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60-578: The Eon Olympia was a glider produced from 1947 by Elliotts of Newbury . Elliotts had been asked in 1945 by Chilton Aircraft Ltd to make one set of wings for the Chilton Olympia , a glider that had been developed in pre-war Germany as the DFS Olympia Meise . This had been designed by Hans Jacobs and selected as the glider for the 1940 Summer Olympics . The German drawings were not detailed and so new drawings were made by Chilton which retained

120-413: A turn and slip indicator are used when there is zero visibility. Increasingly, anti-collision warning systems such as FLARM are also used and are even mandatory in some European countries. An Emergency Position-Indicating Radio Beacon ( ELT ) may also be fitted into the glider to reduce search and rescue time in case of an accident. Much more than in other types of aviation, glider pilots depend on

180-423: A variometer and an airband radio ( transceiver ), each of which may be required in some countries. A transponder may be installed to assist controllers when the glider is crossing busy or controlled airspace. This may be supplemented by ADS-B . Without these devices access to some airspace may become increasingly restricted in some countries. In countries where cloud-flying is allowed, an artificial horizon or

240-501: A day if the weather is suitable. Early gliders had no cockpit and the pilot sat on a small seat located just ahead of the wing. These were known as " primary gliders " and they were usually launched from the tops of hills, though they are also capable of short hops across the ground while being towed behind a vehicle. To enable gliders to soar more effectively than primary gliders, the designs minimized drag. Gliders now have very smooth, narrow fuselages and very long, narrow wings with

300-406: A flight and even, in some cases, for take-off . Some high-performance motor gliders (known as "self-sustaining" gliders) may have an engine-driven retractable propeller which can be used to sustain flight. Other motor gliders have enough thrust to launch themselves before the engine is retracted and are known as "self-launching" gliders. Another type is the self-launching "touring motor glider", where

360-620: A flight by Gordon Rondel on 18 June 1960 in a thunderstorm to 9,321 m (30,580 ft) with gain of height of 8,870 m (29,100 ft), absolute National height and gain of height records. An example is now on display at the Gliding Heritage Centre . Data from Ellison, 1971 Data from The World's Sailplanes:Die Segelflugzeuge der Welt:Les Planeurs du Monde General characteristics Performance Related development Aircraft of comparable role, configuration, and era Glider (sailplane) A glider or sailplane

420-418: A glider's contest ID when flying in close proximity to one another to alert them of potential dangers. For example, during gatherings of multiple gliders within thermals (known as "gaggles"), one pilot might report "Six-Seven-Romeo I am right below you". Fibreglass gliders are invariably painted white to minimise their skin temperature in sunlight. Fibreglass resin loses strength as its temperature rises into

480-423: A height of 300 metres (1,000 ft). Glide slope control devices are then used to adjust the height to assure landing at the desired point. The ideal landing pattern positions the glider on final approach so that a deployment of 30–60% of the spoilers/dive brakes/flaps brings it to the desired touchdown point. In this way the pilot has the option of opening or closing the spoilers/air-brakes to extend or steepen

540-433: A high aspect ratio and winglets . The early gliders were made mainly of wood with metal fastenings, stays and control cables. Later fuselages made of fabric-covered steel tube were married to wood and fabric wings for lightness and strength. New materials such as carbon-fiber , fiber glass and Kevlar have since been used with computer-aided design to increase performance. The first glider to use glass-fiber extensively

600-701: A higher speed at any given glide angle. This is an advantage in strong conditions when the gliders spend only a small amount of time climbing in thermals. The pilot can jettison the water ballast before it becomes a disadvantage in weaker thermal conditions. Another use of water ballast is to dampen air turbulence such as might be encountered during ridge soaring . To avoid undue stress on the airframe, gliders must jettison any water ballast before landing. Most gliders are built in Europe and are designed to EASA Certification Specification CS-22 (previously Joint Aviation Requirements -22). These define minimum standards for safety in

660-713: A large degree due to post-World War I regulations forbidding the construction and flight of motorised planes in Germany, so the country's aircraft enthusiasts often turned to gliders and were actively encouraged by the German government, particularly at flying sites suited to gliding flight like the Wasserkuppe . The sporting use of gliders rapidly evolved in the 1930s and is now their main application. As their performance improved, gliders began to be used for cross-country flying and now regularly fly hundreds or even thousands of kilometres in

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720-508: A minimum loss of height in between. Sailplanes have rigid wings and either skids or undercarriage . In contrast hang gliders and paragliders use the pilot's feet for the start of the launch and for the landing. These latter types are described in separate articles, though their differences from sailplanes are covered below. Sailplanes are usually launched by winch or aerotow, though other methods, auto tow and bungee, are occasionally used. These days almost all gliders are sailplanes, but in

780-464: A mountain. Provided that there is a steady increase in wind strength with altitude without a significant change in direction, standing waves may be created. They were discovered by a glider pilot, Wolf Hirth , in 1933. These waves reach heights much greater than the original obstruction and so can permit gliders to climb to the stratosphere. Pilots use supplementary oxygen to avoid hypoxia because most gliders do not have pressurized cockpits. This lift

840-445: A separate control. Although there is only a single main wheel, the glider's wing can be kept level by using the flight controls until it is almost stationary. Pilots usually land back at the airfield from which they took off, but a landing is possible in any flat field about 250 metres long. Ideally, should circumstances permit, a glider would fly a standard pattern , or circuit , in preparation for landing, typically starting at

900-456: A wide range of characteristics such as controllability and strength. For example, gliders must have design features to minimize the possibility of incorrect assembly (gliders are often stowed in disassembled configuration, with at least the wings being detached). Automatic connection of the controls during rigging is the common method of achieving this. The two most common methods of launching sailplanes are by aerotow and by winch. When aerotowed,

960-547: Is a wind from the sea that develops over land near coasts. In a sea-breeze front, cold air from the sea meets the warmer air from the land and creates a boundary like a shallow cold front along a shear line . This creates a narrow band of soarable lift with winds as light as 10 knots (19 km/h). These permit the gaining of altitude by flying along the intersection as if it were a ridge of land. Convergence may occur over considerable distances and so may permit virtually straight flight while climbing. In dynamic soaring energy

1020-449: Is a type of glider aircraft used in the leisure activity and sport of gliding (also called soaring). This unpowered aircraft can use naturally occurring currents of rising air in the atmosphere to gain altitude. Sailplanes are aerodynamically streamlined and so can fly a significant distance forward for a small decrease in altitude. In North America the term 'sailplane' is also used to describe this type of aircraft. In other parts of

1080-431: Is also possible to gain energy, though this uses differences in wind speeds rather than rising air. Thermals are columns of rising air that are formed on the ground through the warming of the surface by sunlight. If the air contains enough moisture, the water will condense from the rising air and form cumulus clouds . Thermal lift is often used by birds, such as raptors , vultures and storks . Although thermal lift

1140-442: Is gained by repeatedly crossing the boundary between air masses of different horizontal velocity rather than by rising air. Such zones of high " wind gradient " are usually too close to the ground to be used safely by gliders, but Albatrosses and model gliders use this phenomenon. A pilot can create an indication of lift on uncompensated instruments by entering a climb by pulling back on the stick (hence " stick thermal "). This

1200-417: Is known as "soaring". By finding lift sufficiently often, experienced pilots fly cross-country , often on pre-declared tasks of hundreds of kilometers, usually back to the original launch site. Cross-country flying and aerobatics are the two forms of competitive gliding . For information about the forces in gliding flight, see lift-to-drag ratio . Pilots need some form of control over the glide slope to land

1260-615: Is known as "thermalling". Climb rates depend on conditions, but rates of several meters per second are common. Thermals can also be formed in a line usually because of the wind or the terrain, creating cloud streets . These can allow flying straight while climbing in continuous lift. When the air has little moisture or when an inversion stops the warm air from rising high enough for the moisture to condense, thermals do not create cumulus clouds. Typical locations to find thermals are over towns, freshly ploughed fields and asphalt roads, but thermals are often hard to associate with any feature on

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1320-492: Is often marked by long, stationary lenticular (lens-shaped) clouds lying perpendicular to the wind. A mountain wave was used to set the record for highest altitude by a glider when Jim Payne and Tim Gardner soared to an altitude of 22,657 metres (74,334 ft) on September 2, 2018 over El Calafate , Argentina in the purpose-built Windward Performance Perlan II . The current world distance record of 3,008 km (1,869 statute miles) by Klaus Ohlmann (set on 21 January 2003)

1380-468: Is sometimes confusion about gliders/sailplanes, hang gliders and paragliders. In particular, paragliders and hang gliders are both foot-launched. The main differences between the types are: Eight competition classes of glider have been defined by the FAI . They are: A large proportion of gliders have been and are still made in Germany, the birthplace of the sport. In Germany there are several manufacturers but

1440-445: Is sufficient wind blowing up the hill. Bungee launching was the predominant method of launching early gliders. Some modern gliders can self-launch by using retractable engines or just retractable propellers. (see motor glider ). These engines can use internal combustion or battery power. Once launched, gliders try to gain height using thermals , ridge lift , lee waves or convergence zones and can remain airborne for hours. This

1500-447: The variometer article for more information). Variometers are sometimes fitted with mechanical or electronic devices to indicate the optimal speed to fly for given conditions. The MacCready setting can be input electronically or adjusted using a ring surrounding the dial. These devices are based on the mathematical theory attributed to Paul MacCready though it was first described by Wolfgang Späte in 1938. MacCready theory solves

1560-501: The Space Shuttle with a glide ratio of 4.5:1. High aerodynamic efficiency is essential to achieve a good gliding performance, and so gliders often have aerodynamic features seldom found in other aircraft. The wings of a modern racing glider are designed by computers to create a low-drag laminar flow airfoil . After the wings' surfaces have been shaped by a mould to great accuracy, they are then highly polished. Vertical winglets at

1620-440: The variometer , which is a very sensitive vertical speed indicator , to measure the climb or sink rate of the plane. This enables the pilot to detect minute changes caused when the glider enters rising or sinking air masses. Most often electronic 'varios' are fitted to a glider, though mechanical varios are often installed as back-up. The electronic variometers produce a modulated sound of varying amplitude and frequency depending on

1680-505: The English-speaking world, the word 'glider' is more common. Gliders benefit from producing very low drag for any given amount of lift, and this is best achieved with long, thin wings , a slender fuselage and smooth surfaces with an absence of protuberances. Aircraft with these features are able to soar – climb efficiently in rising air produced by thermals or hills. In still air, sailplanes can glide long distances at high speed with

1740-462: The Meise Olympia's aerodynamic shape. The wing redesign resulted in a stronger and heavier (+30 kg) aircraft. To maintain employment at their factory, Elliotts refused to sell the wing jigs that they had made for the prototype. Consequently, Chilton gave up all aircraft work, agreeing to sell to Elliotts the production rights, fuselage jigs, and work in hand on all Olympia gliders. Production of

1800-546: The Olympia (originally called Type 5) started in 1946 as a batch of 100, and the first flight was made in January 1947. Elliotts and their design consultants Aviation & Engineering Products Ltd made improvements to the original design before starting production. Marks 1, 2 and 3 were produced, mainly distinguishable by the landing gear. The Mark 1 had only a skid whereas the Olympia 2 had a built-in main wheel. The Eon Olympia 3's wheel

1860-618: The Olympia, another improved version, called the EoN Olympia 4 was produced in 1954. This is regarded as being sufficiently different from the original as being a new type. This type in turn led to a succession of variants. On 24 August 1950 an Eon Olympia flown by Bill Bedford broke the British distance record by flying 310 km in 3:50 hr. On 2 May 1951 Bedford broke his record with a flight of 413 km from Farnborough to Newcastle. Olympias also broke height records on occasions, culminating in

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1920-425: The control stick, thus creating friction between the skid and the ground. The wing tips also have small skids or wheels to protect the wing tips from ground contact. In most high performance gliders the undercarriage can be raised to reduce drag in flight and lowered for landing. Wheel brakes are provided to allow stopping once on the ground. These may be engaged by fully extending the spoilers/air-brakes or by using

1980-439: The descent to reach the touchdown point. This gives the pilot wide safety margins should unexpected events occur. If such control devices are not sufficient, the pilot may utilize maneuvers such as a forward slip to further steepen the glider slope. Most gliders require assistance to launch, though some have an engine powerful enough to launch unaided. In addition, a high proportion of new gliders have an engine which will sustain

2040-401: The ends of the wings decrease drag and so improve wing efficiency. Special aerodynamic seals are used at the ailerons , rudder and elevator to prevent the flow of air through control surface gaps. Turbulator devices in the form of a zig-zag tape or multiple blow holes positioned in a span-wise line along the wing are used to trip laminar flow air into turbulent flow at a desired location on

2100-545: The glass-fiber Libelle of the 1960s increased that to 36:1, and modern flapped 18 meter gliders such as the ASG29 have a glide ratio of over 50:1. The largest open-class glider, the Eta , has a span of 30.9 meters and has a glide ratio over 70:1. Compare this to the Gimli Glider , a Boeing 767 which ran out of fuel mid-flight and was found to have a glide ratio of 12:1, or to

2160-678: The glider in the air, but is insufficiently powerful to launch the glider. Compared with self-launchers these lower powered engines have advantages in weight, lower costs and pilot licensing. The engines can be electric, jet, or two-stroke gasoline. Gliders in continental Europe use metric units, like km/h for airspeed and m/s for lift and sink rate . In the United States, United Kingdom, Australia and some other countries gliders use knots and ft / min in common with commercial aviation worldwide. In addition to an altimeter , compass , and an airspeed indicator , gliders are often equipped with

2220-409: The glider to Earth in a short distance. Early glider designs used skids for landing, but modern types generally land on wheels. Some of the earliest gliders used a dolly with wheels for taking off and the dolly was jettisoned as the glider left the ground, leaving just the skid for landing. A glider may be designed so the center of gravity (CG) is behind the main wheel so the glider sits nose high on

2280-427: The glider. In powered aircraft, this is done by reducing engine thrust. In gliders, other methods are used to either reduce the lift generated by the wing, increase the drag of the entire glider, or both. Glide slope is the distance traveled for each unit of height lost. In a steady wings-level glide with no wind, glide slope is the same as the lift/drag ratio (L/D) of the glider, called "L-over-D". Reducing lift from

2340-521: The ground. Other designs may have the CG forward of the main wheel so the nose rests on a nose-wheel or skid when stopped. Skids are now mainly used only on training gliders such as the Schweizer SGS 2–33 . Skids are around 100 millimetres (4 in) wide by 900 mm (3 ft) long and run from the nose to the main wheel. Skids help with braking after landing by allowing the pilot to put forward pressure on

2400-413: The ground. Occasionally thermals are caused by the exhaust gases from power stations or by fires. As it requires rising heated air, thermalling is only effective in mid-latitudes from spring into late summer. Despite these limitations, it is the most common source of lift used by glider pilots, as ridge lift and lee waves require mountainous terrain, and may thus not be found near a given airfield. During

2460-456: The improvements in aerodynamics , the performance of gliders has increased. One measure of performance is the glide ratio . A ratio of 30:1 means that in smooth air a glider can travel forward 30 meters while losing only 1 meter of altitude. Comparing some typical gliders that might be found in the fleet of a gliding club – the Grunau Baby from the 1930s had a glide ratio of just 17:1,

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2520-450: The off-season, when thermals are weaker, ridge and wave lift can still be used and some pilots travel to more mountainous areas to fly. Ridge lift , or Orographic lift , is caused by rising air on the windward side of a slope. Ridge lift is used extensively by sea birds and by aircraft. In places where a steady wind blows, a ridge may allow virtually unlimited time aloft. In ridge lift, pilots typically fly long straight legs parallel to

2580-526: The past many gliders were not. These types did not soar . They were simply engine-less aircraft towed by another aircraft to a desired destination and then cast off for landing. The prime example of non-soaring gliders were military gliders (such as those used in the Second World War). They were often used just once and then usually abandoned after landing, having served their purpose. Motor gliders are gliders with engines which can be used for extending

2640-561: The pilot can switch the engine on and off in flight without retracting the propeller. Sir George Cayley 's gliders achieved brief wing-borne hops from around 1849. In the 1890s, Otto Lilienthal built gliders using weight shift for control. In the early 1900s, the Wright Brothers built gliders using movable surfaces for control. In 1903, they successfully added an engine. After World War I gliders were first built for sporting purposes in Germany. Germany's strong links to gliding were to

2700-413: The problem of how fast a pilot should cruise between thermals, given both the average lift the pilot expects in the next thermal climb, as well as the amount of lift or sink encountered in cruise mode. Electronic variometers make the same calculations automatically, after allowing for factors such as the glider's theoretical performance , water ballast, headwinds/tailwinds and insects on the leading edges of

2760-481: The range achievable in direct sun on a hot day. Color is not used except for a few small bright patches on wing tips; these patches (typically orange or red) improving a glider's visibility to other airborne aircraft. Such patches are obligatory for mountain flying in France. Non-fibreglass gliders made of aluminum or wood are not so subject to deterioration at higher temperatures and are often quite brightly painted. There

2820-428: The ridge. If the maximum height of the lift is not achieved, the pilot may turn around and fly in the other direction above the same slope. With winds of 20 to 25 knots (46 km/h), it is possible for aircraft to soar at an altitude up to twice the height of the obstacle. Ridge lift can also be augmented by thermals when the slopes also face the sun. Lee waves occur when a wind of 25 knots (46 km/h) blows over

2880-456: The sailplane is towed behind a powered aircraft using a rope about 60 metres (200 ft) long. The sailplane pilot releases the rope after reaching the desired altitude. However, the rope can be released by the towplane also in case of emergency. Winch launching uses a powerful stationary engine located on the ground at the far end of the launch area. The sailplane is attached to one end of 800 to 1,200 metres (2,600 to 3,900 ft) of cable and

2940-399: The strength of the lift or sink, so that the pilot can concentrate on centering a thermal, watching for other traffic, on navigation, and weather conditions. Rising air is announced to the pilot as a rising tone, with increasing pitch as the lift increases. Conversely, descending air is announced with a lowering tone, which advises the pilot to escape the sink area as soon as possible. (Refer to

3000-696: The three principal companies are: Germany also has Stemme and Lange Aviation . Elsewhere in the world, there are other manufacturers such as Jonker Sailplanes in South Africa, Sportinė Aviacija in Lithuania, Allstar PZL in Poland, Let Kunovice and HpH in the Czech Republic and AMS Flight in Slovenia. Lift (soaring) Energy can be gained by using rising air from four sources: In dynamic soaring it

3060-685: The underside of a single wing, and also on the fin and rudder . Registration marks are assigned by gliding associations such as the US Soaring Society of America , and are unrelated to national registrations issued by entities such as the US Federal Aviation Administration . This need for visual ID has somewhat been supplanted by GPS position recording. Insignias are useful in two ways: First, they are used in radio communications between gliders, as pilots use their competition number as their call signs . Secondly, to easily tell

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3120-423: The water ballast is advantageous if the lift is likely to be strong, and may also be used to adjust the glider's center of mass . Moving the center of mass toward the rear by carrying water in the vertical stabilizer reduces the required down-force from the horizontal stabilizer and the resultant drag from that down-force. Although heavier gliders have a slight disadvantage when climbing in rising air, they achieve

3180-448: The winch rapidly winds it in. The sailplane can gain about 270 to 910 metres (900 to 3,000 ft) of height with a winch launch, depending on the headwind. Less often, automobiles are used to pull sailplanes into the air, either by pulling them directly or through the use of a reverse pulley in a similar manner to the winch launch. Elastic ropes (known as bungees ) are occasionally used at some sites to launch gliders from slopes, if there

3240-400: The wing. This flow control prevents the formation of laminar flow bubbles and ensures the absolute minimum drag. Bug-wipers may be installed to wipe the wings while in flight and remove insects that are disturbing the smooth flow of air over the wing. Modern competition gliders carry jettisonable water ballast (in the wings and sometimes in the vertical stabilizer). The extra weight provided by

3300-462: The wings and/or increasing drag will reduce the L/D allowing the glider to descend at a steeper angle with no increase in airspeed. Simply pointing the nose downwards only converts altitude into a higher airspeed with a minimal initial reduction in total energy. Gliders, because of their long low wings, create a high ground effect which can significantly increase the glide angle and make it difficult to bring

3360-640: The wings. Soaring flight computers running specialized soaring software, have been designed for use in gliders. Using GPS technology in conjunction with a barometric device these tools can: After the flight the GPS data may be replayed on computer software for analysis and to follow the trace of one or more gliders against a backdrop of a map, an aerial photograph or the airspace. So that ground-based observers may identify gliders in flight or in gliding competition , registration marks ("insignias" or "competition numbers" or "contest ID") are displayed in large characters on

3420-525: Was also flown using mountain waves in South America . A rare wave phenomenon is known as Morning Glory , a roll cloud producing strong lift. Pilots near Australia's Gulf of Carpentaria make use of it in springtime . Birds have been observed using wave lift to cross mountainous regions. The boundaries where two air masses meet are known as convergence zones . These can occur in sea breezes or in desert regions. A sea-breeze (or onshore breeze )

3480-450: Was jettisonable after takeoff. The first batch of 100 was completed in 1947 but the market could not absorb such a large number, despite the low price of £425. Even by 1953, 40 of the first 100 Olympias were still unsold. Nevertheless, a second batch of 50 was built. Gliders from the second batch were still being offered for sale for £800 as late as 1957 in order to clear the stock, despite being below cost price. After building three marks of

3540-416: Was known to the Wright Brothers in 1901, it was not exploited by humans until 1921 by Wilhelm Leusch at the Wasserkuppe in Germany. It was not until about 1930 that the use of thermals for soaring in gliders became commonplace. Once a thermal is encountered, the pilot flies in circles to keep within the thermal, so gaining altitude before flying off to the next thermal and towards the destination. This

3600-534: Was the Akaflieg Stuttgart FS-24 Phönix which first flew in 1957. This material is still used because of its high strength to weight ratio and its ability to give a smooth exterior finish to reduce drag. Drag has also been minimized by more aerodynamic shapes and retractable undercarriages. Flaps are fitted to the trailing edges of the wings on some gliders to optimise lift and drag at a wide range of speeds. With each generation of materials and with

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