Misplaced Pages

#658341

102-529: Development of the ERJ ;145 was launched in 1989. Its early design took the form of a turbofan -powered stretch of the existing turboprop -powered EMB 120 Brasilia regional aircraft. After the project was temporarily suspended in 1990, work on a revised configuration was undertaken during the early 1990s. While retaining the three-abreast seating of the Brasilia, the twinjet featured a new swept wing and

204-476: A chase plane , to verify items like altitude , airspeed , and general airworthiness . A maiden flight is only one stage in the development of an aircraft type. Unless the type is a pure research aircraft (such as the X-15 ), the aircraft must be tested extensively to ensure that it delivers the desired performance with an acceptable margin of safety. In the case of civilian aircraft, a new type must be certified by

306-434: A corresponding increase in pressure and temperature in the exhaust duct which in turn cause a higher gas speed from the propelling nozzle (and higher KE and wasted fuel). Although the engine would use less fuel to produce a pound of thrust, more fuel is wasted in the faster propelling jet. In other words, the independence of thermal and propulsive efficiencies, as exists with the piston engine/propeller combination which preceded

408-419: A discordant nature known as "buzz saw" noise. All modern turbofan engines have acoustic liners in the nacelle to damp their noise. They extend as much as possible to cover the largest surface area. The acoustic performance of the engine can be experimentally evaluated by means of ground tests or in dedicated experimental test rigs. In the aerospace industry, chevrons are the "saw-tooth" patterns on

510-410: A fixed total applied fuel:air ratio, the total fuel flow for a given fan airflow will be the same, regardless of the dry specific thrust of the engine. However, a high specific thrust turbofan will, by definition, have a higher nozzle pressure ratio, resulting in a higher afterburning net thrust and, therefore, a lower afterburning specific fuel consumption (SFC). However, high specific thrust engines have

612-426: A high dry SFC. The situation is reversed for a medium specific thrust afterburning turbofan: i.e., poor afterburning SFC/good dry SFC. The former engine is suitable for a combat aircraft which must remain in afterburning combat for a fairly long period, but has to fight only fairly close to the airfield (e.g. cross border skirmishes). The latter engine is better for an aircraft that has to fly some distance, or loiter for

714-497: A higher altitude for one-engine-inoperable conditions." CommuteAir is the only operator of the ERJ 145XR. February 2011 Embraer presented its new EMB-145 AEW&C for India. Despite the multiple variants, pilots need only one type rating to fly any variant of the ERJ aircraft. Companies like American Eagle utilizes this benefit with its mixed fleet of ERJ 135ER/LR and ERJ145EP/LR/XR. Shared type-ratings allow operators to utilize

816-416: A higher nozzle pressure ratio than the turbojet, but with a lower exhaust temperature to retain net thrust. Since the temperature rise across the whole engine (intake to nozzle) would be lower, the (dry power) fuel flow would also be reduced, resulting in a better specific fuel consumption (SFC). Some low-bypass ratio military turbofans (e.g. F404 , JT8D ) have variable inlet guide vanes to direct air onto

918-590: A long time, before going into combat. However, the pilot can afford to stay in afterburning only for a short period, before aircraft fuel reserves become dangerously low. The first production afterburning turbofan engine was the Pratt & Whitney TF30 , which initially powered the F-111 Aardvark and F-14 Tomcat . Low-bypass military turbofans include the Pratt & Whitney F119 , the Eurojet EJ200 ,

1020-403: A pure-jet of the same thrust, and jet noise is no longer the predominant source. Turbofan engine noise propagates both upstream via the inlet and downstream via the primary nozzle and the by-pass duct. Other noise sources are the fan, compressor and turbine. Modern commercial aircraft employ high-bypass-ratio (HBPR) engines with separate flow, non-mixing, short-duct exhaust systems. Their noise

1122-603: A reduced payload, it had a 36,375 lb (16,500 kg) maximum takeoff weight (MTOW) and a 21,045 lb (9,546 kg) operating empty weight . In early 1990, no engine supplier willing to share the risk of the $ 250 million development was yet selected. The Allison GMA3007 (later renamed the Rolls-Royce AE 3007 ) was selected in March 1990, with a maximum 40 kN (7,100 lbf) take-off thrust and growth capability to 45 kN (10,000 lbf), first flight

SECTION 10

#1732790742659

1224-506: A relatively high level of commonality with the Embraer Legacy 600 business jet; the principal difference being the addition of winglets and additional fuel tanks as standard on the latter. The airframe is composed of stretched, machined and chemically milled aluminium, with CFRP for moving parts, GFRP for fairings and sidewalls, kevlar for leading edges and Nomex honeycomb-CFRP/GFRP sandwiches for floors. The EMB145 family

1326-498: A semi-private aircraft configuration, and that the conversion process can be performed at Embraer-owned service centers. Numerous aftermarket companies have also offered their own conversions of ERJ family aircraft, often involving various levels of interior refurbishment, such as the installation of an expanded galley, redesigned lavatories, seat track relocation, at-seat power provision, Wi-Fi , alternative ceilings, LED lighting upgrades, and various storage options. In December 1996,

1428-408: A single pilot pool for any ERJ aircraft. As of November 2023, the civilian operators with ten or more ERJs are: The ERJ 135/140/145 has been involved in 26 aviation accidents and incidents , including 8 hull losses , which resulted in zero fatalities. Related development Aircraft of comparable role, configuration, and era Related lists Turbofan A turbofan or fanjet

1530-569: A static thrust of 4,320 lb (1,960 kg), and had a bypass ratio of 6:1. The General Electric TF39 became the first production model, designed to power the Lockheed C-5 Galaxy military transport aircraft. The civil General Electric CF6 engine used a derived design. Other high-bypass turbofans are the Pratt & Whitney JT9D , the three-shaft Rolls-Royce RB211 and the CFM International CFM56 ; also

1632-473: A turbofan engine is the ratio between the mass flow rate of the bypass stream to the mass flow rate entering the core. A bypass ratio of 6, for example, means that 6 times more air passes through the bypass duct than the amount that passes through the combustion chamber. Turbofan engines are usually described in terms of BPR, which together with overall pressure ratio, turbine inlet temperature and fan pressure ratio are important design parameters. In addition BPR

1734-421: A turbojet engine uses all of the engine's output to produce thrust in the form of a hot high-velocity exhaust gas jet, a turbofan's cool low-velocity bypass air yields between 30% and 70% of the total thrust produced by a turbofan system. The thrust ( F N ) generated by a turbofan depends on the effective exhaust velocity of the total exhaust, as with any jet engine, but because two exhaust jets are present

1836-496: A turbojet even though an extra turbine, a gearbox and a propeller are added to the turbojet's low-loss propelling nozzle. The turbofan has additional losses from its greater number of compressor stages/blades, fan and bypass duct. Froude, or propulsive, efficiency can be defined as: η f = 2 1 + V j V a {\displaystyle \eta _{f}={\frac {2}{1+{\frac {V_{j}}{V_{a}}}}}} where: While

1938-704: A turbojet which accelerates a smaller amount more quickly, which is a less efficient way to generate the same thrust (see the efficiency section below). The ratio of the mass-flow of air bypassing the engine core compared to the mass-flow of air passing through the core is referred to as the bypass ratio . Engines with more jet thrust relative to fan thrust are known as low-bypass turbofans , those that have considerably more fan thrust than jet thrust are known as high-bypass . Most commercial aviation jet engines in use are high-bypass, and most modern fighter engines are low-bypass. Afterburners are used on low-bypass turbofans on combat aircraft. The bypass ratio (BPR) of

2040-489: A typical commuter/airliner configuration, the ERJ 145 can accommodate up to 60 seats, although many operators would have fewer seats than this on their selected configuration. Embraer has offered a premium cabin configuration, which seats between 16 and 28 passengers in a more comfortable and spacious arrangement. The cabin can accommodate various interiors, these being customisable to fulfil each customer's own requirements. The fittings can be suited to various market sectors, from

2142-530: Is 1.42 metres (4.7 ft) shorter, seating 44 passengers, and has 96% parts commonality with the ERJ145. The only significant changes are a shorter fuselage , a slightly derated engine and an increased range. The ERJ140 was designed with fewer seats in order to meet the needs of some major United States airlines, which have an agreement with the pilots' union to limit the number of 50-seat aircraft that can be flown by their affiliates. At launch, Embraer estimated

SECTION 20

#1732790742659

2244-578: Is 79 cm (31 in). A further stretch to 50–55 passengers is limited by a 12° rotation angle. Embraer continued to look for partners to share the $ 350 million development as first flight was expected for late 1994. In December 1994, Embraer was privatised for 80% to Brazilian and US investors while 20% was kept by the Brazilian Government. The definitive ERJ 145 first flew on August 11, 1995, with 18 firm orders, 16 options and 127 letters of intent. A 1,300h flight-test programme for

2346-434: Is a type of airbreathing jet engine that is widely used in aircraft propulsion . The word "turbofan" is a combination of references to the preceding generation engine technology of the turbojet and the additional fan stage. It consists of a gas turbine engine which achieves mechanical energy from combustion, and a ducted fan that uses the mechanical energy from the gas turbine to force air rearwards. Thus, whereas all

2448-507: Is best suited to high supersonic speeds. If it is all transferred to a separate big mass of air with low kinetic energy, the aircraft is best suited to zero speed (hovering). For speeds in between, the gas power is shared between a separate airstream and the gas turbine's own nozzle flow in a proportion which gives the aircraft performance required. The trade off between mass flow and velocity is also seen with propellers and helicopter rotors by comparing disc loading and power loading. For example,

2550-410: Is considerable potential for reducing fuel consumption for the same core cycle by increasing BPR.This is achieved because of the reduction in pounds of thrust per lb/sec of airflow (specific thrust) and the resultant reduction in lost kinetic energy in the jets (increase in propulsive efficiency). If all the gas power from a gas turbine is converted to kinetic energy in a propelling nozzle, the aircraft

2652-430: Is due to the speed, temperature, and pressure of the exhaust jet, especially during high-thrust conditions, such as those required for takeoff. The primary source of jet noise is the turbulent mixing of shear layers in the engine's exhaust. These shear layers contain instabilities that lead to highly turbulent vortices that generate the pressure fluctuations responsible for sound. To reduce the noise associated with jet flow,

2754-492: Is equipped with Rolls-Royce AE 3007A1 engines which provide 15% more power. The engines are flat rated at 33.1 kN (7,440 lb) thrust to provide improved climb characteristics and improved cruise performance in high ambient temperatures. The extra-long-range ERJ 145XR aircraft is equipped with Rolls-Royce AE 3007A1E engines. The high performance engines provide lower specific fuel consumption (SFC) and improved performance in hot and high conditions. The engines also yield

2856-437: Is generally powered by a pair of Rolls-Royce AE 3007 series turbofan engines. Each engine has a bypass ratio of 5:1 and can generate up to 8,917 lbf of thrust. The engines are controlled by a dual Full Authority Digital Engine Controls (FADEC) arrangement, which is capable of controlling virtually all aspects of the engine and sending engine data to be displayed on the engine-indicating and crew-alerting system (EICAS) for

2958-516: Is longer, allowing using jetways , and the fuselage was lengthened from 25.8 to 26 m (85 to 85 ft). During June 1991, the Brazilian Government loaned $ 600 million to Embraer and in July the programme was re-evaluated while tooling was 80% complete. By November 1991, Embraer was still looking for partners to share the risk of the $ 350 million project, hoping to obtain Government approval by

3060-456: Is powered by two rear-fuselage-mounted Rolls-Royce AE 3007 turbofans for a range up to 2,000 nautical miles [nmi] (3,700 km; 2,300 mi). By the time of its maiden flight on 11 August 1995, Embraer had garnered 18 firm orders, 16 options and 127 letters of intent for the type. On 10 December 1996, the ERJ 145 received its type certificate ; it entered revenue service with ExpressJet Airlines on 6 April 1997. Embraer prioritised

3162-413: Is quoted for turboprop and unducted fan installations because their high propulsive efficiency gives them the overall efficiency characteristics of very high bypass turbofans. This allows them to be shown together with turbofans on plots which show trends of reducing specific fuel consumption (SFC) with increasing BPR. BPR can also be quoted for lift fan installations where the fan airflow is remote from

Embraer ERJ family - Misplaced Pages Continue

3264-420: Is sufficient core power to drive the fan. A smaller core flow/higher bypass ratio cycle can be achieved by raising the inlet temperature of the high-pressure (HP) turbine rotor. To illustrate one aspect of how a turbofan differs from a turbojet, comparisons can be made at the same airflow (to keep a common intake for example) and the same net thrust (i.e. same specific thrust). A bypass flow can be added only if

3366-415: Is the first occasion on which it leaves the ground under its own power. The same term is also used for the first launch of rockets . In the early days of aviation it could be dangerous, because the exact handling characteristics of the aircraft were generally unknown. The maiden flight of a new type is almost invariably flown by a highly experienced test pilot . Maiden flights are usually accompanied by

3468-411: Is very fuel intensive. Consequently, afterburning can be used only for short portions of a mission. Unlike in the main engine, where stoichiometric temperatures in the combustor have to be reduced before they reach the turbine, an afterburner at maximum fuelling is designed to produce stoichiometric temperatures at entry to the nozzle, about 2,100 K (3,800 °R; 3,300 °F; 1,800 °C). At

3570-552: Is what differs between the various models in regards to total thrust capability. The extended range version, the ERJ 145ER, has Rolls-Royce AE 3007A engines rated at 31.3 kN (7,036 lb) thrust, with the option of more powerful AE 3007A1 engines. A, A1, A1P models are mechanically identical but differ in thrust due to variations in FADEC software. The A1E engine, however, has not only new software, but significantly upgraded mechanical components. The long-range ERJ 145LR aircraft

3672-479: The Bristol Olympus , and Pratt & Whitney JT3C engines, increased the overall pressure ratio and thus the thermodynamic efficiency of engines. They also had poor propulsive efficiency, because pure turbojets have a high specific thrust/high velocity exhaust, which is better suited to supersonic flight. The original low-bypass turbofan engines were designed to improve propulsive efficiency by reducing

3774-590: The Canadair CRJ . The jet was anticipated to be able to travel at 400 knots (740 km/h; 460 mph), equipped with the CFE738 , Lycoming ALF 502 or Rolls-Royce/Allison AB580 turbofan engines, with the model 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 by 1995. It aimed for half of a market for 1,000 aircraft with break-even after twelve years with 400 sold. Keeping 75% of

3876-702: The General Electric F110 , the Klimov RD-33 , and the Saturn AL-31 , all of which feature a mixed exhaust, afterburner and variable area propelling nozzle. To further improve fuel economy and reduce noise, almost all jet airliners and most military transport aircraft (e.g., the C-17 ) are powered by low-specific-thrust/high-bypass-ratio turbofans. These engines evolved from the high-specific-thrust/low-bypass-ratio turbofans used in such aircraft in

3978-520: The bypass ratio . The engine produces thrust through a combination of these two portions working together. Engines that use more jet thrust relative to fan thrust are known as low-bypass turbofans ; conversely those that have considerably more fan thrust than jet thrust are known as high-bypass . Most commercial aviation jet engines in use are of the high-bypass type, and most modern fighter engines are low-bypass. Afterburners are used on low-bypass turbofan engines with bypass and core mixing before

4080-421: The 1960s. Modern combat aircraft tend to use low-bypass ratio turbofans, and some military transport aircraft use turboprops . Low specific thrust is achieved by replacing the multi-stage fan with a single-stage unit. Unlike some military engines, modern civil turbofans lack stationary inlet guide vanes in front of the fan rotor. The fan is scaled to achieve the desired net thrust. The core (or gas generator) of

4182-533: The 2020s, various operators had elected to retire their ERJ 145 fleets in favour of newer airliners; they have often been replaced by members of Embraer's E-Jet family . Aircraft formerly used as regional airliners have often been sold on to charter operators. To capitalise on the growing sector of corporate/private travellers, some customers have elected to acquire secondhand ERJ145s from regional operators and refurbishing them with new interiors with more luxurious fittings to suit their new role. As of August 2021,

Embraer ERJ family - Misplaced Pages Continue

4284-782: The Brasilia 0.48 bar (7.0 psi). Following the engine selection, design was revised: length decreased from 27.08 to 26.74 m (88.8 to 87.7 ft), span increased from 22.37 to 22.49 m (73.4 to 73.8 ft), aspect ratio to 9.3 from 9.2. MTOW rose from 16,500 to 18,500 kg (36,400 to 40,800 lb), basic operating weight from 9,560 to 10,940 kg (21,080 to 24,120 lb), maximum fuel from 3,900 to 4,210 kg (8,600 to 9,280 lb) and payload from 4,500 to 5,160 kg (9,920 to 11,380 lb); wing loading increased from 330 to 370 kg/m (68 to 76 lb/sq ft), time-to-climb to FL400 gained 5 min to 30 min and maximum cruise rose from 405 kn (750 km/h) to 428 kn (787 km/h) at FL360. The first delivery in 1993

4386-707: The Brasilia parts and systems, the EMB 145 Amazon aimed for a 1991 first flight. The stretch resulted from two 11-foot (3.4 m) plugs of the 7-foot-6-inch (2.29 m) diameter fuselage in the front and behind the redesigned 538-square-foot (50.0 m) wing. Its supercritical airfoil with a 14% root thickness had its chord extended at the leading edge with a slight sweepback , increased aspect ratio and winglets. The overwing podded engines were expected to generate 6,400 pounds-force (28 kN) of thrust. Designed for 500–600 nmi (930–1,110 km; 580–690 mi) stages, up to 1,400 nmi (2,600 km; 1,600 mi) with

4488-628: The EMB145 was expected to offer lower operating costs than the similarly priced Saab 2000 high-speed turboprop and the CRJ . Its $ 15 million price was $ 4 million lower than the CRJ. The Flight Test campaign took four aircraft: S/N 801, PT-ZJA, S/N 001, PT-ZJB, S/N 002, PT-ZJC and S/N 003, PT-ZJD. Only S/N 003 was fitted with passenger seats and had no FTI (flight test instrumentation) and was used for functional and reliability tests. In July 1996, its certification

4590-509: The ERJ 135 was leased $ 33,000 to $ 43,000 per month ($ 396,000 to $ 516,000 per year) and the ERJ 145 $ 38,000 to $ 55,000 per month ($ 456,000 to $ 660,000 per year). As of 18 March 2018, the Embraer ERJ family was involved in 24 incidents, incurring a total of eight hull losses without any fatalities. The physical engines are the same ( Rolls-Royce AE 3007 ), however, the FADEC (Full Authority Digital Engine/Electronic Control) logic

4692-515: The ERJ 145 in Harbin for the Chinese market. The assembly line was sized to produce a maximum of 24 aircraft per year, assembling complete knock down kits prepared by Embraer at its facilities overseas. During February 2004, the first delivery of a Chinese-assembled ERJ 145 took place; two months later, China Southern took delivery for two of the locally-built ERJ145s. In April 2009, it

4794-464: The aerospace industry has sought to disrupt shear layer turbulence and reduce the overall noise produced. Fan noise may come from the interaction of the fan-blade wakes with the pressure field of the downstream fan-exit stator vanes. It may be minimized by adequate axial spacing between blade trailing edge and stator entrance. At high engine speeds, as at takeoff, shock waves from the supersonic fan tips, because of their unequal nature, produce noise of

4896-422: The afterburner, raising the temperature of exhaust gases by a significant degree, resulting in a higher exhaust velocity/engine specific thrust. The variable geometry nozzle must open to a larger throat area to accommodate the extra volume and increased flow rate when the afterburner is lit. Afterburning is often designed to give a significant thrust boost for take off, transonic acceleration and combat maneuvers, but

4998-409: The afterburner. Modern turbofans have either a large single-stage fan or a smaller fan with several stages. An early configuration combined a low-pressure turbine and fan in a single rear-mounted unit. The turbofan was invented to improve the fuel consumption of the turbojet. It achieves this by pushing more air, thus increasing the mass and lowering the speed of the propelling jet compared to that of

5100-404: The air taken in by a turbojet passes through the combustion chamber and turbines, in a turbofan some of that air bypasses these components. A turbofan thus can be thought of as a turbojet being used to drive a ducted fan, with both of these contributing to the thrust . The ratio of the mass-flow of air bypassing the engine core to the mass-flow of air passing through the core is referred to as

5202-474: The average stage loading and to maintain LP turbine efficiency. Reducing core flow also increases bypass ratio. Bypass ratios greater than 5:1 are increasingly common; the Pratt & Whitney PW1000G , which entered commercial service in 2016, attains 12.5:1. Further improvements in core thermal efficiency can be achieved by raising the overall pressure ratio of the core. Improvements in blade aerodynamics can reduce

SECTION 50

#1732790742659

5304-610: The cabin. The standard maximum ramp weight is 19,300 and 20,300 kg (42,500 and 44,800 lb) for the extended-range, it is fitted with Honeywell Primus 1000 integrated avionics. The estimated $ 300 million development cost is divided between Embraer for 34%, risksharing partners for 33% (including Belgium's SONACA supplying centre and rear fuselage sections, doors, engine pylons and wing leading-edges), long-term loans from Brazilian development-funding institutions for 23% and participating suppliers for 10%. On both 370 km (200 nm) hubfeeder and 1,100 km hub-bypass sectors,

5406-462: The cost of an ERJ140 to be approximately US $ 15.2 million. The estimated cost of development of the ERJ140 was US $ 45 million. The ERJ 135 is 3.54 metres (11.6 ft) shorter, seating 37 passengers, and has 95% parts commonality with the ERJ145. The first ERJ 135 entered service in 1999. The Embraer ERJ family is a series of twin-engine jet-powered regional jets . The ERJ family retains

5508-420: The end of the year. Sold at $ 12 million with an all-digital cockpit and 31.8 kN (7,100 lbf) engines, it had letters of intent for 337 units. The scheduled date for the first flight slipped to 1992 and certification for late 1993. After re-evaluation late in 1991, the layout was again revised with two rear-fuselage-mounted engines, and a Mach 0.8 cruise speed would be tested in the wind tunnel. Seat pitch

5610-448: The engine and doesn't flow past the engine core. Considering a constant core (i.e. fixed pressure ratio and turbine inlet temperature), core and bypass jet velocities equal and a particular flight condition (i.e. Mach number and altitude) the fuel consumption per lb of thrust (sfc) decreases with increase in BPR. At the same time gross and net thrusts increase, but by different amounts. There

5712-427: The engine must generate enough power to drive the fan at its rated mass flow and pressure ratio. Improvements in turbine cooling/material technology allow for a higher (HP) turbine rotor inlet temperature, which allows a smaller (and lighter) core, potentially improving the core thermal efficiency. Reducing the core mass flow tends to increase the load on the LP turbine, so this unit may require additional stages to reduce

5814-524: The exhaust velocity to a value closer to that of the aircraft. The Rolls-Royce Conway , the world's first production turbofan, had a bypass ratio of 0.3, similar to the modern General Electric F404 fighter engine. Civilian turbofan engines of the 1960s, such as the Pratt & Whitney JT8D and the Rolls-Royce Spey , had bypass ratios closer to 1 and were similar to their military equivalents. The first Soviet airliner powered by turbofan engines

5916-494: The fan nozzle. The amount of energy transferred depends on how much pressure rise the fan is designed to produce (fan pressure ratio). The best energy exchange (lowest fuel consumption) between the two flows, and how the jet velocities compare, depends on how efficiently the transfer takes place which depends on the losses in the fan-turbine and fan. The fan flow has lower exhaust velocity, giving much more thrust per unit energy (lower specific thrust ). Both airstreams contribute to

6018-529: The first delivery of the ERJ 145 was made to ExpressJet Airlines (then the regional division of Continental Airlines flying as Continental Express ). As a newly-established company, ExpressJet chose the ERJ 145 with which to launch its operations; this was achieved in April 1997, the same month that Embraer completed deliveries to the operator. Particular value was attached the American market as there

6120-450: The first fan rotor stage. This improves the fan surge margin (see compressor map ). Since the 1970s, most jet fighter engines have been low/medium bypass turbofans with a mixed exhaust, afterburner and variable area exit nozzle. An afterburner is a combustor located downstream of the turbine blades and directly upstream of the nozzle, which burns fuel from afterburner-specific fuel injectors. When lit, large volumes of fuel are burnt in

6222-718: The flight crew. The ERJ 145 family initially shared its cockpit layout with that of the aborted CBA123. It is equipped with the Honeywell Primus 1000 avionics suite. This provides an electronic flight instrument system (EFIS) that comprises five monitors; from left to right, these consists of a Primary Flight Display (PFD), Multi-Function Display (MFD), Engine Indication and Crew Alerting System (EICAS), Multi-Function Display (MFD) (Co-pilot) and Primary Flight Display (PFD) (Co-pilot). While these are CRT displays as standard, they can be upgraded to LCD counterparts, which are lighter and have additional functionality. In

SECTION 60

#1732790742659

6324-496: The fuel used to move the aircraft forwards. A turbofan harvests that wasted velocity and uses it to power a ducted fan that blows air in bypass channels around the rest of the turbine. This reduces the speed of the propelling jet while pushing more air, and thus more mass. The other penalty is that combustion is less efficient at lower speeds. Any action to reduce the fuel consumption of the engine by increasing its pressure ratio or turbine temperature to achieve better combustion causes

6426-429: The gross thrust of the engine. The additional air for the bypass stream increases the ram drag in the air intake stream-tube, but there is still a significant increase in net thrust. The overall effective exhaust velocity of the two exhaust jets can be made closer to a normal subsonic aircraft's flight speed and gets closer to the ideal Froude efficiency . A turbofan accelerates a larger mass of air more slowly, compared to

6528-474: The hot nozzle to convert to kinetic energy. Turbofans represent an intermediate stage between turbojets , which derive all their thrust from exhaust gases, and turbo-props which derive minimal thrust from exhaust gases (typically 10% or less). Extracting shaft power and transferring it to a bypass stream introduces extra losses which are more than made up by the improved propulsive efficiency. The turboprop at its best flight speed gives significant fuel savings over

6630-557: The inherent fuel economy of the turboprop aircraft which were in service and in development. The 45–48 seat EMB 145, nicknamed Amazon, was launched at the Paris Air Show in 1989 as an 18-foot (5.5 m) stretch of the EMB 120 Brasilia developed for US$ 150 million plus $ 50 million for training and marketing, one third the cost of the cancelled Short Brothers FJX project. Its $ 11 million unit cost would have been $ 3 million less than

6732-446: The joint venture took place. Two months later, the discontinuation of the local assembly initiative was announced; it was reported that in excess of 40 ERJ 145 and five Legacy 650s has been completed by this point. Embraer has introduced two shortened versions of the ERJ145. All three aircraft share the same crew type rating , allowing pilots to fly any of the three aircraft without the need for further training. The ERJ   140

6834-415: The largest operator of the ERJ 145 is CommuteAir , which serves as United Express under United Airlines , possessing a fleet of 165 aircraft. During September 1999, the slightly smaller ERJ140 was introduced; it performing its first flight on 27 June 2000, and entering commercial service in July 2001. Envoy Air , the regional jet subsidiary of American Airlines flying as American Eagle , operated

6936-565: The majority of the ERJ140s built, including the first to be delivered ( N800AE ) However, Envoy Air opted to withdraw all of their ERJ140 fleet in mid-2020. By early 2005, 74 ERJ140s had been delivered; while this model has been marketed as ERJ140 , its designation on the company's internal documents and on FAA certification is EMB 135KL . In March 2007, ExpressJet entered into a short-term agreement to operate some regional routes for JetBlue Airways using its ERJ 145 aircraft. In May 2017,

7038-417: The mechanical power produced by the turbine. In a bypass design, extra turbines drive a ducted fan that accelerates air rearward from the front of the engine. In a high-bypass design, the ducted fan and nozzle produce most of the thrust. Turbofans are closely related to turboprops in principle because both transfer some of the gas turbine's gas power, using extra machinery, to a bypass stream leaving less for

7140-539: The number of extra compressor stages required, and variable geometry stators enable high-pressure-ratio compressors to work surge-free at all throttle settings. The first (experimental) high-bypass turbofan engine was the AVCO-Lycoming PLF1A-2, a Honeywell T55 turboshaft-derived engine that was first run in February 1962. The PLF1A-2 had a 40 in diameter (100 cm) geared fan stage, produced

7242-477: The prototype and three pre-series aircraft (excluding two ground-test airframes) was planned within 13 months for certification in the third quarter of 1996, before deliveries in the fourth quarter of 1996 to launch customer Flight West . The $ 14.5 million aircraft is developed with risk-sharing partners including Spain's Gamesa producing the wing; Chile's Enaer for the tail; and the USA's C&D Interiors equipping

7344-497: The rapid expansion of the family, leading to the introduction of the shortened ERJ 135 and ERJ 140 in 1999. The ERJ series' primary competition came from the similarly sized Bombardier CRJ100/200 regional jets. In December 2002, Embraer entered a partnership with the Chinese aerospace manufacturer Harbin Aircraft Industry Group to jointly produce the ERJ 145 in Harbin , China; this production line

7446-426: The relatively modest commuter to the more luxury-inclined VIP traveller. It is typical, but not compulsory, for ERJ 135/145 airliners to be configured with an offset aisle. Dependent on an individual aircraft's role, overhead bins may be installed; their exclusion gives more headroom but reduces the available storage space for carry-on luggage. Embraer has stated that every ERJ 145 is capable of being converted into

7548-467: The required thrust still maintained by increasing the mass accelerated. A turbofan does this by transferring energy available inside the engine, from the gas generator, to a ducted fan which produces a second, additional mass of accelerated air. The transfer of energy from the core to bypass air results in lower pressure and temperature gas entering the core nozzle (lower exhaust velocity), and fan-produced higher pressure and temperature bypass-air entering

7650-399: The same helicopter weight can be supported by a high power engine and small diameter rotor or, for less fuel, a lower power engine and bigger rotor with lower velocity through the rotor. Bypass usually refers to transferring gas power from a gas turbine to a bypass stream of air to reduce fuel consumption and jet noise. Alternatively, there may be a requirement for an afterburning engine where

7752-559: 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. The Pratt & Whitney JT9D engine was the first high bypass ratio jet engine to power a wide-body airliner. Maiden flight The maiden flight , also known as first flight , of an aircraft

7854-502: The sole requirement for bypass is to provide cooling air. This sets the lower limit for BPR and these engines have been called "leaky" or continuous bleed turbojets (General Electric YJ-101 BPR 0.25) and low BPR turbojets (Pratt & Whitney PW1120). Low BPR (0.2) has also been used to provide surge margin as well as afterburner cooling for the Pratt & Whitney J58 . Propeller engines are most efficient for low speeds, turbojet engines for high speeds, and turbofan engines between

7956-409: The span by almost 2 to 20.5 m (6 ft 7 in to 67 ft 3 in), reducing its aspect ratio from 9.3 to 8.4 and wing area from 50 to 47 m (540 to 510 sq ft). The semi-monocoque wing has two main and one auxiliary spar and holds 4,500 kg (9,900 lb) of fuel, it has double-slotted fowler flaps and spoilers . To accommodate the underwing engines, the landing gear

8058-454: The speed of the propelling jet has to be reduced because there is a price to be paid in producing the thrust. The energy required to accelerate the gas inside the engine (increase in kinetic energy) is expended in two ways, by producing a change in momentum ( i.e. a force), and a wake which is an unavoidable consequence of producing thrust by an airbreathing engine (or propeller). The wake velocity, and fuel burned to produce it, can be reduced and

8160-536: The technology and materials available at the time. The first turbofan engine, which was only run on a test bed, was the German Daimler-Benz DB 670 , designated the 109-007 by the German RLM ( Ministry of Aviation ), with a first run date of 27 May 1943, after the testing of the turbomachinery using an electric motor, which had been undertaken on 1 April 1943. Development of the engine

8262-497: The thrust equation can be expanded as: F N = m ˙ e v h e − m ˙ o v o + B P R ( m ˙ c ) v f {\displaystyle F_{N}={\dot {m}}_{e}v_{he}-{\dot {m}}_{o}v_{o}+BPR\,({\dot {m}}_{c})v_{f}} where: The cold duct and core duct's nozzle systems are relatively complex due to

8364-673: The trailing edges of some jet engine nozzles that are used for noise reduction . The shaped edges smooth the mixing of hot air from the engine core and cooler air flowing through the engine fan, which reduces noise-creating turbulence. Chevrons were developed by GE under a NASA contract. Some notable examples of such designs are Boeing 787 and Boeing 747-8  – on the Rolls-Royce Trent 1000 and General Electric GEnx engines. Early turbojet engines were not very fuel-efficient because their overall pressure ratio and turbine inlet temperature were severely limited by

8466-428: The turbine inlet temperature is not too high to compensate for the smaller core flow. Future improvements in turbine cooling/material technology can allow higher turbine inlet temperature, which is necessary because of increased cooling air temperature, resulting from an overall pressure ratio increase. The resulting turbofan, with reasonable efficiencies and duct loss for the added components, would probably operate at

8568-425: The turbojet uses the gas from its thermodynamic cycle as its propelling jet, for aircraft speeds below 500 mph there are two penalties to this design which are addressed by the turbofan. Firstly, energy is wasted as the propelling jet is going much faster rearwards than the aircraft is going forwards, leaving a very fast wake. This wake contains kinetic energy that reflects the fuel used to produce it, rather than

8670-445: The turbojet, is lost. In contrast, Roth considers regaining this independence the single most important feature of the turbofan which allows specific thrust to be chosen independently of the gas generator cycle. The working substance of the thermodynamic cycle is the only mass accelerated to produce thrust in a turbojet which is a serious limitation (high fuel consumption) for aircraft speeds below supersonic. For subsonic flight speeds

8772-453: The turbojet. This is done mechanically by adding a ducted fan rather than using viscous forces. A vacuum ejector is used in conjunction with the fan as first envisaged by inventor Frank Whittle . Whittle envisioned flight speeds of 500 mph in his March 1936 UK patent 471,368 "Improvements relating to the propulsion of aircraft", in which he describes the principles behind the turbofan, although not called as such at that time. While

8874-476: The two flows may combine within the ducts, and share a common nozzle, which can be fitted with afterburner. Most of the air flow through a high-bypass turbofan is lower-velocity bypass flow: even when combined with the much-higher-velocity engine exhaust, the average exhaust velocity is considerably lower than in a pure turbojet. Turbojet engine noise is predominately jet noise from the high exhaust velocity. Therefore, turbofan engines are significantly quieter than

8976-418: The two. Turbofans are the most efficient engines in the range of speeds from about 500 to 1,000 km/h (270 to 540 kn; 310 to 620 mph), the speed at which most commercial aircraft operate. In a turbojet (zero-bypass) engine, the high temperature and high pressure exhaust gas is accelerated when it undergoes expansion through a propelling nozzle and produces all the thrust. The compressor absorbs

9078-573: The type for operational use in North America. Embraer delivered 892 units of all variants through 2006, and predicted that another 102 units would be delivered in the 2007–2016 time period. During December 2002, Embraer entered a partnership with the Chinese aerospace manufacturer Harbin Aircraft Industry Group , resulting in the creation of Harbin Embraer Aircraft Industry , a joint venture company, to locally produce

9180-508: The type on behalf of the national flag carrier British Airways . During the early 2000s, various governments opted to procure the ERJ 145 as dedicated transports for high-ranking officials, amongst some other purposes. One such country was Belgium , who operated a pair of ERJ145s for VIP transport, regularly carrying the Belgian prime minister, cabinet members, members of the royal family, or military officials, between 2001 and 2020. By

9282-510: The use of two separate exhaust flows. In high bypass engines, the fan is situated in a short duct near the front of the engine and typically has a convergent cold nozzle, with the tail of the duct forming a low pressure ratio nozzle that under normal conditions will choke creating supersonic flow patterns around the core . The core nozzle is more conventional, but generates less of the thrust, and depending on design choices, such as noise considerations, may conceivably not choke. In low bypass engines

9384-701: The world, with an experience base of over 10 million service hours. The CF700 turbofan engine was also used to train Moon-bound astronauts in Project Apollo as the powerplant for the Lunar Landing Research Vehicle . A high-specific-thrust/low-bypass-ratio turbofan normally has a multi-stage fan behind inlet guide vanes, developing a relatively high pressure ratio and, thus, yielding a high (mixed or cold) exhaust velocity. The core airflow needs to be large enough to ensure there

9486-561: Was 7% better than predicted. Before the Summer 1996 Farnborough Airshow , Embraer held 62 firm orders and 218 options. Continental Express then purchased 25 EMB145s and took 175 options. More than 50 seats would need a wider fuselage for four-abreast seating, an enlarged wing and a more powerful turbofan. On 10 December 1996, type certification was issued by the Federal Aviation Administration (FAA), clearing

9588-670: Was a near-insatiable hunger for regional aircraft at this time, and thus a substantial amount of potential sales to capitalise upon. The ERJ 145 quickly entered service with various other operators throughout the Americas, being particularly popular on high-demand regional routes. However, the type proved to be less successful in the European market allegedly on account of logistical difficulties. Nonetheless, several European operators did emerge; LOT Polish Airlines operated as many as 14 ERJ145s, while British Regional Airlines also flew

9690-614: Was abandoned with its problems unsolved, as the war situation worsened for Germany. Later in 1943, the British ground tested the Metrovick F.3 turbofan, which used the Metrovick F.2 turbojet as a gas generator with the exhaust discharging into a close-coupled aft-fan module comprising a contra-rotating LP turbine system driving two co-axial contra-rotating fans. Improved materials, and the introduction of twin compressors, such as in

9792-468: Was announced that Hainan Airlines had halved its original order for 50 ERJ145s from the joint venture. By April 2011, 41 aircraft had reportedly been produced in China, considerably less than the line's capacity. By this time, the company was undertaking changes to facilitate the local production of the similar Embraer Legacy 650 business jet as well. In March 2016, the final delivery of aircraft produced by

9894-574: Was derived from the General Electric J85/CJ610 turbojet 2,850 lbf (12,700 N) to power the larger Rockwell Sabreliner 75/80 model aircraft, as well as the Dassault Falcon 20 , with about a 50% increase in thrust to 4,200 lbf (19,000 N). The CF700 was the first small turbofan to be certified by the Federal Aviation Administration (FAA). There were at one time over 400 CF700 aircraft in operation around

9996-399: Was shuttered in 2016 after producing 41 aircraft. Overall production of the type was terminated in 2020, by which point 1,231 aircraft were built. By this point, the ERJ family had been eclipsed by the newer and more advanced E-Jet family . The ERJ 145 was designed for a perceived new market for regional jet aircraft, where the increased speed, comfort and passenger appeal would outweigh

10098-573: Was slated to Comair , which ordered 60. In November 1990, a major reduction in Brazilian government spending, which held 61% of its voting share, resulted in Embraer laying off 32% of its 12,800 employees and suspending development of the EMB   145 for six months. In March 1991, a revised configuration started wind tunnel testing: the quarter chord wing sweep increased to 22.3° with underslung engines for lower aerodynamic drag . This reduced

10200-452: Was targeted for October, and the unit cost was then forecast to be US$ 15 million. The first delivery was planned for late November, while 29 aircraft were to be produced in 1997, 38 in 1998 and at least 48 per year thereafter. Its MTOW could be raised from the standard 19,200 to 20,600 kg (42,300 to 45,400 lb) for an Enhanced Range version. Flight tests allowed to increase its cruise speed to Mach 0.78 from 0.74, and showed fuel economy

10302-587: Was the Tupolev Tu-124 introduced in 1962. It used the Soloviev D-20 . 164 aircraft were produced between 1960 and 1965 for Aeroflot and other Eastern Bloc airlines, with some operating until the early 1990s. The first General Electric turbofan was the aft-fan CJ805-23 , based on the CJ805-3 turbojet. It was followed by the aft-fan General Electric CF700 engine, with a 2.0 bypass ratio. This

10404-528: Was then due in September 1991. Rolls-Royce could participate in the fan and low-pressure turbine, its original responsibility on the RB.580 joint development. By May, it had 296 commitments from 19 operators, and was seeking external finance. In June, maiden flight was expected by the end of 1990 before mid-1993 deliveries for $ 11.5 million each, cabin pressurisation was increased to 0.55 bar (8.0 psi) from

#658341