frames made of wood from the jujube tree had ox-leather straps "fastened to returning blades" that could allow the device to soar high into the air.Temple, Robert. (1986). "The Genius of China: 3,000 Years of Science, Discovery, and Invention". With a forward by Joseph Needham. New York: Simon and Schuster, Inc. ISBN 0671620282. Page 176.] As a form of execution, the notoriously cruel Emperor Wenxuan of Northern Qi (r. 550–559) had members of the rival Yuan and Tuoba clans attached to kites and launched from the top of the Tower of the Golden Phoenix in the capital, Ye, China, as test pilots; Yuan Huangtou (d. 559) glided for a while and survived the landing, but he was executed shortly after. The Venetian traveler Marco Polo (1254–1324) wrote that "some fool or drunkard" of the crew of a Chinese ship was the standard candidate to be strapped into a man-flying kite (which he called a "hurdle" made of willow stems attached to eight cords), which served the purpose of fortune-telling (i.e. they believed that if the man strapped to the kite rose fine, a prosperous voyage was ahead, if not, no foreign merchant would make deals with them). [Temple, Robert. (1986). "The Genius of China: 3,000 Years of Science, Discovery, and Invention". With a forward by Joseph Needham. New York: Simon and Schuster, Inc. ISBN 0671620282. Page 177–178.]

There are accounts of two attempts at flight by a Abbas Ibn Firnas near Cordoba, Spain in the 9th century. His first, in 852 CE, was a parachute jump using a huge wing-like cloak to break his fall; the second, in 875 CE, at the age of 70, employed a rudimentary glider. Both efforts ended in crashes and injury. [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), p. 97-111 [100-101] .] [ [http://www.saudiaramcoworld.com/issue/196401/first.flights.htm First Flights] , "Saudi Aramco World", January-February 1964, p. 8-9.] It is possible that word of Ibn Firnas' wing-like parachute reached the monk Eilmer of Malmesbury of England, [White, L., Jr., "Eilmer of Malmesbury, an Eleventh Century Aviator". Medieval Religion and Technology. Los Angeles: University of California Press, 1978, Chapter 4. ] a scholar of mathematics and astrology. A fellow monk and historian, William of Malmesbury, reported that Eilmer flew off the roof of an Abbey in Malmesbury, England sometime between 1000 and 1010 AD, gliding about convert|200|m|yd before crashing, breaking a leg.

According to a story recorded by Evliya Çelebi, in 1638 AD, Hezarfen Ahmet Celebi took flight from the convert|62.59|m|ft tall Galata Tower in Istanbul and landed on the opposite side of the Bosporus in Doğancılar Square- about convert|3380|m|ft away; [Implies a minimum glide ratio of 1:39.49 in stable air from the tower peak.] he was rewarded 1,000 dinars for his flight. [ [http://www.islamonline.net/english/science/2003/05/article04.shtml Flights of Fancy on Manmade Wings] ]

The Kraków Museum of Ethnography in Poland claims that in 1866, painter and carpenter Jan Wnęk completed construction of an ash wood glider frame which he covered with linen impregnated with varnish and that Wnęk was firmly strapped to the glider by the chest and hips. It is claimed but not verified, that Jan Wnęk made several public flights from the local church tower during 1866-1869. [Jan Wnęk [http://www.dziecidodzieci.republika.pl/wnekfr.htm] , [http://www.avia.tarman.pl/index.php?action=histwnek] , [http://www.mek.krakow.pl/] ]

Starting in the 1880s advancements were made in aerodynamics and construction that led to the first truly practical gliders; this information was often shared and published by early aviators and inventors, building a long series of incremental achievements. Through the 1880’s several aviation pioneers emerged in different countries around the world all perusing glider designs with varying degrees of success. Chief among these were Otto Lilienthal in Berlin, Germany, Lawrence Hargrave in Sydney, Australia, Percy Pilcher in the United Kingdom, John Joseph Montgomery at Otay Mesa near San Diego, California (1880s) as well as at Santa Clara, California (1905) Octave Chanute and his team in Gary, Indiana in the U.S.A., just to name a few.

Otto Lilienthal duplicated some of his contemporaries' work and greatly expanded on it from 1874, publishing all of his research in 1889. ["The Flight of Birds as a Basis of Aviation". ISBN-10: 0938716581; ISBN-13: 978-0938716587] He also produced a series of gliders, and in 1891 was able to make flights of convert|25|m|ft or more routinely, as well as some soaring flights. He rigorously documented his work, influencing later designers; for this reason he is one of the best known and influential of the early aviation pioneers. His type of aircraft is now known as a hang glider. By 1896 he had made about 2000 flights on a number of his designs when he crashed from a height of roughly convert|17|m|ft fracturing his spine.
Percy Pilcher took a growing interest in aviation and built a glider called "The Bat" which he flew for the first time in 1895. Later that year Pilcher met and consulted with Otto Lilienthal, who was the leading expert in gliding; these discussions led to Pilcher building two more hang gliders, "The Beetle" and "The Gull". [Pilcher's gliders: [http://www.first-to-fly.com/History/History%20of%20Airplane/pilots.htm] ] Based on the work of his mentor Otto Lilienthal, in 1897 Pilcher built a third hang glider called "The Hawk" with which he broke the world distance record when he flew convert|250|m|ft|0. [Percy Pilcher [http://www.spartacus.schoolnet.co.uk/AVpilcher.htm] ]

Wasserkuppe

The hang glider lost some importance through the introduction of wing warping in 1902 by the Wright brothers and subsequently of aileron control by the French. When the World War I ended in 1918, the Treaty of Versailles practically ended engine driven flights in Germany, thus, in the 1920s and 1930s, while aviators and aircraft makers in the rest of the world were working to improve the performance of powered aircraft, the Germans were designing, developing and flying ever more efficient gliders and discovering ways of using the natural forces in the atmosphere to make them fly farther and faster. These activities in Wasserkuppe promoted a renaissance of gliding aviation. Many of these gliders flown in 1920 were hang gliders in that they were controlled by the pilot's weight shift alone. [Wasserkuppe, gliding [http://www.soaringissa.org/wasserkuppe/] ] [Glider history [http://www.glider-pilot.co.uk/Wings%20of%20%20Wasserkuppe/Wings%20of%20%20Wasserkuppe.htm] [http://www.geocities.com/achilles36606/wings.html] ] The first Wasserkuppe glider competition was held in 1920. Over the next decade, the contest grew in popularity. As many as 70 glider clubs from Europe sent their best gliders and pilots to compete for duration, altitude and distance prizes, the most coveted prize was that donated by President von Hindenburg. As many as 60,000 spectators dotted the mountain slopes to watch these events. [Spectators at Wasserkuppe [http://www.geocities.com/achilles36606/wings.html] ] Virtually every European aeronautical engineer of the time tested and modified their aircraft there and reports were generated. ["Glider Construction and Design" from Der Gleit and Segelflugzeugbau, 1925. (Translated to English): [http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19930090798_1993090798.pdf] ] Some competing hang glider designers were Alfried Gymnich, [Alfried Gymnich [http://ntrs.nasa.gov/index.jsp?method=order&oaiID=19930090793] ] Gottlob Espenlaub, [Gottlob Espenlaub 1922 delta hang glider: [http://www.drachenarchiv.de/Seiten/e_espenlaub.html] . During the Wasserkuppe 1921 hang gliding competition, he met Alexander Lippisch and both engaged in collaboration on drafts and models of gliders and hanging gliders.] Alexander Lippisch, [Alexander Lippisch [http://www.ctie.monash.edu.au/hargrave/lippisch.html] ] Heinz Schneider, [Heinz Schneider's hang glider [http://www.es-heftche.de/ausgabe032/heinz_schneider/schneider.html] ] Francis Chardon, [Francis Chardon, [http://www.objectifreussir.ch/fr/cadre_repertoire/sport/Parapente/parapente.html] ] Willi Pelzner, [Willi Pelzner [http://www.fiddlersgreen.net/AC/aircraft/Blaue-Maus-Glider/maus.php] , [http://www.reiner-schneider.com/Heini.html] ] Hans Richter [Hans Richter [http://www.britannica.com/eb/art/print?id=96511&articleTypeId=0] ] and Segelflieger Peltzner, [Segelflieger Peltzner: [http://www.luene-info.de/preussen/landesmuseum2.html?http://www.luene-info.de/preussen/windkraft/sondost.html] ] while engineer Henri Mignet was busy in France [Henri Mignet [http://www.premiumwanadoo.com/aeroscope/essais.htm] [http://pou.guide.free.fr/connaitre/biographie_hm/biographie.htm] [http://jolly.roger.free.fr/brouette.htm] ] and Czesław Tański was busy in Turkey. Czesław Tański [http://www.elknet.pl/historia-lotnictwa/av_hist/index.php?position=0.0.66] ]

Invention of the flexible wing

On 1948, aeronautical engineer Francis Rogallo invented a self-inflating wing which he patented on March 20, 1951 [As an acknowledgement of his wife’s enormous contribution to the project, Francis put the patent in his wife’s name. Gertrude Rogallo holds the patent on the flexible wing (flexwing). This was not simply a tribute to Francis’ love for his wife, but the acknowledgement that she was a significant partner in his research. Gertrude Rogallo still holds the patent.] [Rogallo's patents: [http://kitepatents.wordpress.com/] ] [Article: "How to Fly Without a Plane" by Robert Zimmerman, aerospace writer. [http://www.americanheritage.com/articles/magazine/it/1998/4/1998_4_22.shtml] ] as the "Flexible Wing", [ Diagrams of Rogallo's flexible wing. [http://www.fang-den-wind.de/rogallo_eng.htm] ] also known as the "flexwing" and Rogallo wing. Francis Rogallo had first proposed his flexible wing concept to the Langley Research Center in the late 1940s as a simple, inexpensive approach to recreational flying, but the idea was not accepted as a project. [Rogallo wing proposed for recreational flying in the late 1940s: [http://www.nasa.gov/centers/dryden/about/Organizations/Technology/Facts/TF-2004-09-DFRC.html] ]

It was on October 4, 1957 when the Russian satellite Sputnik became a concern to the United States and marked the beginning of the 'space race' and the creation of NASA. Rogallo was in position to seize the opportunity and with his help at the wing tunnels, NASA began a series of experiments testing Rogallo's flexible wing, which got renamed "Parawing", in order to evaluate it as a recovery system for the project Gemini space capsules. [Also evaluated for recovery of used Saturn rocket stages: "Space Flight Revolution" [http://history.nasa.gov/SP-4308/ch11.htm#382] ] Rogallo designed his flexible wing to allow the astronauts to deploy it like a parachute at subsonic speeds during reentry, then glide their capsule to a specified touchdown point. [On 1965 Jack Swigert, who would later be one of the Apollo 13 astronauts, softly landed a full-scale Gemini capsule using a Parawing stiffened with inflatable tubes along the wing’s edges] F. Rogallo's team collaborated with at least two American aircraft companies, Ryan Aeronautical Company and North American Aviation, as there was potential for gliders, dirigible parachutes, and other new types of manned aircraft; this mainly involved stabilizing the leading edges with compressed air beams or rigid structures like aluminium tubes. By 1961 NASA had already made test flights of an experimental STOL 'aerial utility aircraft' called Ryan XV-8 (the "Flying Jeep" or "Fleep") [ The earliest photographic press release of a Rogallo flexible wing in record dates to August 14, 1961 by "Aviation Week and Space Technology" magazine.] [Memoirs of a "Ryan" engineer on the Fleep: [http://home.insightbb.com/~p51h/Bruce/bruce.html] ] and by March 1962, of a weight-shift glider called Paresev.

Round parachutes were selected over the Rogallo wing to be used on the Gemini spacecraft and on 1965, funding on flexible wings stopped.

Flexible wing hang gliders

The simplicity of the Rogallo wing, ease of construction, capability of slow flight and its gentle landing characteristics did not go unnoticed by some hang glider and ultralight glider enthusiasts.The publicity [Press release of the XV-8 'Fleep': August 14, 1961 by "Aviation Week and Space Technology" magazine.] on the Fleep and the Paresev tests sparked interest in independent builders like Barry Palmer [Barry Palmer's web site. Dated photos. [http://members.aol.com/hiitec/kite/trike.html] . Video of his first flights in 1961 loaded in YouTube: [http://www.youtube.com/watch?v=sswv4WUi0aY] ] and John Dickenson, who separately explored distinct airframes and control systems to be adapted to a Rogallo wing and be flown as a hang glider.

On August 1961, American engineer Barry Palmer developed and flew the first foot-launched Rogallo wing hang glider. [Several Langley employees shared Rogallo's enthusiasm for the innovative flight technology and even conducted manned flexible wing flight research during weekends on the Outer Banks with privately owned equipment. Although qualitative in nature, these investigations proved "valuable in providing quick answers and indicating promising directions for the much more costly and time consuming instrumented but unmanned NASA flight research." [http://history.nasa.gov/SP-4308/ch11.htm] ] This took place near Latrobe, east of Sacramento, California. Palmer used aluminium tubing and no wires for construction, fearing kinking during assembly. Most flights were performed with just a set of inclined parallel bars that split his weight between his underarms and hands and he demonstrated that the Rogallo wing, when used as a hang glider, could also be controlled by weight-shift alone. The last of Palmer's foot-launched hang gliders flew in the summer of 1962 and it had a ski-lift type of seat mounted to the keel with a universal joint for pendulum weight-shift control; a single control stick was projected down from the wing. During the period from 1961 to 1963 Barry Palmer made tens of flights using this concept. His longest flight ranged in length up to convert|180|m|ft, at altitudes up to convert|24|m|ft, and had an overall glide ratio of 4.5 to 1.
Palmer's wing was heavy by today's standards and was not particularly portable. Palmer relates that he had a good aerospace job and was flying for fun. He did not attempt to modernize or market the flexible wing hang glider and shared all details with anybody interested. [Interview with Gerard Farell on 1/23/2007 - 1/24/2007.] Palmer moved on to invent the first ultralight trike: "The Paraplane", registered by the FAA on 4/24/1967 as the Palmer Parawing D-6, serial 1A, N7144. No limitations were noted. The second craft, "Skyhook" was powered by a single cylinder snowmobile engine (17 hp at 5000rpm).] Palmer corresponded Richard Miller, who in 1964 developed the "Bamboo Butterfly", ["Lesson no. 1 comes as a bit of a surprise, lateral movement to turn the Rogallo or keep it on course, call for all the gymnastic experience one can muster. When the glider turns it is in a flat skidding arc with no bank whatsoever." – Richard Miller. "Taking the Leap" article published in Nov. 1968 by "Low & Slow and Out of Control" magazine.] followed by Tara Kiceniuk's "Batso". The plans of these hang gliders circulated in some magazines in the mid 1960s. [The papers written by Rogallo as well as government reports and photographs, became available to the general public. Dave Kilbourne published his plan for a Rogallo wing "Kilbo Kite" hang glider in the early 1970s. The Rogallo wing was turned into an easily constructed, inexpensive, foot-launchable glider. Word of its success got out and more were built. This presented the Rogallos with a dilemma, whether to defend their patent or not. The Rogallo’s chose to let manufacturers freely produce their invention. [http://www.hangglidingspectacular.com/rogallohistory.html] [http://members.bellatlantic.net/~vze26db3/Miscellaneous/rogallo.htm] ]

In April of 1963 Mike Burns gave public maiden flight to Skiplane, a kited-hung-pilot pontooned glider that donned mechanically a wing appearing as a Charles Richards wing [Sky Sports, pgs 39-42, 1989 edition] , as the NASA literature had been studied. In Septermber 1963, Australian John Dickenson set out to build a water ski wing that could be released at altitude and glide to a safe landing. After seeing a Rogallo airfoil in a magazine, Dickenson designed the ski kite he called the "Ski Wing". [Ski Wing [http://grafton.nsw.free.fr/ski_wing/] , [http://www.hgfa.asn.au//skysailor/Issues/0609/gmrept.htm] ] [Hang Gliding History and Origins - [http://www.usairnet.com/encyclopedia/?category=/Recreation/Aviation/Aircraft/Flex_Wing/Hang_Glider/History/] ] Dickenson fashioned an airframe that incorporated a triangle control frame and utilized wire bracing to distributed the load to the wing- a Rogallo airfoil; the pilot sat on a swinging seat. [Article by Mark Woodhams, British Columbia Hang Gliding and Paragliding Association: [http://bchpa.org/newsletter/may04/hghistory.htm] ] [Western Museum of Flight: [http://www.wmof.com/rsw.htm] ] [The Australian Ultralight Federation -History: [http://www.auf.asn.au/operations/benchmarks.html] ] [The weight-shift (swinging seat) and control frame are two key control concepts J. Dickenson 'imported' from water ski kites into his "Ski Wing".] Dickenson's Ski Wing was stable and controllable compared to the flat manned kites used at water ski shows at the time. [Stability and weight-shift control are inherent flex-wing characteristics previously established and described by its inventor F. Rogallo and by NASA engineers in the Paresev and Fleep programs.] The Ski Wing was first flown in public at the Grafton Jacaranda Festival, Australia, in September 1963 by Rod Fuller while towed behind a motorboat. The Ski Wing was light and portable- Dickenson decided to file for a patent; however, lacking resources, Dickenson procured a provisional patent - which would later lapse. [On October/11/1963 Dickenson filed for a patent, and a provisional protection was awarded for his application number 36189/63 but the patent was not finally awarded: [http://www.innovated.gov.au/Innovated%5Ccase_studies%5CHang_Glider.pdf] ] Australian builders Bill Bennett and Bill Moyes developed the Dickenson format of water ski kite into a foot launched hang glider by 1972. [Patent filed by Bill Bennettin on September 24, 1969: U.S. Pat. D224248 "PASSENGER CARRYING TOW KITE" [http://www.google.com/patents?id=s6Y8AAAAEBAJ] , approved in July 11, 1972.]

Rigid wing hang gliders

There have been several rigid wing hang gliders flown since Otto Lilienthal took his first flights in the 1890s. [Antique rigid wings [http://www.jumpnfly.privat.t-online.de/nitony.htm] ] Jack Lambie from California, designed in 1971 the popular "Hang Loose" Chanute hang glider, [Hang Loose biplane hang glider: [http://privitt.com/hang_gliding.htm] ] [Jack Lambie [http://1000aircraftphotos.com/Contributions/Brink/2130.htm] ] [Jack Lambie was a school teacher; he helped build the first Human powered Aircraft, the Gossmer Condor. [http://www.raes.org.uk/cms/uploaded/files/SG_HPAG_condor.pdf] Many of Jack’s innovative design concepts have made their way into modern everyday life. He designed the first cab over Diesel Semi Truck fairing (the Fuel Saver) that is now used “stock” on practically all 18 wheelers. His teardrop/Dart Vader Bicycle helmet (the Lambie Lid) was first used by U.S.A. 84’ Olympic Bike team to win Gold. Jack was singularly responsible for organizing the first modern era hang glider meet, the original Otto Meet, on the hills of Balboa in Sept., 1972.] and the first two high performing modern hang gliders were the "Mitchell Wing" and the "Icarus".

On 1971 and 1972 the Icarus I and Icarus II were built, respectively. [ Smithsonian Air & Space Museum. Icarus hang glider development. [http://www.nasm.si.edu/research/aero/aircraft/icarus.htm] ] These were rigid biplane flying wing designs by Taras Kiceniuk, Jr. The Icarus V was essentially a monoplane version of the previous Icarus designs. All of the hang gliders in the Icarus series had hand-controlled rudders and the pilot flew in a reclining position (rather than a prone position as with other hang gliders). Although many Icarus II and Icarus V gliders were built from plans sold by Kiceniuk, they were never commercially produced.

In the early 1940s Don Mitchell, an aeronautical engineer, first became involved with flying wing glider design and construction. WWII interrupted his research until 1974, with the advent of hang glider mania, adventurers were experimenting with design and exploring records worldwide. It was then that Mitchell's flying wing resurfaced. Dr. Howard Long took an interest and asked Don Mitchell to make him a refined 'flying wing' hang glider. The result was the foot-launched "Mitchell Wing". When the foot-launched Mitchell Wing B-10 flew in the 1977 U.S.A. Nationals, the hang gliding world was completely astounded. The Mitchell Wing then went on to set and hold every world record in its class. In 1980, George Worthington soared to convert|17000|ft|m high and glided convert|105|mi|km, setting two new rigid wing records. The Mitchell Wing had a single "D" spar with aircraft birch plywood torsion proof leading edge and 3-axes control. [The Mitchell Wing B-10 Ultralight Motor Glider - U.S. Pacific George Worthington, holder of eight world records in hang gliding and author of the book "In Search of World Records", wrote in the book..."I predict that the Mitchell Wing will be the highest performance foot-launched hang glider we'll see for a long time." [http://home.earthlink.net/~mitchellwing/b10.html] ] Foam ribs placed every convert|4.5|in|mm hold the D shape. The built-up truss ribs aft of the spar are covered with fabric. This structural design is simple, extremely strong and light (under 80 Lbs).

The "Exxtacy", designed by Felix Ruehle In the early 1990s, followed by the "IXBO", became the first two rigid wing hang gliders on the market with a leading edge of carbon fiber. Ruehle then produced the "ATOS" in 1999. The nose angle and wing span of modern rigid wings are a little larger than flexible wings and the sail is rather stiff. [ A.I.R. [http://www.a-i-r.de/ A.I.R.(AERONAUTIC INNOVATION RÜHLE)] ]

Popularity

The recent world wide rise of hang gliding popularity is the direct effect of new portable gliders made available to a society in particular need of self expression. The extreme nature of foot-launched hang gliding appealed to the freewheeling culture of the late 1960s across America more as an expression of freedom than an air sport. [Hang Gliding Mayhem - Article: [http://www.privitt.com/hang_loose.htm] ] The flights and Rogallo wing plans by Dave Kilbourne and Richard Miller added greatly to the presence of Rogallo wings in California in various formats. The sudden commercial availability of finished water ski hang gliders in 1969 by manufacturers like Bill Bennett [Contributions by Bill Bennet as explained by the 'Smithsonian National Air & Space Museum':Delta Wing Phoenix VI [http://www.nasm.si.edu/research/aero/aircraft/delta_wing_phoenix_vib.htm] , Delta Wing Phoenix VI: [http://www.nasm.si.edu/research/aero/aircraft/delta_wing_phoenix_vi.htm] , Delta Wing Phoenix Mariah M-9: [http://www.nasm.si.edu/research/aero/aircraft/delta_wing_M-9.htm] , Delta Wing Model 162: [http://www.nasm.si.edu/research/aero/aircraft/delta_wing_162.htm] , Delta Wing Phoenix Viper 175: [http://www.nasm.si.edu/research/aero/aircraft/delta_wing_phoenix_viper.htm] , Delta Wing Streak 130: [http://www.nasm.si.edu/research/aero/aircraft/delta_wing_130.htm] .] ("Delta Wing") and Bill Moyes [Moyes' story: [http://www.moyes.com.au/articledetail.asp?ID=41&Cat=] , The History of Moyes: [http://www.moyes.com.au/articledetail.asp?ID=61&Cat=] ] [ABC History -an interview with Moyes: [http://www.abc.net.au/gnt/history/Transcripts/s1227269.htm] ] ("Moyes Gliders") added to the Rogallo wing's popularity, which began to rise world wide as a full fledged sport. Popularity was further fueled by the distribution of specialized international publications such as the "Low & Slow" magazine founded in 1971, "Hang Glider Weekly" [ "Low & Slow" magazine produced by Joe Faust (1971) was likely the most powerful publicity tool during the early years. He followed "Low & Slow" with "Hang Glider Weekly" to reach 23 nations through 1981. Joe's publications were written by a staff of scores of correspondents worldwide.] and "Ground Skimmer" in 1972 [A monthly publication, "Ground Skimmer" was started in May of 1972 as a newsletter for club members in California. It soon grew to be a comprehensive magazine, recording the history of the hang gliding movement as it happened. By the end of 1973, the organization had become truly national in scope and in November of 1976, the name of the magazine was changed to "Hang Gliding". Glider Rider also appeared. In 2002, "Hang Gliding" and "Paragliding" magazines were combined and the resulting magazine was named "Hang Gliding & Paragliding" magazine.] and "Glider Rider" in 1975. ["Glider Rider" magazine -Founded by Tracy Knauss. His magazine became the "Ultralight Flying!" magazine ] Hang gliding was simultaneously promoted by major international publications such as Popular Mechanics, [Bates glider (
http://www.earlyaviators.com/ebates1.htm] [http://www.iawings.com/publications/history.htm] ) -In 1898, Carl Bates, a 14-year-old from Clear Lake, built and flew the first man-carrying glider in Iowa. In 1909 Carl Bates wrote an article entitled "How to Build a Glider". The article was published in Popular Mechanics magazine that year. The craft became known simply as "the Popular Mechanics Glider" and hundreds were built [http://mywebpages.comcast.net/JerryCY/PMGlider/] ] Popular Science ["Popular Mechanics" and "Popular Science" magazines: [http://support.atmos.com/hg/early/early.htm] ] and the Life magazine, ["Life" magazine- September 3, 1971 issue: "The Endless Weekend." ] all three magazines distributed world-wide in 1971; the "Sky Raiders" hang gliding movie was released in 1976 [The Swallowtail hang glider was featured in the 1976 movie "Sky Riders" (filmed in Greece during 1975) starring James Coburn, Robert Culp, Susannah York, and Charles Aznavour. After filming of the action was complete, the Wills Wing team toured Europe and stopped by in England to win the British Championships at Mere, Wiltshire, in August 1975;] [James Bond (Agent 007) "Live and Let Die" movie released in 1972, also included a segment on hang gliding.] with a powerful effect. The British "SkyWings" magazine has been published monthly since 1975 ["SkyWings", British hang gliding magazine. [http://www.shop.bhpa.co.uk/section.php?xSec=9] ] and "Cross Country", the first truly international hang gliding magazine began publication in 1988. [Cross Country magazine: [http://www.xcmag.com/Spinner/read/article.cfm?id=1210] ]

Free hang gliding took longer to catch on in Australia, where hang gliding was a water skiing sport and part of the "New South Wales Water Skiing Association". In fact, Dickenson's Ski Wing was competing in the NSWWSA kite-flying section against the polygonal Japanese style flat kites. [Note by Mr. Stephane Malbos (Commission Internationale de Vol Libre, the Hang Gliding and Paragliding Commission of FAI) in the OZ Forum.] The first recorded foot-launched flight in Australia occurred in 1972 and the "Australian Self Soaring Association" was formed by foot-launched pilots in 1974. The first foot-launched Australian Championships were held in 1976. [The Hang Gliding Federation of Australia - history: [http://www.hgfa.asn.au/HGFA/HGFA.htm] ]

First flights in the early 1970s from Mt. Kilimanjaro by Moyes, and Caril Ridley’s flights in India met with headlines. On 1973 the ZDF German Television produced a 30 min documentary on Mike Harker's world record hang glider flight from Mt. Zugspitze in Germany, this TV documentary helped promote the development of hang gliding in Europe. Harker also produced other hang gliding documentaries in the mid 1970s which were presented in TV by 16 countries. [Mike Harker: [http://www.h-tv.com/mike/resume.htm] [www.lilienthal-museum.de/olma/esoest.htm] ]

Although by the early 1970s many rigid wings were developed, none sold terribly well, while dozens of flexible wing hang glider companies were springing up all over the world. The mid 1970s underwent significant improvements in hang glider design as manufacturers were bringing out new and improved models at a fast rate. From the simple structures of the early 1970s, the aspect ratio of the gliders increased dramatically, sails became tighter, battens became the rule, and the gliders became safer. In the late 1970s preformed aluminium battens became common and in 1980, the "Comet" [ "The Comet" was produced from 1980-1984 by "Ultralight Products" (UP). First of the double surface flexwing gliders; best performance and easier to land than its contemporaries. [http://topaflyers.com/kites/kites.html#up] ] took the industry by storm and popularized the free-floating internalized crossbar and double-surface sail construction that has since become the standard.

As usual, essentially parallel developments can be difficult to sort out and serialize, but in fact, the flexible wing hang glider popularity started with the publicized Paresev and Fleep concept, followed by John Dickenson's adaptation and the aggressive entrepreneurial energies of Bill Bennett, Bill Moyes, Joe Faust, Dick Eipper, Mike Riggs, the Wills brothers [Wills wing: [http://www.willswing.com/articles/history.asp] ] and the massive enthusiasm of thousands of people wanting to self-soar, and began what is now an estimated $50 million USD annual industry. [Annual hang gliding revenues estimate by NASA: [http://media.nasaexplores.com/lessons/03-005/9-12_1.pdf] ] Ironically, Dickenson never made any money [Article by Mark Woodhams: [http://bchpa.org/newsletter/may04/hghistory.htm] ] and Francis Rogallo never claimed the rights to the patent he held, thus allowing his flexible wing airfoil to be used royalty free. [Francis Rogallo gave the U.S. government royalty-free license to use its patents, which it did in a ceremony in Washington on 18 July 1963. In a short speech, Rogallo expressed his hopes for the invention: "We feel confident that the civil and military agencies of the government will carry on this work, and we hope private industry will promote use of the concept for business and pleasure as effectively as they have for astronautics and military aeronautics." [http://history.nasa.gov/SP-4308/ch11.htm] ] [ This presented the Rogallos with two choices: defend the patent and receive royalties for each kite manufactured or let people fly these newly affordable wings for free. In a gesture unparall in aviation history, the Rogallos decided to give their invention to the people of the world and let manufacturers freely produce gliders using their patented invention. [http://www.hangglidingspectacular.com/rogallohistory.html] ]

It is certain that many people from many countries, made contributions to the development of the flexible wing hang glider. In the aviation context of 'first flights' and recreational vs. commercial developments, it must be noted that new and old inventions often complement in synergy; it is in this evolutionary and social context that the crucial developments put together by Francis Rogallo and John Dickenson, were the ones that were most successful and influential on the evolution of hang gliders.

Timeline

*1804 AD. Sir George Cayley built several gliders, distinguished between lift and drag and formulated the concepts of vertical tail surfaces, steering rudders and rear elevators.

*1883 John Joseph Montgomery independently built several gliders in the United States and used wind and water tables to formulate thoughts on lifting surfaces.

*1891 First controlled flights, Otto Lilienthal of Germany. His gliders have many features in common with modern hang gliders; they were foot-launched and controlled by displacing the center of gravity, referred to as 'weight-shift'.

*1891-1896. First soaring flights. Germany, near Berlin at Gross Lichterfelde. Otto Lilienthal.

*1904, February 15th. Jan Lavezzari flew a double lateen sail hang glider off Berck beach, France.

*1905 Aeronaut Daniel Maloney pilots a ballon-launched tandem wing Montgomery glider from a release thousands of feet above the ground to a landing at a predescribed location.

*1908. In Breslau a gliding club member demonstrated cable-stayed triangle control bar for a hang glider that would be seen strongly and instructed again in 1929 by George A. Spratt.
*1920. Soaring becomes organized sport at Wasserkuppe, Germany as the World War I Versailles treaty outlaws flying powered aircraft in Germany. [http://www.hanggliderhistory.com/ Breslau gliding Klub with cable-stayed triangle control frame on a hang glider.]

*1921. Dr. Wolfgang Klemperer breaks the Wright Brothers 1911 soaring record with a 13 minute flight in Germany. Both flights used ridge lift.

*1921. Gottlob Espenlaub demonstrates triangle control frame (TCF) for hang gliders in Rhon, Germany.

*1923. Platz Glider. Not foot-launchable by the pilot alone. Controlled by the pilot directly deforming the front canard wings. It was not a weight-shift hang glider but it was simple enough to be folded into a single length to be carried by Platz while riding a bicycle. [Platz glider model: [http://www.inter-ex.com/english/interex18/bild303e.htm] . The Platz glider was somewhat refined by Ferdinand Schulz. Ferdinand Schulz: [http://www.luene-info.de/preussen/landesmuseum2.html?http://www.luene-info.de/preussen/windkraft/sondost.html] ]

*1928. Austrian Robert Kronfeld proved that thermal lift could be used by a sailplane to gain altitude by making a short out and return flight.

*1929. Aero towing becomes popular, the three forms of lift are becoming well known.
*1929. George A. Spratt demonstrated the use of the [http://web.archive.org/web/20040407122659/www.georgespratt.org/images/EarlySpratt6.jpgtriangular control frame] for hang glider pendulum weight-shift control, mechanically similar to that used in 1908 in a hang glider in Breslau. [http://web.archive.org/web/20070117015324/www.georgespratt.org/docs/MoreArticles.htm] . Later in the 1930s he invented the "Control Wing" aircraft.

*1933. Wave lift was discovered by Wolf Hirth and one of his students in Germany.

*1948. Francis Rogallo invents the flexible wing (Rogallo wing). [Article: How "to Fly Without a Plane" by Robert Zimmerman, aerospace writer. [http://www.americanheritage.com/articles/magazine/it/1998/4/1998_4_22.shtml] . Patent allowed march 20, 1951. [http://www.fang-den-wind.de/rogallo_eng.htm] ]

*1956. Aeronautical engineer Paul MacCready invents the MacCready Speed Ring, used by glider pilots the world over to select optimum flight speed.

*1957, October. Francis Rogallo released the flexible wing patent to the U.S.A. government and NASA, producing the Parawing, to be used as a deployable space capsule parachute/glider.

*1960. Paresev (a.k.a: Parawing Research Vehicle, Paraglider Research Vehicle (formal).) This experimental spacecraft re-entry kite/glider made use of the Rogallo wing; design and manufacture by NASA at Dryden Flight Research Center, flight tests made in early 1962 and inspired manufacture of Rogallo wing hang gliders. Eight pilots free-flighted hung glided in various versions of the wing and hung-seat arrangement.

*1961. Fleep. Flexible wing aircraft design & manufacture begins.

*1961-1962. First documented foot-launch with a Rogallo flex wing hang glider: Barry Hill Palmer, California, U.S.A. Hang glider inspired from a photo of NASA's Fleep. [ Barry Palmer's web site & dated photos: [http://members.aol.com/hiitec/kite/trike.html] . Video of his first flights in 1961 loaded in YouTube at: [http://www.youtube.com/watch?v=sswv4WUi0aY] ] [The last of the series flew in the summer of 1962, and had a swinging seat. [http://members.aol.com/hiitec/kite/trike.html] ] [During 1960 to 1963 Barry Palmer and friends made tens of flights using the Rogallo wing concept. Those flights ranged in length up to 180 meters, at altitudes up to convert|80|ft|m, and an overall glide ratio of 4.5 to 1.] [Palmer's hang glider [http://ozreport.com/forum/viewtopic.php?p=23240] . See also Harv|HGPAMag|2005.

*1961. Celebrity Jim Hobson (of Lawrence Welk Show fame) began experimenting with the Rogallo wing in model form, leading to the construction of a full size glider which he flew it at Dockweiler Beach on January 2, 1962. The glider frame was fabricated from aluminum and aircraft bolts supported by aircraft cable attached to hardware store eye bolts and turnbuckles. [Sport Aviation magazine, September, 1962; see picture. He had kinescope and video tape of the hang glider's use in a production number on "The Lawrence Welk Show", that was aired on January 27, 1962.] A second larger hang glider was taken to Dockweiler Beach; it featured a 4 mil polyester film reinforced with fiberglass tape. Movies of August, 1962 flights were made.

*1961. Engineer Thomas Purcell builds a convert|4.9|m|ft wide Rogallo airfoil glider with an aluminium frame, wheels, a seat and basic control rods. [Thomas Pourcell: [http://www.madehow.com/Volume-5/Hang-Glider.html] ]

*1962. Ryan Aeronautical Company publicizes images of the Fleep flexible wing aircraft.

*1962. Mike Burns and Dick Swinbourne from "Aerostructures", Sydney, Australia, design the "Skiplane" glider based on the Rogallo wing. It used pendulum weight-shift control and floats.

*1963. John Dickenson, Australia. Making of the "Ski Wing", an influential hang glider model encompassing a control frame and used weight-shift control. [Ski Wing [http://www.lilienthal-museum.de/olma/edick.htm] ] [Hundreds of flights and five model upgrades were made over the next three years. The first manned-kite/glider was built of banana plastic sail, TV aerial wire, douglas fir leading edges and keel, aluminium cross bar, U shaped control bar - later changed to a triangular control bar by October 1963. Provisional patent applied for on 8 October 1963. Full patent was not filed for so it was not awarded: [http://www.innovated.gov.au/Innovated%5Ccase_studies%5CHang_Glider.pdf] ]

*1963, September. First flight of the Ski Wing, towed behind a motor boat. The kite/glider was piloted by Rod Fuller and then John Dickenson. Grafton, NSW, Australia. [Ski Wing [http://grafton.nsw.free.fr/ski_wing/] . Interview with J. Dickenson, B. Moyes and F. Rogallo (1988): [http://www.ozreportradio.com/video/?Rogallo_Dickenson_Moyes_interview_1988.avi] ]

*1963. First release and land of a Ski Wing. Grafton, Australia. Pilot: John Dickenson.

*1960s England. Tony Prentice designed and flew several non-Rogallo hang gliders. [Tony Prentice. Split wing - The idea is that the wing can "morph" into a single surface for normal flight but can open up for slow speed take off and landing. "This variable geometry provided for a greater speed range and for short field capability." -T. Prentice [http://www.jumpnfly.privat.t-online.de/nitony.htm] ]

*1966. Mike Burns and Dick Swinbourne ("Aerostructures") begin commercial production of Dickenson's Mark V model.

*1966. Early flex wing hang glider, Vista Del Mar. California, U.S.A. by Richard Miller. His gliders, based on Barry Palmer's hang glider, were named "Batso" and Bamboo "Butterfly". Their photos and plans were published in a few magazines during the 1960s. (See the "Popularity" section.)

*1966. "Irvin Industries" start marketing a commercial version of the Rogallo Wing to sport parachuting enthusiasts. [Irvin Industries' parawing sport parachute: [http://www.hickoksports.com/images/parawing_chute.jpg] ]

*1967, March. Bill Moyes and Bill Bennett taught to fly the Mark V hang glider by Mike Burns and John Dickenson.

*1967. First foot-launch of a flexible without auxiliary power (no towing). Launched from a snowed mountain with snow skis.- Bill Moyes. Mt. Crackenback, Australia. [Bill Moyes foot-launches from a mountain: [http://www.moyes.com.au/articledetail.asp?ID=63&Cat=Interest] , [http://www.abc.net.au/gnt/history/Transcripts/s1227269.htm] ] The hang glider was a Mark V purchased from "Aerostructures".

*1969. Initial tether into headwind then released onto ridge to soar (32 minutes). Bill Moyes. NSW, Australia. [Footage: [http://www.moyes.com.au/articledetail.asp?ID=63&Cat=Interest] , Interview: [http://www.ozreportradio.com/video/?Rogallo_Dickenson_Moyes_interview_1988.avi] ]

*1969. Tony Prentice. First flex wing hang glider foot-launch in the United Kingdom.

*1971. Foot-launch and soaring on ridge and thermal lift (1 hour). Dave Kilbourne. Mission Peak, California, U.S.A. This seems to be the first foot-launch of a flexible wing not using skis.

*1971. Alfio Caronti, first flexible wing launched in Italy. [Alfio Caronti [http://icaro2000.com/About-us/Historical-pictures-it.htm] .]

*1972. Rick Poynter and Murray Sargeson introduce hang gliding to New Zealand at the 'Fly a Kite Day' in Auckland. The New Zealand Hang Gliding Association is formed as a result of this.

*1973. Rock Poynter starts Pacific Sails in Auckland, New Zealand, manufacturing U.S. and Australian Hang Glider designs under license (Seagull III, Stinger), and developing competitive indigenous designs (Falcon, Lancer I, II, IV).

*1974. Caril Ridley conducted high altitude flights soaring from a Maharaja's lookout tower near Sonar Hot Springs, India. The event got world wide coverage.

*1976. Rudy Kishazy performs the first loop and series of loops at Grands Montets, France. [Rudy Kishazy - Loops. [http://federation.ffvl.fr/node/473] ; YouTube video: [http://www.youtube.com/watch?v=lSEG412uomA] ]

*1977. Jerry Katz first to soar convert|161|km|mi.

*1978. Terry DeLore from New Zealand is crowned first World Hang Gliding Champion.

*1983. Gérard Thévenot, the manufacturer of the "Cosmos" trike, introduced aerotowing, the use of weak links, parachute retrieval system of tow line and centre of thrust towing.

Production era

The following generations follow the classification from the British Hang Gliding Museum's "Hang Gliding History: Development in Britain of the Flexwing hang glider." [http://www.british-hang-gliding-museum.co.uk/acatalog/Online_Museum_Development_in_Britain_of_the_Flexwing_hang_glider_2.html]

*1971-1975. First Generation - Interest in the sport grew worldwide; development of hang gliders on a commercial scale.

*1974-1976. Second Generation - Increased nose angle, deflexors.

*1977-1979. Third Generation - Multiple deflexors.

*1978-1980. Fourth Generation- Enclosed keel and tip rods.
*1978. The "Atlas" (La Mouette) entered the market. The pilot flew in a prone position. The "Atlas" had all of the safety elements that can still be found today.

*1980-1997. Fifth Generation - Preformed battens. Floating cross bar. Cross bar enclosed in double surface. Hang glider performance then increased rapidly. The first truly successful "double surface" hang gliders were Tom Peghiny's Kestrel and later the UP "Comet" designed by Roy Haggard (1980). Virtually all hang gliders over the next decade were refinements of the Comet. The first fifth generation hang gliders to dispense with a raised keel pocket were the Wills Wing "HP" in the U.S.A. and Enterprise Wings "Foil" in Australia (1984). Bob Trampenau of "Seedwings" introduced the VG (variable geometry), which was copied on most other hang gliders.

*1997- Present. Sixth Generation - Topless (without kingpost). While topless gliders had been experimented with in the past using struts or cantilever nose plates, in the late 1990s the use of strong carbon fiber crossbars allowed the kingpost on top of the wing to be more conveniently removed to further increase performance by reducing drag.

See also

* Hang gliding
* Paragliding
* Glider
* Rogallo wing
* Aviation history
* Timeline of aviation
* First flying machine
* Powered hang glider
* A-frame for hang gliders, trikes, and ultralights

References

Print

* Harvard reference
Surname=HGPAMag
Title=April 2005 Issue
Journal=Hang Gliding and Paragliding Magazine
Year=2005
Publisher=USHGPA .
* Harvard reference
Author=Martin Hunt and David Hunn, Contribution by Dan Poynter.
Title=Hang Gliding.
Year=1977
*.
* Harvard reference
Surname=Lilienthal
Given=Otto
Authorlink=Otto Lilienthal
Title=Fliegesport und Fliegepraxis
Journal=Prometheus, Illustrirte Wochenschrift über die Fortschritte in Gewerbe, Industrie und Wissenschaft
Volume=7 | Issue=322
Year=1895
URL=http://www.lilienthal-museum.de/olma/el2058.htm | Access-date=2005-12-27 (no. 322. vol. VII, 4. XII)
* Harvard reference
Author=Stéphane Malbos and Noel Whittall
Title=And the World Could Fly
Publisher=FAI Hang Gliding and Paragliding Commission (CIVL)
Year=2005
URL=http://www.fai.org/hang_gliding/And_The_World_Could_Fly
* Harvard reference
Surname=Markowski
Title=The Hang Glider's Bible
Year=1977
URL=http://olivercowdery.com/texts/1851Trn1.htm#turn1851
* cite web
title=Who invented the flex wing hang glider?
author=Mark Woodhams
work=Newsletter of the British Columbia Hang Gliding and Paragliding Association, Volume 2 Issue 2
url=http://www.bchpa.org/newsletter/may04/hghistory.htm
year=2004-05
accessdate=2006-10-24

External links

* [http://ozreport.com/ The Oz Report - Worldwide Hang Gliding eZine and blog]
* [http://www.twitt.org/adpage.htm Horten flying wing]
* [http://www.nestofdragons.net/horten_hxb_main.htm Horten flying wings]
* [http://www.twitt.org/Bowers_TWITT_Pres.pdf The Wing Is The Thing (TWITT)]
* [http://www.nurflugel.com/Nurflugel/nurflugel.html Flying wings]
* [http://www.nurflugel.com/Nurflugel/n_o_d/index2.htm Nurflugel]

Web and news

*cite web
title=Rogallos of old
work=The Oz Report, Volume 6, Number 218 8 PM Monday, October 22nd, 2002
url=http://ozreport.com/6.218#2
accessdate=2006-10-24 Picture of Lavezzari Glider.
*cite web
title=The Flying Prentice's
work=Homepage Stephan Nitsch > Links > Tony Prentice > Pictures
url=http://www.jumpnfly.privat.t-online.de/ni.htm
accessdate=2006-01-01
*cite web
year=1948
title=Patent of Rogallos Flexible Kite
url=http://www.fang-den-wind.de/rogallo_eng.htm
accessdate=2005-12-27
*cite web
year=1993
title=Dick Cheney, Aircraft Designer/Builder
work=Published in October 1993 HANG GLIDING Magazine by John Heiney
url=http://www.johnheiney.com/articles/Cheney/Dick_Cheney.htm
accessdate=2007-03-24
*cite web
title=Hang Gliding and the Ultralight Trike
work=Barry Palmer's Web Site
url=http://members.aol.com/hiitec/kite/trike.html
accessdate=2006-10-17
*cite web
title=Chanute glider of 1896
work=Encyclopaedia Britannica
url=http://www.britannica.com/eb/article-9436292/Chanute-glider-of-1896
accessdate=2007-12-15
* cite news
title=Grafton's Ski Wing
date=1963-10-21
publisher=The Daily Examiner
url=http://grafton.nsw.free.fr/ski_wing/
* cite news
first=Negus
last=George
title=Hang Gliders
date=2004-10-25 18:30
publisher=Australian Broadcasting Corporation
url=http://www.abc.net.au/gnt/history/Transcripts/s1227269.htm
* cite web
title=Video of Francis Rogallo, John Dickenson, and Bill Moyes together
work=?
url=http://www.ozreportradio.com/video/?Rogallo_Dickenson_Moyes_interview_1988.avi
year=?
accessdate=2006-10-28 88 MB.
* cite web
title=Paresev (Parawing Research Vehicle)
work=NASA Dryden Photo Collections
url=http://www.dfrc.nasa.gov/Gallery/Photo/Paresev/
accessdate=2005-12-27
* cite web
title=Hang Gliding History: Development in Britain of the Flexwing hang glider
work=British Hang Gliding Museum
url=http://www.british-hang-gliding-museum.co.uk/acatalog/Online_Museum_Development_in_Britain_of_the_Flexwing_hang_glider_2.html | accessdate=2005-12-26

Video

* cite web
title=Video of Francis Rogallo, John Dickenson, and Bill Moyes interviewed together
work=
url=http://www.ozreportradio.com/video/?Rogallo_Dickenson_Moyes_interview_1988.avi
year=
accessdate=2006-10-28 88 MB.