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80-748: Oxford Gliding Club (OGC) is a UK gliding club, and is one of the oldest still in operation in the UK. Currently it operates from RAF Weston-on-the-Green , north of Oxford . In 2012, the club celebrated its 75th anniversary. The pre-war ancestor to the club was the "Oxford University and City Gliding Club" which had its inaugural meeting at Christchurch College on Thursday 2 December 1937. The founders were predominantly Oxford academics, including author and anthropologist Robert Sutherland Rattray , Professor H H Price , philosopher Professor Gilbert Ryle and physicist Professor Frederick Lindemann, 1st Viscount Cherwell (later Lord Cherwell). They were helped in their search for

160-447: A 1,000 to 2,500-metre (3,000 to 7,500 ft) cable, made of high-tensile steel wire or a synthetic fiber , attached to the glider. The cable is released at a height of about 35% of the cable length after a short, steep ride. A strong headwind will result in higher launches. Winch launches are much cheaper than aerotows and permit a higher launch frequency. A winch may also be used at sites where an aerotow could not operate, because of

240-519: A five-hour duration flight, and has flown cross-country for a straight-line distance of at least 50 kilometres (31 mi): these three attainments are usually, but not invariably, achieved in separate flights. A pilot who has earned the Gold badge has achieved an altitude gain of 3,000 metres (9,843 ft), made a flight of five-hours duration, and flown cross-country for a straight-line distance of at least 300 kilometres (186 mi). A pilot who has completed

320-447: A given time. If lift is weaker than expected, or if an off-field landing is imminent, the pilot can jettison the water ballast by opening the dump valves. On days with particularly strong and widespread lift pilots can attain high average speeds by alternating periods of fast flight with pull-ups, merely slowing down in areas of lift without deviating from the course. This 'dolphining' technique can result in high average speeds because

400-490: A glider to gain kinetic energy by repeatedly crossing the boundary between air masses of different horizontal velocity. However, such zones of high " wind gradient " are usually too close to the ground to be used safely by gliders. Most gliders do not have engines or at least engines that would allow a take-off under their own power. Various methods are therefore used to get airborne. Each method requires specific training, therefore glider pilots must be in current practice for

480-431: A glider's speed around the day's task in a competition have been developed, including the optimum speed to fly , navigation using GPS and the carrying of water ballast . If the weather deteriorates pilots are sometimes unable to complete a cross-country flight. Consequently, they may need to land elsewhere, perhaps in a field, but motorglider pilots can avoid this by starting an engine. Powered-aircraft and winches are

560-501: A height that includes a margin that would still allow a safe landing out to be made, if there were a failure to start. In a competition, using the engine ends the soaring flight. Unpowered gliders are lighter and, as they do not need a safety margin for starting the engine, they can safely thermal at lower altitudes in weaker conditions. Consequently, pilots in unpowered gliders may complete competition flights when some powered competitors cannot. Conversely, motor glider pilots can start

640-412: A lightweight manufactured Rope -like material. Dyneema is substantially lighter than the traditional multistrand steel cable, and enables higher launch heights, which in turn provide a longer flight. Combined with the longer than average "runs" at the club, the average winch launch height at OGC is in excess of 1400 feet, though with the right conditions launches have reached 2500 feet. OGC operates

720-573: A public Air Show at RAF Upper Heyford in the summer of 1938. The Club moved from Cumnor to the Chiltern ridge at Aston Rowant, close to the Lambert Arms pub, for the 1939 season. The formation of the Oxford Gliding Co. Ltd. dates from 1939, including the original £4,000 share capital which is still on the books to this day. On the outbreak of war in 1939, all recreational aviation ceased, and the club

800-567: A rating called the "K-Factor". Maximum points are given for the maneuver if it is flown perfectly; otherwise, points are deducted. Efficient maneuvers also enable the whole program to be completed with the height available. The winner is the pilot with the most points. Unlike hang gliders and paragliders , gliders surround the pilots with strong structures and have undercarriages to absorb impacts when landing. These features prevent injuries from otherwise minor incidents, but there are some hazards. Although training and safe procedures are central to

880-406: A ridge may allow virtually unlimited time aloft, although records for duration are no longer recognized because of the danger of exhaustion . The powerfully rising and sinking air in mountain waves was discovered by glider pilot, Wolf Hirth , in 1933. Gliders can sometimes climb in these waves to great altitudes, although pilots must use supplementary oxygen to avoid hypoxia . This lift

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960-399: A sailplane with a heavier wing loading cannot circle within a thermal as tightly as one with a lower, unballasted wing loading. But if lift is strong, typically either from thermals or wave, the disadvantage of slower climbs is outweighed by the higher cruising speeds between lift areas. Thus, the pilot can improve the average speed over a course by several percent or achieve longer distances in

1040-410: A strong breeze using a substantial multi-stranded rubber band, or " bungee ". For this launch method, the glider's main wheel rests in a small concrete trough. The hook normally used for winch-launching is instead attached to the middle of the bungee. Each end is then pulled by three or four people. One group runs slightly to the left, the other to the right. Once the tension in the bungee is high enough,

1120-432: A suitable site by aviator Amy Johnson . Lindemann went on to become scientific advisor to Winston Churchill and was paymaster general during World War II. A meeting in early 1938 at Rhodes House considered the establishment of a club further. Attendees at this meeting included Joan Meakin , Mary Bailey , Amy Johnson and Naomi Heron-Maxwell . Flying began on Saturday, 7 May 1938, at a site known as Cumnor meadow, which

1200-547: A two-seat glider fitted with dual controls. The instructor performs the first launches and landings, typically from the back seat, but otherwise the student manages the controls until the student is deemed to have the skill and the airmanship necessary to fly solo. Simulators are also beginning to be used in training, especially during poor weather. After the first solo flights glider pilots are required to stay within gliding range of their home airfield. In addition to solo flying, further flights are made with an instructor until

1280-400: A useful source of revenue for the clubs. Glider pilots can stay airborne for hours by flying through air that is ascending as fast or faster than the glider itself is descending, thus gaining potential energy . The most commonly used sources of rising air are Ridge lift rarely allows pilots to climb much higher than about 600 metres (2,000 ft) above the terrain; thermals, depending on

1360-471: A varied fleet, consisting of both single and dual seat aircraft. In addition to the aircraft that it owns, it has access to the fleet of OUGC as part of the facilities agreement. (1 OUGC) (G-DESB) (1 OUGC) (G-CFEF) (1 on loan from WGC ) (G-DEED) 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

1440-411: Is 203.1 kilometres per hour (126.2 mph) and required unusually good conditions, but even in places with less favorable conditions (such as Northern Europe ) a skilled pilot can expect to complete flights over 500 kilometres (310 mi) every year. As the performance of gliders improved in the 1960s, the concept of flying as far away as possible became unpopular with the crews who had to retrieve

1520-473: Is a decentralized Internet-based competition called the Online Contest , in which pilots upload their GPS data files and are automatically scored based on distance flown. Worldwide, 6,703 pilots registered for this contest in 2010. Soaring pioneer Paul MacCready is usually credited with developing mathematical principles for optimizing the speed at which to fly when cross-country soaring, although it

1600-437: Is also a limit, 193 centimetres (6 ft 4 in), on the tallest pilots who can safely fit into a typical glider's cockpit. Windrushers Gliding Club The club also hosted Oxford University Gliding Club at their site until Windrusher's closure, where OUGC then relocated to Oxford Gliding Club . During their tenancy, the gliding Varsity match between Oxford University Gliding Club and Cambridge University Gliding Club

1680-470: Is dependent on an aircraft's class, and can typically range from 44:1 (for modern designs in the Standard Class) up to 70:1 (for the largest aircraft). A good gliding performance combined with regular sources of rising air enables modern gliders to fly long distances at high speeds. The weather is a major factor in determining cross-country speeds. The record average speed for 1,000 kilometres (620 mi)

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1760-409: Is most effective in mid-latitudes from spring through late summer. During winter, the sun's heat can only create weak thermals, but ridge and wave lift can still be used during this period. A ridge soaring pilot uses upward air movements caused when the wind blows on to the sides of hills. It can also be augmented by thermals when the slopes also face the sun. In places where a steady wind blows,

1840-445: Is not found during a cross-country flight, for example because of deteriorating weather, the pilot must choose a location to "land out". Although inconvenient and often mistaken for " emergency landings ", landing out (or "outlanding") is a routine event in cross-country gliding. A location needs to be identified where the glider can land safely without damaging the glider, the pilot, or property such as crops or livestock. The glider and

1920-506: Is now on the bed of Farmoor Reservoir . The Club fleet consisted of two open primary gliders , one of which had a streamlined nacelle. Club members had to build an access road to the site, including a bridge over a ditch, and a basic hangar. The famous Austrian gliding pioneer, Robert Kronfeld became manager and CFI (Chief Flying Instructor) of the Club in June 1938. Club pilots and gliders took part in

2000-440: Is often marked by long, stationary lenticular (lens-shaped) clouds lying perpendicular to the wind. Wave lift was used to set the current altitude record (to be ratified) of 23,202 metres (76,122 ft) on 2 September 2018 over El Calafate , Argentina . The pilots, Jim Payne and Tim Gardner , wore pressure suits. The current world distance record of 3,008 kilometres (1,869 mi) by Klaus Ohlmann (set on 21 January 2003)

2080-465: Is rarer nowadays. The direct autotow requires a hard surface and a powerful vehicle that is attached to the glider by a long steel cable. After gently taking up slack in the cable, the driver accelerates hard and as a result the glider rises rapidly to about 400 metres (1,300 ft), especially if there is a good headwind and a runway of 1.5 kilometres (0.93 mi) or more. This method has also been used on desert dry lakes . A variation on

2160-432: Is the pilot who has amassed the greatest number of points over all the contest days. However, these competitions have as yet failed to draw much interest outside the gliding community for several reasons. Because it would be unsafe for many gliders to cross a start line at the same time, pilots can choose their own start time. Furthermore, gliders are not visible to the spectators for long periods during each day's contest and

2240-545: The FLARM warning system is used to help avoid mid-air collisions between gliders. A few modern gliders have a ballistic emergency parachute to stabilize the aircraft after a collision. In addition to national laws controlling aviation, the sport in many countries is regulated through national gliding associations and then through local gliding clubs. Much of the regulation concerns safety and training. Many clubs provide training for new pilots. The student flies with an instructor in

2320-761: The Global Positioning System and improved weather forecasting have since allowed many pilots to make flights that were once extraordinary. Today over 550 pilots have made flights over 1,000 kilometres (620 mi). Although there is no Olympic competition, there are the World Gliding Championships . The first event was held at the Samedan in 1948. Since World War II it has been held every two years. There are now six classes open to both sexes, plus three classes for women and two junior classes. The latest worldwide statistics for 2011 indicate that Germany,

2400-662: The Royal Air Force Gliding & Soaring Association . In July 2004 the club was reformed as a separate entity after the RAFGSA moved to RAF Halton . The following year it hosted the UK Junior National Championship and its own Regional championship. It also later achieved the British Gliding Association's accreditation as a Junior Gliding Centre. During their operation, Windrushers hosted

2480-654: The Wasserkuppe in 1920, organized by Oskar Ursinus . The best flight lasted two minutes and set a world distance record of 2 kilometres (1.2 mi). Within ten years, it had become an international event in which the achieved durations and distances had increased greatly. In 1931, Gunther Grönhoff flew 272 kilometres (169 mi) on the front of a storm from Munich to Kadaň (Kaaden in German) in Western Czechoslovakia , farther than had been thought possible. In

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2560-567: The 1930s, gliding spread to many other countries. In the 1936 Summer Olympics in Berlin gliding was a demonstration sport , and it was scheduled to be a full Olympic sport in the 1940 Games . A glider, the Olympia , was developed in Germany for the event, but World War II intervened. By 1939 the major gliding records were held by Russians, including a distance record of 748 kilometres (465 mi). During

2640-480: The CASC guidelines on disposing of assets (such as aircraft) to other eligible CASC organisations in the local area. This meant that the majority of their fleet is unavailable for use by either their own members or those in the local area following advice from the British Gliding Association and the insurers. The club has leased some of the aircraft to some clubs, however the terms of the leases are not clear as they are not in

2720-593: The Olympics has occasionally been proposed by the world governing body, the Fédération Aéronautique Internationale (FAI), but has been rejected on the grounds of lack of public interest. In many countries during the 1950s, a large number of trained pilots wanted to continue flying. Many were also aeronautical engineers who could design, build and maintain gliders. They started both clubs and manufacturers , many of which still exist. This stimulated

2800-512: The ability of the pilot to find the strongest lift. On cross-country flights on days when strong lift is forecast, pilots fly with water ballast stored in tanks or bags in the wings and fin. The fin tank is used to reduce trim drag by optimizing the center of gravity , which typically would shift forward if water is stored only in the wings ahead of the spar. Ballast enables a sailplane to attain its best lift-to-drag ratio (L/D) at higher speeds but slows its climb rate in thermals, in part because

2880-455: The aerotow, the glider pilot keeps the glider behind the tow-plane in either the "low tow" position, just below the wake from the tow-plane, or the "high tow" position just above the wake. In Australia the convention is to fly in low tow, whereas in the United States and Europe the high tow prevails. One rare aerotow variation is attaching two gliders to one tow-plane, using a short rope for

2960-471: The airfield is not otherwise in use, and when there are sufficient members available to commence operations. Like most UK gliding clubs, there are no paid employees and all members (subject to age and regulatory requirements) are trained in the various elements of airfield operation. In addition to the day-to-day operations, the club also undertakes various maintenance tasks including grass-cutting, aircraft inspection as per BGA requirements and general upkeep of

3040-408: The airfield under the new proposed terms which meant that no new lease was on offer, the club would have to book the airfield for the day if they wanted to fly and would become just another "airfield user" rather than the leaseholder. When the club ceased operations, it maintained that it was not being dissolved and was instead entering a state of "hibernation", which meant they did not need to follow

3120-436: The airfield, including the recently renovated clubrooms and workshops. In July 2020, the club left the airfield, with members leaving for various different gliding clubs in the local area such as Oxford Gliding Club , Shenington Gliding Club at Shenington Airfield , Banbury Gliding Club and others further afield. The club states its lease was terminated on December 12th, 2019 and it would have been impossible for them to stay at

3200-412: The altitude. The MacCready speed represents the optimal trade-off between cruising and circling. Most competition pilots use MacCready theory to optimize their average speeds, and have the calculations programmed in their flight computers, or use a "McCready ring", a rotatable bezel on the glider's variometer to indicate the best speed to fly. The greatest factor in maximizing average speed, however, remains

3280-440: The atmosphere to remain airborne. The word soaring is also used for the sport. Gliding as a sport began in the 1920s. Initially the objective was to increase the duration of flights but soon pilots attempted cross-country flights away from the place of launch. Improvements in aerodynamics and in the understanding of weather phenomena have allowed greater distances at higher average speeds. Long distances are now flown using any of

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3360-405: The climate and terrain, can allow climbs in excess of 3,000 metres (9,800 ft) in flat country and much higher above mountains; wave lift has allowed a glider to reach an altitude of 23,202 metres (76,122 ft). In a few countries such as the UK, gliders may continue to climb into the clouds in uncontrolled airspace, but in many European countries the pilot must stop climbing before reaching

3440-481: The cloud base (see Visual Flight Rules ). Thermals begin as bubbles 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. 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. Without clouds or dust devils to mark

3520-562: The development of both gliding and gliders, for example the membership of the Soaring Society of America increased from 1,000 to 16,000 by 1980. The increased numbers of pilots, greater knowledge and improving technology helped set new records, for example the pre-war altitude record was doubled by 1950, and the first 1,000-kilometre (620 mi) flight was achieved in 1964. New materials such as glass fiber and carbon fiber , advances in wing shapes and airfoils, electronic instruments,

3600-403: The direct autotow is known as the "reverse pulley" method. In this method, the truck drives towards the glider being launched. The cable passes around a pulley at the far end of the airfield, resulting in an effect similar to that of a winch launch. Bungee launching was widely used in the early days of gliding, and occasionally gliders are still launched from the top of a gently sloping hill into

3680-420: The engine if conditions will no longer support soaring flight, while unpowered gliders will have to land out, away from the home airfield, requiring retrieval by road using the glider's trailer. World and European Aerobatic competitions are held regularly. In this type of competition , the pilots fly a program of maneuvers (such as inverted flight, loop, roll, and various combinations). Each maneuver has

3760-555: The ethos of the sport, a few fatal accidents occur every year, almost all caused by pilot error. In particular there is a risk of mid-air collisions between gliders, because two pilots might choose to fly to the same area of lift and so might collide. To avoid other gliders and general aviation traffic, pilots must comply with the Rules of the Air and keep a good lookout. They also usually wear parachutes . In several European countries and Australia,

3840-548: The facilities. As part of the agreement with OUGC, members of each club are able to use the fleet of both clubs. The club's instructors operate under the BGA training system, and do not charge for their time. This is common (but not universal) in gliding, unlike other general aviation areas. In late 2023 the club upgraded to a new skylaunch winch, having previously operated a club manufactured winch. Both winches are powered by Liquefied petroleum gas , and are fitted with Dyneema cable,

3920-460: The following competitions; After discussions that took place in early 2020, the new owners of Bicester Airfield , Bicester Heritage, sought to change the lease that allowed WGC to operate on the airfield. WGC would have lost privileges they enjoyed over other users of the airfield, which would have resulted in increased cost and reduced independence to run competitions or expand operations. Bicester Heritage also looked to take over WGC property within

4000-406: The glider is released and the glider's wheel pops out of the trough. The glider gains just enough energy to leave the ground and fly away from the hill. A glider can simply be pushed down a slope until gravity can create enough speed for it to take off. One of the measures of a glider's performance is the distance that it can fly for each meter it descends, known as its glide ratio . Glide ratio

4080-405: The glider pilot releases the tow-rope. A weak link is often fitted to the rope to ensure that any sudden loads do not damage the airframe of the tow-plane or the glider. Under extreme loads the weak link will fail before any part of the glider or plane fails. There is a remote chance that the weak link might break at low altitude, and so pilots plan for this eventuality before launching. During

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4160-412: The glider within the thermal, thus gaining altitude before flying toward the destination or to the next thermal. This is known as "thermalling". Alternatively, glider pilots on cross-country flights may choose to 'dolphin'. This is when the pilot merely slows down in rising air, and then speeds up again in the non-rising air, thus following an undulating flight path. Dolphining allows the pilot to minimize

4240-491: The gliders. Pilots now usually plan to fly around a course (called a task ) via turn-points , returning to the starting point. In addition to just trying to fly further, glider pilots also race each other in competitions . The winner is the fastest, or, if the weather conditions are poor, the furthest round the course. Tasks of up to 1,000 km have been set and average speeds of 120 km/h are not unusual. Initially, ground observers confirmed that pilots had rounded

4320-660: The half century between Sir George Cayley's coachman in 1853 and the Wright brothers in 1903 mainly involved gliders (see History of aviation ). However, the sport of gliding only emerged after the First World War, as a result of the Treaty of Versailles , which imposed severe restrictions on the manufacture and use of single-seat powered aircraft in Germany's Weimar Republic . Thus, in the 1920s and 1930s, while aviators and aircraft makers in

4400-462: The height lost can be minimised until particularly strong lift is encountered when circling would be most effective. Achievements in gliding have been marked by the awarding of badges since the 1920s. For the lower badges, such as the first solo flight, national gliding federations set their own criteria. Typically, a bronze badge shows preparation for cross-country flight, including precise landings and witnessed soaring flights. Higher badges follow

4480-455: The high-towed glider and a long rope for the low tow. The current record is nine gliders in the same aerotow. Gliders are often launched using a stationary ground-based winch mounted on a heavy vehicle. This method is widely used at many European clubs, often in addition to an aerotow service. The engine is usually powered by LPG , petrol or diesel , though hydraulic fluid engines and electrical motors are also used. The winch pulls in

4560-544: The inconvenience of landing out. The power units can be internal combustion engines, electrical motors, or retractable jet engines . Retractable propellers are fitted to high performance sailplanes, though in another category, called touring motor gliders , non-retractable propellers are used. Some powered gliders are "self launching", which makes the glider independent of a tow plane. However some gliders have "sustainer" engines that can prolong flight but are not powerful enough for launching. All power units have to be started at

4640-444: The loss of height over great distances without spending time turning. Climb rates depend on conditions, but rates of several meters per second are common and can be maximized by gliders equipped with flaps . Thermals can also be formed in a line usually because of the wind or the terrain, creating cloud streets . These can allow the pilot to fly straight while climbing in continuous lift. As it requires rising heated air, thermalling

4720-621: The main sources of rising air: ridge lift , thermals and lee waves . When conditions are favourable, experienced pilots can now fly hundreds of kilometres before returning to their home airfields; occasionally flights of more than 1,000 kilometres (621 mi) are achieved. Some competitive pilots fly in races around pre-defined courses. These gliding competitions test pilots' abilities to make best use of local weather conditions as well as their flying skills. Local and national competitions are organized in many countries, and there are biennial World Gliding Championships . Techniques to maximize

4800-469: The pilot(s) can then be retrieved by road from the outlanding location using a purpose-built trailer. If this is not possible due to an inaccessible location such as a mountain range, the glider may be loaded into its trailer and airlifted by helicopter. In some instances, a tow-plane can be summoned to re-launch the aircraft. Although adding to the weight and expense, some gliders are fitted with small power units and are known as motor gliders . This avoids

4880-459: The public domain. The cost of storing and insuring he fleet forced the Management to sell of some of the aircraft. Following different attempts to find an alternative location to restart the club, it was decided at a members meeting in 2023 that all attempts had come to nothing and that Windrushers Gliding Club would have to fold. Following CASC rules it was decided to monetise any assets left and pass

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4960-504: 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. With the active support of the German government, there were 50,000 glider pilots by 1937. The first German gliding competition was held at

5040-538: The scoring is complex, so traditional gliding competitions are difficult to televise. In an attempt to widen the sport's appeal, a new format, the Grand Prix , has been introduced. Innovations introduced in the Grand Prix format include simultaneous starts for a small number of gliders, cockpit mounted cameras, telemetry giving the positions of the gliders, tasks consisting of multiple circuits, and simplified scoring. There

5120-399: The shape of the field or because of noise restrictions. The height gained from a winch is usually less than that from an aerotow, so pilots need to find a source of lift soon after releasing from the cable, or else the flight will be short. A break in the cable or the weak link during a winch launch is a possibility for which pilots are trained. Another method of launching, the "autotow",

5200-534: The sport's birthplace, is still a center of the gliding world: it accounted for 27 percent of the world's glider pilots, and the three major glider manufacturers are still based there. However the meteorological conditions that allow soaring are common and the sport has been taken up in many countries. At the last count, there were over 111,000 active civilian glider pilots and 32,920 gliders, plus an unknown number of military cadets and aircraft. Clubs actively seek new members by giving trial flights, which are also

5280-661: The standards set down by the Gliding Commission of the Fédération Aéronautique Internationale (FAI). The FAI's Sporting Code defines the rules for observers and recording devices to validate the claims for badges that are defined by kilometres of distance and metres of altitude gained. The Silver-C badge was introduced in 1930. Earning the Silver Badge shows that a glider pilot has achieved an altitude gain of at least 1,000 metres (3,281 ft), made

5360-478: The student is capable of taking a glider cross-country and of handling more difficult weather. Cross-country flights are allowed when they have sufficient experience to find sources of lift away from their home airfield, to navigate, and to select and land in a field if necessary. In most countries pilots must take a written examination on the regulations, navigation, use of the radio, weather, principles of flight and human factors. Proposals are being made to standardise

5440-431: The thermals, thermals are not always associated with any feature on the ground. The pilot must then use both skill and luck to find them using a sensitive vertical speed indicator called a variometer that quickly indicates climbs and descents. Occasionally reliable thermals can be found in the exhaust gases from power stations or from fires. Once a thermal is encountered, the pilot can fly in tight circles to keep

5520-460: The three parts of the Diamond Badge has flown 300 kilometres (186 mi) to a pre-defined goal, has flown 500 kilometres (311 mi) in one flight (but not necessarily to a pre-defined goal) and gained 5,000 metres (16,000 ft) in height. The FAI also issues a diploma for a flight of 1,000 kilometres (621 mi) and further diplomas for increments of 250 kilometres (155 mi). If lift

5600-426: The training requirements across European countries. In addition to the regulation of pilots, gliders are inspected annually and after exceeding predetermined flight times. Maximum and minimum payloads are also defined for each glider. Because most gliders are designed to the same specifications of safety, the upper weight limit for a pilot, after allowing for a parachute, is usually 103 kilograms (227 lb). There

5680-425: The turn-points. Later, the glider pilots photographed these places and submitted the film for verification. Today, gliders carry secure GNSS Flight Recorders that record the position every few seconds from GPS satellites. These recording devices now provide the proof that the turn-points have been reached. National competitions generally last one week, with international championships running over two. The winner

5760-521: The two most common means of launching gliders. These and other launch methods require assistance and facilities such as airfields, tugs, and winches. These are usually provided by gliding clubs who also train new pilots and maintain high safety standards. Although in most countries the standards of safety of the pilots and the aircraft are the responsibility of governmental bodies, the clubs and sometimes national gliding associations often have delegated authority. The development of heavier-than-air flight in

5840-459: The type of launch being used. Licensing rules in some countries, such as the US, differentiate between aerotows and ground launch methods, due to the widely different techniques. In an aerotow a powered aircraft is attached to a glider with a tow rope. Single-engined light aircraft or motor gliders are commonly used. The tow-plane takes the glider to the height and location requested by the pilot where

5920-533: The war, the sport of gliding in Europe was largely suspended, though several German fighter aces in the conflict, including Erich Hartmann , began their flight training in gliders. Gliding did not return to the Olympics after the war for two reasons: a shortage of gliders, and the failure to agree on a single model of competition glider. (Some in the community feared doing so would hinder development of new designs.) The re-introduction of air sports such as gliding to

6000-415: The warmer air from the land and creates a boundary between two masses of air like a shallow cold front . Glider pilots can gain 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. Glider pilots have occasionally been able to use a technique called " dynamic soaring " allowing

6080-456: Was a part of OGC until 1970 when it became a separate entity and moved to RAF Bicester under the predecessor to Windrushers Gliding Club , the RAF Gliding and Soaring Association . Whilst the club operates from an RAF airfield, it is not affiliated with nor is it a military organisation. The club operates mainly on weekends and bank holidays , however may occasionally operate on weekdays when

6160-465: 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 . The boundaries where two air masses meet are known as convergence zones . These can occur in sea breezes or in desert regions. In a sea-breeze front, cold air from the sea meets

6240-417: Was eventually reformed at Kidlington ( London Oxford Airport )in 1951. An increase in powered aircraft activity at Kidlington resulted in the club relocating to RAF Weston-on-the-Green in 1956. In July 2020, Oxford University Gliding Club returned to RAF Weston-on-the-Green. It operates as an independent organisation, however OGC facilitates its operations by providing the necessary operational capacity. It

6320-427: Was first described by Wolfgang Späte in 1938. The speed to fly theory allows the optimal cruising speed between thermals to be computed, using thermal strength, glider performance and other variables. It accounts for the fact that if a pilot flies faster between thermals, the next thermal is reached sooner. However at higher speeds the glider also sinks faster, requiring the pilot to spend more time circling to regain

6400-584: Was held at Bicester Airfield every other year, the other years it was held at Gransden Lodge Airfield . Due to the COVID-19 pandemic these competitions were not held but in the early summer of 2022 the series was restarted and held at Oxford Gliding Club . Prior to its closure, and since operations ceased the club has maintained Community amateur sports club (CASC) status, a favourable tax status. Windrushers originally started at operations at Little Rissington before moving to Bicester in 1956, later merging with

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