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140-433: The Tupolev Tu-154 ( Russian : Tyполев Ту-154 ; NATO reporting name : " Careless ") is a three-engined , medium-range , narrow-body airliner designed in the mid-1960s and manufactured by Tupolev . A workhorse of Soviet and (subsequently) Russian airlines for several decades, it carried half of all passengers flown by Aeroflot and its subsidiaries (137.5 million/year or 243.8 billion passenger-km in 1990), remaining

280-674: 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

420-651: 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 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

560-519: 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

700-419: A discordant nature known as "buzz saw" noise. All modern turbofan engines have acoustic liners in the nacelle to damp their noise. They extend as much as possible to cover the largest surface area. The acoustic performance of the engine can be experimentally evaluated by means of ground tests or in dedicated experimental test rigs. In the aerospace industry, chevrons are the "saw-tooth" patterns on

840-410: A fixed total applied fuel:air ratio, the total fuel flow for a given fan airflow will be the same, regardless of the dry specific thrust of the engine. However, a high specific thrust turbofan will, by definition, have a higher nozzle pressure ratio, resulting in a higher afterburning net thrust and, therefore, a lower afterburning specific fuel consumption (SFC). However, high specific thrust engines have

980-667: 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) Low-bypass turbofan The ratio of the mass-flow of air bypassing the engine core to the mass-flow of air passing through the core is referred to as the bypass ratio . The engine produces thrust through a combination of these two portions working together. Engines that use more jet thrust relative to fan thrust are known as low-bypass turbofans ; conversely those that have considerably more fan thrust than jet thrust are known as high-bypass . Most commercial aviation jet engines in use are of

1120-558: A hard or soft counterpart, and 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

1260-426: A high dry SFC. The situation is reversed for a medium specific thrust afterburning turbofan: i.e., poor afterburning SFC/good dry SFC. The former engine is suitable for a combat aircraft which must remain in afterburning combat for a fairly long period, but has to fight only fairly close to the airfield (e.g. cross border skirmishes). The latter engine is better for an aircraft that has to fly some distance, or loiter for

1400-416: A higher nozzle pressure ratio than the turbojet, but with a lower exhaust temperature to retain net thrust. Since the temperature rise across the whole engine (intake to nozzle) would be lower, the (dry power) fuel flow would also be reduced, resulting in a better specific fuel consumption (SFC). Some low-bypass ratio military turbofans (e.g. F404 , JT8D ) have variable inlet guide vanes to direct air onto

1540-484: 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

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1680-588: 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

1820-590: A long time, before going into combat. However, the pilot can afford to stay in afterburning only for a short period, before aircraft fuel reserves become dangerously low. The first production afterburning turbofan engine was the Pratt & Whitney TF30 , which initially powered the F-111 Aardvark and F-14 Tomcat . Low-bypass military turbofans include the Pratt & Whitney F119 , the Eurojet EJ200 ,

1960-622: 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

2100-401: A pound of thrust, more fuel is wasted in the faster propelling jet. In other words, the independence of thermal and propulsive efficiencies, as exists with the piston engine/propeller combination which preceded the turbojet, is lost. In contrast, Roth considers regaining this independence the single most important feature of the turbofan which allows specific thrust to be chosen independently of

2240-403: A pure-jet of the same thrust, and jet noise is no longer the predominant source. Turbofan engine noise propagates both upstream via the inlet and downstream via the primary nozzle and the by-pass duct. Other noise sources are the fan, compressor and turbine. Modern commercial aircraft employ high-bypass-ratio (HBPR) engines with separate flow, non-mixing, short-duct exhaust systems. Their noise

2380-526: 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

2520-461: A relatively high thrust-to-weight ratio , giving the type excellent performance, though at the expense of lower fuel efficiency . This became an important factor in later decades as fuel costs grew. The cockpit is fitted with conventional dual yoke control columns . Flight control surfaces are hydraulically operated. The cabin of the Tu-154, although of the same six-abreast seating layout, gives

2660-569: A static thrust of 4,320 lb (1,960 kg), and had a bypass ratio of 6:1. The General Electric TF39 became the first production model, designed to power the Lockheed C-5 Galaxy military transport aircraft. The civil General Electric CF6 engine used a derived design. Other high-bypass turbofans are the Pratt & Whitney JT9D , the three-shaft Rolls-Royce RB211 and the CFM International CFM56 ; also

2800-473: A turbofan engine is the ratio between the mass flow rate of the bypass stream to the mass flow rate entering the core. A bypass ratio of 6, for example, means that 6 times more air passes through the bypass duct than the amount that passes through the combustion chamber. Turbofan engines are usually described in terms of BPR, which together with overall pressure ratio, turbine inlet temperature and fan pressure ratio are important design parameters. In addition BPR

2940-421: A turbojet engine uses all of the engine's output to produce thrust in the form of a hot high-velocity exhaust gas jet, a turbofan's cool low-velocity bypass air yields between 30% and 70% of the total thrust produced by a turbofan system. The thrust ( F N ) generated by a turbofan depends on the effective exhaust velocity of the total exhaust, as with any jet engine, but because two exhaust jets are present

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3080-496: A turbojet even though an extra turbine, a gearbox and a propeller are added to the turbojet's low-loss propelling nozzle. The turbofan has additional losses from its greater number of compressor stages/blades, fan and bypass duct. Froude, or propulsive, efficiency can be defined as: η f = 2 1 + V j V a {\displaystyle \eta _{f}={\frac {2}{1+{\frac {V_{j}}{V_{a}}}}}} where: While

3220-704: A turbojet which accelerates a smaller amount more quickly, which is a less efficient way to generate the same thrust (see the efficiency section below). The ratio of the mass-flow of air bypassing the engine core compared to the mass-flow of air passing through the core is referred to as the bypass ratio . Engines with more jet thrust relative to fan thrust are known as low-bypass turbofans , those that have considerably more fan thrust than jet thrust are known as high-bypass . Most commercial aviation jet engines in use are high-bypass, and most modern fighter engines are low-bypass. Afterburners are used on low-bypass turbofans on combat aircraft. The bypass ratio (BPR) of

3360-539: 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,

3500-481: 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

3640-401: 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

3780-610: 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

3920-613: Is becoming obsolete with the retirement of the oldest Soviet-era planes. The latest variant (Tu-154M-100, introduced 1998) includes an NVU-B3 Doppler navigation system, a triple autopilot , which provides an automatic ILS approach according to ICAO category II weather minima, an autothrottle , a Doppler drift and speed measure system, and a "Kurs-MP" radio navigation suite. A stability and control augmentation system improves handling characteristics during manual flight. Modern upgrades normally include modernised TCAS , GPS , and other systems (mostly American- or EU-made). Early versions of

4060-488: 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

4200-507: Is best suited to high supersonic speeds. If it is all transferred to a separate big mass of air with low kinetic energy, the aircraft is best suited to zero speed (hovering). For speeds in between, the gas power is shared between a separate airstream and the gas turbine's own nozzle flow in a proportion which gives the aircraft performance required. The trade off between mass flow and velocity is also seen with propellers and helicopter rotors by comparing disc loading and power loading. For example,

4340-624: 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

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4480-410: Is considerable potential for reducing fuel consumption for the same core cycle by increasing BPR.This is achieved because of the reduction in pounds of thrust per lb/sec of airflow (specific thrust) and the resultant reduction in lost kinetic energy in the jets (increase in propulsive efficiency). If all the gas power from a gas turbine is converted to kinetic energy in a propelling nozzle, the aircraft

4620-430: Is due to the speed, temperature, and pressure of the exhaust jet, especially during high-thrust conditions, such as those required for takeoff. The primary source of jet noise is the turbulent mixing of shear layers in the engine's exhaust. These shear layers contain instabilities that lead to highly turbulent vortices that generate the pressure fluctuations responsible for sound. To reduce the noise associated with jet flow,

4760-573: 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

4900-564: 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

5040-521: Is powered by three rear-mounted, low-bypass turbofan engines arranged similarly to those of the Boeing 727 , but it is slightly larger than its American counterpart. Both the 727 and the Tu-154 use an S-duct for the middle (number-two) engine. The original model was equipped with Kuznetsov NK-8-2 engines, which were replaced with Soloviev D-30KU-154s in the Tu-154M. All Tu-154 aircraft models have

5180-413: Is quoted for turboprop and unducted fan installations because their high propulsive efficiency gives them the overall efficiency characteristics of very high bypass turbofans. This allows them to be shown together with turbofans on plots which show trends of reducing specific fuel consumption (SFC) with increasing BPR. BPR can also be quoted for lift fan installations where the fan airflow is remote from

5320-402: 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

5460-569: 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

5600-585: 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

5740-420: Is sufficient core power to drive the fan. A smaller core flow/higher bypass ratio cycle can be achieved by raising the inlet temperature of the high-pressure (HP) turbine rotor. To illustrate one aspect of how a turbofan differs from a turbojet, comparisons can be made at the same airflow (to keep a common intake for example) and the same net thrust (i.e. same specific thrust). A bypass flow can be added only if

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5880-424: Is that combustion is less efficient at lower speeds. Any action to reduce the fuel consumption of the engine by increasing its pressure ratio or turbine temperature to achieve better combustion causes a corresponding increase in pressure and temperature in the exhaust duct which in turn cause a higher gas speed from the propelling nozzle (and higher KE and wasted fuel). Although the engine would use less fuel to produce

6020-518: 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

6160-498: Is unlikely to come back into service, since the government operates a fleet of brand-new, more fuel-efficient jets like the Gulfstream G550 and the Boeing 737 NG . In 2020 it was revealed by the investigation team, led by Antoni Macierewicz , that the aircraft was structurally damaged. The access to the aircraft was restricted by the general prosecutor, and entering its hangar requires a special permission. As of June 2015,

6300-411: Is very fuel intensive. Consequently, afterburning can be used only for short portions of a mission. Unlike in the main engine, where stoichiometric temperatures in the combustor have to be reduced before they reach the turbine, an afterburner at maximum fuelling is designed to produce stoichiometric temperatures at entry to the nozzle, about 2,100 K (3,800 °R; 3,300 °F; 1,800 °C). At

6440-470: 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

6580-1000: 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

6720-657: 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 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

6860-479: The Bristol Olympus , and Pratt & Whitney JT3C engines, increased the overall pressure ratio and thus the thermodynamic efficiency of engines. They also had poor propulsive efficiency, because pure turbojets have a high specific thrust/high velocity exhaust, which is better suited to supersonic flight. The original low-bypass turbofan engines were designed to improve propulsive efficiency by reducing

7000-413: 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

7140-702: The General Electric F110 , the Klimov RD-33 , and the Saturn AL-31 , all of which feature a mixed exhaust, afterburner and variable area propelling nozzle. To further improve fuel economy and reduce noise, almost all jet airliners and most military transport aircraft (e.g., the C-17 ) are powered by low-specific-thrust/high-bypass-ratio turbofans. These engines evolved from the high-specific-thrust/low-bypass-ratio turbofans used in such aircraft in

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7280-570: The Russian Armed Forces . In October 2020 ALROSA , the last Russian passenger airline to operate this aircraft, retired its last remaining Tu-154. Latavio Between 1970 and December 2016 there were 110 serious incidents involving the Tu-154, including 73 hull losses, with 2,911 fatalities. Of the fatal incidents, five resulted from terrorist or military terrorist action (two other wartime losses were non-fatal), several from poor runway conditions in winter (including one in which

7420-575: The Russian Defence Ministry grounded all Tu-154s in Russia pending investigation into the 25 December 2016 Tupolev Tu-154 crash which killed 64 members of the Alexandrov Ensemble , an official Red Army Choir of the Russian Armed Forces . Related development Aircraft of comparable role, configuration, and era Related lists Russian language Russian is an East Slavic language belonging to

7560-627: The Russian Ministry of Defence announced that it had grounded all of its Tu-154s until the end of the investigation into the December 2016 crash of a 1983 Tupolev Tu-154. This was followed by the grounding of all Tu-154s in Russia. The Tu-154 had crashed into the Black Sea just after takeoff from Sochi , Russia, on 25 December 2016 killing all 92 people on board, including 64 members of the Alexandrov Ensemble , an official army choir of

7700-584: 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

7840-721: 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

7980-667: The 154M model was still occurring as of January 2009, despite previous announcements of the end of production in 2006. In total, 1025 Tu-154s have been built, 214 of which were still in service as of 14 December 2009. The last serial Tu-154 was delivered to the Russian Defense Ministry on 19 February 2013 from the Aviakor factory, equipped with upgraded avionics, a VIP interior, and a communications suite. The factory has four unfinished airframes in its inventory, which can be completed if new orders are received. The Tu-154

8120-421: The 1960s. Modern combat aircraft tend to use low-bypass ratio turbofans, and some military transport aircraft use turboprops . Low specific thrust is achieved by replacing the multi-stage fan with a single-stage unit. Unlike some military engines, modern civil turbofans lack stationary inlet guide vanes in front of the fan rotor. The fan is scaled to achieve the desired net thrust. The core (or gas generator) of

8260-570: The 1970s and 1980s. The first project chief was Sergey Yeger  [ ru ] ; in 1964, Dmitryi S. Markov  [ ru ] assumed that position. In 1975, the project lead role was turned over to Aleksandr S. Shengardt  [ ru ] . The Tu-154 first flew on 4 October 1968. The first deliveries to Aeroflot were in 1970 with freight (mail) services beginning in May 1971 and passenger services in February 1972. Limited production of

8400-519: 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

8540-471: 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

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8680-532: 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,

8820-590: 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

8960-526: 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

9100-807: 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

9240-458: 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

9380-458: 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

9520-661: The Tu-154 (B variant) until the fatal fire incident in Surgut had been investigated. Its operation in Iran ceased in February 2011 due to a number of crashes and incidents involving the type (almost 9% of all Tu-154 losses have occurred in Iran). This grounding compounded the effects of US embargo on civil aircraft parts, substantially decreasing the number of airworthy aircraft in the Iranian civil fleet. In 2010 there were two fatal losses of

9660-516: The Tu-154 cannot be modified to meet the current Stage III noise regulations , so are no longer allowed to fly into airspace where such regulations are enforced, such as the European Union, but the Tu-154M's D-30 engines can be fitted with hush kits , allowing them to meet noise regulations. Many variants of this airliner have been built. Like its Western counterpart, the Boeing 727, many of

9800-540: The Tu-154 due to pilot error and/or weather conditions (a Polish presidential jet attempting a rural airfield landing in heavy fog, the 2010 Polish Air Force Tu-154 crash , and a Russian-registered plane that suffered engine stall after a crew member accidentally de-activated a fuel transfer pump). Following these accidents, in March 2011 the Russian Federal Bureau of Aviation recommended a withdrawal of remaining Tu-154Ms from service. On 27 December 2016,

9940-478: The Tu-154s in service have been hush-kitted, and some converted to freighters. As of August 2017, there were 44 Tupolev Tu-154 aircraft of all variants still in civil, governmental or military service. A 45th aircraft has been sighted flying with Air Kyrgyzstan in 2017, but is not listed by the airline as part of its fleet. A 46th aircraft, a Polish Tu-154 with operational number 102, is currently in storage at

10080-467: 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

10220-464: The aerospace industry has sought to disrupt shear layer turbulence and reduce the overall noise produced. Fan noise may come from the interaction of the fan-blade wakes with the pressure field of the downstream fan-exit stator vanes. It may be minimized by adequate axial spacing between blade trailing edge and stator entrance. At high engine speeds, as at takeoff, shock waves from the supersonic fan tips, because of their unequal nature, produce noise of

10360-422: The afterburner, raising the temperature of exhaust gases by a significant degree, resulting in a higher exhaust velocity/engine specific thrust. The variable geometry nozzle must open to a larger throat area to accommodate the extra volume and increased flow rate when the afterburner is lit. Afterburning is often designed to give a significant thrust boost for take off, transonic acceleration and combat maneuvers, but

10500-441: The aircraft is going forwards, leaving a very fast wake. This wake contains kinetic energy that reflects the fuel used to produce it, rather than the fuel used to move the aircraft forwards. A turbofan harvests that wasted velocity and uses it to power a ducted fan that blows air in bypass channels around the rest of the turbine. This reduces the speed of the propelling jet while pushing more air, and thus more mass. The other penalty

10640-516: The airplane struck snow plows on the runway), cargo overloading in the lapse of post-Soviet federal safety standards, and mid-air collisions due to faulty air traffic control . Other incidents resulted from mechanical problems, running out of fuel on unscheduled routes, pilot errors (including inadequate flight training for new crews), and cargo fires; several accidents remain unexplained. On 2 January 2011, Russia's Federal Transport Oversight Agency advised airlines to stop using remaining examples of

10780-474: The average stage loading and to maintain LP turbine efficiency. Reducing core flow also increases bypass ratio. Bypass ratios greater than 5:1 are increasingly common; the Pratt & Whitney PW1000G , which entered commercial service in 2016, attains 12.5:1. Further improvements in core thermal efficiency can be achieved by raising the overall pressure ratio of the core. Improvements in blade aerodynamics can reduce

10920-403: 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

11060-485: The contemporary Boeing 727 have dihedral (upward sweep). The anhedral means that Russian airliners have poor lateral stability compared to their Western counterparts, but also are more resistant to Dutch roll tendencies. Considerably heavier than its predecessor Soviet-built airliner, the Ilyushin Il-18 , the Tu-154 was equipped with an oversized landing gear to reduce ground load, enabling it to operate from

11200-572: 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

11340-448: The engine and doesn't flow past the engine core. Considering a constant core (i.e. fixed pressure ratio and turbine inlet temperature), core and bypass jet velocities equal and a particular flight condition (i.e. Mach number and altitude) the fuel consumption per lb of thrust (sfc) decreases with increase in BPR. At the same time gross and net thrusts increase, but by different amounts. There

11480-427: The engine must generate enough power to drive the fan at its rated mass flow and pressure ratio. Improvements in turbine cooling/material technology allow for a higher (HP) turbine rotor inlet temperature, which allows a smaller (and lighter) core, potentially improving the core thermal efficiency. Reducing the core mass flow tends to increase the load on the LP turbine, so this unit may require additional stages to reduce

11620-416: The engine, from the gas generator, to a ducted fan which produces a second, additional mass of accelerated air. The transfer of energy from the core to bypass air results in lower pressure and temperature gas entering the core nozzle (lower exhaust velocity), and fan-produced higher pressure and temperature bypass-air entering the fan nozzle. The amount of energy transferred depends on how much pressure rise

11760-524: The exhaust velocity to a value closer to that of the aircraft. The Rolls-Royce Conway , the world's first production turbofan, had a bypass ratio of 0.3, similar to the modern General Electric F404 fighter engine. Civilian turbofan engines of the 1960s, such as the Pratt & Whitney JT8D and the Rolls-Royce Spey , had bypass ratios closer to 1 and were similar to their military equivalents. The first Soviet airliner powered by turbofan engines

11900-413: 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,

12040-411: The fan is designed to produce (fan pressure ratio). The best energy exchange (lowest fuel consumption) between the two flows, and how the jet velocities compare, depends on how efficiently the transfer takes place which depends on the losses in the fan-turbine and fan. The fan flow has lower exhaust velocity, giving much more thrust per unit energy (lower specific thrust ). Both airstreams contribute to

12180-456: 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

12320-450: The first fan rotor stage. This improves the fan surge margin (see compressor map ). Since the 1970s, most jet fighter engines have been low/medium bypass turbofans with a mixed exhaust, afterburner and variable area exit nozzle. An afterburner is a combustor located downstream of the turbine blades and directly upstream of the nozzle, which burns fuel from afterburner-specific fuel injectors. When lit, large volumes of fuel are burnt in

12460-483: The fuel consumption of the turbojet. It achieves this by pushing more air, thus increasing the mass and lowering the speed of the propelling jet compared to that of the turbojet. This is done mechanically by adding a ducted fan rather than using viscous forces. A vacuum ejector is used in conjunction with the fan as first envisaged by inventor Frank Whittle . Whittle envisioned flight speeds of 500 mph in his March 1936 UK patent 471,368 "Improvements relating to

12600-400: The gas generator cycle. The working substance of the thermodynamic cycle is the only mass accelerated to produce thrust in a turbojet which is a serious limitation (high fuel consumption) for aircraft speeds below supersonic. For subsonic flight speeds the speed of the propelling jet has to be reduced because there is a price to be paid in producing the thrust. The energy required to accelerate

12740-443: The gas inside the engine (increase in kinetic energy) is expended in two ways, by producing a change in momentum ( i.e. a force), and a wake which is an unavoidable consequence of producing thrust by an airbreathing engine (or propeller). The wake velocity, and fuel burned to produce it, can be reduced and the required thrust still maintained by increasing the mass accelerated. A turbofan does this by transferring energy available inside

12880-692: 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

13020-480: 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

13160-429: The gross thrust of the engine. The additional air for the bypass stream increases the ram drag in the air intake stream-tube, but there is still a significant increase in net thrust. The overall effective exhaust velocity of the two exhaust jets can be made closer to a normal subsonic aircraft's flight speed and gets closer to the ideal Froude efficiency . A turbofan accelerates a larger mass of air more slowly, compared to

13300-409: The high-bypass type, and most modern fighter engines are low-bypass. Afterburners are used on low-bypass turbofan engines with bypass and core mixing before the afterburner. Modern turbofans have either a large single-stage fan or a smaller fan with several stages. An early configuration combined a low-pressure turbine and fan in a single rear-mounted unit. The turbofan was invented to improve

13440-474: The hot nozzle to convert to kinetic energy. Turbofans represent an intermediate stage between turbojets , which derive all their thrust from exhaust gases, and turbo-props which derive minimal thrust from exhaust gases (typically 10% or less). Extracting shaft power and transferring it to a bypass stream introduces extra losses which are more than made up by the improved propulsive efficiency. The turboprop at its best flight speed gives significant fuel savings over

13580-490: The impression of an oval interior, with a lower ceiling than is common on Boeing and Airbus airliners. The passenger cabin accommodates 128 passengers in a two-class layout and 164 passengers in single-class layout, and up to 180 passengers in high-density layout. The layout can be modified to a winter version where some seats are taken out and a wardrobe is installed for passenger coats. The passenger doors are smaller than on its Boeing and Airbus counterparts. Luggage space in

13720-417: The mechanical power produced by the turbine. In a bypass design, extra turbines drive a ducted fan that accelerates air rearward from the front of the engine. In a high-bypass design, the ducted fan and nozzle produce most of the thrust. Turbofans are closely related to turboprops in principle because both transfer some of the gas turbine's gas power, using extra machinery, to a bypass stream leaving less for

13860-578: The military airport in Mińsk Mazowiecki . It was operated by 36th Special Aviation Regiment , but after the 2010 Polish Air Force Tu-154 crash of the Tu-154 101, the Regiment has been disbanded and the plane was grounded. It was fully operational, but the government decided not to use or sell it until the investigation into the Smoleńsk crash is finished. As of June 2021 the aircraft is not flying, and it

14000-524: 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

14140-483: The number of extra compressor stages required, and variable geometry stators enable high-pressure-ratio compressors to work surge-free at all throttle settings. The first (experimental) high-bypass turbofan engine was the AVCO-Lycoming PLF1A-2, a Honeywell T55 turboshaft-derived engine that was first run in February 1962. The PLF1A-2 had a 40 in diameter (100 cm) geared fan stage, produced

14280-515: 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

14420-461: 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,

14560-517: The overhead compartments is very limited. Like the Tupolev Tu-134 , the Tu-154 has a wing swept back at 35° at the quarter- chord line. The British Hawker Siddeley Trident has the same sweepback angle, while the Boeing 727 has a slightly smaller sweepback angle of 32°. The wing also has anhedral (downward sweep) which is a distinguishing feature of Russian low-wing airliners designed during this era. Most Western low-wing airliners such as

14700-446: 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

14840-453: 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

14980-459: 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

15120-418: 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

15260-479: 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

15400-472: 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 ,

15540-414: The propulsion of aircraft", in which he describes the principles behind the turbofan, although not called as such at that time. While the turbojet uses the gas from its thermodynamic cycle as its propelling jet, for aircraft speeds below 500 mph there are two penalties to this design which are addressed by the turbofan. Firstly, energy is wasted as the propelling jet is going much faster rearwards than

15680-447: The remaining operators are: In January 2010 Russian flag carrier Aeroflot announced the retirement of its Tu-154 fleet after 40 years, with the last scheduled flight being Aeroflot Flight 736 from Yekaterinburg to Moscow on 31 December 2009. In December 2010, Uzbekistan Airways also declared that it was retiring its Tu-154s. In February 2011, all remaining Iranian Tu-154s were grounded after two incidents. On 27 December 2016,

15820-491: 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

15960-399: The same helicopter weight can be supported by a high power engine and small diameter rotor or, for less fuel, a lower power engine and bigger rotor with lower velocity through the rotor. Bypass usually refers to transferring gas power from a gas turbine to a bypass stream of air to reduce fuel consumption and jet noise. Alternatively, there may be a requirement for an afterburning engine where

16100-415: The same runways. The aircraft has two six-wheel main bogies fitted with large, low-pressure tires that retract into pods extending from the trailing edges of the wings (a common Tupolev feature), plus a two-wheel nose gear unit. Soft oleo struts ( shock absorbers ) provide a much smoother ride on bumpy airfields than most airliners, which very rarely operate on such poor surfaces. The original requirement

16240-502: The sole requirement for bypass is to provide cooling air. This sets the lower limit for BPR and these engines have been called "leaky" or continuous bleed turbojets (General Electric YJ-101 BPR 0.25) and low BPR turbojets (Pratt & Whitney PW1120). Low BPR (0.2) has also been used to provide surge margin as well as afterburner cooling for the Pratt & Whitney J58 . Propeller engines are most efficient for low speeds, turbojet engines for high speeds, and turbofan engines between

16380-430: The standard domestic-route airliner of Russia and former Soviet states until the mid-2000s. It was exported to 17 non-Russian airlines and used as a head-of-state transport by the air forces of several countries. The aircraft has a cruising speed of 850 km/h (460 kn; 530 mph) and a range of 5,280 km (3,280 mi). Capable of operating from unpaved and gravel airfields with only basic facilities, it

16520-679: 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

16660-459: 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

16800-536: The technology and materials available at the time. The first turbofan engine, which was only run on a test bed, was the German Daimler-Benz DB 670 , designated the 109-007 by the German RLM ( Ministry of Aviation ), with a first run date of 27 May 1943, after the testing of the turbomachinery using an electric motor, which had been undertaken on 1 April 1943. Development of the engine

16940-497: The thrust equation can be expanded as: F N = m ˙ e v h e − m ˙ o v o + B P R ( m ˙ c ) v f {\displaystyle F_{N}={\dot {m}}_{e}v_{he}-{\dot {m}}_{o}v_{o}+BPR\,({\dot {m}}_{c})v_{f}} where: The cold duct and core duct's nozzle systems are relatively complex due to

17080-673: The trailing edges of some jet engine nozzles that are used for noise reduction . The shaped edges smooth the mixing of hot air from the engine core and cooler air flowing through the engine fan, which reduces noise-creating turbulence. Chevrons were developed by GE under a NASA contract. Some notable examples of such designs are Boeing 787 and Boeing 747-8  – on the Rolls-Royce Trent 1000 and General Electric GEnx engines. Early turbojet engines were not very fuel-efficient because their overall pressure ratio and turbine inlet temperature were severely limited by

17220-428: The turbine inlet temperature is not too high to compensate for the smaller core flow. Future improvements in turbine cooling/material technology can allow higher turbine inlet temperature, which is necessary because of increased cooling air temperature, resulting from an overall pressure ratio increase. The resulting turbofan, with reasonable efficiencies and duct loss for the added components, would probably operate at

17360-476: The two flows may combine within the ducts, and share a common nozzle, which can be fitted with afterburner. Most of the air flow through a high-bypass turbofan is lower-velocity bypass flow: even when combined with the much-higher-velocity engine exhaust, the average exhaust velocity is considerably lower than in a pure turbojet. Turbojet engine noise is predominately jet noise from the high exhaust velocity. Therefore, turbofan engines are significantly quieter than

17500-786: 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

17640-418: The two. Turbofans are the most efficient engines in the range of speeds from about 500 to 1,000 km/h (270 to 540 kn; 310 to 620 mph), the speed at which most commercial aircraft operate. In a turbojet (zero-bypass) engine, the high temperature and high pressure exhaust gas is accelerated when it undergoes expansion through a propelling nozzle and produces all the thrust. The compressor absorbs

17780-511: 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

17920-510: The use of two separate exhaust flows. In high bypass engines, the fan is situated in a short duct near the front of the engine and typically has a convergent cold nozzle, with the tail of the duct forming a low pressure ratio nozzle that under normal conditions will choke creating supersonic flow patterns around the core . The core nozzle is more conventional, but generates less of the thrust, and depending on design choices, such as noise considerations, may conceivably not choke. In low bypass engines

18060-697: 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 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

18200-701: The world, with an experience base of over 10 million service hours. The CF700 turbofan engine was also used to train Moon-bound astronauts in Project Apollo as the powerplant for the Lunar Landing Research Vehicle . A high-specific-thrust/low-bypass-ratio turbofan normally has a multi-stage fan behind inlet guide vanes, developing a relatively high pressure ratio and, thus, yielding a high (mixed or cold) exhaust velocity. The core airflow needs to be large enough to ensure there

18340-614: Was abandoned with its problems unsolved, as the war situation worsened for Germany. Later in 1943, the British ground tested the Metrovick F.3 turbofan, which used the Metrovick F.2 turbojet as a gas generator with the exhaust discharging into a close-coupled aft-fan module comprising a contra-rotating LP turbine system driving two co-axial contra-rotating fans. Improved materials, and the introduction of twin compressors, such as in

18480-679: Was also stipulated as a requirement. Conceptually similar to the British Hawker Siddeley Trident , which first flew in 1962, and the American Boeing 727 , which first flew in 1963, the medium-range Tu-154 was marketed by Tupolev at the same time as Ilyushin was marketing its long-range Ilyushin Il-62 . The Soviet Ministry of Aircraft Industry chose the Tu-154, as it incorporated the latest in Soviet aircraft design and best met Aeroflot's anticipated requirements for

18620-660: Was derived from the General Electric J85/CJ610 turbojet 2,850 lbf (12,700 N) to power the larger Rockwell Sabreliner 75/80 model aircraft, as well as the Dassault Falcon 20 , with about a 50% increase in thrust to 4,200 lbf (19,000 N). The CF700 was the first small turbofan to be certified by the Federal Aviation Administration (FAA). There were at one time over 400 CF700 aircraft in operation around

18760-686: Was developed to meet Aeroflot's requirement to replace the jet -powered Tu-104 and the Antonov An-10 and Ilyushin Il-18 turboprops . The requirements called for either a payload capacity of 16–18 t (35,000–40,000 lb) with a range of 2,850–4,000 km (1,540–2,160 nmi) while cruising at 900 km/h (490 kn), or a payload of 5.8 t (13,000 lb) with a range of 5,800–7,000 km (3,100–3,800 nmi) while cruising at 850 km/h (460 kn). A take-off distance of 2,600 m (8,500 ft) at maximum takeoff weight

18900-405: 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

19040-421: 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

19180-587: Was the Tupolev Tu-124 introduced in 1962. It used the Soloviev D-20 . 164 aircraft were produced between 1960 and 1965 for Aeroflot and other Eastern Bloc airlines, with some operating until the early 1990s. The first General Electric turbofan was the aft-fan CJ805-23 , based on the CJ805-3 turbojet. It was followed by the aft-fan General Electric CF700 engine, with a 2.0 bypass ratio. This

19320-402: 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

19460-427: Was to have a three-person flight crew – captain , first officer , and flight engineer – as opposed to a four- or five-person crew, as on other Soviet airliners. A fourth crew member, a navigator , was soon found to be still needed, and a seat was added on production aircraft, although that workstation was compromised due to the limitations of the original design. Navigators are no longer trained, and this profession

19600-399: Was widely used in the extreme Arctic conditions of Russia's northern/eastern regions, where other airliners were unable to operate. Originally designed for a 45,000-hour service life (18,000 cycles), but capable of 80,000 hours with upgrades, it was expected to continue in service until 2016, although noise regulations have restricted flights to Western Europe and other regions. The Tu-154

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