In the end, though, all these improvements to turbofans lead simply to better turbofans.
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Turbofans are complicated beasts, put together from about 25,000 component parts.
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It has been making carbon-fibre blades for its turbofans since the 1990s.
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For larger aircraft, electric turbofans that are vastly more powerful—perhaps up 20MW—will be needed.
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These look like miniature versions of the turbofans on passenger jets, except they use electric motors.
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As with making large aircraft themselves, the business of building turbofans is confined to a few big firms.
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Both of these arrangements—and particularly turbofans—move more air, and thus create more thrust, than the turbojet within is capable of generating by itself.
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This aircraft will be powered by two rear-mounted 500kW electric turbofans (which turn a fan inside a shroud and so look a bit like jet engines).
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The turbofans will be supplied with electricity by a small jet-powered generator in the rear of the fuselage, which will also top up batteries contained in the wings.
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This is most commonly required for high- bypass turbofans with large diameter fans.
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The F101 also became the basis for the highly successful CFM56 series of civil turbofans.
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Schematic diagram illustrating the operation of a low-bypass turbofan engine. Turbofans differ from turbojets in that they have an additional fan at the front of the engine, which accelerates air in a duct bypassing the core gas turbine engine. Turbofans are the dominant engine type for medium and long-range airliners. Turbofans are usually more efficient than turbojets at subsonic speeds, but at high speeds their large frontal area generates more drag.
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Modern military turbofans also tend to use a single HP turbine stage and a modest HP compressor.
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Ducting on a Dassault/Dornier Alpha Jet – At subsonic speeds, the increasing diameter of the inlet duct slows incoming air, causing its static pressure to increase. Most of the configurations discussed above are used in civilian turbofans, while modern military turbofans (e.g., Snecma M88) are usually basic two-spool.
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A T-1A parked at Centennial Airport (2008) ;T-1A :United States military designation for the Model 400T powered by two JT15D-5B turbofans, 180 built. ;T-400 :Japanese military designation for the Model 400T powered by two JT15D-5F turbofans, also known by the project name TX; 13 built.
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To boost fuel economy and reduce noise, almost all of today's 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 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.
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It would be powered by three dry turbofans; a derivative or a clean-sheet design will be selected in 2019.
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11 surviving C-135Fs upgraded to C-135FRs with CFM International F108 turbofans between 1985 and 1988. Later modified with MPRS wing pods.
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They differ from turbofans in that a traditional propeller, rather than a ducted fan, provides the majority of thrust. Most turboprops use gear- reduction between the turbine and the propeller. (Geared turbofans also feature gear reduction), but they are less common. The hot-jet exhaust is an important minority of thrust, and maximum thrust is obtained by matching the two thrust contributions.
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International Aero Engines (IAE) supplies the V2500-E5 turbofans, its first military application. Fábrica Argentina de Aviones supplies the tail cone, cargo door and landing gear doors.
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The first jetliners, introduced in the 1950s, used the simpler turbojet engine; these were quickly supplanted by designs using turbofans, which are quieter and more fuel-efficient.
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The -420, powered by Rolls-Royce Conway low-bypass turbofans The 707-420 was identical to the -320, but fitted with Rolls-Royce Conway 508 (RCo.12) turbofans (or by-pass turbojets as Rolls-Royce called them) of thrust each. The first announced customer was Lufthansa. BOAC's controversial order was announced six months later, but the British carrier got the first service-ready aircraft off the production line.
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There is, however, a rise in nozzle pressure, because overall pressure ratio increases faster than the turbine expansion ratio, causing an increase in the hot mixer entry pressure. Consequently, net thrust increases, whilst specific fuel consumption (fuel flow/net thrust) decreases. A similar trend occurs with unmixed turbofans. So turbofans can be made more fuel efficient by raising overall pressure ratio and turbine rotor inlet temperature in unison.
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The Energy Efficient Engine was a program funded by NASA in the 1970s to develop technologies suitable for energy efficient turbofans. Its goal was to improve thrust specific fuel consumption by 12% compared to a GE CF6-50C. Both General Electric and Pratt & Whitney produced turbofans for the program. The GE core featured a 23:1 high-pressure (HP) ratio ten-stage HP compressor, later used in the GE90 and GEnx.
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Both turboprops and turbofans were considered for the initial design; the mockup shown at Le Bourget had turboprops, which would allow longer endurance at the cost of slower climbing.
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Work on the Yak-77 began in 1992, the project manager being S A Yakovlev. The aircraft was to have two AE 3010/12 turbofans, uprated members of the Allison 3000 family of two-shaft turbofans, each with a takeoff rating of 4,500 kg (9,920 lb). Avionics were to have been a Collins Pro Line 4 system. In configuration for a business jet, the aircraft would have had seating for eight in a generous cabin.
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Military turbofans tend to have a much higher design fan pressure ratio than civil engines. Consequently, the final (mixed) nozzle is choked at all flight speeds, over most of the throttle range. However, at low throttle settings the nozzle will unchoke, causing the lower end of the working lines to have a short curved tail, particularly at low flight speeds. However, ultra-high bypass ratio turbofans have a very low design fan pressure ratio (e.g.
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Consequently, modern military turbofans usually have only 5 or 6 HP compressor stages and require only a single-stage HP turbine. Low- bypass-ratio military turbofans usually have one LP turbine stage, but higher bypass ratio engines need two stages. In theory, by adding IP compressor stages, a modern military turbofan HP compressor could be used in a civil turbofan derivative, but the core would tend to be too small for high thrust applications.
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Turbofans were among the first engines to use multiple spools—concentric shafts that are free to rotate at their own speed—to let the engine react more quickly to changing power requirements. Turbofans are coarsely split into low- bypass and high-bypass categories. Bypass air flows through the fan, but around the jet core, not mixing with fuel and burning. The ratio of this air to the amount of air flowing through the engine core is the bypass ratio.
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Low- bypass engines are preferred for military applications such as fighters due to high thrust-to-weight ratio, while high-bypass engines are preferred for civil use for good fuel efficiency and low noise. High-bypass turbofans are usually most efficient when the aircraft is traveling at 500 to 550 miles per hour (800 to 885 km/h), the cruise speed of most large airliners. Low-bypass turbofans can reach supersonic speeds, though normally only when fitted with afterburners.
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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.
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The design was therefore revised again to a reconnaissance aircraft capable of operating from conventional runways, the RSR. As ramjets could not be used for take-off, they were replaced by turbofans. The RSR was primarily of aluminium construction, with a long circular-section fuselage, which housed a pressurized cabin for the pilot together with cameras and fuel, with thin, low-aspect-ratio trapezoidal wings. The engines, two Soloviev D-21 turbofans, were mounted at the tips of the wings.
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A large part of the noise reduction is due to reduced fan tip speeds. In conventional turbofans the fan tips exceed the speed of sound causing a characteristic drone, requiring sound deadening. Geared turbofans operate the fan at sufficiently low rotational speed to avoid supersonic tip speeds. After considering a geared design, General Electric avoided it for its CFM LEAP among weight and reliability concerns, postponing its use for a future application, while Pratt & Whitney developed the competing geared PW1000G,.
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Modern civil turbofans have multi-stage LP turbines (anywhere from 3 to 7). The number of stages required depends on the engine cycle bypass ratio and the boost (on boosted two-spools). A geared fan may reduce the number of required LPT stages in some applications. C. Riegler, C. Bichlmaier:, 1st CEAS European Air and Space Conference, 10–13 September 2007, Berlin, Germany Because of the much lower bypass ratios employed, military turbofans require only one or two LP turbine stages.
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Kingfisher Purchases Five Airbus A340-500 flykingfisher.com The A340-500IGW is powered by four thrust Rolls-Royce Trent 556 turbofans. Like the A340-200, a shortened derivative of the -300, the -500 was unpopular.
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Launch decision was deferred in December 2000 and again thereafter to an undisclosed date. Shelved by mid-2003. ;717-100X Lite : Proposed 75-seat version, powered by Rolls-Royce Deutschland BR710 turbofans; later abandoned.
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In the future, mixed flow compressors may feature at the small end of the market, particularly in turbofans, where the relatively large diameter across the diffuser of a centrifugal compressor is a significant disadvantage.
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The high bypass ratios used in modern civil turbofans tend to reduce the relative diameter of the T-stages, reducing their mean tip speed. Consequently, more T-stages are required to develop the necessary pressure rise.
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142"American Airlines Experience with Turbojet/Turbofan Engines" K. F. Whatley , The American Society of Mechanical Engineers. 1962, ASME 62-GTP-16, p.5. Today most civil and military turbofans have a two spool configuration, a notable exception being the Rolls-Royce Trent turbofan series which has three spools. Incidentally, most modern civil turbofans use all three of the above options to handle the extremely high overall pressure ratios employed today (50:1 typically). As the Applications section below indicates, during the 1950s the J57 was an extremely popular engine, with numerous military applications.
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Shortly after, 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 the smaller TF34. More recent large high-bypass turbofans include the Pratt & Whitney PW4000, the three-shaft Rolls-Royce Trent, the General Electric GE90/GEnx and the GP7000, produced jointly by GE and P&W.
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Propeller engines are most efficient for low speeds, turbojet engines – for high speeds, and turbofan engines – between the two. Turbofans are the most efficient engines in the range of speeds from about , the speed at which most commercial aircraft operate.. Turbofans retain an efficiency edge over pure jets at low supersonic speeds up to roughly . In a zero-bypass (turbojet) engine the high temperature and high pressure exhaust gas is accelerated by expansion through a propelling nozzle and produces all the thrust. The compressor absorbs all the mechanical power produced by the turbine.
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US Warplanes.net. Retrieved: 21 October 2011. ;Aérospatiale Pégase :A Canadair T-33AN was modified by Aérospatiale with an S17a 17% thickness wing section. ;Boeing Skyfox: A comprehensive upgrade and re-engine project, powered by 2 Garrett TFE-731 turbofans.
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The MTOW Cessna Citation I first flew on 15 September 1969, powered by two Pratt & Whitney Canada JT15D turbofans. Produced between 1969 and 1985 for a total of 689 examples, it is the first of the Cessna Citation family.
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Power is provided by two Pratt & Whitney Canada PW615F turbofans, mounted in pods on the aft fuselage. It was built at the Cessna production facility in Independence, Kansas. Like many other light jets, the Mustang is approved for single-pilot operation.
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On their large civil turbofans, Rolls-Royce split the compression system into three: a fan, an intermediate-pressure (IP) compressor and an HP compressor, each unit being driven by its own turbine unit. The RB199 military turbofan also has this arrangement.
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A propfan engine A propfan engine (also called "unducted fan", "open rotor", or "ultra-high bypass") is a jet engine that uses its gas generator to power an exposed fan, similar to turboprop engines. Like turboprop engines, propfans generate most of their thrust from the propeller and not the exhaust jet. The primary difference between turboprop and propfan design is that the propeller blades on a propfan are highly swept to allow them to operate at speeds around Mach 0.8, which is competitive with modern commercial turbofans. These engines have the fuel efficiency advantages of turboprops with the performance capability of commercial turbofans.
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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 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).
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The DGEN program aims at developing a family of high-bypass-ratio two-spool unmixed-flow jet engines (turbofans) - the DGEN 380 and 390 - intended to equip 4- to 6-seat aircraft in a twin-engine configuration with a maximum take-off weight (MTOW) between 1400 and 2150 kg. The DGEN engines are recognizedPrice induction toujours à la recherche d’un avionneur, Aerobuzz, April 2011 as being the only turbofans designed for the flight envelope of the general aviation (altitude under 25,000 ft, speed under Mach 0,35). The DGEN engines have an architecture typical of the civil aviation's turbofans and integrate innovations such as a geared fan and an "all-electric" concept. DGEN 380 begins endurance testing, Aviation International News, April 2010 The DGEN engine has been exhibited at the Paris Air Show, the General Aviation's Aero Expo in FriedrichshafenPremière à Friedrichshafen pour Price Induction, Aerobuzz, mars 2010 and the EAA AirVenture Oshkosh.
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On 2 October 1966 the first large business jet first flew, the MTOW Grumman Gulfstream II, powered by two Rolls-Royce Spey turbofans. From 1967 to the late 70s, 258 were built and it led to the ongoing Gulfstream Aerospace long range family.
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The FADEC-controlled PW305A turbofans have a 6,000 h TBO and reserves amount to $360 per hour per engine. In September 2018, there were 112 Model 60XRs in service, priced between $2.5 million for a 2007 model to $4.0 million for a 2013 one.
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12 were built for the French Air Force with the addition of a drogue adapter on the refueling boom. Given Boeing model numbers 717-164 and 717-165. ;C-135FR: 11 surviving C-135Fs upgraded with CFM International F108 turbofans between 1985 and 1988.
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595 (online archive version). Retrieved: December 15, 2008."Aeronews." Air Progress magazine, July 1969, pp. 19–20. It shared the tail and cockpit with the Merlin/Metro. The two engines were to be Garrett TFE731 turbofans then in development;"Aero Engines 1970" (online archive version).
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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 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)."The turbofan engine ", page 7. SRM Institute of Science and Technology, Department of aerospace engineering Extracting shaft power and transferring it to a bypass stream introduces extra losses which are more than made up by the improved propulsive efficiency.
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F28 with new Rolls-Royce Tay turbofans, a wider wing The F28 Mark 0100 “Fokker 100” is based on the Fokker F28 Mark 4000 re-engined with two Rolls-Royce RB.183 Tay high by-pass ratio turbofans and a fuselage stretched by . Its wing is wider by , has new flaps and larger ailerons, and extended leading and trailing edges improve aerodynamics and increase the wing chord. The landing gear is strengthened and has new wheels and brakes, and the horizontal stabilizer is widened by . Maximum weights are increased while fuel capacity, max speed and ceiling remain the same, and passenger capacity went from 85 to 109.
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It burns in the first hour, in the second hour, in the third hour then /hr. Scheduled maintenance is done every 200 h or six months and major inspections every 96 months includes $110,000 landing gear overhauls, the CF34-3B turbofans costs $375 per engine per hour.
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Powered by four Pratt & Whitney JT3C turbojets, the initial 720 could cover a range with 131 passengers in two classes. Powered by JT3D turbofans, the 720B first flew on October 6, 1960, and entered service in March 1961. It could seat 156 passengers in one class over a range.
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A-6E Intruder of VA-52, 1981 ;A-6E :A-6A with improved electronics. ;A-6F Intruder II :Advanced version with updated electronics and General Electric F404 turbofans; only 5 built. ;A-6G :Proposed cheaper alternative to the A-6F, with its advanced electronics, but existing J52 turbojets.
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Boeing is studying a re-engined 767-XF for around 2025, based on the 767-400ER with an extended landing gear to accommodate General Electric GEnx turbofans. The cargo market is the main target, but a passenger version could be a cheaper alternative to the proposed New Midsize Airplane.
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Turbofans designed for subsonic civilian aircraft also usually have a just a single front fan, because their additional thrust is generated by a large additional mass of air which is only moderately compressed, rather than a smaller amount of air which is greatly compressed. Military turbofans, however, have a relatively high specific thrust, to maximize the thrust for a given frontal area, jet noise being of less concern in military uses relative to civil uses. Multistage fans are normally needed to reach the relatively high fan pressure ratio needed for high specific thrust. Although high turbine inlet temperatures are often employed, the bypass ratio tends to be low, usually significantly less than 2.0.
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639 Thus, the lower speed exhaust jets emitted from engines such as high bypass turbofans are the quietest, whereas the fastest jets, such as rockets, turbojets, and ramjets, are the loudest. For commercial jet aircraft the jet noise has reduced from the turbojet through bypass engines to turbofans as a result of a progressive reduction in propelling jet velocities. For example, the JT8D, a bypass engine, has a jet velocity of 1450 ft/sec whereas the JT9D, a turbofan, has jet velocities of 885 ft/sec (cold) and 1190 ft/sec (hot)."The Aircraft Gas Turbine Engine and its operation" United Technologies Pratt & Whitney Part No. P&W; 182408 December 1982 Sea level static internal pressures and temperatures pp.
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Tsybin R-020. www.testpilot.ru. Retrieved 28 February 2008. More conventional Tumansky R-11 turbojets (the engine used in the MiG-21) replaced the unavailable Soloviev turbofans. Five R-020 airframes were virtually complete, only awaiting engines by April 1961, with another 10 planned, when Soviet Premier Nikita Khrushchev cancelled the program.
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The airport shared its grounds with the Bykovo Aircraft Repair Facility, specializing in repairs and overhauls of Soloviev D-30 turbofans; the factory continues to use the runway for cargo delivery. The new Zhukovsky International Airport (a.k.a. Ramenskoye) is located a few kilometers to the southeast from the Bykovo Airport.
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The engine configuration describes the fundamental operating principles by which internal combustion engines are categorized. Piston engines are often categorized by their cylinder layout, valves and camshafts. Wankel engines are often categorized by the number of rotors present. Gas turbine engines are often categorized into turbojets, turbofans, turboprops and turboshafts.
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It shares its fuselage cross-section with these aircraft, paired with a new T-tail and wing. The latter is a supercritical airfoil with a 35° wing sweep and winglets. This flexible wing naturally attenuates turbulence. It was initially powered by two BMW-Rolls- Royce BR710 turbofans controlled by FADEC.
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Logan 1998, p. 19. Most F-111 variants included a terrain-following radar system connected to the autopilot. The aircraft was powered by two Pratt & Whitney TF30 afterburning turbofan engines. The F-111's variable-geometry wings, escape capsule, terrain following radar and afterburning turbofans were new technologies for production aircraft.
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In addition to three-steam adaptive cycle configuration, the engine also uses new heat-resistant materials such as ceramic matrix composites to enable higher turbine temperatures and improved performance. According to GE, the engine can offer up to 35% increased range and 25% reduction in fuel burn over current turbofans.
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Modern High bypass turbofans are not only more fuel efficient, but also much quieter than older turbojet and low-bypass turbofan engines. On newer engines noise-reducing chevrons further reduce the engine's noise, while on older engines the use of hush kits are used to help mitigate their excessive noise.
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Some airplanes use LNG to power their turbofans. Aircraft are particularly sensitive to weight and much of the weight of an aircraft goes into fuel carriage to allow the range. The low energy density of natural gas even in liquid form compared to conventional fuels give it a distinct disadvantage for flight applications.
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The PowerJet SaM146 turbofans provides of thrust for 70-120 seat aircraft. Russia CIS Observer qualifies it as the most important Russian civil aircraft. The Russian Ministry of Industry and Trade supports it as a priority project. Development cost $1.4 billion excluding the SaM146 engine, with 25% funded from the federal budget.
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The Morane-Saulnier MS.760 Paris had a gross weight of , initially powered by two Turboméca Marboré turbojets of thrust, although most aircraft were later upgraded to units. The aircraft seated a single pilot and up to three passengers under a sliding canopy, and was first flown on 29 July 1954. 219 were built. The Lockheed JetStar is the earliest business jet with a center aisle The Lockheed JetStar, designed to meet USAF UCX requirements and seating ten passengers and two crew, first flew on 4 September 1957. A total of 204 aircraft were produced from 1957 to 1978 powered by several different engines; four Pratt & Whitney JT12 turbojets, then Garrett TFE731 turbofans for a MTOW, then two General Electric CF700 turbofans.
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By contrast, military turbofans often feature fairly high specific thrust (45-110 lbf/(lb/s)), which keeps the cross-sectional area of the engine low to more easily accommodate a narrow fuselage, which minimizes drag. A high specific thrust usually results in higher noise levels, which is not an important consideration for most military applications.
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Originally, three versions of the all-composite aircraft were envisioned, one powered by piston engines, one by turboprops and one by turbofans. The only one built was the turbofan version with engines mounted on top of the wings,Garrison, Peter. "The Unconventional Burt Rutan" Aviation History magazine, September 20, 2009. Retrieved March 29, 2015.
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Beechcraft considered a jet-powered version in the mid-1970s. The first prototype King Air 200 was re-engined with Pratt & Whitney Canada JT15D turbofans in overwing nacelles.Phillips 1992, p. 66. Given the designation PD 290 (for Preliminary Design), the aircraft was flown in this configuration for the first time on March 12, 1975.
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The Mirabel Aerospace Centre (MAC), in Mirabel, Quebec, supports flight testing for Pratt & Whitney Canada engines, including turboprops and turbofans up to of thrust. A facility, the Mirabel Aerospace Centre represents a $360-million investment. Approximately 300 people are employed at the facility located within Montréal–Mirabel International Airport., P&WC; Press release, Oct.
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Ilyushin Il-96-400VVIP The Il-96-400 is similar to the Il-96M, but features Russian avionics and engines. It is powered by four Aviadvigatel PS-90A1 turbofans and can carry up to 436 passengers. Typical two-class configuration will have 386 passengers. Range with 315 passengers in a three-class configuration is about 10,000 km.
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The draft listed two models, a nine-seater executive aircraft and a 15-passenger commercial aircraft, both low-winged and possessing a T-tail. The Il-108 is powered by two Lotarev DV-2 turbofans attached to the top of the rear fuselage on either side of the tail, each providing a thrust of 21.6 kN.
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Other new features include extended raked wingtips, redesigned main landing gear, and additional structural strengthening. As with the -300ER and 777F, the -200LR is equipped with wingtip extensions of 12.8 ft (3.90 m). The -200LR is powered by GE90-110B1 or GE90-115B turbofans. The first -200LR was delivered to Pakistan International Airlines on February 26, 2006.
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The United States Air Force (USAF) launched its Next Generation Trainer (NGT) program to replace the Cessna T-37 Tweet primary trainer in 1981.Braybrook 1985, p. 274. Fairchild-Republic submitted a shoulder-winged monoplane with a twin tail, powered by two Garrett F109 turbofans and with pilot and instructor sitting side by side.Braybrook 1985, p. 275.
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The combination of engine placement, wing and fuselage was achieved using computer simulations and wind tunnels.Garrison, Peter. "Technicalities" page 83 Flying, December 2006 HondaJet has a retractable tricycle landing gear with both main and nose landing gear single-wheeled. The aircraft is powered by two GE Honda HF120 turbofans, developed with GE Aviation under the GE-Honda partnership.
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Further tests simulating Mach5 were planned, with temperature reduction expected from . These further tests were successfully completed by October 2019. The successful HTX test could lead to spin-off precooler applications which could be developed before a scalable SABRE demonstrator is completed; suggested uses are to expand gas turbines capabilities, in advanced turbofans, hypersonic vehicles, and industrial applications.
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The redesigned compressor will be tested in July 2019 to prove the engine operation. On October 15, 2018, fractional operator NetJets announced the purchase of up to 150 Hemispheres, priced at $35 million each, along 175 Citation Longitude, sold for $26 million. In July 2019, Textron suspended the development as its Safran Silvercrest turbofans did not meet objectives.
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The 1963 Learjet 23 was the first light jet. The first large, long range jet was the Grumman Gulfstream II in 1966. The MTOW British Aerospace 125 first flew on 13 August 1962 as the de Havilland DH.125, powered by two Armstrong Siddeley Viper turbojets. Its engines were replaced by Garrett TFE731s, then Pratt & Whitney Canada PW300 turbofans.
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The bypass ratio (BPR) of a turbofan engine is the ratio between the mass flow rate of the bypass stream to the mass flow rate entering the core.. A 10:1 bypass ratio, for example, means that 10 kg of air passes through the bypass duct for every 1 kg of air passing through the core. 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 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.
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"Day after crash, IAF grounds Sukhoi fleet for checks." The Times of India, 2 December 2009. An estimated 920 AL-31FP turbofans are to be manufactured at HAL's Koraput Division, while the mainframe and other accessories are to be manufactured at HAL's Lucknow and Hyderabad divisions. Final integration and test flights of the aircraft are carried out at HAL's Nasik Division.
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The "N" variant would also be re-engined to use General Electric F414 turbofans instead of the older General Electric F404s. The aircraft would be optionally fitted with hardpoints, allowing for an additional of payload, and a new ground-attack radar with air-to-air capability. In that role the F-117N could carry AIM-120 AMRAAM air-to-air missiles.
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"CFM56-3 High By-Pass Technology for Single Aisle Twins". 1981 AIAA/SAE/ASCE/ATRIF/TRB International Air Transportation Conference, 26–28 May 1981, Atlantic City, New Jersey. AIAA-1981-0808. Since the small initial launch order for twenty 737-300s split between two airlines, over 5,000 Boeing 737 aircraft had been delivered with CFM56 turbofans by April 2010.Boeing 737 Deliveries.
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After the death of Shvetsov in 1953, leadership was taken over by Pavel Alexandrovich Soloviev, and the OKB was referred to afterwards as the Soloviev Design Bureau. Under Soloviev, the company became notable for the D-15 engine that powered the Myasishchev M-50 in 1957. Other notable designs included the D-25 turboshaft and D-20 and D-30 turbofans.
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"AD places limit on rare Hansa jet." AIN Online, 21 September 2006. In 1969, the $840,000 HFB 320 was to be developed into the $1.7 million, Mach 0.76 HFB 330: flight-testing was to start in 1971 for FAR 25 certification by late 1972. It would have been stretched by and powered by Garrett ATF3 turbofans with thrust reversers for short-field operation.
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These are usually used for long-haul flights between airline hubs and major cities. A smaller, more common class of airliners is the narrow-body or single-aisle. These are generally used for short to medium-distance flights with fewer passengers than their wide-body counterparts. Regional airliners typically seat fewer than 100 passengers and may be powered by turbofans or turboprops.
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Thus civil turbofans today have a low exhaust speed (low specific thrust – net thrust divided by airflow) to keep jet noise to a minimum and to improve fuel efficiency. Consequently, the bypass ratio (bypass flow divided by core flow) is relatively high (ratios from 4:1 up to 8:1 are common), with the Rolls- Royce Trent XWB approaching 10:1. Only a single fan stage is required, because a low specific thrust implies a low fan pressure ratio. Turbofans in civilian aircraft usually have a pronounced large front area to accommodate a very large fan, as their design involves a much larger mass of air bypassing the core so they can benefit from these effects, while in military aircraft, where noise and efficiency are less important compared to performance and drag, a smaller amount of air typically bypasses the core.
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A downgraded version of the F-16 Fighting Falcon with a J79 was proposed as a low-cost fighter for export, and though a prototype aircraft was flown, it found no customers. The J79 was replaced by the late 1960s in new fighter designs by afterburning turbofans such as the Pratt & Whitney TF30 used in the F-111 and F-14, and newer generation turbofans with the Pratt & Whitney F100 used in the F-15 Eagle which give better cruise fuel efficiency by-passing air around the core of the engine. For their part in designing the J79, Gerhard Neumann and Neil Burgess of General Electric Aircraft Engines were jointly awarded the Collier Trophy in 1958, also sharing the honor with Clarence Johnson (Lockheed F-104) and the US Air Force (Flight Records).Collier Trophy winners, 1950–1959 , National Aeronautic Association.
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The engine demonstrated an extremely low specific fuel consumption (SFC) of at ground level, which GE claimed was over 20% more efficient than any of the existing turbofans on offer. GE had also predicted a cruise SFC of 0.49 for the demonstrator engine; however, the cruise SFC would drop to 0.40-0.41 with a new gas generator design called "Supercore," compared with 0.56 for existing turbofans. Snecma was to design the high-pressure compressor (HPC) and the combustion chamber. The engine configuration selected for the MD-91 and MD-92 was designed to meet the Chapter 4 community noise standards of the International Civil Aviation Organization's (ICAO's) Committee on Aviation Environmental Protection (CAEP), which would go into effect in 2006 and be a reduction of ten effective perceived noise decibels (EPNdB) from the existing Chapter 3 standards that were established in 1977.
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Yak-42 seen from behind with rear airstair deployed Yakovlev Yak-42D of Lviv Airlines In 1972, the Yakovlev design bureau started work on a short- to medium-range airliner capable of carrying 100–120 passengers. It was intended to be a replacement for the Tupolev Tu-134 jet as well as the Ilyushin Il-18, Antonov An-24 and An-26 turboprop airliners. While the new airliner was required to operate out of relatively small airfields while maintaining good economy, as many Soviet airports had been upgraded to accommodate more advanced aircraft, it did not have to have the same ability to operate from grass strips as Yakovlev's smaller Yak-40. The requirement resulted in the largest, heaviest and most powerful aircraft designed by Yakovlev,Gordon, Komissarov and Komissarov 2005, p. 311.Gunston and Gordon 1997, p. 194. until the even larger MC-21 took flight in 2017. Initial design proposals included a straight-wing airliner powered by two Soloviev D-30 turbofans and resembling an enlarged Yak-40, but this was rejected as it was considered uncompetitive compared to Western airliners powered by high bypass ratio turbofans. Yakovlev settled on a design powered by three of the new Lotarev D-36 three-shaft high-bypass turbofans, which were to provide 63.90 kN (14,330 lbf) of thrust.
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The Yakovlev Yak-48 was developed in 1989 as a long-range business jet capable of seating up to eight passengers and traveling from New York to Paris, or as a local-service airliner with seats for up to eighteen. It was to have been powered by two rear-mounted Pratt & Whitney Canada PW305 turbofans. Once the design was completed development proceeded quickly.Gunston, Bill.
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The aircraft was powered by a pair of General Electric YJ101-GE-100 turbofans, a development of the GE15, mounted next to each other to minimize thrust asymmetry in the event of an engine loss. For ease of maintenance, the engines are mounted in a steady-rest that allows removal from below the aircraft, without disturbing the empennage controls. Each engine drove an independent hydraulic system.
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Development suffered a major setback when the engine manufacturer, Noel Penny Turbines, ceased business, leading to the grounding of the prototype. A second, refined prototype (registration ) was then constructed to use Williams International turbofans. This aircraft also incorporated a pressurised cabin, revised undercarriage, and a generally strengthened airframe. This second prototype was unveiled at the 1996 Farnborough International Airshow and first flew on 9 April 1997.
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Although it is a two-seat aircraft, it can be flown by a single pilot. Textron AirLand selected Cobham plc to design the cockpit, which will feature modern flat-panel displays. The aircraft will not have fly-by-wire to keep costs down and simplify the design. The demonstrator, as well as production versions, are powered by two Honeywell TFE731 turbofans producing of thrust total.
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Construction is aluminum for both wing and fuselage. The cabin is 7 inches shorter and 6 inches narrower than the Columbus design. Initially, the Snecma Silvercrest engine was selected to power the aircraft, however the production model is powered by Honeywell HTF7000 turbofans. The Silvercrest was planned for the larger Citation Hemisphere, but Textron suspended its development in July 2019 as the turbofan did not meet objectives.
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In 2010, Australian inventor and engineer Chris Malloy constructed a hoverbike that uses turbofans to enter flight. It is claimed to fly up to 10,000 feet and fly at a horizontal speed of 173 miles an hour. The hoverbike has been repeatedly compared to the hoverbikes seen in the Star Wars films. It is unclear, however, whether these hoverbikes were actually inspired by Star Wars or not.
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Some turbofans have an intermediate pressure (IP) compressor located between the fan and the high pressure (HP) compressor to increase overall pressure ratio. US civil engines tend to mount the IP compressor on the LP shaft, directly behind the fan, whereas Rolls- Royce normally mount the IP compressor on a separate (i.e. IP) shaft, which is driven by an IP turbine. Either way, matching problems can arise.
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MFD and sidesticks They are low wing, T-tail airplanes with cabin pressurization, powered by two rear mounted turbofans. The landing gear is fully retractable and designed to be operated on paved runways only. The glass cockpit includes four multi-function displays. The operation is made through a flight management system with autopilot, autothrottle and closed-loop control and monitoring of flight controls Fly-By-Wire.
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"Air Transport." Flight International, 23 December 1971. p. 997. These aircraft had a greater seating capacity than required and were powered by four Rolls-Royce Conway engines, an older generation engine type than the four Pratt and Whitney JT3D turbofans which powered the ex-American 707-123Bs it had originally selected to replace its Comet fleet. This meant that the ex-BOAC 707s had higher operating costs.
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Fast STOL - Lockheed's Speed Agile - Aviationweek.com, 15 October 2010 In August 2011, the AFRL released pictures of the Lockheed Speed Agile concept demonstrator. A 23% scale model went through wind tunnel tests to demonstrate its hybrid powered lift, which combines a low drag airframe with simple mechanical assembly to reduce weight and better aerodynamics. The model had four engines, including two Williams FJ44 turbofans.
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The A310 introduced a two-crew glass cockpit, later adopted for the A300-600 with a common type rating. It was powered by the same General Electric CF6-80 or Pratt & Whitney JT9D then PW4000 turbofans. It can seat 220 passengers in two classes, or 240 in all-economy, and can fly up to . It has overwing exits between the two main front and rear door pairs.
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The final commercial aircraft design to be made by McDonnell Douglas came in 1988. The MD-90 was a stretched version of the MD-80, equipped with International Aero Engines V2500 turbofans, the largest rear-mounted engines ever on a commercial jet. The MD-95, a modern regional airliner closely resembling the DC-9-30, was the last McDonnell Douglas designed commercial jet produced.
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The new wing features single-slotted outboard flaps and double-slotted inboard flaps. The 747-8 has two GEnx turbofans under each wing, in a nacelle with chevrons Raked wingtips, similar to the ones used on the 777-200LR, 777-300ER, and 787 aircraft, are used on the new 747 variant instead of winglets used on the .Thomas, Geoffrey. "A Timely Stretch". Air Transport World, December 2005.
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The arrival of the more fuel-efficient turbofans made easier the possibility of longer flights. The Aerolíneas Argentinas route was the longest scheduled flight by distance until 1976, when the Boeing 747-SP entered service. In April 1976, Pan American World Airways set the new record with its New York City-JFK/Tokyo-Haneda route. In December, the airline set another record with Sydney–San Francisco, covering .
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CJ2 side view, six windows ;CitationJet CJ2 :Model 525A serial numbers 0001 to 0299, marketed as the CitationJet CJ2 is a 5-foot stretch of the CJ1 (Model 525) powered by Williams FJ44-2C turbofans and first delivered in 2000. ;CitationJet CJ2+ :Model 525A serial numbers 0300 and higher, marketed as the CitationJet CJ2+ and first delivered in April 2006, offer increased performance with updated avionics and Williams FJ44-3A-24 turbofans with FADEC control, with 4-passenger NBAA IFR range increased to 1550 nmi, max cruise speed of 413 kn, and decreased runway requirements; many features such as TCAS and TAWS were made standard. ;CitationJet CJ2+ Alpine Edition :In 2014, Cessna started offering an upgrade package for the CJ2+ called Alpine Edition. It incorporates Garmin G3000 avionics and new cabin stylings similar to those introduced by Cessna to the CJ1+ when it became the M2.
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Most modern combat aircraft can carry at least a pair of air-to-air missiles. A USAF F-22A Raptor stealth fighter. In the 1970s, turbofans replaced turbojets, improving fuel economy enough that the last piston engined support aircraft could be replaced with jets, making multi-role combat aircraft possible. Honeycomb structures began to replace milled structures, and the first composite components began to appear on components subjected to little stress.
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Viewed from below, showing moderate wing sweep with a straight trailing edge and exposed wheels. The PC-24 is the company's first jet-powered aircraft. Several competing business aircraft were identified early on, including Embraer's Phenom 300 and Cessna's Citation CJ4. It is a low-wing cantilever cabin monoplane powered by two Williams FJ44-4A turbofans, each mounted in a nacelle on the side of the rear fuselage.
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The company was one of the largest of its kind in the worldFlight 6 Feb 1959Flight 28 August 1959 and offered a wider range of engines than any other manufacturer. Aero engines produced by the company included piston engines, turboprops, turboshafts, turbojets, turbofans, auxiliary power units, ramjets and liquid propellant rocket engines. Outside the aeronautical field its products were gas turbines for marine and industrial use, diesel engines, and automatic transmissions.
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The flight controls were Hands On Throttle-And- Stick (HOTAS)-compatible and incorporated a departure prevention system. Power was provided by a pair of Turbo-Union RB199-104 afterburning turbofans, previously used as the Panavia Tornado ADV's powerplant. To reduce costs, the rear fuselage and tailfin of a Tornado was used as the basis of the unit that was eventually fitted to the EAP prototype.Braybrook Air International June 1986, p. 307.
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The Honeywell ALF502 and LF507 turbofans power the British Aerospace 146 family of airliners.By Ernst-Heinrich Hirschel, Horst Prem and Gero Madelung. Published by Springer. "Aeronautical research in Germany: from Lilienthal until today, Volume 147." Page 427. Honeywell also partners with General Electric Aircraft Engines in a company called CFE Corporation that develops the CFE738 series, a 6,000 pound thrust engine.Gunston, Bill (2006). World Encyclopedia of Aero Engines, 5th Edition.
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The list price for new a G650ER aircraft was $66.5 million in 2014. ; G700 : Announced at the October 2019 NBAA convention: stretched by 10 ft 1 in ( m) for a longer cabin with five areas and ten windows per side, up from eight, 2-3% more efficient 18,250 lbf / 81.2 kN Rolls-Royce Pearl 700 turbofans, 4,000 lb ( kg) heavier MTOW for the same 7,500 nmi (13,900 km) range.
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Until the beginning of the Jet Age, piston engines were common on propliners such as the Douglas DC-3. Nearly all modern airliners are now powered by turbine engines, either turbofans or turboprops. Gas turbine engines operate efficiently at much higher altitudes, are more reliable than piston engines, and produce less vibration and noise. The use of a common fuel type – kerosene-based jet fuel – is another advantage.
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However, some energy will be lost as heat in the gear mechanism and weight saved on turbine and compressor stages is partly offset by that of the gearbox. There are manufacturing cost and reliability implications as well. The lower fan speed allows higher bypass ratios, leading to reduced fuel consumption and much reduced noise. The BAe 146 is fitted with geared turbofans and is still one of the quietest commercial aircraft.
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For the first time, Airbus entered the bond market, through which it raised $480 million (€475 million) to finance development costs. An additional $180 million (€175 million) was borrowed from European Investment Bank and private investors. The maiden flight of the Airbus A321 came on 11 March 1993, when the prototype, registration F-WWIA, flew with IAE V2500 engines; the second prototype, equipped with CFM56-5B turbofans, flew in May.
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Affected airlines considered filing compensation claims with Airbus. The A340-600HGW (High Gross Weight) version first flew on 18 November 2005 and was certified on 14 April 2006. It has an MTOW of and a range of up to , made possible by strengthened structure, increased fuel capacity, more powerful engines and new manufacturing techniques like laser beam welding. The A340-600HGW is powered by four thrust Rolls-Royce Trent 560 turbofans.
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Most civil turbofans use a high-efficiency, 2-stage HP turbine to drive the HP compressor. The CFM International CFM56 uses an alternative approach: a single-stage, high-work unit. While this approach is probably less efficient, there are savings on cooling air, weight and cost. In the RB211 and Trent 3-spool engine series, the HP compressor pressure ratio is modest so only a single HP turbine stage is required.
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For air-breathing jet engines, particularly turbofans, the actual exhaust velocity and the effective exhaust velocity are different by orders of magnitude. This is because a good deal of additional momentum is obtained by using air as reaction mass. This allows a better match between the airspeed and the exhaust speed, which saves energy/propellant and enormously increases the effective exhaust velocity while reducing the actual exhaust velocity.
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An animated turbofan engine Most modern jet engines are turbofans. The low pressure compressor (LPC), usually known as a fan, compresses air into a bypass duct whilst its inner portion supercharges the core compressor. The fan is often an integral part of a multi-stage core LPC. The bypass airflow either passes to a separate 'cold nozzle' or mixes with low pressure turbine exhaust gases, before expanding through a 'mixed flow nozzle'.
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In the 1960s there was little difference between civil and military jet engines, apart from the use of afterburning in some (supersonic) applications. Today, turbofans are used for airliners because they have an exhaust speed that is better matched to the subsonic flight speed of the airliner. At airliner flight speeds, the exhaust speed from a turbojet engine is excessively high and wastes energy. The lower exhaust speed from a turbofan gives better fuel consumption.
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The large fan could lead to gull-wing airframes. By July 2018, the UltraFan configuration was frozen before detailed design and then component manufacture, for 2021 ground tests. The diameter planetary gearbox has five planet gears, is sized to power turbofans and amassed over 250 hours of run time by early 2019. In February 2019, potential introduction was delayed to 2027, to re-engine current aircraft, after full- scale ground tests in 2021.
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However, S-duct designs are extremely complex and costly. Furthermore, the central engine bay would require structural changes in the event of a major re-engining. For example, the 727's central bay was only wide enough to fit a low-bypass turbofan and not the newer high-bypass turbofans which were quieter and more powerful. Boeing decided that a redesign was too expensive and ended its production instead of pursuing further development.
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Mattingly, pp. 9–11 Therefore, in supersonic flight, and in military and other aircraft where other considerations have a higher priority than fuel efficiency, fans tend to be smaller or absent. Because of these distinctions, turbofan engine designs are often categorized as low-bypass or high-bypass, depending upon the amount of air which bypasses the core of the engine. Low-bypass turbofans have a bypass ratio of around 2:1 or less.
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The Mirage 4000 was noticeably larger and heavier than the single-engined Mirage 2000, the 4000 having two SNECMA M53-2 turbofans. It also featured small canards above the engine air intakes and a true bubble canopy, compared to the Mirage 2000 and previous Mirages. Despite the changes, the two aircraft remained similar, sharing the delta wing design, semi-circular air intakes, and general configuration. The Mirage 4000 first flew on 9 March 1979.
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The study also projected that at existing technology levels, open rotors would be nine percent more fuel-efficient but remain 10–12 decibels louder than turbofans. Snecma, however, maintains that open-rotor tests show that its propfan engines would have about the same noise levels as its CFM LEAP turbofan engine, which entered service in 2016. Further reductions can be achieved by redesigning the aircraft structure to shield noise from the ground.
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The Citation V is a slightly stretched Citation II/SP, allowing a standard eight seats, with more powerful Pratt & Whitney Canada JT15D5A turbofans. The Model 560 variants are the fastest and farthest flying jets with the type certificate of the original Citation 500. The passenger cabin is long, wide and high with a dropped aisle, has seven windows on each side and accommodates a four-seat club plus three chairs and a closed, belted lavatory.
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Graphic representation of an acoustic liner installed on a turbofan engine inlet A composite sandwich acoustic liner (A) with perforate face-sheet (B) honeycomb core (C) and back-skin (D) Aircraft engines, typically turbofans, use acoustic liners to damp engine noise. Liners are applied on the internal walls of the engine nacelle, both in the intake and by-pass ducts, and use Helmholtz resonance principle for the dissipation of incident acoustic energy.
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The pilot sat in an armoured cockpit under a bubble canopy. The concept was developed further into the Addax S, intended as a supersonic air superiority fighter. The Addax S had a blended wing body configuration, with four, all-moving, tail surfaces in "X-configuration", and was powered by two afterburning turbofans of in underwing nacelles, while two or three small gas turbines located behind the cockpit supplied air to the flap-blowing system.
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Higher overall pressure ratios can be achieved by either raising the HP compressor pressure ratio or adding compressor (non-bypass) stages or T-stages to the LP spool, between the fan and the HP compressor, to boost the latter. All of the large American turbofans (e.g. General Electric CF6, GE90 and GEnx plus Pratt & Whitney JT9D and PW4000) feature T-stages. The Rolls- Royce BR715 is a non-American example of this.
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Logistics support responsibility for the aircraft was made virtually complete in March 1985 when AFLC gave SA-ALC management and repair responsibility for the C-17 engines, the Pratt & Whitney F117-PW-100 turbofans. With the transfer of B-52 repair and overhaul to Oklahoma City in 1993, Kelly's workers shifted their attention to keeping the T-38 jet trainers of Air Education and Training Command ready to fly. This workload moved to Kelly in the spring of 1993.
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The Rotor Systems Research Aircraft (RSRA) was developed by Sikorsky for NASA and the Army. The RSRA was developed to allow the inflight measurement of helicopter rotor characteristics. The airframe was developed using an existing Sikorsky S-61 main rotor, an S-61 roller gearbox, and a highly modified Sikorsky S-67 airframe. The RSRA could be fitted with TF34 turbofans and wings to allow compound helicopter configurations to be experimentally investigated at speeds up to .
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Theoretically, a PDE can operate from subsonic up to a hypersonic flight speed of roughly Mach 5. An ideal PDE design can have a thermodynamic efficiency higher than other designs like turbojets and turbofans because a detonation wave rapidly compresses the mixture and adds heat at constant volume. Consequently, moving parts like compressor spools are not necessarily required in the engine, which could significantly reduce overall weight and cost. PDEs have been considered for propulsion since 1940.
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The RJX-70, RJX-85, and RJX-100 variants represented advanced versions of the Avro RJ Series. The RJX series used Honeywell AS977 turbofans for greater efficiency (15% less fuel burn, 17% increased range), quieter performance, and 20% lower maintenance costs. Bhutan carrier Drukair ordered two RJX-85s, while British European placed firm orders for 12 RJX-100s and eight options.British European Confirms Order for 20 Avro 20 RJX-100 Airliners and Selects Jetspares & EFDMS, BAE Systems.
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The A321neo has larger CFM LEAP or PW1000G turbofans On 1 December 2010, Airbus launched the A320neo family (neo for New Engine Option) with more range and 15% better fuel efficiency thanks to new CFM International LEAP-1A or Pratt & Whitney PW1000G engines and large sharklets. The lengthened A321neo prototype made its first flight on 9 February 2016. It received its type certification on 15 December 2016. The first entered service in May 2017 with Virgin America.
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Design of the advanced jet trainer began in 1975 with a conventional low-wing configuration with a tricycle undercarriage, tandem seat cockpit, and twin turbofans mounted in nacelles on either side of the fuselage. After the design was approved in 1978, two prototypes were produced. The first aircraft rolled out on 17 July 1980 and made its maiden flight on 16 September 1980. Alt URL Further evaluation resulted in a contract for 60 AT-3As for the ROCAF.
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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 the engine must generate enough power to drive the fan at its design flow and pressure ratio. Improvements in turbine cooling/material technology allow a higher (HP) turbine rotor inlet temperature, which allows a smaller (and lighter) core and (potentially) improving the core thermal efficiency.
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In the 1940s, NACA started researching propellers with similar sweep. Since the inside of the propeller is moving more slowly than the outside, the blade becomes progressively more swept toward the outside, leading to a curved shape similar to that of a scimitar. The propfan concept was intended to deliver 35% better fuel efficiency than contemporary turbofans, and in this they succeeded. In static and air tests on a modified DC-9, propfans reached a 30% improvement.
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Both aircraft would ultimately receive shared design features, including avionics, flight management systems, instruments, and handling characteristics. Combined development costs were estimated at $3.5 to $4 billion. Forward view of a alt=Forward view of aircraft, showing fuselage profile, two circular engines Early 767 customers were given the choice of Pratt & Whitney JT9D or General Electric CF6 turbofans, marking the first time that Boeing had offered more than one engine option at the launch of a new airliner.
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49, pp. 1513–1520, 2012. although final testing usually involves some physical experiments (see birdstrike simulator). Based on US NTSB recommendation following the 2009 US Airways Flight 1549, the EASA in 2017, followed a year after by the FAA, proposed that engines should sustain a bird strike not only on takeoff where turbofans are turning at their fastest, but also in climb and descent when they turn more slowly; new regulations could apply for the Boeing NMA engines.
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With the same airframe, it has an updated avionics package and FADEC engine control. : The GE Honda HF120 engine was announced as a retrofit option for the CJ/CJ1/CJ1+ in 2014. ;Citation M2 :Model 525 marketed as Cessna Citation M2 are powered by improved FJ44-1AP-21 turbofans offering 10 to 15% more cruise thrust and up to 5% more hot-and-high thrust, and are equipped with modern Garmin G3000 avionics replacing Rockwell Collins Pro Line 21. Launched in September 2011, it is based on the then out-of-production CJ1 variant and features a new cabin layout and a more efficient FJ44 version. The initial M2 prototype first flew on 9 March 2012, it was not a conforming airframe but was testing the Garmin G3000 avionics and Williams FJ44-1AP-21 turbofans while one another aircraft was expected to join the certification program in May 2012 to be used for aerodynamics testing. Compared to the CJ1+, it climbs more quickly, offers a more comfortable cabin and is faster by at FL 410.
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Dry specific thrust has impact upon the performance of afterburning turbofans. A low (dry) specific thrust engine has a low tailpipe temperature, which means that the temperature rise across the afterburner can be high, giving a good thrust boost in afterburning. Nevertheless, the afterburning specific thrust is still relatively low. The total fuel flow (main combustor plus afterburner) is fixed by the temperature rise from air intake to nozzle and, for a given airflow, changes little with dry specific thrust.
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Installing the high technology systems envisaged for the MC2A on an increasingly obsolete airframe would not provide the capability required. The availability of powerful and reliable turbofans allowed a twinjet to be considered. In August 2003, Air International reported that the goal of integrating air- and ground- search radars on a single airframe was abandoned. Electronic interference between the active electronically scanned array (AESA) and ground-surveillance radars as well as the power requirements for both systems were cited as the reason.
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The Learjet 50 series was first announced at the 1977 Paris air show with larger cabins than the existing Learjets. The series was to have three variants, the Learjet 54, 55 and 56 but only the Learjet 55 was built. The Learjet 55 was a low-wing cantilever monoplane with NASA developed winglets, the winglets gave rise to the nickname Longhorn. The aircraft has a T-tail and is powered by two Garrett TFE731 turbofans mounted each side of the rear fuselage.
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Concorde needed to fly long distances to be economically viable; this required high efficiency from the powerplant. Turbofan engines were rejected due to their larger cross-section producing excessive drag. Olympus turbojet technology was available to be developed to meet the design requirements of the aircraft, although turbofans would be studied for any future SST. The aircraft used reheat (afterburners) at take-off and to pass through the upper transonic regime and to supersonic speeds, between Mach 0.95 and 1.7.
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A Tupolev Tu-204C operated for DHL by Aviastar-TU at Sheremetyevo International Airport in Moscow, Russia. Certified in January 1995, this initial version is powered by Soloviev (now Aviadvigatel) PS90 turbofans with 157 kN (35,300 lbf) of thrust, and uses Russian avionics in addition to its Russian engines. The Tu-204-200 is a heavier version with extra fuel for more range. Only one was built by Aviastar-SP in Ulyanovsk but has not yet been delivered (RA-64036).
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One of the most significant orders was when Northwest Airlines placed an order for 100 A320s in October 1986, later confirmed at the 1990 Farnborough Airshow, powered by CFM56 engines. During the A320 development programme, Airbus considered propfan technology, backed by Lufthansa. At the time unproven, it was essentially a fan placed outside the engine nacelle, offering speed of a turbofan at turboprops economics; eventually, Airbus stuck with turbofans. Power on the A320 would be supplied by two CFM56-5-A1s rated at .
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Slightly longer than the -300, the -500 has a larger wing, larger Rolls-Royce Trent 500 turbofans and three 4-wheel bogies for the main landing gear, it was introduced by Emirates in 2003. When the A340-500 was introduced, it was the world's longest-range commercial airliner. It first flew on 11 February 2002 and was certified on 3 December 2002. Air Canada was supposed to be the launch customer, but filed for bankruptcy in January 2003, delaying delivery to March.
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Most people use the term 'jet aircraft' to denote gas turbine based airbreathing jet engines, but rockets and scramjets are both also propelled by jet propulsion. Cruise missiles are single-use unmanned jet aircraft, powered predominately by ramjets or turbojets or sometimes turbofans, but they will often have a rocket propulsion system for initial propulsion. The fastest airbreathing jet aircraft is the unmanned X-43 scramjet at around Mach 9–10. The fastest manned (rocket) aircraft is the X-15 at Mach 6.85.
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Rolls-Royce chose a three-spool configuration for their large civil turbofans (i.e. the RB211 and Trent families), where the T-stages of the boosted two-spool configuration are separated into a separate intermediate pressure (IP) spool, driven by its own turbine. The first three-spool engine was the earlier Rolls-Royce RB.203 Trent of 1967. The Garrett ATF3, powering the Dassault Falcon 20 business jet, has an unusual three spool layout with an aft spool not concentric with the two others.
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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. Current low-bypass military turbofans include the Pratt & Whitney F119, the Eurojet EJ200, 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.
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Propfan engines use contra-rotating scimitar propellers to achieve turboprop efficiency levels at high subsonic air speeds comparable to that of turbofans. Turboprops operate best at speeds below about 450 mph (725 km/h). All propellers lose efficiency at high speed, due to an effect known as wave drag, which occurs just below supersonic speeds. This powerful form of drag exhibits sudden onset, and it led to the concept of a sound barrier when it was first encountered in the 1940s.
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From the 1960s through the 1970s, it set several world records in the categories of maximum payload-to-height ratio and maximum payload lifted to altitude. Of lesser note is the use of the NK-12 engine in the A-90 Orlyonok, a mid-size Soviet ekranoplan. The A-90 uses one NK-12 engine mounted at the top of its T-tail, along with two turbofans installed in the nose. In the 1980s, Kuznetsov continued to develop powerful contra-rotating engines.
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The -320B, powered by JT3D turbofans The 707-320B had the application of the JT3D turbofan to the Intercontinental, but with aerodynamic refinements. The wing was modified from the -320 by adding a second inboard kink, a dog-toothed leading edge, and curved low-drag wingtips instead of the earlier blunt ones. These wingtips increased overall wingspan by 3.0 ft. Takeoff gross weight was increased to . The 175 707-320B aircraft were all new-build; no original -320 models were converted to fan engines in civilian use.
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A Boeing 707 at Frankfurt Airport in 1972 Qantas entered the Jet Age in July 1959 with Boeing 707 services to the United States. The service was extended to London via New York. Sydney to London services via Bombay began in October 1959. With the certification of the turbofan engine, Qantas modified its existing 707–138 fleet with the turbofans, naming its Boeing 707 aircraft V-Jets, from the Latin vannus, meaning "fan" as commonly accepted, but really standing for "thing that blows against the grain".
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However, ducts designed for static conditions degraded in performance at high advance ratio, whereas a duct designed for axial cruise could regain good high-speed performance at the expense of static figure of merit. The Doak VZ-4 and the Bell X-22 especially had problems achieving high flight speeds. Therefore, to achieve both high hovering efficiency and high forward speed, the best way is to use a low disc loading lift fan or fans, in addition to turbofans for forward propulsion at cruise speed.
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The British versions of the McDonnell Douglas F-4 Phantom II (designated Phantom FG.Mk.1 and FGR.Mk.2) replaced the 16,000 lb wet thrust J79 turbojets with a pair of 20,515 lb wet thrust Spey 201 turbofans. These provided extra thrust for operation from smaller British aircraft carriers, and provided additional bleed air for the boundary layer control system for slower landing speeds. The air intake area was increased by twenty per cent, while the aft fuselage under the engines had to be redesigned.
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Boom wants to use moderate bypass turbofans without afterburners, unlike Concorde's Rolls- Royce/Snecma Olympus. The only available choices are jet fighter engines, which have neither the fuel economy nor the reliability required for commercial aviation. As of November 2016, no engine manufacturer can develop such an engine based on sales of only 10 options. Boom needs to address the noise of the high jet speed engine and the tripled fuel consumption per unit distance and per seat of a modern wide-body aircraft.
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The ICCT also estimated it would burn at least three times as much fuel as a subsonic business-class passenger. Engines won't be an exotic new design but a modified version of current turbofans, although they will have higher maintenance costs. They should be selected in 2018: a derivative of a commercial engine or a clean- sheet design, unlikely a military engine due to export controls. The 55-seat airliner will be powered by three engines without afterburners, with shorter maintenance intervals than subsonic jets.
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Development of 1950s–1960s engines like the GE J79, GE YJ93, GE4, PW J58 or Rolls-Royce Olympus ended when more efficiencies were pursued and subsequent advances in materials science for much hotter cores are not optimized for long supersonic endurance. The PW JT8D or GE J79 are better suited than current engines and staggering development costs render new low-bypass-ratio turbofans unlikely. In July 2020 the company announced that they had entered into an agreement with Rolls-Royce to collaborate on engine development.
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G8-01 is on public display at the Musée de l'Air et de l'Espace The basic Mirage G was developed into a twin-engine, two-seat nuclear strike fighter, the Mirage G4 after a separate contract was issued in 1968 for two aircraft to be built. These aircraft were intended to be powered by Snecma M53 turbofans in production. While the aircraft were under construction the requirements changed and the French military requested that the design be converted into a dedicated interceptor, the Mirage G8.
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Vehicle noise is predominantly from the engine at low vehicle speeds and from tires and the air flowing past the vehicle at higher speeds. Electric motors are quieter than internal combustion engines. Thrust-producing engines, such as turbofans, turbojets and rockets emit the greatest amount of noise due to the way their thrust-producing, high-velocity exhaust streams interact with the surrounding stationary air. Noise reduction technology includes intake and exhaust system mufflers (silencers) on gasoline and diesel engines and noise attenuation liners in turbofan inlets.
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Most currently operational vectored thrust aircraft use turbofans with rotating nozzles or vanes to deflect the exhaust stream. This method can successfully deflect thrust through as much as 90 degrees, relative to the aircraft centerline. However, the engine must be sized for vertical lift, rather than normal flight, which results in a weight penalty. Afterburning (or Plenum Chamber Burning, PCB, in the bypass stream) is difficult to incorporate and is impractical for take-off and landing thrust vectoring, because the very hot exhaust can damage runway surfaces.
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The F-111A mockup was inspected in September 1963. The first test F-111A was rolled out of Plant 4 of General Dynamics' Fort Worth, Texas facility on 15 October 1964. It was powered by YTF30-P-1 turbofans and used a set of ejector seats as the escape capsule was not yet available. The F-111A first flew on 21 December 1964 from Carswell Air Force Base, Texas, U.S. The first F-111B was also equipped with ejector seats and first flew on 18 May 1965.
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Finished in a gloss black night operations paint scheme, it became known as the "Black Bomber". Its performance at low level was superior to that of the B.1 (or any other V-bomber), particularly at sea level, with the aircraft being cleared for at low level (with speeds of up to being reached in testing). This was compared to the B.1's sea-level limit of . The Air Ministry ordered 17 production B.2s, which were to be powered by Rolls-Royce Conway turbofans.
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The X-55 is a one-off aircraft intended to demonstrate the use of advanced composite materials in the fuselage of an otherwise conventional high-wing transport aircraft. There are no plans to place the X-55 into production. Lockheed Martin's design for Advanced Composite Cargo Aircraft (ACCA) was chosen over Aurora Flight Sciences' design based on the Antonov An-72 in 2007. The aircraft is powered by 2 Pratt & Whitney PW306B turbofans. The X-55 design is based on the existing Fairchild Dornier 328JET.
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Reaction engines generate the thrust to propel an aircraft by ejecting the exhaust gases at high velocity from the engine, the resultant reaction of forces driving the aircraft forwards. The most common reaction propulsion engines flown are turbojets, turbofans and rockets. Other types such as pulsejets, ramjets, scramjets and pulse detonation engines have also flown. In jet engines the oxygen necessary for fuel combustion comes from the air, while rockets carry oxygen in some form as part of the fuel load, permitting their use in space.
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GECAS has a fleet of over 1,970 aircraft, used by 270 clients in over 75 countries. GECAS' primary competitor is AerCap, although other companies such as Air Lease Corporation, Aviation Capital Group, BBAM and SMBC Aviation Capital are players in the aviation finance industry. GE Aviation, another GE subsidiary, is part of the CFM International joint venture with Safran. Previously, GECAS had a policy of exclusively selecting GE engines for 99% of its airliners, and had only eight B757s with Pratt & Whitney or Rolls-Royce turbofans.
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Technical information and drawings are available at the United States Patent and Trademark Office. The WASP II uses a slightly modified and derated version of the WR-19-A7D, yielding 600 lbf thrust from its micro turbofan engine and is designated WR19-7, rated at 570 lbf thrust, after minor modifications and said derating. Modifications to the WR-19-A7D included accessories — replacement of pyro starter with electric/air start — and exhaust system modifications. No internal modifications to the counter-rotating micro turbofans were performed.
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Eclipse 500 flight test aircraft at Mojave Eclipse Aviation was founded by Vern Raburn in 1998 in Scottsdale, Arizona, and the company started to design the twin-engined Eclipse 500 very light jet. Due to investments by the State of New Mexico and incentives and concessions from the City of Albuquerque, the company decided to set up its production facilities there and moved its headquarters in 2000. Construction of the first prototype started in 2001 and it first flew on August 26, 2002. Originally powered by two Williams International EJ22 turbofans, these were found to be unsuitable, and the aircraft was redesigned to accommodate a pair of Pratt & Whitney Canada PW610F-A turbofans. The engine change caused a delay in the programme and the PW610F-equipped prototype first flew in 2004. The aircraft was FAA certified on July 27, 2006 and the first customer aircraft was delivered in January 2007. European Aviation Safety Agency certification for private use was achieved on November 21, 2008. In February 2006 the company was named the winner of the Collier Trophy for 2005 by the National Aeronautic Association for its work with the Eclipse 500.
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C-390 glass cockpit with fly-by- wire controls Embraer built the C-390 around the long, 3.45 m (11.3 ft) wide and high hold with a rear ramp. Its twin IAE V2500-E5 turbofans are mounted forward on the high wing with anhedral angle, slats and up to 40° flaps High- lift devices. The landing gear has low-pressure tires, two on the nose and four on either side bogies for soft, unpaved ground or damaged runways. Fly- by-wire flight controls with active sidesticks allows load factors up to 3g.
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After two years of evaluation and negotiations, on 30 November 1996, India signed a US$1.462 billion deal with Sukhoi for 50 Russian-produced Su-30MKIs in five batches. The first batch were eight Su-30MKs, the basic version of Su-30. The second batch were to be 10 Su-30Ks with French and Israeli avionics. The third batch were to be 10 Su-30MKIs featuring canard foreplanes. The fourth batch of 12 Su-30MKIs and final batch of 10 Su-30MKIs were to have the AL-31FP turbofans.
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The first F-14B was to be an improved version of the F-14A with more powerful "Advanced Technology Engine" F401 turbofans. The F-14C was a projected variant of this initial F-14B with advanced multi- mission avionics.Spick 2000, p. 75. Grumman also offered an interceptor version of the F-14B in response to the U.S. Air Force's Improved Manned Interceptor Program to replace the Convair F-106 Delta Dart as an Aerospace Defense Command interceptor in the 1970s. The F-14B program was terminated in April 1974.
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In 1959, Pan American World Airways ordered 12 of Lockheed's GL-207 Super Hercules to be delivered by 1962, to be powered by four 6,000 eshp Allison T56 turboprops.René J. Francillon: Lockheed Aircraft since 1913. Putnam Aeronautical Books, London 1987, , p. 372. Slick Airways was to receive 6 such aircraft later in 1962. The Super Hercules was to be longer than the C-130B; a variant powered by 6,445 eshp Rolls-Royce Tynes and a jet-powered variant with four Pratt & Whitney JT3D-11 turbofans were also under development.
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Bombardier Aerospace developed the 108 to 160-seat CSeries powered by two Pratt & Whitney PW1000G geared turbofans. The smaller CS100 entered service in July 2016 with Swiss Global Air Lines and the larger CS300 entered service with airBaltic in December. After the April 2016 CSeries dumping petition by Boeing, Airbus acquired a 50.01% majority stake in the program in October 2017 and renamed it the A220-100/300 in July 2018. In 2017, Embraer started calling large, almost narrowbody regional jets "crossover" jets, for the Embraer E-Jet E2 and the CSeries.
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Thrust depends on two things: the velocity of the exhaust gas and the mass of the gas. A jet engine can produce more thrust by either accelerating the gas to a higher velocity or ejecting a greater mass of gas from the engine. Designing a basic turbojet engine around the second principle produces the turbofan engine, which creates slower gas, but more of it. Turbofans are highly fuel efficient and can deliver high thrust for long periods, but the design tradeoff is a large size relative to the power output.
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A development of an existing commercial engine core with a new low-pressure spool is preferred over a clean-sheet design. Larger-diameter fans have higher cruise thrust requirements for a higher fuel-burn and lower range but are preferred for higher bypass and lower takeoff noise. Intake compression would need a low pressure core, and derivatives of existing 3–4:1 bypass-ratio turbofans are a compromise between takeoff noise and wave drag with a good fuel efficiency. For Lockheed Martin Skunk Works' Dave Richardson, suitable engines with low overall pressure ratio are scarce.
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Safran open rotor mockup in 2017. The European Commission launched in 2008 an Open Rotor demonstration led by Safran within the Clean Sky program with 65 million euros funding over eight years. A demonstrator was assembled in 2015, and ground tested in May 2017 on its open-air test rig in Istres, aiming to reduce fuel consumption and associated CO2 emissions by 30% compared with current CFM56 turbofans. After the completion of ground testing at the end of 2017, Safran's geared open rotor engine had reached a technology readiness level of TRL 5.
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Because of the aerodynamic efficiency of propellers and fans, it is more fuel efficient to accelerate a large mass by a small amount, which is why high-bypass turbofans and turboprops are commonly used on cargo planes and airliners. Some aircraft, like fighter planes or experimental high speed aircraft, require very high excess thrust to accelerate quickly and to overcome the high drag associated with high speeds. For these airplanes, engine efficiency is not as important as very high thrust. Modern combat aircraft usually have an afterburner added to a low bypass turbofan.
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In November 2003, AASI (by now, MASG) offered the entire Jetcruzer project for auction, and sold it to Innova Aircraft in February 2004. Shortly after the purchase, Innova announced its intentions of offering a new version of the aircraft in kit form, marketed by a new subsidiary, Jetcruzer LLC. This will feature a modified wing to overcome the problems faced by the Jetcruzer 500, and will be powered by a pair of Pratt & Whitney Canada JT15D turbofans. It was expected to fly by late 2004 or early 2005.
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The A-9 was a shoulder-wing monoplane of all-riveted aluminum alloy construction, with honeycomb structures and chemically milled skins. The required twin turbofans were fitted in nacelles under the aircraft's wing roots. Northrop selected the Lycoming YF102 engine for the YA-9 rather than the more powerful () General Electric TF34 used by the A-10, although either engine could be accommodated. The F-102 engine was a new design, based on the T55 turboshaft that powered the CH-47 helicopter, which was selected in order to minimize costs.
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If the modification is carried out, the E-3s could take off with full fuel loads using runways only long, and also at higher ambient temperatures and altitudes. An E-8 test aircraft was briefly fitted with new Pratt & Whitney JT8D-219 turbofans, claimed to have one-half the cost of the competing engine, the CFM56. NATO intends to extend the operational status of its AWACS until 2035.NATO summit Warsaw July 2016 To comply, fourteen AWACS aircraft will be significantly modified in the Final Lifetime Extension Program (FLEP).
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Many turbofans have at least basic two-spool configuration where the fan is on a separate low pressure (LP) spool, running concentrically with the compressor or high pressure (HP) spool; the LP spool runs at a lower angular velocity, while the HP spool turns faster and its compressor further compresses part of the air for combustion. The BR710 is typical of this configuration. At the smaller thrust sizes, instead of all-axial blading, the HP compressor configuration may be axial-centrifugal (e.g., CFE CFE738), double-centrifugal or even diagonal/centrifugal (e.g.
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At high flight speeds, high-specific-thrust engines can pick up net thrust through the ram rise in the intake, but this effect tends to diminish at supersonic speeds because of shock wave losses. # Thrust growth on civil turbofans is usually obtained by increasing fan airflow, thus preventing the jet noise becoming too high. However, the larger fan airflow requires more power from the core. This can be achieved by raising the overall pressure ratio (combustor inlet pressure/intake delivery pressure) to induce more airflow into the core and by increasing turbine inlet temperature.
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Together, these parameters tend to increase core thermal efficiency and improve fuel efficiency. # Some high-bypass-ratio civil turbofans use an extremely low area ratio (less than 1.01), convergent-divergent, nozzle on the bypass (or mixed exhaust) stream, to control the fan working line. The nozzle acts as if it has variable geometry. At low flight speeds the nozzle is unchoked (less than a Mach number of unity), so the exhaust gas speeds up as it approaches the throat and then slows down slightly as it reaches the divergent section.
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It keeps the Citation Sovereign wing, twin Pratt & Whitney Canada PW306D turbofans and cruciform tail. Its clean sheet, all metal stand-up circular fuselage has a flat floor and seats nine. Typical missions are 2.0–2.7 hours and with block speeds and most operators can fly 5–6 hours at Mach 0.72–0.76 for a 2,000–2,400 nmi range, with short takeoff requirements and good hot and high performance. A first hour fuel burn of followed by the second hour and fuel burn can reach for a 2-hour trip with favorable conditions.
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With the development of the Jet Engine, at long last designers have the power to realize the dreams of aerial transport. Key to this were new generation turbojets and resulting turbofans, beginning with the General Electric J79. The Lockheed C-141 Starlifter and its contribution to the Vietnam War and transporting casualties home is reviewed. With the advent of the Pratt & Whitney JT9D, true giants such as the Lockheed C-5 Galaxy take to the air - an aircraft with the ability to accomplish the entire Berlin Airlift in only 5 flights.
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Aircraft gas turbine engines (jet engines) are responsible for much of the aircraft noise during takeoff and climb, such as the buzzsaw noise generated when the tips of the fan blades reach supersonic speeds. However, with advances in noise reduction technologies—the airframe is typically more noisy during landing. The majority of engine noise is due to jet noise—although high bypass-ratio turbofans do have considerable fan noise. The high velocity jet leaving the back of the engine has an inherent shear layer instability (if not thick enough) and rolls up into ring vortices.
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An SJ30 prototype Ed Swearingen announced a new design for a light twin business jet in October 1986, the SA-30 Fanjet. The SA-30 was to be a 6 to 8 person aircraft powered by two Williams FJ44 turbofans and with a highly swept wing of relatively small area. It was planned to be more efficient than contemporary business jets, and to sell for $2 million. In October 1988 an agreement was signed with Gulfstream Aerospace with the SA-30 to be manufactured and sold by Gulfstream as the Gulfstream Gulfjet.
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The Caspian Sea Monster at Kaspiysk photographed with a KH-8 reconnaissance satellite in 1984. It remained the heaviest aircraft in the world throughout its 15-year service life, and served as the basis for Lun's development. Unlike the Lun, the KM featured a constant-chord main wing and a stabilizer with notable dihedral (visible in the image as a difference in brightness between the left and right side of the stabilizer) and an unswept aft trailing edge. Lun-class at Kaspiysk, Russia, in 2010 The Lun was powered with eight Kuznetsov NK-87 turbofans, mounted on forward canards, each producing of thrust.
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Another study of a somewhat different APT concept was done at Martin Marietta during January through May 1994, this one of a near-term suborbital X-Plane that could serve as a demonstration vehicle for the APT concept. The study was led by engineer Robert Zubrin, who wrote about his experiences in his book Entering Space. Because the vehicle was about half the size of Black Horse, it was called "Black Colt." This concept used an existing NK-31 RP/O2 rocket engine with two Garrett F-125 turbofans used for takeoff, loiter during aerial propellant transfer, and landing propulsion.
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The fan diameter of the SuperFan was planned to be 107 in (2.72 m), resulting in a nacelle with a diameter of 120 in (3.05 m) made from composite materials. To ensure a good performance also in partload ratings and to support the thrust reverser, a variable-pitch mechanism for the 18 fan blades would have been installed. The blades itself were designed as hollow titanium blades. The fan blades would be shrouded by a cowling, but unlike with normal turbofans, the fan cowling would not extend backward, and the rest of the engine would be enclosed in a separate, slimmer cowling.
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Most modern jet engine designs are turbofans, which have largely replaced turbojets. These modern engines use a gas turbine engine core with high overall pressure ratio (about 40:1 in 1995) and high turbine entry temperature (about 1800 K in 1995),"Gas Turbine Technology Evolution: A Designer's Perspective" Bernard L.Koff Journal of Propulsion and Power Vol20 No4 July–August 2004 Fig.34/41 and provide a great deal of their thrust with a turbine-powered fan stage, rather than with pure exhaust thrust as in a turbojet. These features combine to give a high efficiency, relative to a turbojet.
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Boeing SUGAR Volt concept aircraft SUGAR Volt is a hybrid aircraft concept proposed by a team led by Boeing's Research & Technology division. It is one of a series of concepts put forward in response to a request for proposals for future aircraft issued by NASA. It is proposed that SUGAR Volt would use two hybrid turbofans that burn conventional jet fuel when taking off, then use electric motors to power the engines while flying. SUGAR stands for Subsonic Ultragreen Aircraft Research, the "volt" part of the "SUGAR Volt" name suggests that it would be at least partly powered by electricity.
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CJ3 side view, seven windows ;CitationJet CJ3 :Model 525B are marketed as the CitationJet CJ3 are a further stretch of the CJ2 powered by Williams FJ44-3A turbofans. Unveiled at the September 2002 National Business Aviation Association convention, it first flew on April 17, 2003, was FAA certified in October 2004 and deliveries began in December of that year. The cockpit with Rockwell Collins avionics is designed for single-pilot operation but can accommodate two crew members. Its customizable cabin typically has six club seats in a center-style configuration with an accessible in flight baggage compartment and external baggage access.
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The longest CitationJet, the CJ4, has 5+1 starboard windows ; Cessna Citation CJ4 (Model 525C) : The stretched CJ4 was launched at the October 2006 NBAA conference. Its wing design comes from the moderately swept wing of the Citation Sovereign. Powered by Williams FJ44-4A turbofans, it has a maximum range of 2,165 nmi (4,010 km). Its cabin is 21 inches longer than the CJ3 and can seat up to nine people plus one in the cockpit. It first lifted off on May 5, 2008, from McConnell AFB in Wichita, Kansas and first deliveries started in 2010.
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First run in August 1990 as the model Trent 700, the Trent has achieved significant commercial success, having been selected as the launch engine for all three of the 787 variants (Trent 1000), the A380 (Trent 900) and the A350 (Trent XWB). Its overall share of the markets in which it competes is around 40%. Sales of the Trent family of engines have made Rolls- Royce the second biggest supplier of large civil turbofans after General Electric, relegating rival Pratt & Whitney to third position. By June 2019, the Trent family had completed over 125 million hours.
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USAF procurement of the Boeing 707 was very limited, amounting to three Model 707-153s designated VC-137A. When delivered in 1959 these had four 13,500 lb (6123 kg) dry thrust Pratt & Whitney J57 (JT3C6) turbojets; when subsequently re-engined with 18,000 lbf (80.1 kN) dry thrust TF33-P-5 (JT3D) turbofans they were redesignated VC-137B. Only one other variant served with the USAF: this was the VC-137C Air Force One presidential transport, the two examples of which were Model 707-320B Intercontinentals with specialized interior furnishings and advanced communications equipment. Two further non-presidential C-137C aircraft were later added.
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By October 2018, Safran had amassed over 9,000 test hours and 300 in flight. Safran needs a second customer to justify its investment, but is still optimistic for the engine's future. In July 2019, Textron suspended the Cessna Citation Hemisphere development as its turbofans did not meet objectives: the new high pressure compressor exceeded expectations during ground tests but further trials are necessary to "confirm engine improvements and complete overall engine performance and durability validation" and Safran will continue the effort as an "R&T; platform". For Safran, insufficient skills retention is causing the repetition of technical issues as design engineers retire.
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Kay, p. Previous design efforts in Germany had investigated ducted fans (turbofans / by-pass turbojets) and contra-rotating compressor spools, but Leist incorporated both into the ZTL6000 (precursor to the ZTL 6001 / DB 007), resulting in a very complex design. Another novel feature was a turbine which passed alternately through the combustion chamber efflux and cooling air tapped from the bypass flow. By the Summer of 1942 design goals had been revised down and the new engine was given the designations ZTL6001 (company) and DB 007 / ZTL 109-007 (RLM), ZTL being an acronym for Zweikreiststurbinen-Luftstrahltriebwerk (two-circuit turbojet engine).
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Turboprops and most propfans are rated by the amount of shaft horsepower (shp) that they produce, as opposed to turbofans and the UDF propfan type, which are rated by the amount of thrust they put out. This difference can be somewhat confusing when comparing different types of engines. The rule of thumb is that at sea level with a static engine, is roughly equivalent of thrust, but at cruise altitude, that changes to about thrust. That means a narrowbody aircraft with two engines can theoretically be replaced with a pair of propfans or with two UDF propfans.
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Auxiliary power units (APUs) are backup systems that deliver power to the engines, flight control and other avionics on an aircraft in the event the main power systems fail. The Honeywell 131-9 APU was used in an emergency landing when U.S. Airways Flight 1549 splash landed in New York City’s Hudson River on January 15, 2009, called the Miracle on the Hudson. Both CFM56 turbofans were damaged and electrical generators went off line. The pilot told the National Transportation Safety Board (NTSB) that his first command after birds flew into the turbine engines was to activate the Honeywell APU.
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World Air Power Journal Summer 1994, p.27. GSh-23L twin-barreled cannon The Il-102 was a low-winged monoplane with moderately swept (30 degrees) wings, powered by two Klimov RD-33I turbofans (non-afterburning versions of the engines that power the Mikoyan MiG-29 fighter). It was highly unusual for its time in having a rear gun turret, something not seen in ground-attack aircraft since the World War II Il-2 Shturmovik and Il-10, the Il-102's spiritual ancestors, controlled remotely by a gunner sitting in a cockpit above the trailing edge of the wing.
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One of the earliest turbofans was a derivative of the General Electric J79 turbojet, known as the CJ805-23, which featured an integrated aft fan/low-pressure (LP) turbine unit located in the turbojet exhaust jetpipe. Hot gas from the turbojet turbine exhaust expanded through the LP turbine, the fan blades being a radial extension of the turbine blades. This aft-fan configuration was later exploited in the General Electric GE36 UDF (propfan) demonstrator of the early 80s. One of the problems with the aft fan configuration is hot gas leakage from the LP turbine to the fan.
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Turbofans were invented to circumvent the undesirable characteristic of turbojets being inefficient for subsonic flight. To raise the efficiency of a turbojet, the obvious approach would be to increase the burner temperature, to give better Carnot efficiency and fit larger compressors and nozzles. However, while that does increase thrust somewhat, the exhaust jet leaves the engine with even higher velocity, which at subsonic flight speeds, takes most of the extra energy with it, wasting fuel. Instead, a turbofan can be thought of as a turbojet being used to drive a ducted fan, with both of those contributing to the thrust.
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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 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.
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Mockup with compressor and turbine cutaway In summer 1993 Pratt & Whitney started to test its Advanced ducted Prop (ADP) demonstrator at the NASA Ames wind tunnel, using a 4:1, gearbox. Its fan with 18 reversing pitch composite blades had a 15:1 bypass ratio. It aimed to cut fuel consumption by 6–7%, emissions by 15%, and generate less noise due to lower fan tip speed of , down from in conventional 5:1 bypass turbofans. While the gearbox and larger fan weighed more, this was mitigated by using 40% composites by weight up from 15%.
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MiG-35D taking off The MiG-35 is powered by two FADEC RD-33MK Morskaya Osa (, literally: "Sea Wasp" or Chironex fleckeri) turbofans. The RD-33MK a highly improved variant and the latest version of the Klimov RD-33 turbofan and was intended to power the MiG-29K and MiG-29KUB. It has 7% more power compared to the baseline model due to the use of modern materials in the cooled blades, providing a higher thrust of 9,000 kgf. In response to earlier criticism, the new engines are smokeless and include systems that reduce infrared and optical visibility.
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At high overall pressure ratios, the compression system is usually split into two units; a low-pressure (LP) compressor mounted on one shaft followed by a high- pressure (HP) compressor mounted on the HP shaft and driven by its own (HP) turbine. On civil turbofans, the first stage of the LP compressor is often a single-stage fan. If the HP compressor pressure ratio exceeds about 4.5:1, then the unit will probably have variable geometry (i.e. variable stators) on the first few stages, to make the surge line on the compressor map more shallow, to accommodate the shallow working line.
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Planform view, showing wing sweep It is a small, low-winged twin- turbofan aircraft of all metal construction, flown by a crew of two pilots and accommodating eight passengers in a pressurised cabin. Its wings use a computer designed, supercritical airfoil in order to minimise drag. Its two Pratt & Whitney Canada JT15D turbofans are mounted on the rear fuselage. Powered by JT15D-5/-5R, it can fly with four passengers, cruising at Mach 0.71–0.73, and most pilots are comfortable flying it over three hours, about cruising at Mach 0.73–0.76, typical missions are 1.5 to 2.0 hours with block speeds.
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It identified the market "sweet spot" for the NMA as being a 200 to 250-seat twin-aisle aircraft with more than range, but less expensive to operate than existing small twin aisles. The notional aircraft, which would enter service in the middle of the next decade, would need advanced high-bypass turbofans with higher pressure ratios. Boeing development resources were committed on the 777X, 787-10 and 737 MAX, whereas Airbus's R&D; spending profile appeared to leave room for new development; however, Airbus believed that the A321LR and A330neo were sufficient to address the segment.
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AL-41F1 engine compressor stall at MAKS-2011 Preproduction T-50 and initial production batches of the Su-57 will use interim engines, a pair of NPO Saturn izdeliye 117,The Russian term , translit. izdeliye literally means "manufactured article" or "product" or AL-41F1, augmented turbofans."NPO." Saturn Press Release, 29 January 2010. Retrieved: 26 January 2011. The engine is a highly improved and uprated variant of the AL-31 that powers the Su-27 family of aircraft and produces 93.1 kN (21,000 lbf) of dry thrust, 147.1 kN (33,067 lbf) of thrust in afterburner, and has a dry weight of approximately .
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Sedbon July 1986, p. 4. Throughout the flight test programme, the Rafale A performed numerous day and night take-offs and landings aboard the carriers and to investigate the pilot's field of view during carrier operations. It reached a speed of and a height of . The demonstrator was initially powered by General Electric F404-GE-400 afterburning turbofans from the F/A-18 Hornet, instead of the Snecma M88, to reduce the risk that often comes with a first flight, and since the M88 was not considered sufficiently mature for the initial trials programme.Spick 2000, p. 433.
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Almost 1,700 aircraft of all variants, including the Hawker 800, were produced between 1962 and 2013. The Aero Commander 1121 Jet Commander, which later became the IAI Westwind, first flew on 27 January 1963, powered by two General Electric CJ610 turbojets, then Garrett TFE731s. Production of Jet Commanders and Westwinds from 1965 to 1987 came to 442 aircraft; and it was developed as the IAI Astra, later re-branded as the Gulfstream G100. The MTOW Dassault Falcon 20 first flew on 4 May 1963, powered by two General Electric CF700s, then Garrett ATF3 turbofans and Garrett TFE731s.
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Beginning in January 1988, all Block 15 F-16A/B were delivered with an Operational Capability Upgrade (OCU). The Block 15 OCU aircraft incorporate the wide-angle HUD that was first introduced on the F-16C/D Block 25, more reliable F100-PW-220 turbofans, updated defensive systems, the ability to fire the AGM-65 Maverick air-to-ground missile, and the AGM-119 Penguin Mk.3 anti-shipping missile developed by the Norwegian company Kongsberg, and provisions for the AIM-120 AMRAAM. Many foreign customers upgraded their aircraft to the F-16A/B Block 15OCU standard.
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These models feature new avionics, winglets, and powerful engines that use less fuel. The Learjet 40/45 light jet is updated with touchscreen- controlled Garmin G5000 avionics and a modern interior. The combination of aerodynamic improvements, which lowered the design's drag by 2%, and 200 lbs less weight in the nose section resulted in an increased range of 4%. The canted winglet design was incorporated from the Bombardier Global 7500/8000. Both variants are powered by Honeywell TFE731-40BR turbofans with thrust reversers, have a MTOW of and a fuel capacity of for a maximum range of with four passengers.
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2005, p. 131. On 2 February 1965, Prime Minister Harold Wilson announced the intention to order Hawker Siddeley's maritime patrol version of the Comet, the HS.801 as a replacement for Shackleton Mk 2. The Nimrod design was based on that of the Comet 4 civil airliner which had reached the end of its commercial life (the first two prototype Nimrods, XV148 and XV147, were built from two final unfinished Comet 4C airframes). The Comet's turbojet engines were replaced by Rolls-Royce Spey turbofans for better fuel efficiency, particularly at the low altitudes required for maritime patrol.
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Turbojet engine layout Two engineers, Frank Whittle in the UK and Hans von Ohain in Germany, developed the turbojet concept independently into practical engines during the late 1930s. Turbojets consist of an inlet, a compressor, a combustor, a turbine (that drives the compressor) and a propelling nozzle. The compressed air is heated in the combustor and passes through the turbine, then expands in the nozzle to produce a high speed propelling jet Turbojets have a low propulsive efficiency below about Mach 2 and produce a lot of jet noise, both a result of the very high velocity of the exhaust. Modern jet propelled aircraft are powered by turbofans.
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The -320 and -420 are 8 ft (2.4 m) longer than the initial -120; later 707s were powered by JT3D turbofans. The initial standard model was the 707-120 with JT3C turbojet engines. Qantas ordered a shorter-bodied version called the 707-138, which was a -120 with six fuselage frames removed, three in front of the wings, and three aft. The frames in the 707 were set apart, so this resulted in a shortening of to a length of . With the maximum takeoff weight the same as that of the -120 (), the -138 was able to fly the longer routes that Qantas needed.
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Cubana de Aviación Ilyushin Il-96-300 The Il-96-300 is the initial variant and is fitted with Aviadvigatel (Soloviev) PS-90A turbofans with a thrust rating of 16,000 kgf (157 kN, 35,300 lbf). Development started in the mid-80s while the first prototype flew on 28 September 1988. The first Il-96 entered service with Aeroflot in 1993. Range with 262 passengers and fuel reserves (for holding 75 minutes at an altitude of 450 m) in a two-class configuration is about 11,000 km (5,940 nmi), allowing flights from Moscow to US west coast cities, a great improvement over the Ilyushin Il-86.
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This resulted in split seams, enabling flooding in her boiler and turbine rooms that created an eight-degree list to port after the turbofans and pumps failed. Although the crew extinguished a fire in one boiler room, raised steam in another, and restarted the turbogenerator and diesel generator in a machine room, the pumps could not cope with the flooding and the list reached twelve degrees at 05:00. As a result, her captain ordered the crew to abandon ship and about twenty minutes later they had been completely transferred to a minesweeper. The destroyer quickly sank after the explosion of her depth charges.
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Postwar commercial airframe design focused on airliners, on turboprop engines, and then on Jet engines : turbojets and later turbofans. The generally higher speeds and tensile stresses of turboprops and jets were major challenges. Newly developed aluminum alloys with copper, magnesium and zinc were critical to these designs. Flown in 1952 and designed to cruise at Mach 2 where skin friction required its heat resistance, the Douglas X-3 Stiletto was the first titanium aircraft but it was underpowered and barely supersonic; the Mach 3.2 Lockheed A-12 and SR-71 were also mainly titanium, as was the cancelled Boeing 2707 Mach 2.7 supersonic transport.
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Instead P&W; designed a 2-stage unit based on some research they had done to support the J91 nuclear turbojet. On the Boeing 707 the JT3D fan nacelle was relatively short, whereas the Douglas DC-8 installation had a full length fan cowl. Pratt & Whitney provided a kit whereby JT3Cs could be converted to the JT3D standard in an overhaul shop.based on article in Flight magazine 19 December 1958 In 1959, important orders for the engine were the Boeing 707-120B and Boeing 720B when American Airlines ordered one 707 powered by JT3D turbofans and KLM ordered a JT3D powered Douglas DC-8.
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The A320 is a low wing airliner with twin turbofans and a conventional tail The Airbus A320 family are narrow-body (single-aisle) aircraft with a retractable tricycle landing gear and are powered by two wing pylon-mounted turbofan engines. After the oil price rises of the 1970s, Airbus needed to minimise the trip fuel costs of the A320. To that end, it adopted composite primary structures, centre-of-gravity control using fuel, glass cockpit (EFIS) and a two-crew flight deck. Airbus claimed the 737-300 burns 35% more fuel and has a 16% higher operating cost per seat than the V2500-powered A320.
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Off-design performance and stability is, however, affected by engine configuration. The basic element of a turbofan is a spool, a single combination of fan/compressor, turbine and shaft rotating at a single speed. For a given pressure ratio, the surge margin can be increased by two different design paths: # Splitting the compressor into two smaller spools rotating at different speeds, as with the J57; or # Making the stator vane pitch adjustable, typically in the front stages, as with the J79. Most modern western civil turbofans employ a relatively high- pressure-ratio high-pressure (HP) compressor, with many rows of variable stators to control surge margin at low rpm.
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Pratt & Whitney F119 afterburning turbofan on test Since the 1970s, most jet fighter engines have been low/medium bypass turbofans with a mixed exhaust, afterburner and variable area final 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, prodigious amounts of fuel are burnt in 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 flow when the afterburner is lit.
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CFM56-3 turbofan engine A turbofan engine is much the same as a turbojet, but with an enlarged fan at the front that provides thrust in much the same way as a ducted propeller, resulting in improved fuel efficiency. Though the fan creates thrust like a propeller, the surrounding duct frees it from many of the restrictions that limit propeller performance. This operation is a more efficient way to provide thrust than simply using the jet nozzle alone, and turbofans are more efficient than propellers in the transsonic range of aircraft speeds and can operate in the supersonic realm. A turbofan typically has extra turbine stages to turn the fan.
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The original EMB-145 Amazon design with a straight wing and overwing engines The 45–48 seat EMB145 was launched at the Paris Airshow in 1989 as an stretch of the EMB 120 Brasilia developed for $150M plus $50M for training and marketing, one third the cost of the cancelled Short Brothers FJX project. Its $11M unit cost would have been $3M less than the Canadair CRJ. The jet would be powered by GE/Garrett CFE738s, Lycoming ALF 502s or Rolls-Royce plc/Allison Engine AB580s turbofans, to be selected in the summer of 1989. It was targeted for a late 1992 introduction with six produced then ramping to 60 per year in 1995.
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The Challenger stand-up, flat floor cabin The Challenger (here a Royal Canadian Air Force CC-144) has a swept wing, a T-tail and two aft-mounted turbofans The Challenger is a twin-engined business jet, described by Flight International as being ‘’miniturised twinjet airliner in every respect’’. While the Challenger is generally similar in configuration to previous aircraft of its type, some of its features stand out; for example, the use of a widened fuselage that allows a "walk-about cabin". The Challenger was also one of the first business jets to be designed with a supercritical wing. The wing was referred by Canadair as being one of the aircraft's most advanced features.
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A first is the elimination of bleed air systems using high temperature/high pressure air from the propulsion engines to power aircraft systems such as the starting, air-conditioning and anti-ice systems. Both engines enable the move towards the More Electric Aircraft, that is, the concept of replacing previously hydraulic and pneumatic systems with electrical ones to reduce weight, increase efficiency, and reduce maintenance requirements. The GEnx was expected to produce thrust from with first tests commencing in 2006 and service entry by 2008 (delayed by 787 deliveries). Boeing predicts reduced fuel consumption of up to 20% and significantly quieter engines than current turbofans. A thrust version (GEnx-2B67) will be used on the 747-8.
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The Navy version would carry an AN/AWG-9 Pulse-Doppler radar and six AIM-54 Phoenix missiles. The Air Force version would carry the AN/APQ-113 attack radar and the AN/APQ-110 terrain-following radar and air-to-ground ordnance.Baugher, Joe. "General Dynamics F-111A." General Dynamics F-111 Aardvark, 23 December 1999. Lacking experience with carrier-based fighters, General Dynamics teamed with Grumman for assembly and test of the F-111B aircraft. In addition, Grumman would also build the F-111A's aft fuselage and the landing gear. The first test F-111A was powered by YTF30-P-1 turbofans and used a set of ejection seats, since the escape capsule was not yet available.
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Although the Malloy hoverbike may appear very similar to a Star Wars hoverbike in terms of size, shape and performance, its input and levitation is by air propulsion with the use of turbofans as opposed to a Star Wars hoverbike which uses anti- gravity "repulsorlift" engines. Levitation is depicted throughout the Star Wars films, as well as in most other spin-off media of the franchise. Levitation in Star Wars is primarily caused by a type of anti-gravity technology known within the setting as a "repulsorlift engine." According to in-universe material, a fusion-powered repulsorlift or 'antigrav' creates a field of negativity gravity that pushes against the natural gravitational field of a planet.
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The NK-93 engine was developed beginning in the late 1980s, although the design of the engine was allegedly envisioned as early as 1968. Many of the design features were adopted from the Kuznetsov NK-92, the military complement to the NK-93. The core of the NK-93 was to form the foundation of a family of direct-drive turbofans and geared propfans, ranging from in thrust. It was the last major project of Kuznetsov Design Bureau founder Nikolai Dmitriyevich Kuznetsov. The NK-93 was originally scheduled for flight testing in late 1993/early 1994 and certification in 1997 so that it could be used on the Ilyushin Il-96M and Tupolev Tu-204M.
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Early small jets had higher operating costs than turboprops on short routes. The gap narrowed with better turbofans, and closed with the higher utilization due to higher speeds. In 1983 British Aerospace introduced its BAe 146 short-range jet, produced in three sizes between 70 and 112 seats: the −100, −200 and the largest −300, later renamed the Avro Regional Jet. Low aircraft noise and short takeoffs were suited to city-center to city-center service, a small market niche, like the de Havilland Canada Dash 7, but four engines led to higher maintenance costs than twin-engine designs and BAe did not produce a lower operating cost twin-engine design, unlike the Dash 8.
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Most modern jet planes use turbofan jet engines, which balance the advantages of a propeller while retaining the exhaust speed and power of a jet. This is essentially a ducted propeller attached to a jet engine, much like a turboprop, but with a smaller diameter. When installed on an airliner, it is efficient so long as it remains below the speed of sound (or subsonic). Jet fighters and other supersonic aircraft that do not spend a great deal of time supersonic also often use turbofans, but to function, air intake ducting is needed to slow the air down so that when it arrives at the front of the turbofan, it is subsonic.
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To update the oldest aircraft in its fleet, the 727-100QF conversion was introduced (QF=Quiet Freighter). In place of a hush kit, the QF conversion changed the aircraft from Pratt & Whitney JT8D to Rolls-Royce Tay turbofans. In 1991, to gain the ability to fly domestic cargo flights within Europe, UPS entered into a partnership with Danish airline Star Air (part of the Maersk conglomerate), leasing several 727 freighters to the airline (later replaced by 757 freighters). In the early 1990s, to add capacity to its network, UPS Airlines opened additional hubs, with primary hubs in Rockford, Illinois (Chicago) and Philadelphia; secondary hubs were opened in Dallas/Fort Worth; Columbia, South Carolina; and Ontario, California (Los Angeles).
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Victor B.2 aircraft (XL158), at RAF Wittering, Cambridgeshire, undergoing pre- flight preparations The RAF required a higher ceiling for its bombers, and a number of proposals were considered for improved Victors to meet this demand. At first, Handley Page proposed use of the Sapphire 9 engines to produce a "Phase 2" bomber, to be followed by "Phase 3" Victors with much greater wingspan at and powered by Bristol Siddeley Olympus turbojets or Rolls-Royce Conway turbofans. The Sapphire 9 was cancelled, however, and the heavily modified Phase 3 aircraft would have delayed production, so an interim "Phase 2A" Victor was proposed and accepted, to be powered by the Conway and having minimal modifications.Barnes 1976, pp. 509–511.
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Logan 1998, pp. 26, 106–107. The sole operator of this variant was the 27th TFW stationed at Cannon AFB, New Mexico. The F-111D used the new Triple Plow II intakes, which were located four inches (100 mm) further away from the airframe to prevent engine ingestion of the sluggish boundary layer air that was known to cause stalls in the TF30 turbofans. It had more powerful TF30-P-9 engines with 12,000 lbf (53 kN) dry and 18,500 lbf (82 kN) afterburning thrust.Knaack 1978, pp. 250–252. The Mark II avionics were digitally integrated microprocessor systems, some of the first used by the USAF, offering tremendous capability, but substantial problems.
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The ratio of the mass-flow of air bypassing the engine core divided by 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 today are of the high-bypass type, and most modern military fighter engines are low-bypass. Afterburners are not used on high-bypass turbofan engines but may be used on either low-bypass turbofan or turbojet engines.
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J85, sectioned for display. Flow is left to right, multistage compressor on left, combustion chambers center, two-stage turbine on right Airbreathing jet engines are gas turbines optimized to produce thrust from the exhaust gases, or from ducted fans connected to the gas turbines. Jet engines that produce thrust from the direct impulse of exhaust gases are often called turbojets, whereas those that generate thrust with the addition of a ducted fan are often called turbofans or (rarely) fan-jets. Gas turbines are also used in many liquid fuel rockets, where gas turbines are used to power a turbopump to permit the use of lightweight, low-pressure tanks, reducing the empty weight of the rocket.
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A notable spin-off of this technique was the A-90 Orlyonok ekranoplane, which was powered in flight by a massive Kuznetsov NK-12 turboprop (by far the most powerful ever built), and required two large turbofans embedded in the nose for take-off, whose ducts pointed permanently downwards under the wings to provide PAR thrust. These engines were shut down during flight to reduce fuel consumption. Some other craft such as Burt Rutan's PARLC, Russian Strizh PE-201, Volga 2, Ivolga and other WIG craft use this system. Boats that use this system (surface effect ships) require permanent use of PAR thrust in order to achieve enough lift for normal operation.
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The operating and support costs of the Skyfox were less than that of the T-33 and could compete with the costs of the Hawk and the Alpha Jet. Structural improvements, avionics upgrades, electrical rewiring, airframe and systems refurbishment, and powerplant modifications resulted in low cost, low maintenance hours, and low spare parts consumption. The two TFE371-3A turbofans that powered the Skyfox together weighed 17 per cent less than the single J33-A-35 turbojet of the T-33, while producing 60 percent more thrust and consuming 45 percent less fuel. The TFE371-3A turbofan had a ten-fold increase in time between overhauls (TBO) compared with the J33-A-35 turbojet.
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KC-135R aircraft taxiing prior to takeoff. The new engines are CFM56-2 high-bypass turbofans. Winning the contract to re-engine the KC-135 tanker fleet for the USAF would be a huge boon to the CFM56 project (with more than 600 aircraft available to re-engine), and CFMI aggressively pursued that goal as soon as the Request For Proposals (RFP) was announced in 1977. Like other aspects of the program, international politics played their part in this contract. In efforts to boost the CFM56's chances versus its competitors, the Pratt & Whitney TF33 and an updated Pratt & Whitney JT8D, the French government announced in 1978 that they would upgrade their 11 KC-135s with the CFM56, providing one of the first orders for the engine.
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Although Williams originally designed these small turbofans to power target drones while aiming for a contract in the Subsonic Cruise Armed Decoy (SCAD) program, it quickly became apparent that these were valuable tools to be used in the future to power advanced cruise missiles. Originally designated the F107-WR-14A6, then designated the F107-WR-103 by Williams then designated the F112-WR-100 by the USAF. Though the true benefits that the F112 brought to the AGM-129 are classified, it has been said that the F112 increased the range of the AGM-129 to four times that of the AGM-86B. Another benefit is that the infrared heat signature has also been reduced or nearly eliminated, aiding the stealthiness of the AGM-129.
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Lateral bottom view with the annular duct closed off by shutter or louvers After the aircraft reaches the speed of aerodynamic flight, the annular duct is closed off by shutters mounted at the top and bottom of the duct to form a smooth disc wing. The lift fans stop working and are enclosed in the annular duct during cruise flight. The traditional ailerons and elevators located at the rear edge of the outer wing are needed for roll and pitch control, but the rudder probably is not necessary. According to the CFD simulations, turbofans with a thrust-to-weight ratio of 0.3 can enable a top forward speed of Mach 0.62 (759 km/h) based on aerodynamic drag predictions, much faster than helicopters and tiltrotors.
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In 2011, Boeing refined its response to the revamped Airbus A350 XWB with three 777X models, targeting a firm configuration in 2015, flying in late 2017 or 2018, and entering service by 2019. The 407–passenger 777-9X should stretch the 777-300ER by four frames to in length, for a maximum take-off weight (MTOW) and powered by engines, targeting per-seat 21% better fuel burn and 16% better operating cost. The smaller 353-seat 777-8X was to stretch the 777-200ER by ten frames to , with a MTOW and turbofans to compete with the A350-900 with improvements over the -200ER like the 777-9X over the 777-300ER. A 8LX with the 9X MTOW would have a range.
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DC-8s without "fans" (meaning the jet engines, or turbofans). The story of Xenu is covered in OT III, part of Scientology's secret "Advanced Technology" doctrines taught only to advanced members who have undergone many hours of auditing and reached the state of Clear followed by Operating Thetan levels 1 and 2. It is described in more detail in the accompanying confidential "Assists" lecture of October 3, 1968, and is dramatized in Revolt in the Stars (a screen-story – in the form of a novel – written by L. Ron Hubbard in 1977). Hubbard wrote that Xenu was the ruler of a Galactic Confederacy 75 million years ago, which consisted of 26 stars and 76 planets including Earth, which was then known as "Teegeeack".
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Vladivostok Air Tu-204-300 landing at Pulkovo Airport A shortened, longer-range and more efficient derivative of the Tu-204, the Tu-204-300 is also known as Tu-234. About six meters (20 ft) shorter than the basic Tu-204, this variant is available in two versions: the longer-ranged, heavier version, powered by Aviadvigatel PS 90-A2 turbofans, has a maximum take-off weight of 107.5 metric tons and range (with 166 passengers) increased to ; and the lighter, shorter-ranged version, with a maximum take-off weight of 89 metric tons and range of with 166 passengers. The Russian airline Vladivostok Air is the debut customer. This airline's aircraft are in a two- class seating configuration, with a 142-passenger capacity.
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The Sukhoi Superjet 100 was introduced in 2011 United Aircraft Corporation subsidiary Sukhoi developed the Superjet 100, it made its maiden flight on 19 May 2008 and was introduced in April 2011 with Armavia. It typically seats 98 passengers and is powered by two PowerJet SaM146 turbofans from a Safran/NPO Saturn joint venture. Many CRJ100/200 were retired since 2003 and in 2013 the first Embraer ERJ were disassembled: 50-seaters value was dwindling down as US carriers were dropping them. The ERJ retirements could be exacerbated because Rolls-Royce plc restricts parts choice, making engine maintenance more expensive, but its TotalCare agreements provide cost predictability. The Comac ARJ21 is a 78-90 seat jet manufactured by the Chinese State owned aerospace company Comac.
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The Airbus/Rolls-Royce/Siemens E-Fan X is a hybrid electric aircraft demonstrator being developed by a partnership of Airbus, Rolls-Royce plc and Siemens. Announced on 28 November 2017, it follows previous electric flight demonstrators towards sustainable transport for the European Commission's Flightpath 2050 Vision. (Airbus, Rolls-Royce, Siemens) An Avro RJ100 flying testbed will have one of its four Honeywell LF507 turbofans replaced by a Rolls-Royce electric motor, adapted by Rolls-Royce and powered by its AE2100 turboshaft, controlled and integrated by Airbus with a battery. Airbus and Rolls-Royce abandoned the E-Fan X programme several months before the planned first flight as the commercial aircraft industry changed its priorities during the COVID-19 pandemic.
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This allowed early deliveries to the new launch customer, Emirates, allowing the carrier to launch nonstop service from Dubai to New York—its first route in the Americas. The A340-500 can fly 313 passengers in a three- class cabin layout over 16020 km (8650 nm). Compared with the A340-300, the -500 features a fuselage stretch, an enlarged wing, significant increase in fuel capacity (around 50% over the -300), slightly higher cruising speed, a larger horizontal stabilizer and a larger vertical tailplane. The centerline main landing gear was changed to a four-wheel bogie to support the additional weight. The A340-500 is powered by four thrust Rolls-Royce Trent 553 turbofans and uses the Honeywell 331–600[A] APU.
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The variant's main competitor is the 777-300ER. The A340-600 was replaced by the A350-1000. The A340-600 is longer than a -300, more than longer than the Boeing 747-400 and longer than the A380, and has two emergency exit doors added over the wings. It held the record for the world's longest commercial aircraft until the first flight of the Boeing 747-8 in February 2010. The A340-600 is powered by four thrust Rolls-Royce Trent 556 turbofans and uses the Honeywell 331–600[A] APU. As with the -500, it has a four-wheel undercarriage bogie on the fuselage centre-line to cope with the increased MTOW along with the enlarged wing and rear empennage.
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Research into the next generation of commercial jet engines, high-bypass ratio turbofans in the "10-ton" (20,000 lbf; 89 kN) thrust class, began in the late 1960s. Snecma (now Safran), who had mostly built military engines previously, was the first company to seek entrance into the market by searching for a partner with commercial experience to design and build an engine in this class. They considered Pratt & Whitney, Rolls-Royce, and GE Aviation as potential partners, and after two company executives, Gerhard Neumann from GE and René Ravaud from Snecma, introduced themselves at the 1971 Paris Air Show a decision was made. The two companies saw mutual benefit in the collaboration and met several more times, fleshing out the basics of the joint project.Norris, Guy (1999). CFM56: Engine of Change.
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"English Electric Canberra B.Mk 2" would often be shortened to "Canberra B.2"), and "R" was added to the front, the "R" signifying "Rolls" and the original Rover "B" signifying Barnoldswick. This RB designation scheme continued into the late 20th Century, with turbofan designs such as the RB.199, RB.203 and RB.211; the most recent family of Rolls-Royce turbofans (a development of the RB.211) goes under the simple designation "Rolls-Royce Trent", with variants given their own designator number or letter series (i.e. Trent 500, Trent 900, Trent 1000, Trent XWB, etc.). The Rolls-Royce Avro Lancastrian Nene test bed in 1948 fitted with the jet engines in the outboard position Early airborne tests of the Nene were undertaken in an Avro Lancastrian operated by Rolls-Royce from their Hucknall airfield.
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The front-mounted bypass fan has two stages. The annular discharge duct for the bypass fan runs along the full length of the engine, so that both the fan air and exhaust gases can exit through the same nozzle. This arrangement allows some noise attenuation, in that the still-hot fast-moving turbine exhaust is shrouded in much-cooler and slower-moving air (from the bypass fan) before interacting with ambient air. Thus the JT8D noise levels were significantly reduced from previous non-turbofan engines, although the low bypass ratio meant that, compared to subsequently developed turbofans, high noise levels were still produced. Eight models comprise the JT8D standard engine family, covering the thrust range from 12,250 to 17,400 pounds-force (62 to 77 kN) and power 727, 737-100/200, and DC-9 aircraft.
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Developed from the Ivchenko AI-25 turbofan engine, ZVL was also responsible for pre-production and serial engine production. The DV-2 is a two-spool modular aviation turbofan engine with a single-stage overhung fan, two-stage LP compressor, seven-stage HP compressor, single-stage HP turbine, and two-stage LP turbine, and an annular combustion system. Maximum power at T-O is with a specific fuel consumption of 60 kg/(kN h) (0.593 (lb/lbf h)), at Maximum Rating, Sea Level Static, ISA.Russia, Central/Eastern Europe and China Turbofan and Turbojet Engines One of the most unusual features of this military engine is the single stage fan; most trainer and combat engines have multi-staged fans, single stage fans normally being the preserve of civil and military transport turbofans.
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About a decade after German aerospace engineers began exploring the idea of using swept wings to reduce drag on transonic speed aircraft, Hamilton Standard in the 1940s attempted to apply a similar concept to engine propellers. It created highly swept propeller blades with supersonic tip speeds, so that engines with exposed propellers could power aircraft to speeds and cruising altitudes only attained by new turbojet and turbofan engines. Early tests of these blades revealed then-unresolvable blade flutter and blade stress problems, and high noise levels were considered another obstacle. The popularity of turbojets and turbofans curtailed research in propellers, but by the 1960s, interest increased when studies showed that an exposed propeller driven by a gas turbine could power an airliner flying at a speed of Mach 0.7–0.8 and at an altitude of .
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Engine cores are shrinking as they are operating at higher pressure ratios and becoming more efficient, and become smaller compared to the fan as bypass ratios increase. Blade tip clearances are harder to maintain at the exit of the high-pressure compressor where blades are high or less, backbone bending further affects clearance control as the core is proportionately longer and thinner and the fan to low- pressure turbine driveshaft is in constrained space within the core. For Pratt & Whitney VP technology and environment Alan Epstein "Over the history of commercial aviation, we have gone from 20% to 40% [cruise efficiency], and there is a consensus among the engine community that we can probably get to 60%". Geared turbofans and further fan pressure ratio reductions will continue to improve propulsive efficiency.
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The overall effective exhaust velocity of the two exhaust jets can be made closer to a normal subsonic aircraft's flight speed. In effect, a turbofan emits a large amount of air more slowly, whereas a turbojet emits a smaller amount of air quickly, which is a far less efficient way to generate the same thrust (see 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. 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.
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Modern turbofans are a development of the turbojet; they are basically a turbojet that includes a new section called the fan stage. Rather than using all of its exhaust gases to provide direct thrust like a turbojet, the turbofan engine extracts some of the power from the exhaust gases inside the engine and uses it to power the fan stage. The fan stage accelerates a large volume of air through a duct, bypassing the engine core (the actual gas turbine component of the engine), and expelling it at the rear as a jet, creating thrust. A proportion of the air that comes through the fan stage enters the engine core rather than being ducted to the rear, and is thus compressed and heated; some of the energy is extracted to power the compressors and fans, while the remainder is exhausted at the rear.
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Viewed from below, showing wing sweep The 650 has a T-tail and two turbofans In 1974, Cessna studied a long range model 700 stretch of its original Citation I powered by three JT15Ds called Citation III, with a 17,500 lb gross weight, an 8,000 lb empty weight and a 7,500 lb fuel capacity leaving 2,000 lb for the occupants, and targeting 1978 deliveries. This would have gave it a transcontinental range. Cessna announced the 10 to 15 passengers, $2.5 million Citation III at the Fall 1976 NBAA convention. Scheduled for 1980, the model then presented had a cruciform tail and a cockpit similar to previous Citations. As the proposed three-engined Models 600 and 700 timing was inadequate, it would be powered by two TFE731 and would be lifted by a supercritical 35° swept wing.
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For air-breathing engines such as turbojets, energy efficiency and propellant (fuel) efficiency are much the same thing, since the propellant is a fuel and the source of energy. In rocketry, the propellant is also the exhaust, and this means that a high energy propellant gives better propellant efficiency but can in some cases actually give lower energy efficiency. It can be seen in the table (just below) that the subsonic turbofans such as General Electric's CF6 turbofan use a lot less fuel to generate thrust for a second than did the Concorde's Rolls- Royce/Snecma Olympus 593 turbojet. However, since energy is force times distance and the distance per second was greater for the Concorde, the actual power generated by the engine for the same amount of fuel was higher for the Concorde at Mach 2 than the CF6.
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The enlarged aircraft was roughly comparable in capacity to that of the British Vickers Viscount, a successful turboprop airliner. The design was capable of speeds well in excess of turboprop-powered competitors, but retained a relatively low cruise speed in comparison to contemporary jet- powered designs, facilitating its use of a relatively straight low-mounted wing and achieving favourable low-speed characteristics as to enable the type's use from 85% of existing airports used by the F27 and the ubiquitous Douglas DC-3. According to Flying, the tentative airliner could achieve double the productivity of the preceding F27, while the company itself referred to the jetliner as a complement to its turboprop-powered sibling.May 1963, p. 92. At one stage of development, Fokker had reportedly intended for the F28 to be powered by a pair of Bristol Siddeley BS.75 turbofans.
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When the F-111B ran into intractable problems in terms of aircraft performance as an air-to-air fighter and operational difficulties as a sea-based aircraft aboard aircraft carriers, the same systems were instead fitted to the F-14 Tomcat. The Missileer's lasting contribution was not only its systems, but its engines. The TF30, with an afterburner, was used on both the F-111 and F-14, and turbofans are now commonplace in military jets. But while the TF30 was well-suited to the land- based fighter-bomber performance parameters of the F-111s and FB-111s operated by the U.S. Air Force and the Royal Australian Air Force, it was highly susceptible to compressor stalls in high angle-of-attack flight regimes and proved to be a marginal powerplant for the U.S. Navy's air superiority fighter-oriented F-14A Tomcat.
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The type received its FAA type certification in April 1963. The UTX candidate, designated the T-39A, was identical in configuration to the NA-265, but when the contract was awarded and the T-39A entered production, it was powered by two Pratt & Whitney JT12A-8 turbojet engines. The civilian production version, or Series 40, was slightly refined over the prototype, with more speed and a roomier cabin. North American then stretched the design by and , providing greater cabin space, and marketed it as the Series 60, which was certificated in April 1967. The cabin was made taller for the Series 70 and General Electric CF700 turbofans were installed for the Series 75A (also branded as the Series 80)."Sabreliner Structural Repair Manual – All Models NA-265 Aircraft", Report No. NA-66-1032 Revision 10, March 16, 1990.
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Jet engines, particularly turbojets, are a type of gas turbine configured such that most of the work available results from the thrust of the hot exhaust gases. Turbofans, both the high-bypass versions used in all modern commercial jetliners, and the low-bypass versions in most modern military aircraft, produce a combination of jet thrust from the exhaust of burnt fuel, and air thrust from what amounts to an internal propeller. High-bypass turbofan engines achieve most of their thrust from a fan driving air backwards through the engine casing, and driven by a gas turbine, which also contributes jet thrust via its exhaust. The two are in one large engine casing with the fan (propeller) at the front and the jet engine behind, with both turbine exhaust and fan-driven air exiting the rear of the engine casing.
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To use jet power for lift, the impracticality of tail-sitting meant it was necessary for the aircraft to take off and land vertically while still in a horizontal attitude. Solutions tried included lifting fans (typically buried in the wings), swivelling engine pods similar in concept to the convertiplane, dedicated lightweight lift jets or turbofans, thrust-vectoring by deflecting the jet exhaust as needed, and various combinations of these. Only thrust-vectoring stood the test of time, with the introduction of the Rolls-Royce Pegasus bypass turbofan engine having separate vectoring nozzles for the cold fan (bypass) and hot exhaust flows, which first flew in the Hawker P.1127 VTOL research aircraft of 1960. The success of the P.1127 and its successor the Kestrel led directly to the service introduction of the subsonic Hawker Siddeley Harrier "Jump jet" in 1969.
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Over 1,800 Bombardier CRJs have been delivered Regional airliners typically seat fewer than 100 passengers and may be powered by turbofans or turboprops. These airliners are the non-mainline counterparts to the larger aircraft operated by the major carriers, legacy carriers, and flag carriers, and are used to feed traffic into the large airline hubs or focus cities. These particular routes may need the size of a smaller aircraft to meet the frequency needs and service levels customers expect in the marketed product offered by larger airlines and their modern narrow- and wide-body aircraft. Therefore, these short-haul airliners are usually equipped with lavatories, stand-up cabins, pressurization, overhead storage bins, and reclining seats, and have a flight attendant to look after the in-flight needs of the passengers during point-to-point transit routes.
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Exotic cycles, heat exchangers and pressure gain/constant volume combustion can improve thermodynamic efficiency. Additive manufacturing could be an enabler for intercooler and recuperators. Closer airframe integration and hybrid or electric aircraft can be combined with gas turbines. Current Rolls-Royce engines have a 72–82% propulsive efficiency and 42–49% thermal efficiency for a TSFC at Mach 0.8, and aim for theoretical limits of 95% for open rotor propulsive efficiency and 60% for thermal efficiency with stoichiometric turbine entry temperature and 80:1 overall pressure ratio for a TSFC As teething troubles may not show up until several thousand hours, the latest turbofans technical problems disrupt airlines operations and manufacturers deliveries while production rates are rising sharply. Trent 1000 cracked blades grounded almost 50 Boeing 787s and reduced ETOPS to 2.3 hours down from 5.5, costing Rolls-Royce plc almost $950 million.
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The revived Alfa Romeo Avio began to diversify its operation. Its repair and maintenance side expanded to deal with repairing Curtiss-Wright R-1820 and R-3350 piston engines, Rolls-Royce Avon and Wright J65 turbojets, Rolls-Royce Dart turboprops and Rolls-Royce Conway turbofans mounted on Italian and Norwegian airplanes. Alfa Romeo license built the Bristol Siddeley Orpheus for the Fiat G.91 programme, one of a number of examples of cooperation between the companies during the decade, and was the European distributor of the General Electric J85 and CJ610 turbojets. It was also involved, alongside FIAT, FN of Belgium and BMW, in the European production programme for the production of a FIAT (General Electric) J79-GE-11A turbojet to power the Lockheed F-104 Starfighter that was being built in Europe and was used extensively by many NATO air forces.
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A military transport aircraft, over 2,500 Lockheed C-130 Hercules have been built Compared to turbofans, turboprops are most efficient at flight speeds below 725 km/h (450 mph; 390 knots) because the jet velocity of the propeller (and exhaust) is relatively low. Modern turboprop airliners operate at nearly the same speed as small regional jet airliners but burn two-thirds of the fuel per passenger. However, compared to a turbojet (which can fly at high altitude for enhanced speed and fuel efficiency) a propeller aircraft has a lower ceiling. The Beech King Air and Super King Air are the most-delivered turboprop business aircraft, with a combined 7,300 examples as of May 2018 Compared to piston engines, their greater power-to-weight ratio (which allows for shorter takeoffs) and reliability can offset their higher initial cost, maintenance and fuel consumption.
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Around the same time, GE was negotiating with Boeing, which felt that the UDF technology could be useful for short-haul airliners, to test a demonstration engine on a Boeing 727 testbed aircraft. Agreement to flight test the UDF was reached in April, with flights beginning in late 1986 to assess a demonstrator based on a General Electric F404 core. The engine would have a pair of six-stage contra-rotating free turbines, each with large diameters running at slow speeds, and they would be connected directly to a couple of eight-blade, unducted fans. The effective bypass ratio (BPR) was estimated to be about 30:1 for the UDF, which was much larger than the 6:1 bypass ratios of modern turbofans at the time, but less than propeller/turboprop BPRs of approximately 50:1.
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For expedited production of wing spars, the main structural member of aircraft wings, the Everett factory received robotic machinery to automate the process of drilling holes and inserting fasteners. This method of wing construction expanded on techniques developed for the 747. Final assembly of the first aircraft began in July 1979. alt=Airplane assembly hall, featuring an unpainted metallic twin-jet aircraft, a presentation podium, and arranged audience chairs The prototype aircraft, registered N767BA and equipped with JT9D turbofans, rolled out on August 4, 1981. By this time, the 767 program had accumulated 173 firm orders from 17 customers, including Air Canada, All Nippon Airways, Britannia Airways, Transbrasil, and Trans World Airlines (TWA). On September 26, 1981, the prototype took its maiden flight under the command of company test pilots Tommy Edmonds, Lew Wallick, and John Brit.
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The engine was certified by the Canadian authorities on the 27 July 2006. The first Eclipse 500 aircraft, powered by two PW610Fs, was delivered to a customer on 31 December 2006. With a 14.5 inch (36.83 cm) diameter fan, the PW610F is one of the smallest turbofans to enter production. Little is known about the engine cycle, although the bypass ratio is believed to be about 1.83.The Engine Yearbook 2011, p.143 Driven by a single-stage low pressure (LP) turbine, the single stage fan is an advanced snubberless design, with wide chord blades integral with the rotor hub. The layout of the high pressure (HP) compressor is shown in U.S. patent 6,488,469: it has 2 stages, a mixed-flow or diagonal and a centrifugal, and is driven by a single-stage turbine. A reverse-flow combustor and forced mixer/common exhaust are also featured in the design.
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The T-2's configuration was clearly reminiscent of that of the two-seat Jaguar, with the two aircraft having the same overall configuration and some resemblance in details. In particular, the T-2 was also powered by two Rolls-Royce Turbomeca Adour turbofans, the same engine type used by the Jaguar, license-built by Ishikawajima-Harima Heavy Industries under the designation "TF40-IHI-801A". Despite this similarity, the T-2 was not a copy of the Jaguar, and the two aircraft could be distinguished at a glance, the T-2 having a more dartlike appearance, being noticeably longer and having a distinctly shorter wingspan than the Jaguar. The T-2 also had many detail differences. For example, since the JASDF had no rough-field requirement, the T-2 had conventional single-wheeled landing gear and not the distinctive heavy duty landing gear of the Jaguar.
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Customer deliveries should start in 2022. The $75 million jet is a stretch of the G650. The aircraft completed its first flight on February 14, 2020. The G700 should share its fly-by-wire cockpit with the G500/G600: active control sidesticks and Honeywell Primus Epic flight deck with synthetic and enhanced vision systems for a common type rating. The jet is 110 ft (33.5 m) long, about 3 m longer than the G650ER and about shorter than the competing Bombardier Global 7500. Its main cabin is long, high and wide; m longer, 0.1 m wider and a fraction taller than the 7500's cabin. It should carry 19 seated passengers or sleep 10. It will have a MTOW of 107,600 lb (48,800 kg) and the 18,250 lbf (81.2 kN) turbofans should burn 2-3% less fuel than the G650's R-R BR725s.
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The A321 entered service in January 1994 with Lufthansa The Airbus A321 was the first derivative of the A320, also known as the Stretched A320, A320-500 and A325. Its launch came on 24 November 1988, around the same time as the A320 entered service, after commitments for 183 aircraft from 10 customers were secured. final assembly line 3 in the Airbus plant at Hamburg Finkenwerder Airport The maiden flight of the Airbus A321 came on 11 March 1993, when the prototype, registration F-WWIA, flew with IAE V2500 engines; the second prototype, equipped with CFM56-5B turbofans, flew in May 1993. Lufthansa and Alitalia were the first to order the stretched Airbuses, with 20 and 40 aircraft requested, respectively. The first of Lufthansa's V2500-A5-powered A321s arrived on 27 January 1994, while Alitalia received its first CFM56-5B-powered aircraft on 22 March 1994.
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Udvar- Házy also suggested that the NMA should be designed with future changes in mind, such as the possibility of single-pilot operation. In July 2019, Boeing stated that its priority was the safe return to service of the grounded 737 MAX, and that the decision to launch the NMA would depend partly on its confidence in the tools it intends to implement in order to improve development program performance. In September 2019, Airbus estimated the total addressable market for midsize aircraft to represent some 2,000 to 2,500 jets over the next 20 years, and noted that it would be "taking the early market" in this space with the A321XLR and high-density A321 configurations, and with the A330neo. By October, Boeing was studying a re-engined 767-XF for around 2025, based on the 767-400ER with an extended landing gear to accommodate General Electric GEnx turbofans.
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IHI F7-10 engines of a P-1, 2013 The Kawasaki P-1 is a purpose-built maritime patrol aircraft equipped with four engines. The P-1 is powered by four podded IHI F7-10 turbofan engines underneath the low-set wings. The four-engine low-wing loading design adopted for the P-1 results in a flight profile with better maneuverability and stability at low-speed, low-altitude flight and allows the aircraft to continue its mission in the event of a single engine failure as well as greater operational survivability, the high-bypass engines provide for quiet, fuel-efficient operation. The P-1 has reduced transit times in comparison to turboprop-powered competitors, and the turbofans are quieter, making it more difficult for submerged submarines to detect it acoustically. The P-1 is equipped with many newly developed technologies and features, particularly in terms of its avionics and missions systems.
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The initial 737-300 (foreground) is longer than the 737-200 (background) and is re-engined with wider and more efficient CFM56 turbofans Following the success of the Boeing 737-200 Advanced, Boeing wanted to increase capacity and range, incorporating improvements to upgrade the plane to modern specifications, while also retaining commonality with previous 737 variants. Development began in 1979, and in 1980, preliminary aircraft specifications were released at the Farnborough Airshow. The new series featured CFM56 turbofan engines, yielding significant gains in fuel economy and a reduction in noise, but also posing an engineering challenge given the low ground clearance of the 737 - a trait of its 707-derived fuselage. Boeing and engine supplier CFM International solved the problem by placing the engine ahead of (rather than below) the wing, and by moving engine accessories to the sides (rather than the bottom) of the engine pod, giving the 737 a distinctive noncircular air intake.
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A BAe 146 flying testbed will have one of its four turbofans replaced by a electric motor, with provisions to replace a second turbofan. Airbus will build the control architecture and integrate the systems, Rolls-Royce will adapt the Siemens motor and the fan to the existing nacelle, bring the turboshaft, generator and power electronics and Siemens the electric motor and its power electronic control unit, the inverter, DC/DC converter and power distribution. High-power propulsion systems are challenged by thermal effects, electric thrust management, altitude and dynamic effects on electric systems and electromagnetic compatibility issues. An inboard Lycoming ALF502 is replaced with a same thrust Citation X/ERJ-145 AE3007 nacelle, but with its core replaced with the electric motor and inverter and the C-130J's AE2100 turboshaft in the rear fuselage with its air inlet behind the wing - both using the V-22 Osprey tilt-rotor's Liberty T406 core.
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Praetor 600 cabin At the August 2007 NBAA convention, Embraer unveiled a cabin mock-up of two concepts positioned between the $7 million Phenom 300 and the $26 million Legacy 600, called midsize jet (MSJ) and midlight jet (MLJ), positioned on 22% of the market in units. They should share their flat floor, stand-up cabin but the MSJ should be 5 feet longer to accommodate 8 passengers over a 2,800-nm range against 2,200-nm for the smaller version. The program was introduced in April 2008, Embraer planned to invest US$750 million and to introduce the larger model in 2012 and the smaller in 2013. Honeywell HTF7500E turbofans were selected along a Rockwell Collins Pro Line Fusion avionics suite integrated cockpit and a Parker Hannifin fly-by-wire flight control system. At the May 2008 European Business Aviation Convention and Exhibition, the larger was named Legacy 500 and priced at $18.4 million and the smaller Legacy 450, priced at $15.25 million.
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GE Aviation needs to develop a configuration accommodating reasonably well requirements for supersonic speed, subsonic speed and noise levels. Managing the high intake temperatures at high altitudes is a key challenge for the initial design. An engine for supersonic flight needs a lower bypass ratio than modern turbofans, having a higher flow speed for better efficiency. This is limited by noise regulations at takeoff, and a lower compression core like the CFM56 is better suited to higher temperatures encountered supersonically. The engine is a compromise between a big core for power and a small fan for wave drag, and Mach 1.4 is a compromise between higher speed and enough range. The high-pressure core is derived from the nine-stage compressor and single-stage turbine of the CFM56, matched to a new low-pressure section optimised for supersonic speed with a 133 cm (52in) diameter fan instead of the 155-173 cm (61-68.3in) fan of the 6:1 bypass ratio CFM56.
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Lockheed's stealth C-130 successor revealed - Flightglobal.com, 13 September 2011 The Air Force Research Laboratory funded Lockheed and Boeing demonstrators for the Speed Agile concept, which had the goal of making a STOL aircraft that can take off and land at speeds as low as on airfields less than 2,000 ft (610 m) long and cruise at Mach 0.8-plus. Boeing's design used upper-surface blowing from embedded engines on the inboard wing and blown flaps for circulation control on the outboard wing. Lockheed's design also used blown flaps outboard, but inboard used patented reversing ejector nozzles. Boeing's design completed over 2,000 hours of windtunnel tests in late 2009. It was a 5 percent-scale model of a narrowbody design with a payload. When the AFRL increased the payload requirement to , they tested a 5 percent-scale model of a widebody design with a take-off gross weight and an "A400M-size" wide cargo box. It would be powered by four IAE V2533 turbofans.
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Mock-up of the vehicle at Paris Air Show 2007 The Airbus Defence and Space Spaceplane, also called EADS Astrium TBN according to some sources,Radio interview of French ESA astronaut Jean-François Clervoy, during the show of Jacques Pradel on Europe 1, June 21, 2007 is a suborbital spaceplane concept for carrying space tourists, proposed by EADS Astrium (currently Airbus Defence and Space), the space subsidiary of the European consortium EADS (currently Airbus). A full-size mockup was officially unveiled in Paris, France, on June 13, 2007, and is now on display in the Concorde hall of the Musée de l'Air et de l'Espace. The project is the first space tourism entry by a major aerospace contractor. It is a rocket plane with a large wingspan, straight rearwards wing and a pair of canards.Astrium dévoile son projet d'avion-fusée Le Figaro, June 14, 2007, Page 18 Propulsion is ensured by classical turbofan jet engines for the atmospheric phaseSpace jet’s turbofans can cope with vacuum says EADS Rob Coppinger Flightglobal.
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US Air force technicians disassemble and inspects the CFM56 fan blades of a KC-135, inspected every 1,500 hours. The commercial aviation engine MRO market is anticipated by Aviation Week to be $25.9 billion in 2018, a 2.5 billion increase from 2017, led by 21% for the Boeing 737NG' CFM56-7B and the A320's CFM56-5B and IAE V2500 (also on the MD-90) tied for second, followed by the mature widebody engines: the GE90 then the Trent 700. Over the 2017–2026 decade, the largest markets for turbofans will be the B737NG's CFM56-7 with 23%, the V2500-A5 with 21%, the GE90-115B with 13%, the A320's CFM56-5B with 13%, the PW1000G with 7%, the Trent 700 with 6%, the CF6-80C2 with 5%, the CFM LEAP with 5% and the CF34-8 with 4%. Between 2018 and 2022, the largest MRO demand will be for CFM engines with 36%, followed by GE with 24%, Rolls with 13%, IAE with 12% and Pratt with 7%.
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The D-27 would also power the newly announced Yakovlev Yak-46 propfan airliner, which was similar to the Yak-42M competitor but used two propfans instead of three turbofans in the aft fuselage. Three weeks later, Tupolev said that government officials would decide shortly between two D-27 offshoot engines from the Progress design bureau for the final Tu-334 version in 1996: a Progress D-227 propfan, or a Progress D-527 "super contrafan," an ungeared but ducted contra-rotating powerplant with a bypass ratio of 18. Days earlier, the Soviet Union premiered a running propfan engine before Western audiences for the first time, flying an Ilyushin Il-76LL testbed aircraft with one installed Progress D-236 engine to the ILA Air Show in Hannover, Germany. Although the Soviets declined in Hannover to name the aircraft that would use the D-236, an October 1990 article named that geared engine as the powerplant for the final Tu-334 variant, which would compete against the D-27-powered Yak-46 for Aeroflot's Tu-134 replacement order. Work commenced on the Tu-334 in the early 1990s, but proceeded slowly due to funding problems arising from the breakup of the Soviet Union.
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However, a compressor anomaly occurred on another engine during pre-delivery tests, and the maiden flight previously planned for no earlier than June 26 was delayed while the engines are modified to a final certifiable configuration. , GE expressed confidence that the engine would receive certification during the fall and that the first flight of the 777X would still occur in 2019. The 777X test plan was later revised as several months are required to develop and test fixes to the GE9X, and first flight slipped to October-November. By June, the first prototype began low- speed taxi tests. On July 24, Boeing announced that the GE9X engine issue would delay the maiden flight until 2020. The company continued to target first deliveries in 2020, though it intends to boost production of current- generation 777 freighters in 2020. GE Aviation in Ohio is recalling four GE9X turbofans from Boeing in Washington state in Antonov An-124 freighters from Volga-Dnepr Airlines, mounted in 26 x 14 x 13 ft (8 x 4 x 4 m), 36,000 lb (16.3 t) stands. On September 5, in the presence of FAA inspectors, a cargo door blew off on the 777X static test airframe during the ultimate load test, which is conducted with the airplane stressed and pressurized beyond normal operating limits.
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