Lift-induced drag , induced drag , vortex drag , or sometimes drag due to lift, in aerodynamics , is an aerodynamic drag force that occurs whenever a moving object redirects the airflow coming at it. This drag force occurs in airplanes due to wings or a lifting body redirecting air to cause lift and also in cars with airfoil wings that redirect air to cause a downforce . It is symbolized as D i {\textstyle D_{\text{i}}} , and the lift-induced drag coefficient as C D , i {\textstyle C_{D,i}} .
118-413: A ground-effect vehicle ( GEV ), also called a wing-in-ground-effect (WIGE or WIG ), ground-effect craft , wingship , flarecraft or ekranoplan ( Russian : экранопла́н – "screenglider" ), is a vehicle that is able to move over the surface by gaining support from the reactions of the air against the surface of the earth or water. Typically, it is designed to glide over a level surface (usually over
236-674: A constitutional referendum on whether to adopt Russian as a second official language. According to the Central Election Commission, 74.8% voted against, 24.9% voted for and the voter turnout was 71.1%. Starting in 2019, instruction in Russian will be gradually discontinued in private colleges and universities in Latvia, and in general instruction in Latvian public high schools. On 29 September 2022, Saeima passed in
354-519: A new education law which requires all schools to teach at least partially in Ukrainian, with provisions while allow indigenous languages and languages of national minorities to be used alongside the national language. The law faced criticism from officials in Russia and Hungary. The 2019 Law of Ukraine "On protecting the functioning of the Ukrainian language as the state language" gives priority to
472-645: A $ 700m deal to begin operating 25 REGENT seagliders between destinations in New Zealand. The order includes 15 12-seater Viceroys and 10 100-seater Monarchs. Russian language Russian is an East Slavic language belonging to the Balto-Slavic branch of the Indo-European language family . It is one of the four extant East Slavic languages, and is the native language of the Russians . It
590-782: A 50-seat passenger GEV named the WSH-500. in 2013 Estonian transport company Sea Wolf Express planned to launch passenger service in 2019 between Helsinki and Tallinn , a distance of 87 km taking only half an hour, using a Russian-built ekranoplan. The company ordered 15 ekranoplans with maximum speed of 185 km/h and capacity of 12 passengers, built by Russian RDC Aqualines. In 2021 Brittany Ferries announced that they were looking into using REGENT (Regional Electric Ground Effect Naval Transport) ground effect craft " seagliders " for cross English Channel services. Southern Airways Express also placed firm orders for seagliders with intent to operate them along Florida's east coast. Around mid-2022,
708-472: A craft was soon recognized, and Alexeyev received support and financial resources from Soviet leader Nikita Khrushchev . Some manned and unmanned prototypes were built, ranging up to eight tonnes in displacement . This led to the development of a 550-tonne military ekranoplan of 92 m (302 ft) length. The craft was dubbed the Caspian Sea Monster by U.S. intelligence experts, after
826-419: A formula with V standing for the nucleus (vowel) and C for each consonant, the maximal structure can be described as follows: (C)(C)(C)(C)V(C)(C)(C)(C) Lift-induced drag For a constant amount of lift, induced drag can be reduced by increasing airspeed. A counter-intuitive effect of this is that, up to the speed-for-minimum-drag, aircraft need less power to fly faster. Induced drag is also reduced when
944-464: A given wing area, high aspect ratio wings are beneficial to flight efficiency. With C L {\displaystyle C_{L}} being a function of angle of attack, induced drag increases as the angle of attack increases. The above equation can be derived using Prandtl's lifting-line theory . Similar methods can also be used to compute the minimum induced drag for non-planar wings or for arbitrary lift distributions. According to
1062-418: A high angle of attack will generate an aerodynamic reaction force with a high drag component. By increasing the speed and reducing the angle of attack, the lift generated can be held constant while the drag component is reduced. At the optimum angle of attack, total drag is minimised. If speed is increased beyond this, total drag will increase again due to increased profile drag . When producing lift, air below
1180-409: A higher angle of attack for the same lift, which tilts the total aerodynamic force rearwards and increases the drag component of that force. The angular deflection is small and has little effect on the lift. However, there is an increase in the drag equal to the product of the lift force and the angle through which it is deflected. Since the deflection is itself a function of the lift, the additional drag
1298-542: A huge, unknown craft was spotted on satellite reconnaissance photos of the Caspian Sea area in the 1960s. With its short wings, it looked airplane-like in planform, but would probably be incapable of flight. Although it was designed to travel a maximum of 3 m (10 ft) above the sea, it was found to be most efficient at 20 m (66 ft), reaching a top speed of 300–400 knots (560–740 km/h) in research flights. The Soviet ekranoplan program continued with
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#17327875524961416-484: A language that "belongs to the European cultural space". The financing of Russian-language content by the state will cease, which the concept says create a "unified information space". However, one inevitable consequence would be the closure of public media broadcasts in Russian on LTV and Latvian Radio, as well as the closure of LSM's Russian-language service. In Lithuania , Russian has no official or legal status, but
1534-588: A lesser extent the languages to the south and the east: Uralic , Turkic , Persian , Arabic , and Hebrew . According to the Defense Language Institute in Monterey, California , Russian is classified as a level III language in terms of learning difficulty for native English speakers, requiring approximately 1,100 hours of immersion instruction to achieve intermediate fluency. Feudal divisions and conflicts created obstacles between
1652-622: A minority language under the Framework Convention for the Protection of National Minorities . 30% of the population was fluent in Russian in 2006, and 2% used it as the main language with family, friends, or at work. In Azerbaijan , Russian has no official status, but is a lingua franca of the country. 26% of the population was fluent in Russian in 2006, and 5% used it as the main language with family, friends, or at work. In Georgia , Russian has no official status, but it
1770-726: A need for reliable navigation. Minister Ustinov died in 1984, and the new Minister of Defence, Marshal Sokolov , cancelled funding for the program. Only three operational Orlyonok -class ekranoplans (with revised hull design) and one Lun -class ekranoplan remained at a naval base near Kaspiysk . Since the dissolution of the Soviet Union , ekranoplans have been produced by the Volga Shipyard in Nizhniy Novgorod . Smaller ekranoplans for non-military use have been under development. The CHDB had already developed
1888-782: A previous period of nearly 10 years of research and development: Bigger concepts are: 25-seater, 32-seater, 60-seater, 80-seater and bigger up to the size of a passenger airplane. Since the 1980s GEVs have been primarily smaller craft designed for the recreational and civilian ferry markets. Germany , Russia and the United States have provided most of the activity with some development in Australia , China , Japan , Korea and Taiwan . In these countries and regions, small craft with up to ten seats have been built. Other larger designs such as ferries and heavy transports have been proposed but have not been carried to completion. Besides
2006-526: A qualitatively new entity can be said to emerge—the general language of the working class... capitalism has the tendency of creating the general urban language of a given society. In 2010, there were 259.8 million speakers of Russian in the world: in Russia – 137.5 million, in the CIS and Baltic countries – 93.7 million, in Eastern Europe – 12.9 million, Western Europe – 7.3 million, Asia – 2.7 million, in
2124-731: A ship designer whereas Lippisch worked as an aeronautical engineer. The influence of Alexeyev and Lippisch remains noticeable in most GEVs seen today. Led by Alexeyev , the Soviet Central Hydrofoil Design Bureau ( Russian : ЦКБ СПК ) was the center of ground-effect craft development in the USSR. The vehicle came to be known as an ekranoplan ( Russian : экранопла́н , экран screen + план plane , from Russian : эффект экрана , literally screen effect , or ground effect in English). The military potential for such
2242-451: A significant portion of the drag affecting an aircraft. The greater the span of a wing, the less induced drag created for each unit of lift and the greater the efficiency of the particular wing. This is the primary reason gliders have long wings. Placing the same wing near a surface such as the water or the ground has the same effect as increasing the aspect ratio because the ground prevents wingtip vortices from expanding, but without having
2360-445: A similar effect is one way to reduce induced drag. The Wright brothers used curved trailing edges on their rectangular wings. Some early aircraft had fins mounted on the tips. More recent aircraft have wingtip-mounted winglets to reduce the induced drag. Winglets also provide some benefit by increasing the vertical height of the wing system. Wingtip mounted fuel tanks and wing washout may also provide some benefit. Typically,
2478-501: A specialist and insider of German airplane industry from 1963 and a colleague of Alexander Lippisch and Hanno Fischer, was founded with a fundamental knowledge of wing in ground effect physics, as well as results of fundamental tests under different conditions and designs having begun in 1960. For over 30 years, Jörg built and tested 15 different tandem-airfoil flairboats in different sizes and made of different materials. The following tandem-airfoil flairboat (TAF) types had been built after
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#17327875524962596-546: A standard hull for water operations, but also incorporated fore- and aft-mounted hydrofoil units designed to lift the craft out of the water during takeoff run, to facilitate lower liftoff speeds. Used by the Russian Rostislav Alexeyev for his ekranoplan. The wings are significantly shorter than those of comparable aircraft, and this configuration requires a high aft-placed horizontal tail to maintain stability. The pitch and altitude stability comes from
2714-435: A typical twin-engine wide-body aircraft at cruise speed, induced drag is the second-largest component of total drag, accounting for approximately 37% of total drag. Skin friction drag is the largest component of total drag, at almost 48%. Reducing induced drag can therefore significantly reduce cost and environmental impact. In 1891, Samuel Langley published the results of his experiments on various flat plates. At
2832-445: A wing of low aspect ratio. While induced drag is inversely proportional to the square of the wingspan, not necessarily inversely proportional to aspect ratio, if the wing area is held constant, then induced drag will be inversely proportional to aspect ratio. However, since wingspan can be increased while decreasing aspect ratio, or vice versa, the apparent relationship between aspect ratio and induced drag does not always hold. For
2950-539: Is Belarusian, among ethnic Belarusians this share is 28.5%; the highest share of those who speak Belarusian at home is among ethnic Poles — 46.0%. In Estonia , Russian is spoken by 29.6% of the population, according to a 2011 estimate from the World Factbook, and is officially considered a foreign language. School education in the Russian language is a very contentious point in Estonian politics, and in 2022,
3068-481: Is a co-official language per article 5 of the Constitution of Kyrgyzstan . The 2009 census states that 482,200 people speak Russian as a native language, or 8.99% of the population. Additionally, 1,854,700 residents of Kyrgyzstan aged 15 and above fluently speak Russian as a second language, or 49.6% of the population in the age group. In Tajikistan , Russian is the language of inter-ethnic communication under
3186-401: Is a high degree of mutual intelligibility between Russian, Belarusian and Ukrainian , and a moderate degree of it in all modern Slavic languages, at least at the conversational level. Russian is written using a Cyrillic alphabet. The Russian alphabet consists of 33 letters. The following table gives their forms, along with IPA values for each letter's typical sound: Older letters of
3304-610: Is a post-posed definite article -to , -ta , -te similar to that existing in Bulgarian and Macedonian. In the Southern Russian dialects , instances of unstressed /e/ and /a/ following palatalized consonants and preceding a stressed syllable are not reduced to [ɪ] (as occurs in the Moscow dialect), being instead pronounced [a] in such positions (e.g. несл и is pronounced [nʲaˈslʲi] , not [nʲɪsˈlʲi] ) – this
3422-532: Is based. However, in 2005, the IMO classified the WISE or GEV under the category of ships. The International Maritime Organization recognizes three types of GEVs: At the time of writing, those classes only applied to craft carrying 12 passengers or more, and (as of 2019) there was disagreement between national regulatory agencies about whether these vehicles should be classified, and regulated, as aircraft or as boats. By
3540-488: Is being used less frequently by Russian-speaking typists in favor of the extension of Unicode character encoding , which fully incorporates the Russian alphabet. Free programs are available offering this Unicode extension, which allow users to type Russian characters, even on Western 'QWERTY' keyboards. The Russian language was first introduced to computing after the M-1 , and MESM models were produced in 1951. According to
3658-624: Is called yakanye ( яканье ). Consonants include a fricative /ɣ/ , a semivowel /w⁓u̯/ and /x⁓xv⁓xw/ , whereas the Standard and Northern dialects have the consonants /ɡ/ , /v/ , and final /l/ and /f/ , respectively. The morphology features a palatalized final /tʲ/ in 3rd person forms of verbs (this is unpalatalized in the Standard and Northern dialects). During the Proto-Slavic (Common Slavic) times all Slavs spoke one mutually intelligible language or group of dialects. There
Ground-effect vehicle - Misplaced Pages Continue
3776-499: Is dangerous because the ground is uneven and the altitude called skimming permits no freedom of maneuver. But on large-sized aircraft, over water, the question may be attempted ..." By the 1960s, the technology started maturing, in large part due to the independent contributions of Rostislav Alexeyev in the Soviet Union and German Alexander Lippisch , working in the United States . Alexeyev worked from his background as
3894-412: Is more difficult for GEVs with short production runs to overcome. For the vehicle to work, its hull needs to be stable enough longitudinally to be controllable yet not so stable that it cannot lift off the water. The bottom of the vehicle must be formed to avoid excessive pressures on landing and taking off without sacrificing too much lateral stability, and it must not create too much spray, which damages
4012-573: Is more spoken than English. Sizable Russian-speaking communities also exist in North America, especially in large urban centers of the US and Canada, such as New York City , Philadelphia , Boston , Los Angeles , Nashville , San Francisco , Seattle , Spokane , Toronto , Calgary , Baltimore , Miami , Portland , Chicago , Denver , and Cleveland . In a number of locations they issue their own newspapers, and live in ethnic enclaves (especially
4130-564: Is odd") – чу́дно ( chúdno – "this is marvellous"), молоде́ц ( molodéts – "well done!") – мо́лодец ( mólodets – "fine young man"), узна́ю ( uznáyu – "I shall learn it") – узнаю́ ( uznayú – "I recognize it"), отреза́ть ( otrezát – "to be cutting") – отре́зать ( otrézat – "to have cut"); to indicate the proper pronunciation of uncommon words, especially personal and family names, like афе́ра ( aféra , "scandal, affair"), гу́ру ( gúru , "guru"), Гарси́я ( García ), Оле́ша ( Olésha ), Фе́рми ( Fermi ), and to show which
4248-451: Is operating at its optimal aerodynamic efficiency. According to the above equations, the speed for minimum drag occurs at the speed where the induced drag is equal to the parasitic drag. This is the speed at which for unpowered aircraft, optimum glide angle is achieved. This is also the speed for greatest range (although V MD will decrease as the plane consumes fuel and becomes lighter). The speed for greatest range (i.e. distance travelled)
4366-401: Is produced by the changing direction of the flow around a wing. The change of direction results in a change of velocity (even if there is no speed change), which is an acceleration. To change the direction of the flow therefore requires that a force be applied to the fluid; the total aerodynamic force is simply the reaction force of the fluid acting on the wing. An aircraft in slow flight at
4484-399: Is proportional to the square of the lift. The vortices created are unstable, and they quickly combine to produce wingtip vortices which trail behind the wingtip. For a planar wing with an elliptical lift distribution, induced drag D i can be calculated as follows: where From this equation it is clear that the induced drag varies with the square of the lift; and inversely with
4602-402: Is recognized as a minority language under the Framework Convention for the Protection of National Minorities . Russian is the language of 9% of the population according to the World Factbook. Ethnologue cites Russian as the country's de facto working language. In China , Russian has no official status, but it is spoken by the small Russian communities in the northeastern Heilongjiang and
4720-569: Is sometimes considered to have played a significant role in the formation of modern Russian. Also, Russian has notable lexical similarities with Bulgarian due to a common Church Slavonic influence on both languages, but because of later interaction in the 19th and 20th centuries, Bulgarian grammar differs markedly from Russian. Over the course of centuries, the vocabulary and literary style of Russian have also been influenced by Western and Central European languages such as Greek, Latin , Polish , Dutch , German, French, Italian, and English, and to
4838-585: Is spoken by 14.2% of the population according to an undated estimate from the World Factbook. In 2005, Russian was the most widely taught foreign language in Mongolia, and was compulsory in Year 7 onward as a second foreign language in 2006. Around 1.5 million Israelis spoke Russian as of 2017. The Israeli press and websites regularly publish material in Russian and there are Russian newspapers, television stations, schools, and social media outlets based in
Ground-effect vehicle - Misplaced Pages Continue
4956-445: Is that the closer the wing operates to an external surface such as the ground, when it is said to be in ground effect , the less drag it experiences. An airfoil passing through air increases air pressure on the underside, while decreasing pressure across the top. The high and low pressures are maintained until they flow off the ends of the wings, where they form vortices which in turn are the major cause of lift-induced drag —normally
5074-435: Is that they are unable to land or take off without a significant amount of help from the ground effect cushion, and cannot climb until they have reached a much higher speed. A GEV is sometimes characterized as a transition between a hovercraft and an aircraft , although this is not correct as a hovercraft is statically supported upon a cushion of pressurized air from an onboard downward-directed fan. Some GEV designs, such as
5192-532: Is the most spoken native language in Europe , the most spoken Slavic language , as well as the most geographically widespread language of Eurasia . It is the world's seventh-most spoken language by number of native speakers , and the world's ninth-most spoken language by total number of speakers . Russian is one of two official languages aboard the International Space Station , one of
5310-493: Is the classification and legislation to be applied. The International Maritime Organization has studied the application of rules based on the International Code of Safety for High-Speed Craft (HSC code) which was developed for fast ships such as hydrofoils , hovercraft, catamarans and the like. The Russian Rules for classification and construction of small type A ekranoplans is a document upon which most GEV design
5428-405: Is the speed at which a straight line from the origin is tangent to the fuel flow rate curve. The curve of range versus airspeed is normally very shallow and it is customary to operate at the speed for 99% best range since this gives 3-5% greater speed for only 1% less range. Flying higher where the air is thinner will raise the speed at which minimum drag occurs, and so permits a faster voyage for
5546-518: Is the stressed word in a sentence, for example Ты́ съел печенье? ( Tý syel pechenye? – "Was it you who ate the cookie?") – Ты съе́л печенье? ( Ty syél pechenye? – "Did you eat the cookie?) – Ты съел пече́нье? ( Ty syel pechénye? "Was it the cookie you ate?"). Stress marks are mandatory in lexical dictionaries and books for children or Russian learners. The Russian syllable structure can be quite complex, with both initial and final consonant clusters of up to four consecutive sounds. Using
5664-470: The 2011 Lithuanian census , Russian was the native language for 7.2% of the population. In Moldova , Russian was considered to be the language of interethnic communication under a Soviet-era law. On 21 January 2021, the Constitutional Court of Moldova declared the law unconstitutional and deprived Russian of the status of the language of interethnic communication. 50% of the population
5782-1000: The Apollo–Soyuz mission, which first flew in 1975. In March 2013, Russian was found to be the second-most used language on websites after English. Russian was the language of 5.9% of all websites, slightly ahead of German and far behind English (54.7%). Russian was used not only on 89.8% of .ru sites, but also on 88.7% of sites with the former Soviet Union domain .su . Websites in former Soviet Union member states also used high levels of Russian: 79.0% in Ukraine, 86.9% in Belarus, 84.0% in Kazakhstan, 79.6% in Uzbekistan, 75.9% in Kyrgyzstan and 81.8% in Tajikistan. However, Russian
5900-413: The Constitution of Tajikistan and is permitted in official documentation. 28% of the population was fluent in Russian in 2006, and 7% used it as the main language with family, friends or at work. The World Factbook notes that Russian is widely used in government and business. In Turkmenistan , Russian lost its status as the official lingua franca in 1996. Among 12% of the population who grew up in
6018-584: The Ukrainian language in more than 30 spheres of public life: in particular in public administration , media, education, science, culture, advertising, services . The law does not regulate private communication. A poll conducted in March 2022 by RATING in the territory controlled by Ukraine found that 83% of the respondents believe that Ukrainian should be the only state language of Ukraine. This opinion dominates in all macro-regions, age and language groups. On
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#17327875524966136-641: The United States Census , in 2007 Russian was the primary language spoken in the homes of over 850,000 individuals living in the United States. Russian is one of the official languages (or has similar status and interpretation must be provided into Russian) of the following: The Russian language is also one of two official languages aboard the International Space Station – NASA astronauts who serve alongside Russian cosmonauts usually take Russian language courses. This practice goes back to
6254-407: The hovercraft in lacking low-speed hover capability in much the same way that a fixed-wing airplane differs from the helicopter . Unlike the hydrofoil , it does not have any contact with the surface of the water when in "flight". The ground-effect vehicle constitutes a unique class of transportation. The Boston-based (United States) company REGENT proposed an electric-powered high-wing design with
6372-410: The wingspan is higher, or for wings with wingtip devices . The total aerodynamic force acting on a body is usually thought of as having two components, lift and drag. By definition, the component of force parallel to the oncoming flow is called drag ; and the component perpendicular to the oncoming flow is called lift . At practical angles of attack the lift greatly exceeds the drag. Lift
6490-541: The 1920s, the ground effect phenomenon was well-known, as pilots found that their airplanes appeared to become more efficient as they neared the runway surface during landing. In 1934 the US National Advisory Committee for Aeronautics issued Technical Memorandum 771, Ground Effect on the Takeoff and Landing of Airplanes , which was a translation into English of a summary of French research on
6608-468: The 20th century, Russian was a mandatory language taught in the schools of the members of the old Warsaw Pact and in other countries that used to be satellites of the USSR. According to the Eurobarometer 2005 survey, fluency in Russian remains fairly high (20–40%) in some countries, in particular former Warsaw Pact countries. In Armenia , Russian has no official status, but it is recognized as
6726-471: The Belarusian society the Russian language prevails, so according to the 2019 census 6,718,557 people (71.4% of the total population) stated that they speak Russian at home, for ethnic Belarusians this share is 61.4%, for Russians — 97.2%, for Ukrainians — 89.0%, for Poles — 52.4%, and for Jews — 96.6%; 2,447,764 people (26.0% of the total population) stated that the language they usually speak at home
6844-571: The Black Sea and Baltic Sea fleets. A few Orlyonoks served with the Soviet Navy from 1979 to 1992. In 1987, the 400-tonne Lun -class ekranoplan was built as an anti-ship missile launch platform. A second Lun , renamed Spasatel , was laid down as a rescue vessel, but was never finished. The two major problems that the Soviet ekranoplans faced were poor longitudinal stability and
6962-661: The FS-8 carried six persons. The FS-8 was to be developed by Fischer Flugmechanik for a Singapore-Australian joint venture called Flightship. Powered by a V8 Chevrolet automobile engine rated at 337 kW, the prototype made its first flight in February 2001 in the Netherlands. The company no longer exists but the prototype craft was bought by Wigetworks, a company based in Singapore and renamed as AirFish 8. In 2010, that vehicle
7080-692: The GEV in a shipyard in southern Iran. The GEV has two engines and no armament. In Singapore, Wigetworks obtained certification from Lloyd's Register for entry into class. On 31 March 2011, AirFish 8-001 became one of the first GEVs to be flagged with the Singapore Registry of Ships, one of the largest ship registries. Wigetworks partnered with National University of Singapore 's Engineering Department to develop higher capacity GEVs. Burt Rutan in 2011 and Korolev in 2015 showed GEV projects. In Korea, Wing Ship Technology Corporation developed and tested
7198-532: The Great and developed from the Moscow ( Middle or Central Russian ) dialect substratum under the influence of some of the previous century's Russian chancery language. Prior to the Bolshevik Revolution , the spoken form of the Russian language was that of the nobility and the urban bourgeoisie. Russian peasants, the great majority of the population, continued to speak in their own dialects. However,
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#17327875524967316-590: The Institute of Russian Language of the Russian Academy of Sciences, an optional acute accent ( знак ударения ) may, and sometimes should, be used to mark stress . For example, it is used to distinguish between otherwise identical words, especially when context does not make it obvious: замо́к ( zamók – "lock") – за́мок ( zámok – "castle"), сто́ящий ( stóyashchy – "worthwhile") – стоя́щий ( stoyáshchy – "standing"), чудно́ ( chudnó – "this
7434-526: The Middle East and North Africa – 1.3 million, Sub-Saharan Africa – 0.1 million, Latin America – 0.2 million, U.S., Canada , Australia, and New Zealand – 4.1 million speakers. Therefore, the Russian language is the seventh-largest in the world by the number of speakers , after English, Mandarin, Hindi -Urdu, Spanish, French, Arabic, and Portuguese. Russian is one of the six official languages of
7552-500: The Russian Lun and Dingo , have used forced blowing under the wing by auxiliary engines to increase the high pressure area under the wing to assist the takeoff; however they differ from hovercraft in still requiring forward motion to generate sufficient lift to fly. Although the GEV may look similar to the seaplane and share many technical characteristics, it is generally not designed to fly out of ground effect. It differs from
7670-807: The Russian alphabet include ⟨ ѣ ⟩ , which merged to ⟨ е ⟩ ( /je/ or /ʲe/ ); ⟨ і ⟩ and ⟨ ѵ ⟩ , which both merged to ⟨ и ⟩ ( /i/ ); ⟨ ѳ ⟩ , which merged to ⟨ ф ⟩ ( /f/ ); ⟨ ѫ ⟩ , which merged to ⟨ у ⟩ ( /u/ ); ⟨ ѭ ⟩ , which merged to ⟨ ю ⟩ ( /ju/ or /ʲu/ ); and ⟨ ѧ ⟩ and ⟨ ѩ ⟩ , which later were graphically reshaped into ⟨ я ⟩ and merged phonetically to /ja/ or /ʲa/ . While these older letters have been abandoned at one time or another, they may be used in this and related articles. The yers ⟨ ъ ⟩ and ⟨ ь ⟩ originally indicated
7788-458: The Russian principalities before and especially during Mongol rule. This strengthened dialectal differences, and for a while, prevented the emergence of a standardized national language. The formation of the unified and centralized Russian state in the 15th and 16th centuries, and the gradual re-emergence of a common political, economic, and cultural space created the need for a common standard language. The initial impulse for standardization came from
7906-405: The Soviet era can speak Russian, other generations of citizens that do not have any knowledge of Russian. Primary and secondary education by Russian is almost non-existent. In Uzbekistan , Russian is the language of inter-ethnic communication. It has some official roles, being permitted in official documentation and is the lingua franca of the country and the language of the elite. Russian
8024-552: The US Defense Advanced Research Projects Agency (DARPA) launched its Liberty Lifter project, with the goal of creating a low-cost seaplane that would use the ground-effect to extend its range. The program aims to carry 90 tons over 6,500 nautical miles (12,000 km), operate at sea without ground-based maintenance, all using low-cost materials. In May 2024, Ocean Glider announced a deal with UK-based investor MONTE to finance $ 145m of
8142-467: The United Nations. Education in Russian is still a popular choice for both Russian as a second language (RSL) and native speakers in Russia, and in many former Soviet republics. Russian is still seen as an important language for children to learn in most of the former Soviet republics. In Belarus , Russian is a second state language alongside Belarusian per the Constitution of Belarus . 77% of
8260-842: The United States Defense Advanced Research Projects Agency (DARPA) studied the Aerocon Dash 1.6 wingship . Universal Hovercraft developed a flying hovercraft, first flying a prototype in 1996. Since 1999, the company has offered plans, parts, kits and manufactured ground effect hovercraft called the Hoverwing. Iran deployed three squadrons of Bavar 2 two-seat GEVs in September 2010. This GEV carries one machine gun and surveillance gear, and incorporates features to reduce its radar signature. In October 2014, satellite images showed
8378-399: The ability of hovercraft or hydrofoils, which are closer to the water surface. Like conventional aircraft, greater power is needed for takeoff, and, like seaplanes, ground-effect vehicles must get on the step before they can accelerate to flight speed. Careful design, usually with multiple redesigns of hullforms, is required to get this right, which increases engineering costs. This obstacle
8496-620: The airframe and the engines. The Russian ekranoplans show evidence of fixes for these problems in the form of multiple chines on the forward part of the hull undersides and in the forward location of the jet engines. Finally, limited utility has kept production levels low enough that it has been impossible to amortize development costs sufficiently to make GEVs competitive with conventional aircraft. A 2014 study by students at NASA's Ames Research Center claims that use of GEVs for passenger travel could lead to cheaper flights, increased accessibility and less pollution. One obstacle to GEV development
8614-403: The broader sense of expanding the use of Russian alongside or in favour of other languages. The current standard form of Russian is generally regarded as the modern Russian literary language ( современный русский литературный язык – "sovremenny russky literaturny yazyk"). It arose at the beginning of the 18th century with the modernization reforms of the Russian state under the rule of Peter
8732-426: The complications associated with a long and slender wing, so that the short stubs on a GEV can produce just as much lift as the much larger wing on a transport aircraft, though it can do this only when close to the earth's surface. Once sufficient speed has built up, some GEVs may be capable of leaving ground effect and functioning as normal aircraft until they approach their destination. The distinguishing characteristic
8850-572: The country. There is an Israeli TV channel mainly broadcasting in Russian with Israel Plus . See also Russian language in Israel . Russian is also spoken as a second language by a small number of people in Afghanistan . In Vietnam , Russian has been added in the elementary curriculum along with Chinese and Japanese and were named as "first foreign languages" for Vietnamese students to learn, on equal footing with English. The Russian language
8968-408: The development of appropriate design and structural configuration, automatic control and navigation systems have been developed. These include altimeters with high accuracy for low altitude flight and lesser dependence on weather conditions. "Phase radio altimeters " have become the choice for such applications beating laser altimeter , isotropic or ultrasonic altimeters . With Russian consultation,
9086-526: The distinction is a prominent feature of the language, which is usually shown in writing not by a change of the consonant but rather by changing the following vowel. Another important aspect is the reduction of unstressed vowels . Stress , which is often unpredictable, is not normally indicated orthographically , though an optional acute accent may be used to mark stress – such as to distinguish between homographic words (e.g. замо́к [ zamók , 'lock'] and за́мок [ zámok , 'castle']), or to indicate
9204-694: The eight-seat Volga-2 in 1985, and Technologies and Transport is developing a smaller version called the Amphistar. Beriev proposed a large craft of the type, the Be-2500, as a "flying ship" cargo carrier, but nothing came of the project. In Germany, Lippisch was asked to build a very fast boat for American businessman Arthur A. Collins . In 1963 Lippisch developed the X-112 , a revolutionary design with reversed delta wing and T-tail. This design proved to be stable and efficient in ground effect, and even though it
9322-511: The elliptical spanwise distribution of lift produces the minimum induced drag for a planar wing of a given span. A small number of aircraft have a planform approaching the elliptical — the most famous examples being the World War II Spitfire and Thunderbolt . For modern wings with winglets, the ideal lift distribution is not elliptical. For a given wing area, a high aspect ratio wing will produce less induced drag than
9440-408: The equations above, for wings generating the same lift, the induced drag is inversely proportional to the square of the wingspan . A wing of infinite span and uniform airfoil segment (or a 2D wing) would experience no induced drag. The drag characteristics of a wing with infinite span can be simulated using an airfoil segment the width of a wind tunnel . An increase in wingspan or a solution with
9558-413: The factory and the industrial plant their local peasant dialects with their phonetics, grammar, and vocabulary, and the very process of recruiting workers from peasants and the mobility of the worker population generate another process: the liquidation of peasant inheritance by way of leveling the particulars of local dialects. On the ruins of peasant multilingual, in the context of developing heavy industry,
9676-456: The final reading amendments that state that all schools and kindergartens in the country are to transition to education in Latvian . From 2025, all children will be taught in Latvian only. On 28 September 2023, Latvian deputies approved The National Security Concept, according to which from 1 January 2026, all content created by Latvian public media (including LSM ) should be only in Latvian or
9794-631: The generation of immigrants who started arriving in the early 1960s). Only about 25% of them are ethnic Russians, however. Before the dissolution of the Soviet Union , the overwhelming majority of Russophones in Brighton Beach, Brooklyn in New York City were Russian-speaking Jews. Afterward, the influx from the countries of the former Soviet Union changed the statistics somewhat, with ethnic Russians and Ukrainians immigrating along with some more Russian Jews and Central Asians. According to
9912-480: The government bureaucracy for the lack of a reliable tool of communication in administrative, legal, and judicial affairs became an obvious practical problem. The earliest attempts at standardizing Russian were made based on the so-called Moscow official or chancery language, during the 15th to 17th centuries. Since then, the trend of language policy in Russia has been standardization in both the restricted sense of reducing dialectical barriers between ethnic Russians, and
10030-515: The lift slope difference between a front low wing in ground-effect (commonly the main wing) and an aft, higher-located second wing nearly out of ground-effect (generally named a stabilizer). Developed by Alexander Lippisch , this wing allows stable flight in ground-effect through self-stabilization. This is the main Class B form of GEV. Tandem wings can have three configurations: Given similar hull size and power, and depending on its specific design,
10148-459: The lower lift-induced drag of a GEV, as compared to an aircraft of similar capacity, will improve its fuel efficiency and, up to a point, its speed. GEVs are also much faster than surface vessels of similar power, because they avoid drag from the water. On the water the aircraft-like construction of GEVs increases the risk of damage in collisions with surface objects. Furthermore, the limited number of egress points make it more difficult to evacuate
10266-524: The northwestern Xinjiang Uyghur Autonomous Region . Russian was also the main foreign language taught in school in China between 1949 and 1964. In Kazakhstan , Russian is not a state language, but according to article 7 of the Constitution of Kazakhstan its usage enjoys equal status to that of the Kazakh language in state and local administration. The 2009 census reported that 10,309,500 people, or 84.8% of
10384-515: The other hand, before the war, almost a quarter of Ukrainians were in favour of granting Russian the status of the state language, while after the beginning of Russia's invasion the support for the idea dropped to just 7%. In peacetime, the idea of raising the status of Russian was traditionally supported by residents of the south and east . But even in these regions, only a third of the respondents were in favour, and after Russia's full-scale invasion , their number dropped by almost half. According to
10502-461: The other three languages in the East Slavic branch. In many places in eastern and southern Ukraine and throughout Belarus, these languages are spoken interchangeably, and in certain areas traditional bilingualism resulted in language mixtures such as Surzhyk in eastern Ukraine and Trasianka in Belarus. An East Slavic Old Novgorod dialect , although it vanished during the 15th or 16th century,
10620-446: The parliament approved a bill to close up all Russian language schools and kindergartens by the school year. The transition to only Estonian language schools and kindergartens will start in the 2024-2025 school year. In Latvia , Russian is officially considered a foreign language. 55% of the population was fluent in Russian in 2006, and 26% used it as the main language with family, friends, or at work. On 18 February 2012, Latvia held
10738-453: The peasants' speech was never systematically studied, as it was generally regarded by philologists as simply a source of folklore and an object of curiosity. This was acknowledged by the noted Russian dialectologist Nikolai Karinsky , who toward the end of his life wrote: "Scholars of Russian dialects mostly studied phonetics and morphology. Some scholars and collectors compiled local dictionaries. We have almost no studies of lexical material or
10856-459: The population aged 15 and above, could read and write well in Russian, and understand the spoken language. In October 2023, Kazakhstan drafted a media law aimed at increasing the use of the Kazakh language over Russian, the law stipulates that the share of the state language on television and radio should increase from 50% to 70%, at a rate of 5% per year, starting in 2025. In Kyrgyzstan , Russian
10974-418: The population was fluent in Russian in 2006, and 67% used it as the main language with family, friends, or at work. According to the 2019 Belarusian census , out of 9,413,446 inhabitants of the country, 5,094,928 (54.1% of the total population) named Belarusian as their native language, with 61.2% of ethnic Belarusians and 54.5% of ethnic Poles declaring Belarusian as their native language. In everyday life in
11092-431: The power required to increase with increasing airspeed.) Induced drag must be added to the parasitic drag to find the total drag. Since induced drag is inversely proportional to the square of the airspeed (at a given lift) whereas parasitic drag is proportional to the square of the airspeed, the combined overall drag curve shows a minimum at some airspeed - the minimum drag speed (V MD ). An aircraft flying at this speed
11210-479: The pronunciation of ultra-short or reduced /ŭ/ , /ĭ/ . Because of many technical restrictions in computing and also because of the unavailability of Cyrillic keyboards abroad, Russian is often transliterated using the Latin alphabet. For example, мороз ('frost') is transliterated moroz , and мышь ('mouse'), mysh or myš' . Once commonly used by the majority of those living outside Russia, transliteration
11328-472: The proper pronunciation of uncommon words or names. Russian is an East Slavic language of the wider Indo-European family . It is a descendant of Old East Slavic , a language used in Kievan Rus' , which was a loose conglomerate of East Slavic tribes from the late 9th to the mid-13th centuries. From the point of view of spoken language , its closest relatives are Ukrainian , Belarusian , and Rusyn ,
11446-491: The respondents), while according to the 2002 census – 142.6 million people (99.2% of the respondents). In Ukraine , Russian is a significant minority language. According to estimates from Demoskop Weekly, in 2004 there were 14,400,000 native speakers of Russian in the country, and 29 million active speakers. 65% of the population was fluent in Russian in 2006, and 38% used it as the main language with family, friends, or at work. On 5 September 2017, Ukraine's Parliament passed
11564-424: The same airspeed and the same angle of attack, plates with higher aspect ratio produced greater lift and experienced lower drag than those with lower aspect ratio. His experiments were carried out at relatively low airspeeds, slower than the speed for minimum drag. He observed that, at these low airspeeds, increasing speed required reducing power. (At higher airspeeds, parasitic drag came to dominate, causing
11682-414: The same amount of fuel. If the plane is flying at the maximum permissible speed, then there is an altitude at which the air density will be sufficient to keep it aloft while flying at the angle of attack that minimizes the drag. The optimum altitude will increase during the flight as the plane becomes lighter. The speed for maximum endurance (i.e. time in the air) is the speed for minimum fuel flow rate, and
11800-436: The sea) by making use of ground effect , the aerodynamic interaction between the moving wing and the surface below. Some models can operate over any flat area such as frozen lakes or flat plains similar to a hovercraft . A ground-effect vehicle needs some forward velocity to produce lift dynamically, and the principal benefit of operating a wing in ground effect is to reduce its lift-dependent drag . The basic design principle
11918-567: The six official languages of the United Nations , as well as the fourth most widely used language on the Internet . Russian is written using the Russian alphabet of the Cyrillic script ; it distinguishes between consonant phonemes with palatal secondary articulation and those without—the so-called "soft" and "hard" sounds. Almost every consonant has a hard or soft counterpart, and
12036-445: The square of the equivalent airspeed; and inversely with the square of the wingspan. Deviation from the non-planar wing with elliptical lift distribution are taken into account by dividing the induced drag by the span efficiency factor e {\displaystyle e} . To compare with other sources of drag, it can be convenient to express this equation in terms of lift and drag coefficients: and This indicates how, for
12154-421: The subject. The French author Maurice Le Sueur had added a suggestion based on this phenomenon: "Here the imagination of inventors is offered a vast field. The ground interference reduces the power required for level flight in large proportions, so here is a means of rapid and at the same time economic locomotion: Design an airplane which is always within the ground-interference zone. At first glance this apparatus
12272-501: The support of Minister of Defence Dmitriy Ustinov . It produced the most successful ekranoplan so far, the 125-tonne A-90 Orlyonok . These craft were originally developed as high-speed military transports and were usually based on the shores of the Caspian Sea and Black Sea . The Soviet Navy ordered 120 Orlyonok -class ekranoplans , but this figure was later reduced to fewer than 30 vessels, with planned deployment mainly in
12390-679: The survey carried out by RATING in August 2023 in the territory controlled by Ukraine and among the refugees, almost 60% of the polled usually speak Ukrainian at home, about 30% – Ukrainian and Russian, only 9% – Russian. Since March 2022, the use of Russian in everyday life has been noticeably decreasing. For 82% of respondents, Ukrainian is their mother tongue, and for 16%, Russian is their mother tongue. IDPs and refugees living abroad are more likely to use both languages for communication or speak Russian. Nevertheless, more than 70% of IDPs and refugees consider Ukrainian to be their native language. In
12508-459: The syntax of Russian dialects." After 1917, Marxist linguists had no interest in the multiplicity of peasant dialects and regarded their language as a relic of the rapidly disappearing past that was not worthy of scholarly attention. Nakhimovsky quotes the Soviet academicians A.M Ivanov and L.P Yakubinsky, writing in 1930: The language of peasants has a motley diversity inherited from feudalism. On its way to becoming proletariat peasantry brings to
12626-786: The two. Others divide the language into three groupings, Northern , Central (or Middle), and Southern , with Moscow lying in the Central region. The Northern Russian dialects and those spoken along the Volga River typically pronounce unstressed /o/ clearly, a phenomenon called okanye ( оканье ). Besides the absence of vowel reduction, some dialects have high or diphthongal /e⁓i̯ɛ/ in place of Proto-Slavic * ě and /o⁓u̯ɔ/ in stressed closed syllables (as in Ukrainian) instead of Standard Russian /e/ and /o/ , respectively. Another Northern dialectal morphological feature
12744-511: The use of the language has some presence in certain areas. A large part of the population, especially the older generations, can speak Russian as a foreign language. However, English has replaced Russian as lingua franca in Lithuania and around 80% of young people speak English as their first foreign language. In contrast to the other two Baltic states, Lithuania has a relatively small Russian-speaking minority (5.0% as of 2008). According to
12862-736: The vehicle in an emergency. Since most GEVs are designed to operate from water, accidents and engine failure typically are less hazardous than in a land-based aircraft, but the lack of altitude control leaves the pilot with fewer options for avoiding collision, and to some extent that negates such benefits. Low altitude brings high-speed craft into conflict with ships, buildings and rising land, which may not be sufficiently visible in poor conditions to avoid. GEVs may be unable to climb over or turn sharply enough to avoid collisions, while drastic, low-level maneuvers risk contact with solid or water hazards beneath. Aircraft can climb over most obstacles, but GEVs are more limited. In high winds, take-off must be into
12980-421: The wind, which takes the craft across successive lines of waves, causing heavy pounding, stressing the craft and creating an uncomfortable ride. In light winds, waves may be in any direction, which can make control difficult as each wave causes the vehicle to both pitch and roll. The lighter construction of GEVs makes their ability to operate in higher sea states less than that of conventional ships, but greater than
13098-438: The wing is at a higher pressure than the air pressure above the wing. On a wing of finite span, this pressure difference causes air to flow from the lower surface, around the wingtip, towards the upper surface. This spanwise flow of air combines with chordwise flowing air, which twists the airflow and produces vortices along the wing trailing edge. The vortices reduce the wing's ability to generate lift, so that it requires
13216-576: Was developed during his consultancy period in South Africa. It was a simple and low-cost design of a first 4-seater tandem-airfoil flairboat completely constructed of aluminium. The prototype was in the SAAF Port Elizabeth Museum from 4 July 2007 until 2013, and is now in private use. Pictures of the museum show the boat after some years outside the museum and without protection against the sun. The consultancy of Günther Jörg,
13334-405: Was first introduced in North America when Russian explorers voyaged into Alaska and claimed it for Russia during the 18th century. Although most Russian colonists left after the United States bought the land in 1867, a handful stayed and preserved the Russian language in this region to this day, although only a few elderly speakers of this unique dialect are left. In Nikolaevsk, Alaska , Russian
13452-421: Was fluent in Russian in 2006, and 19% used it as the main language with family, friends, or at work. According to the 2014 Moldovan census , Russians accounted for 4.1% of Moldova's population, 9.4% of the population declared Russian as their native language, and 14.5% said they usually spoke Russian. According to the 2010 census in Russia , Russian language skills were indicated by 138 million people (99.4% of
13570-548: Was registered as a ship in the Singapore Registry of Ships. The University of Duisburg-Essen is supporting an ongoing research project to develop the Hoverwing . German engineer Günther Jörg, who had worked on Alexeyev's first designs and was familiar with the challenges of GEV design, developed a GEV with two wings in a tandem arrangement, the Jörg-II. It was the third, manned, tandem-airfoil boat, named "Skimmerfoil", which
13688-663: Was successfully tested, Collins decided to stop the project and sold the patents to the German company Rhein Flugzeugbau (RFB), which further developed the inverse delta concept into the X-113 and the six-seat X-114 . These craft could be flown out of ground effect so that, for example, peninsulas could be overflown. Hanno Fischer took over the works from RFB and created his own company, Fischer Flugmechanik, which eventually completed two models. The Airfisch 3 carried two persons, and
13806-673: Was the de facto and de jure official language of the former Soviet Union . Russian has remained an official language of the Russian Federation , Belarus , Kazakhstan , Kyrgyzstan , and Tajikistan , and is still commonly used as a lingua franca in Ukraine , Moldova , the Caucasus , Central Asia , and to a lesser extent in the Baltic states and Israel . Russian has over 258 million total speakers worldwide. It
13924-402: Was the sixth-most used language on the top 1,000 sites, behind English, Chinese, French, German, and Japanese. Despite leveling after 1900, especially in matters of vocabulary and phonetics, a number of dialects still exist in Russia. Some linguists divide the dialects of Russian into two primary regional groupings, "Northern" and "Southern", with Moscow lying on the zone of transition between
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