JT8D | |
---|---|
The JT8D is a low-bypass turbofan often used on early narrowbody jetliners | |
Type | Turbofan |
National origin | United States |
Manufacturer | Pratt & Whitney |
First run | 1960 |
Major applications | Boeing 727 Boeing 737-100/-200 McDonnell Douglas DC-9 McDonnell Douglas MD-80 Dassault Mercure |
Number built | 14,750 [1] |
Developed from | Pratt & Whitney J52 |
Developed into | Volvo RM8 |
The Pratt & Whitney JT8D is a low-bypass (0.96 to 1) turbofan engine introduced by Pratt & Whitney in February 1963 with the inaugural flight of the Boeing 727. It was a modification of the Pratt & Whitney J52 turbojet engine which powered the US Navy A-6 Intruder and A-4 Skyhawk attack aircraft. Eight models comprise the JT8D standard engine family, covering the thrust range from 12,250 to 17,400 pounds-force (54 to 77 kN), and power the 727, 737-100/200, and DC-9. The updated JT8D-200 family, covering the 18,900 to 21,000 pounds-force (84 to 93 kN), powers the MD-80 and re-engined Super 27 aircraft. The JT8D was built under license in Sweden as the Volvo RM8, a redesigned afterburning derivative for the Saab 37 Viggen fighter. [2] Pratt & Whitney also sells static versions for powerplant and ship propulsion as the FT8.
This section needs additional citations for verification .(October 2008) |
The JT8D is an axial-flow front turbofan engine incorporating a two-spool design. There are two coaxially-mounted independent rotating assemblies: one rotating assembly for the low pressure compressor (LPC) which consists of the first six stages (i.e. six pairs of rotating and stator blades, including the first two stages which are for the bypass turbofan), driven by the second (downstream) turbine (which consists of three stages); and a second rotating assembly for the high-pressure compressor (HPC) section, which has seven stages. The high-pressure compressor is driven by the first (upstream) turbine, which has a single stage.
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.
Within the fan inlet case, there are anti-icing air bosses and probes to sense the inlet pressure and temperature. Similar units exist throughout the engine to check temperatures and pressures.
At the 13th (i.e. the final) compressor stage, air is bled out and used for anti-icing. The amount is controlled by the Pressure Ratio Bleed Control sense signal (PRBC). The diffuser case at the aft end of the compressor houses the 13th stage. Its increasing cross-sectional area allows the compressed air to slow down before entering one of the engine's nine burner cans. Again, there are two bosses to extract 13th stage air for anti-icing, de-icing of fuel, and airframe (cabin pressurization) use. Not all the compressed air enters the burner cans at the fuel-ignition point; some bypasses the can completely and cools the first turbine stage, and some is gradually introduced into the burner can's perimeter in such a way that the burning fuel is held near the can's centerline.
There are nine combustion chambers positioned in a can-annular arrangement. Each chamber has three air inlet hole sizes: the smallest is for cooling, the medium is for burning and the largest for forming an air blanket.
In response to environmental concerns that began in the 1970s, the company began developing a new version of the engine, the JT8D-200 series. [3] Designed to be quieter, cleaner, more efficient, yet more powerful than earlier models, the -200 Series power-plant was re-engineered with a significantly higher bypass ratio (1.74 to 1) covering the 18,500 to 21,700 pound-force (82 to 97 kN) thrust range and powering the McDonnell Douglas MD-80 series. This increase was achieved by increasing bypass fan diameter from 39.9 inches (101 cm) to 49.2 inches (125 cm) and reducing fan pressure ratio (from 2.21 to 1.92).[ citation needed ] Overall engine pressure ratio was also increased from 15.4 to 21.0. [4] Since entering service in 1980, more than 2,900 of the -200 series engines have been produced.
The JT8D-217 and -219 engine(s) were tested in 2001 and were deemed suitable replacements for the old TF33 engines on military and commercial aircraft as part of the Super 27 re-engining program. The updated engines offer reduced (Stage-3) noise compliance standards without the need for hush kits, enhanced short field performance, and steeper and faster climb rates with roughly a 10% reduction in fuel burn for extended range.
Pratt & Whitney, in a joint venture with Seven Q Seven (SQS) and Omega Air, developed the JT8D-219 as a re-engine powerplant for Boeing 707-based aircraft. [5] Northrop Grumman used the -219 to re-engine one of the United States Air Force's fleet of 19 Joint Surveillance Target Attack Radar System (E-8 Joint STARS) aircraft, which would allow the JSTARS more time on station due to the engine's 17% [6] greater fuel efficiency. However these plans were cancelled after the single conversion when the decision was taken to retire the platform. NATO originally planned to re-engine their fleet of E-3 Sentry AWACS aircraft, however again this was cancelled after the decision was taken to retire the E-3 platform in preference for the E-7 Wedgetail. The -219 is publicized as being half the cost of the competing 707 re-engine powerplant, the CFM International CFM56, for reasons of geometrical and balance similarity to the engine it is replacing and the associated relative up-front wing modification costs of the two choices. [5] [6]
The proposed Aerion SBJ supersonic business jet, previously under development, was to use a pair of JT8D-219 engines for sustained supersonic flight.
Series | Initial J52 derived variants [7] | Updated -200 series [8] | |||||
---|---|---|---|---|---|---|---|
Model | -1(A/B)/7(A/B) /9(A)/11 | -5 | -15(A) | -17(A/R/AR) | -209 | -217(A/C) | -219 |
Certification | Feb 1, 1963 | Apr 7, 1971 | Feb 1, 1974 | Jun 22, 1979 | Oct 31, 1980 | Feb 22, 1985 | |
Compressor | axial 13-stage | axial 14-stage | |||||
Combustors, turbine | 9 can-annular, 4-stage | ||||||
Maximum Thrust | 14,000–15,000 lbf 62–67 kN | 12,250 lbf 54.5 kN | 15,550 lbf 69.2 kN | 17,000–17,400 lbf 76–77 kN | 18,900 lbf 84 kN | 20,000 lbf 89 kN | 21,000 lbf 93 kN |
Length | 123.56 in (3,138 mm) | 154.20 in (3,917 mm) | |||||
Width | 40.0 in (1,020 mm) | 49.2 in (1,250 mm) | |||||
Dry Weight | 3,205–3,402 lb 1,454–1,543 kg | 3,205 lb 1,454 kg | 3,414–3,474 lb 1,549–1,576 kg | 3,430–3,500 lb 1,560–1,590 kg | 4,588 lb 2,081 kg | 4,623–4,684 lb 2,097–2,125 kg | 4,684 lb 2,125 kg |
LP rpm | 8,600 | 8,500 | 8,800 | 8,800-8,900 | 7,850 | 7,770-8,080 | 8,120 |
HP rpm | 12,250 | 12,100 | 12,250 | 12,250-12,280 | 12,150 | 12,285-12,350 | 12,350 |
More than 14,000 JT8D engines have been produced, totaling more than one-half billion hours of service, with more than 350 operators, making it the most popular of all low-bypass turbofan engines ever produced. [9] [1] Regular production ended in 1985, but some replacement engines were produced for military aircraft in 2011. [10] Mainline airline use of the JT8D continued until 2020 when Delta Air Lines retired their MD-88 fleet early due to the COVID-19 pandemic. [11]
Related development
Comparable engines
Related lists
A turbofan or fanjet 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 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 McDonnell DouglasMD-90 is an American five-abreast single-aisle airliner developed by McDonnell Douglas from its successful model MD-80. The airliner was produced by the developer company until 1997 and then by Boeing Commercial Airplanes. It was a stretched derivative of the MD-80 and thus part of the DC-9 family. After the more fuel-efficient IAE V2500 high-bypass turbofan was selected, Delta Air Lines became the launch customer on November 14, 1989. The MD-90 first flew on February 22, 1993, and the first delivery was in February 1995 to Delta.
The McDonnell Douglas MD-80 is a series of five-abreast single-aisle airliners developed by McDonnell Douglas. It was produced by the developer company until August 1997 and then by Boeing Commercial Airplanes. The MD-80 was the second generation of the DC-9 family, originally designated as the DC-9-80 and later stylized as the DC-9 Super 80 . Stretched, enlarged wing and powered by higher bypass Pratt & Whitney JT8D-200 engines, the aircraft program was launched in October 1977. The MD-80 made its first flight on October 18, 1979, and was certified on August 25, 1980. The first airliner was delivered to launch customer Swissair on September 13, 1980, which introduced it into service on October 10, 1980.
The Pratt & Whitney JT9D engine was the first high bypass ratio jet engine to power a wide-body airliner. Its initial application was the Boeing 747-100, the original "Jumbo Jet". It was Pratt & Whitney's first high-bypass-ratio turbofan.
The CFM International CFM56 series is a Franco-American family of high-bypass turbofan aircraft engines made by CFM International (CFMI), with a thrust range of 18,500 to 34,000 lbf. CFMI is a 50–50 joint-owned company of Safran Aircraft Engines of France, and GE Aerospace (GE) of the United States. GE produces the high-pressure compressor, combustor, and high-pressure turbine, Safran manufactures the fan, gearbox, exhaust and the low-pressure turbine, and some components are made by Avio of Italy and Honeywell from the US. Both companies have their own final assembly line, GE in Evendale, Ohio, and Safran in Villaroche, France. The engine initially had extremely slow sales but has gone on to become the most used turbofan aircraft engine in the world.
The Pratt & Whitney PW2000, also known by the military designation F117 and initially referred to as the JT10D, is a series of high-bypass turbofan aircraft engines with a thrust range from 37,000 to 43,000 lbf. Built by Pratt & Whitney, they were designed for the Boeing 757. As a 757 powerplant, these engines compete with the Rolls-Royce RB211.
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.
The IAE V2500 is a two-shaft high-bypass turbofan engine built by International Aero Engines (IAE) which powers the Airbus A320 family, the McDonnell Douglas MD-90, and the Embraer C-390 Millennium.
The Pratt & Whitney JT3D is an early turbofan aircraft engine derived from the Pratt & Whitney JT3C. It was first run in 1958 and was first flown in 1959 under a B-45 Tornado test aircraft. Over 8,000 JT3Ds were produced between 1959 and 1985. Most JT3D engines still in service today are used on military aircraft, where the engine is referred to by its US military designation of TF33.
The Pratt & Whitney F119, company designation PW5000, is an afterburning turbofan engine developed by Pratt & Whitney for the Advanced Tactical Fighter (ATF) program, which resulted in the Lockheed Martin F-22 Raptor. The engine delivers thrust in the 35,000 lbf (156 kN) class and was designed for sustained supersonic flight without afterburners, or supercruise. Delivering almost 22% more thrust with 40% fewer parts than its F100 predecessor, the F119 allows the F-22 to achieve supercruise speeds of up to Mach 1.8. The F119's nozzles incorporate thrust vectoring that enable them to direct the engine thrust ±20° in the pitch axis to give the F-22 enhanced maneuverability.
The Pratt & Whitney TF30 is a military low-bypass turbofan engine originally designed by Pratt & Whitney for the subsonic F6D Missileer fleet defense fighter, but this project was cancelled. It was later adapted with an afterburner for supersonic designs, and in this form it was the world's first production afterburning turbofan, going on to power the F-111 and the F-14A Tomcat, as well as being used in early versions of the A-7 Corsair II without an afterburner. First flight of the TF30 was in 1964 and production continued until 1986.
The Pratt & Whitney F100 is a low bypass afterburning turbofan engine. It was designed and manufactured by Pratt & Whitney to power the U.S. Air Force's "FX" initiative in 1965, which became the F-15 Eagle. The engine was to be developed in tandem with the F401 which shares a similar core but with an upscaled fan for the U.S. Navy's F-14 Tomcat. The F401 was later abandoned due to costs and reliability issues. The F100 also powered the F-16 Fighting Falcon for the Air Force's Lightweight Fighter (LWF) program.
The Pratt & Whitney J57 is an axial-flow turbojet engine developed by Pratt & Whitney in the early 1950s. The J57 was the first 10,000 lbf (45 kN) thrust class engine in the United States. It is a two spool engine.
The General Electric CF6, US military designations F103 and F138, is a family of high-bypass turbofan engines produced by GE Aviation. Based on the TF39, the first high-power high-bypass jet engine, the CF6 powers a wide variety of civilian airliners. The basic engine core also powers the LM2500 and LM6000 marine and power generation turboshafts. It is gradually being replaced by the newer GEnx family.
The General Electric F404 and F412 are a family of afterburning turbofan engines in the 10,500–19,000 lbf (47–85 kN) class. The series is produced by GE Aerospace. Partners include Volvo Aero, which builds the RM12 variant. The F404 was developed into the larger F414 turbofan, as well as the experimental GE36 civil propfan.
A jet engine performs by converting fuel into thrust. How well it performs is an indication of what proportion of its fuel goes to waste. It transfers heat from burning fuel to air passing through the engine. In doing so it produces thrust work when propelling a vehicle but a lot of the fuel is wasted and only appears as heat. Propulsion engineers aim to minimize the degradation of fuel energy into unusable thermal energy. Increased emphasis on performance improvements for commercial airliners came in the 1970s from the rising cost of fuel.
A variable cycle engine (VCE), also referred to as adaptive cycle engine (ACE), is an aircraft jet engine that is designed to operate efficiently under mixed flight conditions, such as subsonic, transonic and supersonic.
The Volvo RM8 is a low-bypass afterburning turbofan jet engine developed for the Saab 37 Viggen fighter. An augmented bypass engine was required to give both better fuel consumption at cruise speeds and higher thrust boosting for its short take-off requirement than would be possible using a turbojet. In 1962, the civil Pratt & Whitney JT8D engine, as used for airliners such as the Boeing 727, was chosen as the only engine available which could be modified to meet the Viggen requirements. The RM8 was a licensed-built version of the JT8D, but extensively modified for supersonic speeds, with a Swedish-designed afterburner, and was produced by Svenska Flygmotor.
The General Electric Passport is a turbofan developed by GE Aerospace for large business jets. It was selected in 2010 to power the Bombardier Global 7500 and 8000, first run on June 24, 2013, and first flown in 2015. It was certified in April 2016 and powered the Global 7500 first flight on November 4, 2016, before its 2018 introduction. It produces 14,000 to 20,000 lbf of thrust, a range previously covered by the General Electric CF34. A smaller scaled CFM LEAP, it is a twin-spool axial engine with a 5.6:1 bypass ratio and a 45:1 overall pressure ratio and is noted for its large one-piece 52 in (130 cm) fan 18-blade titanium blisk.
The Pratt & Whitney F401 was an afterburning turbofan engine developed by Pratt & Whitney in tandem with the company's F100. The F401 was intended to power the Grumman F-14 Tomcat and Rockwell XFV-12, but the engine was canceled due to costs and development issues.
The JT8D engine has proven itself to be a highly durable and reliable engine, having completed more than 673 million dependable flying hours since entering service. Once deemed the workhorse of the industry, more than 14,750 JT8D engines have flown. Today, there are 2,400 engines still in use.
More than 14,750 JT8D engines have been built, accumulating more than half a billion hours of service. At one point, JT8D engine sales and service contributed about half of United Technologies' profits. Today, it continues to generate revenue through overhauls, spare parts sales and kits to make it quieter and cleaner burning.
This aircraft engine article is missing some (or all) of its specifications. If you have a source, you can help Wikipedia by adding them. |