Hang gliding
Overview
 
Hang gliding is an air sport in which a pilot flies a light and unmotorized foot-launchable aircraft called a hang glider (also known as Delta plane or Deltaplane).
Most modern hang gliders are made of an aluminium alloy
Aluminium alloy
Aluminium alloys are alloys in which aluminium is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon and zinc. There are two principal classifications, namely casting alloys and wrought alloys, both of which are further subdivided into the categories...

 or composite
Composite material
Composite materials, often shortened to composites or called composition materials, are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or...

-framed fabric wing
Wing
A wing is an appendage with a surface that produces lift for flight or propulsion through the atmosphere, or through another gaseous or liquid fluid...

. The pilot is ensconced in a harness suspended from the airframe
Airframe
The airframe of an aircraft is its mechanical structure. It is typically considered to include fuselage, wings and undercarriage and exclude the propulsion system...

, and exercises control by shifting body weight in opposition to a control frame, but other devices, including modern aircraft flight control systems
Aircraft flight control systems
A conventional fixed-wing aircraft flight control system consists of flight control surfaces, the respective cockpit controls, connecting linkages, and the necessary operating mechanisms to control an aircraft's direction in flight...

, may be used.
In the sport's early days, pilots were restricted to gliding down small hills on low-performance hang gliders.
Encyclopedia
Hang gliding is an air sport in which a pilot flies a light and unmotorized foot-launchable aircraft called a hang glider (also known as Delta plane or Deltaplane).
Most modern hang gliders are made of an aluminium alloy
Aluminium alloy
Aluminium alloys are alloys in which aluminium is the predominant metal. The typical alloying elements are copper, magnesium, manganese, silicon and zinc. There are two principal classifications, namely casting alloys and wrought alloys, both of which are further subdivided into the categories...

 or composite
Composite material
Composite materials, often shortened to composites or called composition materials, are engineered or naturally occurring materials made from two or more constituent materials with significantly different physical or chemical properties which remain separate and distinct at the macroscopic or...

-framed fabric wing
Wing
A wing is an appendage with a surface that produces lift for flight or propulsion through the atmosphere, or through another gaseous or liquid fluid...

. The pilot is ensconced in a harness suspended from the airframe
Airframe
The airframe of an aircraft is its mechanical structure. It is typically considered to include fuselage, wings and undercarriage and exclude the propulsion system...

, and exercises control by shifting body weight in opposition to a control frame, but other devices, including modern aircraft flight control systems
Aircraft flight control systems
A conventional fixed-wing aircraft flight control system consists of flight control surfaces, the respective cockpit controls, connecting linkages, and the necessary operating mechanisms to control an aircraft's direction in flight...

, may be used.
In the sport's early days, pilots were restricted to gliding down small hills on low-performance hang gliders. However, modern technology gives pilots the ability to soar
Lift (soaring)
Gliding flight is heavier-than-air flight without the use of thrust. It is employed by gliding animals and by aircraft such as gliders. The most common human application of gliding flight is in sport and recreation using aircraft designed for this purpose...

 for hours, gain thousands of metres of altitude in thermal
Thermal
A thermal column is a column of rising air in the lower altitudes of the Earth's atmosphere. Thermals are created by the uneven heating of the Earth's surface from solar radiation, and are an example of convection. The sun warms the ground, which in turn warms the air directly above it...

 updrafts, perform aerobatics, and glide cross-country for hundreds of kilometres. The Fédération Aéronautique Internationale
Fédération Aéronautique Internationale
The Fédération Aéronautique Internationale is the world governing body for air sports and aeronautics and astronautics world records. Its head office is in Lausanne, Switzerland. This includes man-carrying aerospace vehicles from balloons to spacecraft, and unmanned aerial vehicles...

 and national airspace governing organizations control some aspects of hang gliding. Gaining the safety benefits from being instructed is highly recommended.

History

Most early glider designs did not ensure safe flight; the problem was that early flight pioneers did not sufficiently understand the underlying principles that made a bird's wing work.

Starting in the 1880s technical and scientific advancements were made that led to the first truly practical glider
Glider aircraft
Glider aircraft are heavier-than-air craft that are supported in flight by the dynamic reaction of the air against their lifting surfaces, and whose free flight does not depend on an engine. Mostly these types of aircraft are intended for routine operation without engines, though engine failure can...

s. Otto Lilienthal
Otto Lilienthal
Otto Lilienthal was a German pioneer of human aviation who became known as the Glider King. He was the first person to make well-documented, repeated, successful gliding flights. He followed an experimental approach established earlier by Sir George Cayley...

 built (barely) controllable gliders in the 1890s, with which he could ridge soar. He rigorously documented his work, strongly influencing later designers; for this reason, Lilienthal is one of the best known and most influential early aviation pioneers. His aircraft was controlled by weight shift and is similar to a modern hang glider. (He was attached to the gliders by his shoulders, and swung his feet to control them.)

In the decade 1900-1910 hang gliding saw a stiffened flexible wing hang glider in 1904, when Jan Lavezzari
Jan Lavezzari
Jan Lavezzari was a gifted painter, born in Paris, France from a well known architect: Emile Lavezzari.Jan studied engineering and then moved to Berck-sur-Mer, northern France in 1900, where he decided to become a professional painter instead, and settled there. Jan Lavezzari produced several oil...

 flew a double lateen sail hang glider off Berck Beach, France
France
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan 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. The biplane hang glider was very widely publicized in public magazines with plans for building; such biplane hang gliders were constructed and flown in several nations since Octave Chanute
Octave Chanute
Octave Chanute was a French-born American railway engineer and aviation pioneer. He provided the Wright brothers with help and advice, and helped to publicize their flying experiments. At his death he was hailed as the father of aviation and the heavier-than-air flying machine...

 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, as several builders would have their first hang glider made from following the plan in his article. Volmer Jensen with a biplane hang glider in 1940 called VJ-11 allowed safe three-axis control of a foot-launched hang glider.

On November 23, 1948 Francis Rogallo
Francis Rogallo
Francis Melvin Rogallo was an American aeronautical engineer inventor born in Sanger, California, U.S.A.; he is credited with the invention of the Rogallo wing, or "flexible wing", a precursor to the modern hang glider and paraglider...

 and Gertrude Rogallo
Gertrude Rogallo
Gertrude Rogallo was one of the co-inventors of the flexible wing. These wings are now known as Rogallo wings. She and her husband, Francis Rogallo, invented the wing and obtained two US patents on different versions of it in the early 1950s. Rogallo wings are commonly used today in kites, hang...

 applied for a kite
Kite
A kite is a tethered aircraft. The necessary lift that makes the kite wing fly is generated when air flows over and under the kite's wing, producing low pressure above the wing and high pressure below it. This deflection also generates horizontal drag along the direction of the wind...

 patent for a fully flexible kited wing with approved claims for its stiffenings and gliding uses; the flexible wing or Rogallo wing
Rogallo wing
The Rogallo wing is a flexible type of airfoil. In 1948, Gertrude Rogallo, and her husband Francis Rogallo, a NASA engineer, invented a self-inflating flexible wing they called the Parawing, also known after them as the "Rogallo Wing" and flexible wing...

, which in 1957 the American space agency NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...

 began testing in various flexible and semi-rigid configurations in order to use it as a recovery system for the Gemini space capsule
Space capsule
A space capsule is an often manned spacecraft which has a simple shape for the main section, without any wings or other features to create lift during atmospheric reentry....

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
Barry Hill Palmer
Barry Hill Palmer is an American aeronautical engineer , inventor, builder and pilot of the first hang glider based on the Rogallo wing or flexible wing...

 adapted the flexible wing concept to make foot-launched hang gliders with four different control arrangements. In 1963 Mike Burns adapted the flexible wing to build a kite-hang glider he called Skiplane. In 1963, John W. Dickenson
John W. Dickenson
John Wallace Dickenson is an Australian inventor, who developed some liquid flow measuring devices and designed the most successful hang glider configuration.- The Ski Wing :...

 adapted the flexible wing airfoil
Airfoil
An airfoil or aerofoil is the shape of a wing or blade or sail as seen in cross-section....

 concept to make another water-ski kite glider; for this, the Fédération Aéronautique Internationale
Fédération Aéronautique Internationale
The Fédération Aéronautique Internationale is the world governing body for air sports and aeronautics and astronautics world records. Its head office is in Lausanne, Switzerland. This includes man-carrying aerospace vehicles from balloons to spacecraft, and unmanned aerial vehicles...

 vested Dickenson with the Hang Gliding Diploma (2006) for the invention of the modern hang glider.

Training and safety

Hang gliding has traditionally been considered an unsafe sport. Modern hang gliders are very sturdy when constructed to HGMA, BHPA, DHV, or other certified standards using modern materials. Although lightweight they can be easily damaged, either through misuse or by continued operation in unsafe wind and weather conditions. All modern gliders have built-in dive recovery mechanisms such as luff lines in kingposted gliders. The inherent danger of gliding at the mercy of thermal
Thermal
A thermal column is a column of rising air in the lower altitudes of the Earth's atmosphere. Thermals are created by the uneven heating of the Earth's surface from solar radiation, and are an example of convection. The sun warms the ground, which in turn warms the air directly above it...

 and wind
Wind
Wind is the flow of gases on a large scale. On Earth, wind consists of the bulk movement of air. In outer space, solar wind is the movement of gases or charged particles from the sun through space, while planetary wind is the outgassing of light chemical elements from a planet's atmosphere into space...

 currents has nevertheless resulted in numerous fatal accidents and many serious injuries over the years, even to experienced pilots, and the resulting bad publicity has affected the popularity of hang gliding.

Pilots may carry a backup parachute
Parachute
A parachute is a device used to slow the motion of an object through an atmosphere by creating drag, or in the case of ram-air parachutes, aerodynamic lift. Parachutes are usually made out of light, strong cloth, originally silk, now most commonly nylon...

 in the harness. In case of serious problems the parachute is deployed and carries both pilot and glider down to earth. Pilots also wear helmets and generally carry other safety items such as knives (for cutting their parachute bridle after impact or cutting their harness lines and straps in case of a tree or water landing), light ropes (for lowering from trees to haul up tools or climbing ropes), radios (for calling for help), and first-aid equipment.

The accident rate from hang glider flying has been dramatically decreased by pilot training. Early hang glider pilots learned their sport through trial and error. Training programs have been developed for today's pilot with emphasis on flight within safe limits, as well as the discipline to cease flying when weather conditions are unfavorable, for example: excess wind or risk cloud suck
Cloud suck
Cloud suck is a phenomenon commonly known in paragliding and hang gliding where pilots experience significant lift due to a thermal under the base of cumulus clouds, especially towering cumulus and cumulonimbus...

.

In the UK there is one death per 116,000 flights, a risk comparable to running a marathon or playing football for a year.

Launch

Launch techniques include foot-launching from a hill, tow-launching from a ground-based tow system, aerotowing (behind a powered aircraft), powered harnesses
Powered Hang Glider
A foot-launched powered hang glider , also called powered harness, nanolight, or hangmotor, is a powered hang glider harness with a motor and propeller in pusher configuration...

, 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 winds result in additional length of 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
Hot air balloon
The hot air balloon is the oldest successful human-carrying flight technology. It is in a class of aircraft known as balloon aircraft. On November 21, 1783, in Paris, France, the first untethered manned flight was made by Jean-François Pilâtre de Rozier and François Laurent d'Arlandes in a hot air...

 drops from very high altitude. Flights in non-soarable conditions are referred to as "sled runs".

Soaring flight and cross-country flying

A glider is continuously descending through nearby air, yet glider pilots can stay airborne for hours by flying in areas of rising air. Once this skill has been mastered, pilots can glide long distances to fly cross-country
Cross-country flying
Cross-Country flying is a type of distance flying which is performed in a powered aircraft on legs over a given distance and in operations between two points using navigational techniques; and an unpowered aircraft by using upcurrents to gain altitude for extended flying time...

 (XC). Rising air masses derive from the following sources:

Thermals
The most commonly used source of lift is created by the sun's energy heating the ground which in turn heats the air above it. This warm air rises in columns known as thermals. Soaring pilots quickly become aware of land features which can generate thermals; and of visual indications of thermals such as soaring birds, cumulus cloud
Cumulus cloud
Cumulus clouds are a type of cloud with noticeable vertical development and clearly defined edges. Cumulus means "heap" or "pile" in Latin. They are often described as "puffy" or "cotton-like" in appearance. Cumulus clouds may appear alone, in lines, or in clusters...

s, cloud streets, dust devil
Dust devil
A dust devil is a strong, well-formed, and relatively long-lived whirlwind, ranging from small to large . The primary vertical motion is upward...

s, and haze domes. Also, nearly every glider contains an instrument known as a variometer
Variometer
The term variometer also refers to a type of variable transformer or an instrument for measuring the magnitude and direction of a Magnetic field....

 (a very sensitive vertical speed indicator) which shows visually (and often audibly) the presence of lift and sink. Having located a thermal, a glider pilot will circle within the area of rising air to gain height. In the case of a cloud street thermals can line up with the wind creating rows of thermals and sinking air. A pilot can use a cloud street to fly long straight-line distances by remaining in the row of rising air.


Ridge lift
Ridge lift
Ridge lift
Ridge lift is created when a wind strikes an obstacle, usually a mountain ridge or cliff, that is large and steep enough to deflect the wind upward....

 occurs when the wind meets a mountain, cliff or hill. The air is deflected up the windward face of the mountain, causing lift. Gliders can climb in this rising air by flying along the feature. Another name for flying with ridge lift is slope soaring.


Mountain waves
The third main type of lift used by glider pilots is the lee waves
Lee waves
In meteorology, lee waves are atmospheric standing waves. The most common form is mountain waves, which are atmospheric internal gravity waves...

 that occur near mountains. The obstruction to the airflow can generate standing wave
Standing wave
In physics, a standing wave – also known as a stationary wave – is a wave that remains in a constant position.This phenomenon can occur because the medium is moving in the opposite direction to the wave, or it can arise in a stationary medium as a result of interference between two waves traveling...

s with alternating areas of lift and sink. The top of each wave peak is often marked by lenticular cloud
Lenticular cloud
Lenticular clouds are stationary lens-shaped clouds that form at high altitudes, normally aligned perpendicular to the wind direction. Lenticular clouds can be separated into altocumulus standing lenticularis , stratocumulus standing lenticular , and cirrocumulus standing lenticular...

 formations.


Convergence
Another form of lift results from the convergence
Convergence zone
Convergence zone usually refers to a region in the atmosphere where two prevailing flows meet and interact, usually resulting in distinctive weather conditions....

 of air masses, as with a sea-breeze front
Sea breeze
A sea-breeze is a wind from the sea that develops over land near coasts. It is formed by increasing temperature differences between the land and water; these create a pressure minimum over the land due to its relative warmth, and forces higher pressure, cooler air from the sea to move inland...

. More exotic forms of lift are the polar vortexes which the Perlan Project
Perlan Project
The Perlan Project is a current research project to fly a sailplane to an altitude of 100,000 feet .-Meteorological Basis of the Project:Standing Mountain waves are a source of rising air used in the sport of soaring...

 hopes to use to soar to great altitudes. A rare phenomenon known as Morning Glory
Morning glory cloud
The Morning Glory cloud is a rare meteorological phenomenon occasionally observed in different locations around the world. The southern part of Northern Australia's Gulf of Carpentaria is the only known location where it can be predicted and observed on a more or less regular basis. The settlement...

 has also been used by glider pilots in Australia.

Performance

With each generation of materials and with the improvements in aerodynamics, the performance of hang gliders has increased. One measure of performance is the glide ratio. For example, a ratio of 12:1 means that in smooth air a glider can travel forward 12 meters while only losing 1 meter of altitude.

Some performance figures as of 2006:
  • Topless gliders (no kingpost): glide ratio ~17:1, speed range ~30 to >145 km/h, best glide at ~45 to 60 km/h
  • Rigid wings: glide ratio ~20:1, speed range ~ 35 to > 130 km/h, best glide at ~50 to 60 km/h.


Ballast
The extra weight provided by ballast is advantageous if the lift is likely to be strong. Although heavier gliders have a slight disadvantage when climbing in rising air, they achieve a higher speed at any given glide angle. This is an advantage in strong conditions when the gliders spend only little time climbing in thermals.

Stability and equilibrium

Because hang gliders are most often used for recreational flying, a premium is placed on gentle behavior especially at the stall
Stall (flight)
In fluid dynamics, a stall is a reduction in the lift coefficient generated by a foil as angle of attack increases. This occurs when the critical angle of attack of the foil is exceeded...

 and natural pitch stability. The wing loading must be very low in order to allow the pilot to run fast enough to get above stall speed. Unlike a traditional aircraft with an extended fuselage
Fuselage
The fuselage is an aircraft's main body section that holds crew and passengers or cargo. In single-engine aircraft it will usually contain an engine, although in some amphibious aircraft the single engine is mounted on a pylon attached to the fuselage which in turn is used as a floating hull...

 and empennage
Empennage
The empennage , also known as the tail or tail assembly, of most aircraft gives stability to the aircraft, in a similar way to the feathers on an arrow...

 for maintaining stability, hang gliders rely on the natural stability of their flexible wings to return to equilibrium
Mechanical equilibrium
A standard definition of static equilibrium is:This is a strict definition, and often the term "static equilibrium" is used in a more relaxed manner interchangeably with "mechanical equilibrium", as defined next....

 in yaw and pitch. Roll stability is generally set to be near neutral. In calm air, a properly designed wing will maintain balanced trimmed flight with little pilot input. The flex wing pilot is suspended beneath the wing by a strap attached to his harness. The pilot lies prone (sometimes supine) within a large, triangular, metal control frame. Controlled flight is achieved by the pilot pushing and pulling on this control frame thus shifting his weight fore or aft, and right or left in coordinated maneuvers.

Roll
Most flexible wings are set up with near neutral roll due to sideslip (anhedral
Anhedral
* Anhedral angle, the downward angle from horizontal of the wings or tailplane of a fixed-wing aircraft* Anhedral , a rock texture without crystal faces or cross-section shape in thin section...

 effect). In the roll axis, the pilot shifts his 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 his weight to the right, the right wing trailing edge flexes up more than the left, allowing the right wing to drop and slow down.

Yaw
The yaw axis is stabilized through the sweep back of the wings. The swept planform, when yawed out of the relative wind
Relative wind
In aeronautics, the relative wind is the direction of movement of the atmosphere relative to an aircraft or an airfoil. It is opposite to the direction of movement of the aircraft or airfoil relative to the atmosphere...

, creates more lift
Lift (force)
A fluid flowing past the surface of a body exerts a surface force on it. Lift is the component of this force that is perpendicular to the oncoming flow direction. It contrasts with the drag force, which is the component of the surface force parallel to the flow direction...

 on the advancing wing and also more drag, stabilizing the wing in yaw. If one wing advances ahead of the other, it presents more area to the wind and causes more drag on that side. This causes the advancing wing to go slower and to fall back. The wing is at equilibrium when the aircraft is traveling straight and both wings present the same amount of area to the wind.

Pitch
The pitch control response is direct and very efficient. It is partially stabilized by the sweep
Swept wing
A swept wing is a wing planform favored for high subsonic jet speeds first investigated by Germany during the Second World War. Since the introduction of the MiG-15 and North American F-86 which demonstrated a decisive superiority over the slower first generation of straight-wing jet fighters...

 of the wings. The wing center 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).


Furthermore, the fact that the wing is designed to bend and flex, provides favorable dynamics analogous to a spring suspension. This allows the wing to be less susceptible to turbulence and provides a gentler flying experience than a similarly sized rigid-winged aircraft.

Instruments

To maximize a pilot's understanding of how the hang glider is flying, most pilots carry instruments. The most basic being a variometer and altimeter—often combined. Some more advanced pilots also carry airspeed indicators and radios. When flying in competition or cross country, pilots often also carry maps and/or GPS units. Hang gliders do not have instrument panels as such, so all the instruments are mounted to the control frame of the glider or occasionally based on one's watch.

Variometer

Gliding pilots are able to sense the acceleration
Acceleration
In physics, acceleration is the rate of change of velocity with time. In one dimension, acceleration is the rate at which something speeds up or slows down. However, since velocity is a vector, acceleration describes the rate of change of both the magnitude and the direction of velocity. ...

 forces when they first hit a thermal, but have difficulty gauging constant motion. Thus it is difficult to detect the difference between constantly rising air and constantly sinking air. A variometer
Variometer
The term variometer also refers to a type of variable transformer or an instrument for measuring the magnitude and direction of a Magnetic field....

 is a very sensitive vertical speed indicator. The variometer indicates climb rate or sink rate with audio signals (beeps) and/or a visual display. These units are generally electronic, vary in sophistication, and often include an altimeter
Altimeter
An altimeter is an instrument used to measure the altitude of an object above a fixed level. The measurement of altitude is called altimetry, which is related to the term bathymetry, the measurement of depth underwater.-Pressure altimeter:...

 and an airspeed indicator. More advanced units often incorporate a barograph
Barograph
A barograph is a recording aneroid barometer. It produces a paper or foil chart called a barogram that records the barometric pressure over time....

 for recording flight data and/or a built-in GPS.
The main purpose of a variometer is in helping a pilot find and stay in the ‘core’ of a thermal to maximize height gain, and conversely indicating when he or she is in sinking air and needs to find rising air.
Variometers are sometimes capable of electronic calculations to indicate the optimal speed to fly
Speed to fly
Speed to fly is a principle used by soaring pilots when flying between sources of lift, usually thermals, ridge lift and wave. The aim is to maximize the average cross-country speed by optimizing the airspeed in both rising and sinking air...

 for given conditions. The MacCready
Paul MacCready
Paul B. MacCready, Jr. was an American aeronautical engineer. He was the founder of AeroVironment and the designer of the human-powered aircraft that won the Kremer prize...

 theory answers the question on how fast a pilot should cruise between thermals, given the average lift the pilot expects in the next thermal climb and the amount of lift or sink he encounters in cruise mode. Some electronic variometers make the calculations automatically, allowing for factors such as the glider's theoretical performance (glide ratio), altitude, hook in weight, and wind direction.

Radio

Pilots use radio for training purposes, and for communicating with other pilots in the air – particularly when traveling together on cross-country flights.

One type of radios used are PTT (push-to-talk) transceiver
Transceiver
A transceiver is a device comprising both a transmitter and a receiver which are combined and share common circuitry or a single housing. When no circuitry is common between transmit and receive functions, the device is a transmitter-receiver. The term originated in the early 1920s...

s, operating in or around the FM VHF 2-meter band (144 MHz–148 MHz). Usually a microphone is incorporated in the helmet, and the PTT switch is either fixed to the outside of the helmet, or strapped to a finger. Operating a 2-meter band radio without an appropriate Amateur Radio license is illegal in most countries that have regulated airwaves (such as the United States).

As aircraft operating in airspace occupied by other aircraft, hang glider pilots also use the appropriate type of radio i.e. the aircraft transceiver
Transceiver
A transceiver is a device comprising both a transmitter and a receiver which are combined and share common circuitry or a single housing. When no circuitry is common between transmit and receive functions, the device is a transmitter-receiver. The term originated in the early 1920s...

. It can, of course, be fitted with a PTT switch to a finger and speakers inside the helmet. The use of aircraft transceivers is subject to regulations specific to the use in the air such as frequencies restrictions but has several advantages over FM (i.e. frequency modulated) Amateur Radios. One is the great range it has (without repeaters) because of its amplitude modulation (i.e. AM). Two is the ability to contact, inform and be informed directly by other aircraft pilots of their intentions thereby improving collision avoidance and increasing safety. Three is to allow greater liberty regarding distance flights in regulated airspaces, in which the aircraft radio is normally a legal requirement. Four is the universal emergency frequency monitored by all other users and satellites and used in case of emergency or impending emergency.

GPS

GPS
Global Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...

 (global positioning system) is a necessary accessory when flying competitions, where it has to be demonstrated that way-points
Waypoint
A waypoint is a reference point in physical space used for purposes of navigation.-Concept:Waypoints are sets of coordinates that identify a point in physical space. Coordinates used can vary depending on the application. For terrestrial navigation these coordinates can include longitude and...

 have been correctly passed.

It can also be interesting to view a GPS track of a flight when back on the ground, to analyze flying technique. Computer software
Computer software
Computer software, or just software, is a collection of computer programs and related data that provide the instructions for telling a computer what to do and how to do it....

 is available which allows various analyses of GPS tracks.

Other uses include being able to determine drift due to the prevailing wind when flying at altitude, providing position information to allow restricted airspace to be avoided, and identifying one’s location for retrieval teams after landing-out in unfamiliar territory.

More recently, the use of GPS data, linked to a computer, has enabled pilots to share 3D tracks of their flights on Google Earth
Google Earth
Google Earth is a virtual globe, map and geographical information program that was originally called EarthViewer 3D, and was created by Keyhole, Inc, a Central Intelligence Agency funded company acquired by Google in 2004 . It maps the Earth by the superimposition of images obtained from satellite...

. This fascinating insight allows comparisons between competing pilots to be made in a detailed post-flight analysis.

Records

Records are sanctioned by the FAI
Fédération Aéronautique Internationale
The Fédération Aéronautique Internationale is the world governing body for air sports and aeronautics and astronautics world records. Its head office is in Lausanne, Switzerland. This includes man-carrying aerospace vehicles from balloons to spacecraft, and unmanned aerial vehicles...

. The world record(s) (as of 2005) for "free distance" is held by Manfred Ruhmer with 700.6 km (435.3 mi) in 2001 and Michael Barber flew a distance of 704 km (437.4 mi) on June 19, 2002 in Zapata Texas.

Other records include:

Out-and-Return distance - 332.5 km (206.6 mi), July 5, 2007 by George Stebbins, starting and ending just South of Lone Pine, California.

Largest triangle - 357.12 km (221.9 mi), December 16, 2000 by Tomáš Suchánek
Tomáš Suchánek
Tomáš Suchánek is a motorcycle speedway rider who first rode in the UK for the King's Lynn Stars in the Premier League in 2003....

 a Czech HG and sailplane pilot, starting and ending from Riverside, Australia.

Competition

Competitions started with "flying as long as possible" and spot landings. With increasing performance, cross-country flying replaced them. Usually two to four waypoints have to be passed with a landing at a goal. In the late 1990s low-power GPS
Global Positioning System
The Global Positioning System is a space-based global navigation satellite system that provides location and time information in all weather, anywhere on or near the Earth, where there is an unobstructed line of sight to four or more GPS satellites...

 units were introduced and have completely replaced photographs of the goal. Every two years there is a world championship. The Rigid and Women's World Championship in 2006 was hosted by Quest Air in Florida. Big Spring
Big Spring
-Places:United States* Big Spring, Texas* Big Spring, Wisconsin** Big Spring Independent School District in Big Spring, Texas.* Big Spring School District in Newville, Pennsylvania* Big Spring Township, Seneca County, Ohio...

, Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

 hosted the 2007 World Championship. Hang gliding is also one of the competition categories in World Air Games
World Air Games
World Air Games is an international air sports event organized by Fédération Aéronautique Internationale , inspired by the Olympic Games and held every four years.-Competitions:*Aerobatics*Aeromodeling...

 organized by Fédération Aéronautique Internationale
Fédération Aéronautique Internationale
The Fédération Aéronautique Internationale is the world governing body for air sports and aeronautics and astronautics world records. Its head office is in Lausanne, Switzerland. This includes man-carrying aerospace vehicles from balloons to spacecraft, and unmanned aerial vehicles...

 (World Air Sports Federation - FAI), which maintains a chronology of the FAI World Hang Gliding Championships.

Aerobatics

Hang gliders are not certified for aerobatic flight. Pilots perform aerobatics at their own risk. There are three basic maneuvers in a hang glider, not counting a loop, which is actually a climbover with the same entry and exit heading. The following descriptions are excerpts from a nationally recognized rules book.

3.1 Official Maneuvers
A figure with a bank angle of more than 90° is a maneuver.

3.1.1 Loop
A loop is defined as a maneuver that starts in a wings level dive, climbs, without any rolling, to the apex where the glider is upside down, wings level (heading back where it came from), and then returning to the start attitude and heading, again without rolling, having completed an approximately circular path in the vertical plane.

3.1.2 Spin
A spin is scored from the moment one wing stalls and the glider rotates noticeably into the spin. The entry heading is noted at this point. The glider must remain in the spin for at least 1/2 of a revolution to score any versatility spin points.

3.1.3 Rollover
A Rollover is a maneuver where the apex heading is less than 90° left or right of the entry heading.

3.1.4 Climb over
A Climb over is a maneuver where the apex heading is greater than 90° left or right of the entry heading.

Classes

For competitive purposes, there are three classes of hang glider:
  • Class 1 The flexible wing hang glider, having flight controlled by a wing whose shape changes by virtue of the shifted weight of the pilot. This is not a paraglider.
  • Class 5 The rigid wing hang glider, having flight controlled by spoiler
    Spoiler (aeronautics)
    In aeronautics, a spoiler is a device intended to reduce lift in an aircraft. Spoilers are plates on the top surface of a wing which can be extended upward into the airflow and spoil it. By doing so, the spoiler creates a carefully controlled stall over the portion of the wing behind it, greatly...

    s, typically on top of the wing. In both flexible and rigid wings the pilot hangs below the wing without any additional fairing.
  • Class 2 (designated by the FAI
    Fédération Aéronautique Internationale
    The Fédération Aéronautique Internationale is the world governing body for air sports and aeronautics and astronautics world records. Its head office is in Lausanne, Switzerland. This includes man-carrying aerospace vehicles from balloons to spacecraft, and unmanned aerial vehicles...

     as Sub-Class O-2) where the pilot is integrated into the wing by means of a fairing. These offer the best performance and are the most expensive.


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.

Comparison of gliders, hang gliders and paragliders

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

The main differences between the types are:

See also

  • Gliding
    Gliding
    Gliding is a recreational activity and competitive air sport in which pilots fly unpowered aircraft known as gliders or sailplanes using naturally occurring currents of rising air in the atmosphere to remain airborne. The word soaring is also used for the sport.Gliding as a sport began in the 1920s...

  • Paragliding
    Paragliding
    Paragliding is the recreational and competitive adventure sport of flying paragliders: lightweight, free-flying, foot-launched glider aircraft with no rigid primary structure...

  • Microlift gliding
  • Nanolight
    Nanolight
    A Nanolight is an Australian class of ultralight powered aircraft. It was originally defined as a Powered Hang Glider with an empty weight, including both wing and power system, of less than...

  • Powered paragliding
  • Powered hang gliding
    Powered Hang Glider
    A foot-launched powered hang glider , also called powered harness, nanolight, or hangmotor, is a powered hang glider harness with a motor and propeller in pusher configuration...

  • Comparison with gliders and paragliders
  • Kite types
    Kite types
    Kites are tethered flying objects which fly by using aerodynamic lift, requiring wind, , for generation of airflow over the lifting surfaces.-Kite types:...

     - paragliders and the types of hang gliders having the pilot hang from a kite line are types of kites where the kite lines vary in length and number and the gravity-drawn mass of the pilot is the moving mooring.
  • USHPA
    USHPA
    The United States Hang Gliding and Paragliding Association is a non-profit organization supporting foot-launched soaring flight in the United States. It began in 1971 as the Southern California Hang Gliding Association and became national in scope by the mid-1970s. When paragliding became popular...

    - US Hang Gliding & Paragliding Association

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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