The glider is the motorless flying with gliders , motor gliders and gliders , whereby the power-saving glide of z. B. birds of prey and albatrosses is referred to as sailing . In this type of flying, updrafts are used , the energy of which is converted into altitude and / or flight speed . The aircraft used for gliding are with great extension and aerodynamically favorable shape for the widest possible glide ratio designed.
Even Otto Lilienthal succeeded in 1895 by his gliding experiments, the slope lift to use to extend the flight route. In strong winds he could even gain altitude and hover over his take-off point for some time. At the same time, Alois Wolfmüller also carried out first flight attempts on the Lechhang near Landsberg, largely unnoticed by the public. In 1911 Orville Wright succeeded in hovering without propulsion for almost ten minutes in the stable upwind of the Atlantic coast. This record was only improved on August 30, 1921 by Wolfgang Klemperer with the FVA-2 Blue Mouse on the Wasserkuppe. On August 18, 1922, Arthur Martens carried out the first motorless “hour flight” with the HAWA Vampyr with a flight time of 66 minutes.
With the rapid development of gasoline engines with high performance and low weight, motorized flight succeeded, and glider flight was initially forgotten until the Versailles Treaty banned motorized flight in Germany. "The victors of the world war had closed the sky to the vanquished". Numerous aviation enthusiasts, some of them pilots from the First World War , but also simply those interested in flying, from young people to wealthy heirs, have been gathering on the Wasserkuppe in the Rhön since 1920 to examine motorless flights and try them out in practice. Here they tried out completely different concepts of gliders, launch techniques and use of lift. “This is how the German soaring flight emerged out of bitter misery and genuine Luther pride” (chronicler Peter Supf ). One developer and pilot in particular from the very beginning, Alexander Lippisch , later achieved world fame thanks to his flying wing designs.
Alexander Lippisch and Gottlob Espenlaub were the first so-called "Rhön Indians" who lived on the mountain in simple circumstances all year round. In winter there was meter-deep snow, the periodically appearing heavy fog hindered the testing of flying machines as well as the constant mouse plague. After the construction of a barrack, the living situation improved, in 1920 five people stayed on the Wasserkuppe for the winter, and the air police established an outdoor station with two policemen and a cook, but the "Rhönindians" did not have time to study Wanted to waste names, were addressed only with "1", "2" and "3"; One of these air policemen, Max Kegel , became a glider pilot himself and, since he involuntarily used a thunderstorm to gain altitude, was known as "Gewittermaxe".
They also experimented with new materials. The cell of Ferdinand Schulz's FS-3 , for example, was only made of fir trees and door hinges. The upholstery consisted of old army duvet covers, and the controls were only carried out by two rudder flaps on the wing ends, similar to table tennis bats. This gave this aircraft the nickname "broomstick" . Despite this simple construction, numerous records could be flown with it.
In addition to the Wasserkuppe, other airfields were built, such as the airfield in Hirzenhain built in 1923 (today the municipality of Eschenburg in the Lahn-Dill district ). Flying enthusiasts experimented with self-built aircraft with great public interest.
An important location for German gliding was also the ideally suitable dune area of the Curonian Spit between the Baltic Sea and the Curonian Lagoon in East Prussia . Ferdinand Schulz built the first gliders in 1923 in the Königsberg workshops of the Aviation Association . In the same year, the first competition was held as the "First German Coastal Glider". The Rhön-Rossitten-Gesellschaft founded the famous gliding school in Rossitten in 1926 . Several world records were flown, the last one in 1938 by Boedecker and Zander, an endurance record of 50 hours and 15 minutes. From 1925, people also flew in Korschenruh on the Frischen Haff , where an aviation school was set up in 1933. The Samland cliffs north of Palmnicken were discovered in 1929 as a training area.
The “ Vampyr ” of the Hanoverian Akaflieg, presented in 1921, showed the direction in which glider construction had to develop. Although this monoplane still had small struts, its aerodynamic drag was the winners of the first Rhön competitions thanks to the neatly shaped, planked fuselage with a small cockpit cutout and the choice of a thinner wing profile compared to the pure "Junkers construction" with completely cantilevered, thick wings , FVA-1 Schwatze Düvel and FVA-2 Blue Mouse , significantly reduced. This design resulted in a clear improvement in performance, which made the Vampyr the first real glider and the "ancestor" of all subsequent high-performance gliders.
Only very few were able to control these complex and mostly aerodynamically unstable aircraft without training. Many attempts to self-taught to fly as part of the “testing of self-made equipment” ended with a more or less severe “break”. The first successful glider pilots in the 1920s were former pilots of the First World War who had already mastered flying in principle. Two-seater gliders and gliders suitable for training, on which they could pass on their knowledge, did not yet exist, they seemed too heavy and unwieldy for rubber rope take-offs and close-to-ground slope flights. Fritz Stamer therefore developed the training methodology used until the 1960s on simple single-seat school gliders (Hol's der Teufel, RRG-1 "Zögling") around 1924. It enabled a reasonably safe flight training up to the low-risk switch to the competitive sailors of the time.
National Socialist Germany
The pilots of the Reichswehr knew that gliding offered an excellent training opportunity for future air force personnel. Therefore, after the seizure of power in 1933, the entire air sport in Germany was reorganized. Most of the groups and organizations involved in gliding and other aviation sports were forcibly dissolved and, together with the SA , SS and Stahlhelm squadrons , were merged under the German Air Sports Association (DLV). In addition, soldiers formally retired from the Reichswehr came as aviation . Hermann Göring became chairman . Ultimately, the DLV was a paramilitary front organization for the establishment of the air force . From this point on, glider flights were primarily used for advertising and pre-military flying training for young people and young adults for the future air force. From the research department of the Rhön-Rossitten Society , the German Institute for Glider Flight was developed in 1933 and the German Research Institute for Glider Flight (DFS) in 1937 and became one of the largest German aeronautical research institutes . The high demand for training equipment led to the systematic development of single-seat school gliders such as the SG 38 , which were manufactured in large numbers by companies or as self-assembly.
After the Luftwaffe was disclosed in 1935, the organizations remaining in the DLV were transferred to the newly founded National Socialist Aviation Corps (NFSK) two years later . Thus, the practice of air sports and thus also of gliding in the German Reich had to take place according to the guidelines of the corps leader of the NSFK. The National Socialist Aviation Corps was a public corporation and was directly subordinate to the Reich Aviation Minister Hermann Göring. The corps leader was an active general in the Luftwaffe.
On the basis of an agreement between the Corps Leader NFSK and the Reich Youth Leader, the young pilots were systematically selected. Initially recorded in the working groups of the German Young People (DJ) , the ten to 14-year-olds were instructed in model making and model flying. At the age of 14 to 18 in the air sports groups of the Hitler Youth (HJ), it was time to build gliders and gliders as well as practical training on them. At the age of 18, the takeover in the storms of the NSFK took place for the purpose of further training in gliding and finally motorized flight on small aircraft . The group of people who transferred to the NSFK was automatically recorded by the alternative defense authority and supplemented with a flight assessment by the relevant NSFK instructors. They were part of the Luftgau reserve and were usually drafted into the Air Force for military service.
Outside of the Flieger-HJ and NFSK, gliding operations were only possible to a limited extent (e.g. in Akaflieg ). Every issue of a glider license had to be approved by the corps leader of the NFSK. In addition, from 1936, there was complete monitoring of glider operations by the newly established aerial watch (predecessor of today's flight director ). Selected glider pilots were able to take part in courses at the seven national gliding schools. Only three of these were open to foreigners or unorganized glider pilots, as the others were shielded from the public. At the beginning of the Second World War , in contrast to other sports, glider operations were classified as important to the war effort and intensified in order to meet the increasing demand and pilots for the Wehrmacht . Construction and training operations continued until the end of 1944, most recently due to the air superiority of the Allied aircraft with camouflaged gliders .
Gliding was a demonstration sport at the 1936 Summer Olympics . The competitions took place in Berlin-Staaken . It was to become an Olympic sport at the 1940 Summer Olympics . The DFS Olympia Meise was specially designed for this purpose by the German Research Institute for Gliding .
Each glider must at the start , first with foreign energy assistance at a certain starting level brought before it can continue to fly independently, as long as it does not have another drive (self-starter), which became more frequent in recent years. To do this, it is usually towed by a motorized airplane or a winch. In the USA it is very seldom that a car is towed. In the early days of gliding, the planes were open at the bottom and the pilot had to take off by approaching a slope.
In the past in high-performance gliders , now only in gliders , rubber ropes are also used, which are pulled out by two groups in a V shape and thus tensioned. The aircraft is attached to the ground with an earth anchor and, if there is sufficient tension, released by means of a coupling. The rubber rope start is mostly used on slopes, as the notch heights of 10 to 30 m that can be achieved (initially) are only sufficient for flight on slopes . Due to the seldom found good geographical conditions, this type of launch is still used almost exclusively in well-known locations, such as B. on the Wasserkuppe performed.
Modern cable winches bring a glider to a height at take-off that corresponds to roughly half the length of the tow cable (at most airfields the release heights are between 300 m and 600 m), using either steel or plastic cables. The current maximum height was reached in a special project of 1500 meters, with a rope length of about three kilometers. As a rule, however, the length of the towing routes is only between 800 meters and 1500 meters. After releasing the tow rope, the glider can continue gliding without any further propulsion.
During winch launch, the glider is pulled into the air with the help of a winch . The winch, with an engine power of 100 to over 350 kW, pulls the aircraft on a rope. In the past, only steel ropes were used, but synthetic fiber ropes have been used increasingly for some years. The rope length is limited by the length of the slopes and is usually around 1000 m, but ropes with a length of up to 3000 m have also been used. The rope is rolled up on a winch drum and the glider is accelerated to around 90–130 km / h. Due to the lift that is created on the wings, the glider takes off when there is a sufficient ground angle of attack of the wings. The combination of the high engine power and the low weight of a glider lead to Formula 1-like acceleration values (0 to 100 km / h in about 2 to 3 seconds). The aircraft usually reaches its take-off speed of 80 to 100 km / h after about 20 to 30 meters and takes off. By gently pulling the elevator, the pilot then goes into a climb until the rope is automatically released shortly before overflying the winch. The attainable flight height is one third to one half of the original pitch, in particularly favorable weather conditions such as strong headwinds or moderate crosswind components even more.
Without pulling on the rope, a parachute opens at the end of the rope after releasing, so that the tow rope can be completely wound onto the rope drum down to the last few meters. For the next start, the end of the rope is brought back to the starting point with the return vehicle ( Lepo ).
Winch starts are particularly popular in training because they are inexpensive and allow a quick start sequence. The disadvantage, however, is the limited towing height and the relatively high personnel costs.
Aircraft tow ("F-Schlepp")
In aircraft tow, or "F-tow" for short, the glider is pulled up by a motorized airplane, a motor glider or an ultralight aircraft . Aircraft towing has a number of advantages over winch towing: While the towing height is limited by the rope length with winch towing and the release point is determined by the location of the winch, both can be freely selected in aircraft towing. If necessary, it can then be towed to a thermally better area. There are also places that are located in such a way that the winch can hardly find a thermal connection. Longer flights from such places can only be carried out with aircraft tow. After all, an aircraft tow also needs significantly fewer helpers on the ground, in extreme cases it can also be carried out without any helpers (apart from the tow pilot). The higher costs compared to winch towing are disadvantageous.
The tow ropes used are made of synthetic or hemp fibers. At the end of the rope to the glider there is a predetermined breaking point with a pair of rings, the smaller / last ring of which is hooked into a tow coupling in the area of the glider's nose. In the rear of the fuselage, which is often reinforced, the tow plane either has a coupling or a drum with an electric motor for pulling in the rope after releasing, so that the descent can be carried out without a rope of 40 or 60 meters in length looping at the rear. If the towing aircraft does not have a pull-in winch, the cable is thrown from the motorized aircraft at a predetermined point on the flight area in a low overflight in order to prevent the cable from getting caught in an obstacle during landing.
The aircraft tow launch is less “sporty” than a winch launch. An accompanying guest will find it more pleasant. During the tow, the pilot of the glider flies exactly behind the powered airplane. This requires discipline and precision from both pilots. When the desired towing altitude is reached, the pilot of the glider disengages the tow rope. Tow aircraft and glider pilots then fly opposite curves (in Europe usually tow aircraft left, glider right) in order to safely rule out a collision with the rope or the other aircraft. At the same time, the tow plane begins its descent to land. The F-tow is ideal for thermal or distance and aerobatics, as the glider can be towed directly into an updraft or can reach sufficient height for aerobatics through the tow.
In some gliders a motor with a propeller is built into the fuselage that can be folded out (folding engine), but since 2002 they are no longer legally motorgliders , even if they have the registration number of a motorglider (DK ...). They may be flown with a normal glider license, provided that the glider is not allowed to take off on its own due to the glider's license. The engines of such gliders are called auxiliary engines or "turbo" engines. They are used to be switched on in flight when the range of the glider is to be increased to, for. B. to reach an airfield that would not have been accessible in pure glider flight (avoid landing outside). In the case of motorized gliders that allow self-launch (sufficient motorization and appropriate approval), the pilot must have entered the self-launch take-off type in the pilot's license . To start, the propeller is extended and the engine started. The advance makes the aircraft faster and faster, and can take off and climb. When the desired height is reached, the engine is switched off and retracted. The glider is then, like any non-motorized glider, in pure gliding.
Rubber rope start
The rubber rope start was - after the "running start" as it is still carried out by hang-gliders today - in the early days of gliding, due to the lack of other options, the usual start method. It was "invented" by the students of the Aviation Science Association Aachen (FVA) around Wolfgang Klemperer, who started their FVA-1 "Schwatze Düvel" at the first Rhön competition in 1920. Since this type of take-off only reaches a height of a few meters, it is only useful where this low height is sufficient to slide into the slope wind, i.e. on a mountain or a dune. Historically, the first established glider flying locations were the Wasserkuppe and the dune near Rossitten (now Rybatschi ). Nowadays, the rubber rope launch for high-performance gliders no longer has any practical significance, but is still carried out by enthusiasts with suitable gliders.
With the rubber rope start you start downhill against the wind (see sketch). A starting team of four to ten, and up to fourteen “rubber dogs” ( 3 ) on the level, first tighten the rope construction at walking pace, then with momentum at a run. This consists of two rubber ropes ( 1 ) each approx. 25 m long , which are connected to the aircraft with a short coupling rope ( 2 ). Alternatively, the front pull ropes are inelastic and provided with knots at equal intervals , which the "rubber dogs" grapple with with non-slip gloves; A long elastic rope is then used as the main rope (often a bungee rope ). Shortly before the increasing tension on the front ropes stops the helpers, the holding rope ( 4 ) is cut at the holding peg ( 5 ) or released from a ground anchor device ( 5 ) at the command of the start master (or the start master himself) , and the aircraft takes off quickly Move. Nowadays, the holding peg is often replaced by a four to six-person holding team, or a holding team of around three people complements the function of the holding peg and ensures that the aircraft can take off with horizontal wings after the tether has been cut / released. After take-off, the starter rope is released from the aircraft.
The initial speed of around 45 to 50 km / h achieved with this method is not sufficient for today's heavy aircraft. In addition, much more helpers are required for a rubber rope launch than for a winch or aircraft tow, so that the cost-to-income ratio is unattractive.
Like the F-towing authorization or the winch towing authorization, the start authorization for the rubber rope must be refreshed regularly. However, this does not necessarily have to be done on the slope, but is also possible on the flat. The flight time is usually only a few seconds.
In the case of car towing, which is still in use today in the USA or Great Britain (for example in the Cotswold Gliding Club until 2000 ), a car or truck pulls the aircraft on a rope either directly or via a pulley. Alternatively, a winch on the car can slowly release rope during towing so that the glider can gain more altitude. This type of start is also increasingly taking place in Germany.
Foot launch is also possible with very light and specially equipped aircraft. Suitable aircraft either have an open fuselage or have opening flaps in the fuselage floor through which the pilot can reach the floor with his feet. Theoretically, such a take-off at the winch or in an F-tow is possible without outside help (wing holder), but this combination carries an increased risk of accidents. In practice, this type of start is therefore only used for starting on slopes. Here, as with hang gliders, you can take off without outside help.
A very rare type of start that can only be used on hills or mountains is the roll start or gravitational start. The pilot sitting in the aircraft simply lets it roll down a slope until he has reached take-off speed. Places where the taxi start is practiced regularly nowadays are the glider airfields Bezmiechowa and Jeżów Sudecki (former glider flying school Grunau ).
Gliding and aerodynamics
Gliding means gliding an airplane without a motor. This motorless flight does not differ in principle from that of other aircraft in terms of control. Any airplane with wing surfaces can glide. This means that the potential energy of the aircraft resulting from its own weight and the initial altitude is used for propulsion. Depending on the altitude, weight and aerodynamic quality of the aircraft, you can fly different distances. The aerodynamic quality is the ratio of lift and propulsion and the sum of all individual resistances (air resistance, resistance from air eddies - e.g. the induced resistance at the wing ends). The power (the better the propulsion) to keep a glider in the air at the best glide speed (optimal ratio of sink and speed) is often less than 10 kilos.
When gliding, the aircraft sinks at about 0.5 to 2 m per second, depending on its design and speed. During heavy drinking ( aviation German for “strong sinking” of the air mass surrounding the glider) or during very fast flight, the glider can also sink at 5 to 10 m per second. By using natural energy sources such as thermals , slope winds or lee waves , the glider can regain altitude (in so-called "cranking" with tight updrafts, but also in straight flight with favorable updrafts). This gain in altitude enables the glider pilot to stay in the air for a longer period of time and to achieve further updraft while gliding. Depending on the weather, flights of several hours and distance flights of over 1000 km are possible.
The relationship between the distance covered and the altitude lost (or between the horizontal speed and the rate of descent) is known as the glide ratio and corresponds to the reciprocal of the tangent of the glide angle. If a flight path becomes steeper, the speed increases. In modern gliders, which have a very good glide ratio, competition pilots fill tanks in the wings with water to make the aircraft heavier. This means that the aircraft has more potential energy with the flight altitude, which can be converted into kinetic energy. In practice this means that the aircraft climbs more slowly in the thermal, but flies much faster with the same glide angle with less resistance. With good thermal conditions, the bottom line is a higher average speed, which means that a greater distance can be covered in the available time window. If the thermal gets weaker towards evening, but in any case before landing, the water is drained.
Since any disturbance of the air flow around the wings can lead to poorer flight performance in motorless gliding, competition pilots in particular place great value on the smoothest possible surface. The paintwork of the aircraft is therefore regularly repaired and polished, and dirt and dead insects are removed after every day of flight. The latter can even be done during the flight with the help of mosquito cleaners .
In powered flight , including powered gliders , the supply of power by an engine serves to compensate for the loss of altitude associated with gliding. There is only one speed associated with each configuration and flight position, at which lift and weight balance each other out (steady flight condition). Even an engine does not change that. If more force (propulsion) is supplied in a configuration and flight position than is lost through resistance, the aircraft begins to climb.
A glider can gain altitude if it succeeds in flying in an air mass that is rising faster than the aircraft is falling. Figuratively, this roughly corresponds to the situation when you slowly go down an escalator moving upwards. The same can be observed in the circular flight of birds of prey or storks. Gaining altitude means moving in a circling thermal tube ("beard") as close as possible to the center of the rising air, or alternatively flying in rising air masses such as lee waves or slope winds. Flying with water ballast (or generally with increased take-off weight) usually leads to poorer climbing. This is mainly explained by the fact that due to the higher wing loading, the minimum speed and thus also the circle radius increases, which means that the flight path can no longer be optimally shifted to the center of the thermal during circular flight. When the aircraft is loaded, the pilot also feels the distribution of updraft much weaker. The increased self-sinking also plays a subordinate role. Therefore, in weak thermals, no additional ballast is used.
In addition to knowledge of aerodynamics, gliding also requires knowledge of meteorology and the effects of topology. Since gliding directly affects the flight by operating the basic control elements elevator , rudder and ailerons , the natural conditions also affect the duration of the flight and there are many vertical accelerations and relatively steep turns , pilots consider gliding as "pure Flying ”, described as a gliding sport.
When flying in a slope updraft , the glider flies on the windward side of a mountain slope in an upward air current. Slope wind is found, for example, when a ridge is perpendicular to the direction of the wind. Depending on the wind strength and the shape of the slope, you can climb up to several hundred meters over the edge of the slope. Slope lift was the first form of lift that was used by gliders. Even before thermal flight was discovered in the mid-1920s, slope winds were used on the Wasserkuppe to extend flights in gliders by sliding the height difference between the take-off and landing points. In 1922 the first glider flight of over an hour was made. On May 11, 1924, Ferdinand Schulz flew in his own design FS 3 broomstick box with 8 hours 42 minutes in Rossitten, a world record in endurance flight. In 1954, the long-term flight record of 27 hours and 7 minutes was set on the slope of Laucha airfield , the pilot was Kurt Götze. With the “eternal” Laucha record, Fritz Fliegauf set the last record of more than 30 hours of continuous flight ever flown in Laucha. Later, continuous gliding was banned after falling asleep. International endurance flight records can be found on the website of the Fédération Aéronautique Internationale .
In thermal updrafts, gliders gain altitude up to just below the cloud base, which in Central Europe is around 1000 to gas laws ). Gliders can usually gain height of one to three meters per second, particularly strong thermal updrafts in mountains or over deserts reach speeds of up to 10 meters per second. For the glider pilot, cumulus clouds and sometimes circling birds of prey indicate such updraft zones. During the day, for example, there is hardly any thermals over bodies of water and forests because the sun's heat is absorbed by the subsurface rather than the surface warming up. Only in the evening hours are there calm updrafts here, when these areas warm the air as a result of the stored heat (so-called reverse thermal ). The variometer shows the ascent or descent and is therefore a very important flight instrument in the glider.above sea level, depending on temperature and humidity . In the Alps or other regions, the cloud base can rise to 5000 m or higher. Thermal updrafts are known as “beard” or “hose”. These updraft zones arise mainly on sunny slopes of hills and mountains and to a particularly great extent when the ground is rocky or dark, or on the edges of forests, as the wind can detach the warm air from the ground there. The air heats up over these suitable areas and rises due to the reduction in density (see
In Germany, depending on the airspace class , it is not always allowed to climb directly to the cloud base in visual flight . In order to avoid dangerous approaches to other aircraft, a vertical cloud distance of about 300 m must usually be maintained (see Visual Meteorological Conditions ). These can namely fly in the same airspace according to instrument flight rules and thus also move within clouds.
Cloud flying is permitted if the pilot has the appropriate license and the flight has been approved by air traffic control. In Germany , in addition to the airspeed indicator and altimeter required for visual flight, the glider must also be equipped with a variometer , compass , turning pointer or artificial horizon , dragonfly and radio. A transponder is not mandatory, but it increases the chances of receiving approval. In Switzerland there are special cloud flying zones in which cloud flying is permitted without clearance from air traffic control. The pilots stagger themselves directly with the help of special radio procedures. Thermal gliding is theoretically possible up to the upper cloud limit. In thunderclouds it is up to 9000 m above sea level in our latitudes, in the tropics up to 18,000 m above sea level.
The pioneers of gliding flew in in thunderclouds because of the strong updrafts of up to 15 m / s. They sometimes used complete wooden hoods to protect themselves against hail. In the worst case, the enormous forces of the turbulent updrafts and downdrafts could destroy the aircraft in the cloud. If a pilot was able to parachute himself out of the aircraft in such a situation, he was threatened with hail and cold as well as the parachute rising to heights that would be fatal for humans. That is why hardly anyone flies voluntarily into a thundercloud today, and even large, modern jets fly around them if that is possible.
Artificial thermal sources are called induced thermal. It is possible to use the waste heat from a cooling tower or mining shafts, which release weather into the cooler ambient air. Due to the high energy density , the thermals are often very narrow and therefore usually quite turbulent . Cooling towers also create a lot of turbulence when low wind speeds are encountered.
Power plant thermals are often used in cross-country flights when the natural thermals are weak in the morning and evening. The convection generated by cooling towers often breaks through the barrier layers and enables you to fly over the inversion (see picture). The ascent values are between 1 m / s at 200 m and 5 m / s at 600 m above ground. After the terrorist attacks of September 11, 2001 , flight restriction areas were set up around several nuclear power plants in Germany , so that their cooling towers can only be used as an ascent aid from 600 m.
Leewaves occur in particularly strong winds on the leeward side of an obstacle. Glider pilots often recognize these weather conditions by the characteristic lenticular clouds . In these wind systems they reach altitudes of around 3000 to 8000 m, sometimes more than 10,000 m above the ground. Gliding world records to achieve the greatest possible height or the greatest possible gain in height can only be flown in waves. The effort for this is extremely high and can only be provided in specially designed projects. Special aircraft are even being constructed for this, such as the Windward Performance Perlan II .
For such flights you need oxygen from around 4000 m, from around 7000 m a pressure suit and clothing that protects against the extreme cold. The zero-degree limit even in midsummer to 3000-4000 m, in 10,000 m prevail temperatures around minus 50 ° C . For weight reasons, pressurized cabins or cabin heaters are not possible in series-produced gliders.
It is possible to generate energy from a purely horizontal, sheared flow by coordinating the altitude and direction of flight. Albatrosses, for example, use this method in the shear layer near the surface of the sea to stay in the air for months without their own propulsion.
During the rapid ascent phase against the wind, the subsequent tight turn and the steep descent, the bird is accelerated to leeward, whereby a component of the current speed is always effective as updraft due to the angle of ascent and descent or in the turn due to the transverse slope. Near the surface, the bird then flies a larger arc at high speed, possibly a distance against the wind, and then initiates the climbing phase again. When the wind is lower, the bird is moved to leeward.
Ingo Renner showed on October 24, 1974 in Tocumwal (AUS) that dynamic gliding can basically also be achieved with gliders when he completed a 20-minute dynamic glider flight with a Libelle H301. The wind shear was at an inversion at around 300 meters above ground and was around 70 km / h. In further flights with a 20 of spades he was able to refine his technique to such an extent that he could even fly forward against the wind.
Nevertheless, it is not to be expected that dynamic gliding will ever become important for cross-country flights. On the one hand, it is associated with very high accelerations, which expose the pilot to loads similar to those in aerobatics, which is very quickly tiring. And secondly, wind shears of sufficient strength usually only occur very close to the ground, which makes aviation very dangerous, especially in view of the great stress.
In model flying, on the other hand, dynamic gliding has become established. Neither the physical strain nor the safety problems come into play here, and the model airplanes can maneuver much more extreme and in a much smaller space than man-carrying gliders. As a rule, dynamic model gliding is carried out on wind shears caused by mountain ridges.
A glider approaches the landing with excess energy (altitude reserve and increased speed) - the pilot approaches the landing from above, so to speak. The excess energy is then converted into frictional energy with the help of the brake flaps ( air brake ), by a side glide flight (so-called "slip") or with the help of a braking parachute. Because of this energy conversion, it is possible for gliders to touch down very precisely at the desired landing point. The pilot cannot take off, but has enough reserve to avoid an obstacle that appears at short notice. The slightly increased speed (for comparison: normal thermal flight: 80 km / h, landing: 90–110 km / h) is a safety aspect that ensures controllability as a safety reserve in the event of gusts or air eddies during landing. Landing is generally the most difficult part of the flight and requires the pilot to be extremely focused.
If the pilot is on a cross-country flight and has no more altitude reserves (for example because the thermals have subsided in the evening), he looks for a suitable landing field. He usually chooses one of the numerous glider airfields from which he can fly home (aircraft tow) or drive (aircraft in trailer). If no airfield can be reached, he has to land the glider in a field or meadow ( landing outside ). This process is already learned during training and is permitted for gliders on cross-country flights in Germany.
An offshore landing is often incorrectly referred to as an emergency landing in the media , but differs from it in the lack of an emergency. Depending on the experience of the pilot and the ambition of the route to be flown, outlandings are relatively common. A good cross-country flight preparation therefore includes the organization of a fetcher and more provisions (especially water) for the waiting time in the field.
The flight training to become a glider pilot takes place largely in glider clubs or in commercial flight schools. The training is divided into three parts: The first section includes learning the basic techniques of gliding, such as taking off, turning and landing. This training section takes place in a two-seater glider. It ends with the so-called A-test, the first three solo flights . This is the first time that the aircraft is flown without a flight instructor . In the second section, the basic techniques are practiced in solo flight, and training is given to single-seaters. The so-called B examination is followed by the C examination. In these tests, the trainee pilot must show that he can perform certain tasks in flight with a single-seater even without a flight instructor. The second part of the training ends when you pass the C-exam. The third and final section of the training deals with the preparation of thermal gliding and especially training in cross-country flying. First of all, cross-country flights are carried out with flight instructors, during which the trainee pilot gathers practical experience in navigation using an aviation card and learns to correctly assess the weather situation. After the theoretical examination (which includes the subjects of meteorology, navigation, technology, aerodynamics, aviation law, behavior in special cases and human performance), the student is allowed to perform cross-country flights alone. The practical training is completed with a cross-country flight of at least 50 km. Since 2001, the 50 km cross-country flight has been allowed to be replaced by a cross-country flight over 100 km with a flight instructor. The flight must be documented using a logger or barograph. A confirmation by two witnesses and the flight instructor is sufficient. After the successful cross-country flight, the practical test can be taken. After passing the exam, the training is over and the trainee pilot is in possession of an EASA-FCL glider license , the SPL (Sailplane Pilot License), which replaced the GPL in 2012 and the PPL with supplement C in 2003 .
The training can be started at the age of 14 and lasts at least several months to a maximum of four years, at professional flight schools the training is also possible within a few weeks. The license can be acquired in Germany at the age of 16 through a theoretical and practical examination. Among other things, a medical certificate from a licensed flight doctor is required .
Since the training in the clubs is voluntary, the costs are covered by membership fees for the club in question. Additional costs for obtaining the license are the medical fitness examinations , the acquisition of a radiotelephone certificate and the examination fees.
The medical officer of the Federal Office for Civil Aviation FOCA (Switzerland) or the aviation doctor (Germany) can prescribe glasses or contact lenses, and a generally healthy mental and physical condition is necessary. The hearing impaired must be able to follow a person properly without lip reading . For instrument flight, the conditions in Switzerland are stricter. Internationally, the rules for obtaining a glider license are very different. In some countries, such as Great Britain, the license is awarded by the national sports federation when theoretical and practical tests have been passed (bronze C plus distance gliding).
Distance gliding is either about covering the longest possible distance or completing a given distance in the shortest possible time. The flight routes and the updrafts to be used must be actively selected by the pilot during the entire flight, which places high demands on concentration and endurance.
Various strategies are available for using the updrafts. The pilot can use the thermal up to the highest possible height and then look for a new updraft at a moderate pre-flight speed. The pilot can achieve faster flight speeds if he selects the strongest updraft areas and only uses them to maximize the speed and then fly on to the next thermal; this carries the higher risk of an early landing. Experienced pilots use a mixture of these two strategies, depending on the weather conditions. The speed-to- fly theory deals with the optimization of the cruising speed .
In Central Europe, cross-country flights over several hundred kilometers are possible if the weather is suitable, and the thousand mark is occasionally exceeded. The current world record was set by Klaus Ohlmann in the Andes on January 21, 2003 and is 3008.8 km.
Records with certain types of aircraft of the old timber construction class are still important today. On April 25, 1972, Dr. Siegfried Baumgartl and Walter Schewe from the Luftsportverein Dinslaken e. V. set a world record for two-seater target flight with a flight over 714 kilometers from Dinslaken / Schwarze Heide airfield to Angers in France. Such records with today's airplanes are not comparable, because the risk of landing outside was much greater. The transport of modern aircraft requires a much smaller ground force crew than was necessary for older aircraft.
Competitions are also organized in long-distance gliding. These competitions are essentially about covering a given route as quickly as possible. There are regional competitions, national, European and world championships.
In the simplest form (the “racing task”), the pilots have to fly to two or more “turning points” in a given order. The winner is whoever is back on the starting line fastest. Between the turning points, the choice of the flight path is up to the pilot. The pilot is also free to choose the time of departure - within a specified time window. The time is measured from the actual flight over the departure line to the crossing of the finish line. Thus, in addition to the observation of the current weather (and the actual flight technique), the assessment of the weather development and tactical considerations are central components of the glider competition. The proof that all turning points have been circled is now provided by an electronic logger that records the route data via GPS.
There are also other forms of tasks, but almost all of them are about achieving the highest possible average speed over the specified distance or within the specified period.
The daily task is determined by the competition management in the morning based on their assessment of the weather. She tries to make the most of the day's possibilities. In order to rule out random results as much as possible, a competition extends over several days. The duration ranges from a long weekend for small regional competitions to two weeks for world championships. There are different classes of gliders that are assessed separately.
For some years now, competitions have also been held in the Grand Prix form . In this type of competition, all planes cross the start line at the same time and the first to cross the finish line wins the day. Together with systems for live tracking and on-board cameras, this enables media preparation and presentation of the competition to be effective for the public.
There were plans to introduce gliding as an Olympic discipline in 1940 . The DFS Olympia Meise was designed for this purpose and was to be used as a standard aircraft. These plans were thwarted by the Second World War and later, for various reasons, were never pursued any further.
Every year the German Aero Club organizes the decentralized German championship in distance gliding (DMSt for short) from March 1st to September 30th . In this competition, routes are scored by up to four turning points freely selectable by the pilot. Every kilometer flown counts as one point. A previous registration in the flight data recorder and a successful completion of the flight bring additional bonuses. In order to determine the pure pilot performance, an index is assigned to each aircraft type, which is included in the calculation of the final number of points for the flight. A list of the indices for all aircraft types is published by the German Aero Club.
In addition, central German championships in various competition classes as well as women's and junior championships are held every two years. Within these competitions, qualification for the international championships, i.e. the respective European and world championships, takes place.
The Glider League (OLC League)
A relatively new variant of long-distance gliding is the gliding league ( OLC -League) launched in 2001 . This team competition for clubs is held as a decentralized competition on an online platform. The pilots fly for the points nationwide in around 19-20 weekly laps. The three fastest flights of a club are evaluated, whereby the calculation of the speed takes place in a time window of two and a half hours and this average is evaluated with an aircraft index. In Germany, the 1st Bundesliga (30 clubs), the 2nd Bundesliga (30 clubs) as well as the qualification league (approx. 500 clubs) and the respective national league of the 16 federal states are evaluated. In Switzerland, all around 35 clubs are rated in the same league.
Some glider pilots can be trained in aerobatics . There are also competitions for this.
The aerobatic competition is about flying a given program in a cube with an edge length of 1000 m as precisely and energy-efficiently as possible. For safety reasons, this cube, the so-called box, is moved upwards by 400 m, in advanced classes by 200 m above ground, so that the glider pilot has to end his program there. A competition consists of several rounds: known duty, freestyle and one or more unknown duties that are announced by the organizer shortly before the round and that may not be practiced. Similar to figure skating, the flights are rated by referees who assess the execution of the individual figures, but also the general harmony of the program with points.
- World altitude record: 23,200 m, set by Jim Payne (USA) and Tim Gardner in a unique piece called " Windward Performance Perlan II " on September 2nd, 2018.
- Track world record: 3009 km, set up by Klaus Ohlmann (GER) and Karl Rabeder (AUT) in Argentina in a Schempp-Hirth Nimbus 4DM (two-seater) on January 21, 2003.
- Speed over a 1000 km triangle: 169.72 km / h, Helmut H. Fischer (GER) in South Africa in a Schempp-Hirth Ventus on January 5, 1995.
- Average speed in a glider over 300 km / h over a flight distance of 1000 kilometers by Klaus Ohlmann in 2006.
Further world records can be found on the website of the Fédération Aéronautique Internationale under the tab "Records".
- Continuous gliding has not been recognized since the mid-1950s (see section "Upwind"). The last world record recognized by the FAI was set in 1954 by the two Frenchmen Bertrand Dauvin and Henry Couston on Kranich III . The flight was operated from April 6th to 8th and lasted a total of 57 hours and 10 minutes.
Gliding is a historically grown cultural asset , i. H. “Something that has endured and is preserved as a cultural value” . After the aviation pioneer Otto Lilienthal had provided the first scientific basis and practical experience in the 1890s, a continuous further development of the aerodynamic knowledge and the perfecting of the technical materials for today's mature gliding sport took place. It has a sporting, health, social, experiential and cultural significance. Recognition of the soaring flight on the Wasserkuppe as an intangible cultural heritage of UNESCO at the request of the Society for the Promotion of Glider Flight on the Wasserkuppe has so far been rejected. The main reason is the failure to come to terms with the National Socialist past and the transition phase in post-war Germany of German gliding.
The sporting importance results from the physical, mental, movement-technical, emotional and social demands when practicing the sport. This begins with the joint maintenance, care, starting and recovery of the machines in the group and continues with physical activity in the air. The rapid gain in height when taking off from the winch or towing an aircraft and circling in thermal , dynamic updrafts or lee waves represent a high level of circulatory stress. Unstable weather conditions can result in rates of rise and fall of five to ten meters per second. Gliding can be realized as a recreational sport, but also as a high-performance sport in various championship classes. Flights of several hours and distances of over three thousand kilometers (world record 3009 km / 2003) can be achieved. In addition, there is the highly demanding aerobatics , in which extreme G-loads (centrifugal forces when pulling up or in the interception curve) act on the body and a high level of technical flying skills is required on the part of the pilot.
The health significance results from its character as an outdoor activity and outdoor sport. Even short flights of a few minutes in the traffic area cause healthy circulation training due to the climbing and sinking movements. Regular medical health checks and a valid medical medical certificate are mandatory. Because of the breathing relief at altitude, gliding clubs often offer children who suffer from bronchial asthma to fly on special flight days.
Societal and social importance
Gliding is of social importance insofar as it is a sport that enables interested people to spend their leisure time in a meaningful way and at the same time fulfills a community-building function. Since the training to become a glider pilot can already begin at the age of 14, even young people benefit from the educational effect of the sport, also as part of the risk education in the group.
Gliding is only conceivable as a community sport. Helpfulness and camaraderie as well as community-oriented thinking and acting are required, which come into play when starting aid and when hauling in the planes after landing, even from remote landing sites, when operating the winch, the tow plane and the Lepo (rope retrieval vehicle). They show themselves in the participation in the hall service and the commitment in the maintenance and care of the machines. And last but not least, they prove themselves in the form of patience and tolerance of having to sit on the ground waiting while a fellow pilot uses the joint plane for hours of flight in the most beautiful thermals.
In order to be able to practice community sport in a meaningful way, the aviation enthusiasts organized themselves early on in glider clubs, which were able to maintain professional and private exchanges on the club's own or community-provided flying grounds, thus enabling them to grow into an often lifelong aviation community.
Gliding is a sport with a high level of experience. Taking off from the ground and dealing with the air currents require courage and self-confidence. But you thank it with a happy experience. The experience, a seemingly difficult task of being able to confidently master an attractive sport by acquiring appropriate skills, is of high educational value for character development, especially in the self-discovery phase of young people. So gliding can also be found in outward-bound education and corresponding experiential educational institutions. The venture researcher Siegbert A. Warwitz names five reasons for the attractiveness and the educational importance of aviation:
- the "gain of space" , which makes the air space available as additional living and design space for the athlete,
- the "gain in perspective" , which changes perception by allowing the view of the earth from a "bird's eye view" to be discovered,
- the "body and movement gain" that creates a new body feeling and new scope for movement,
- the "intellectual gain" , which consists in the intelligent use of aircraft, flight technology and natural knowledge,
- the “spiritual gain” , which reveals itself in the feelings of happiness when releasing from earth attachment and experiencing freedom.
The philosopher Gotthard Günther achieved the International Achievement Badge ("Silver C") in the early 1930s and later completed a course in "engineering gliding" at the German Research Institute for Glider Pilots in Darmstadt. About the influence of aviation on his thinking, he said: "You see, 'philosophy' is just another name for 'idealism', and idealism is the ascent to the abstract regions of being, is detachment from the concrete conditions of being. [...] In the plane up there in the sky I felt similar to the snowy mountains on skis: I took a deep breath. I had an affinity for it, I don't know why. And I also had an affinity for idealism. "
Adventure and story
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- Basic training
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- Jochen von Kalckreuth: Sailing over the Alps. Motorbuch Verlag, Stuttgart 2000 (1st edition 1972), ISBN 3-613-02047-5
- Peter Mallinson, Mike Wollard: Manual of glider aerobatics . Eqip Verlag, Königswinter 2001, ISBN 3-9806773-5-4 (translation, 1st edition of the English original 1999)
- Helmut Reichmann: distance gliding. Motorbuch Verlag, Stuttgart 2005 (1st edition 1975), ISBN 3-613-02479-9
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