The Pratt & Whitney JT8D is a
low-bypass (0.96 to 1)
turbofan
The turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft propulsion. The word "turbofan" is a portmanteau of "turbine" and "fan": the ''turbo'' portion refers to a gas turbine engine which achieves mechanic ...
engine introduced by
Pratt & Whitney in February 1963 with the inaugural flight of the
Boeing 727
The Boeing 727 is an American narrow-body airliner that was developed and produced by Boeing Commercial Airplanes.
After the heavy 707 quad-jet was introduced in 1958, Boeing addressed the demand for shorter flight lengths from smaller airpo ...
. It was a modification of the
Pratt & Whitney J52 turbojet
The turbojet is an airbreathing jet engine which is typically used in aircraft. It consists of a gas turbine with a propelling nozzle. The gas turbine has an air inlet which includes inlet guide vanes, a compressor, a combustion chamber, an ...
engine which powered the
US Navy
The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage ...
A-6 Intruder
The Grumman A-6 Intruder is an American twinjet all-weather attack aircraft developed and manufactured by American aircraft company Grumman Aerospace and operated by the U.S. Navy and U.S. Marine Corps.
It was designed in response to a 1957 r ...
and
A-4 Skyhawk
The Douglas A-4 Skyhawk is a single-seat subsonic carrier-capable light attack aircraft developed for the United States Navy and United States Marine Corps in the early 1950s. The delta-winged, single turbojet engined Skyhawk was designed ...
attack aircraft. Eight models comprise the JT8D standard engine family, covering the thrust range from 12,250 to 17,400
pounds-force
The pound of force or pound-force (symbol: lbf, sometimes lbf,) is a unit of force used in some systems of measurement, including English Engineering units and the foot–pound–second system.
Pound-force should not be confused with pound-ma ...
(62 to 77 kN), and power
727,
737-100/200, and
DC-9
The McDonnell Douglas DC-9 is an American five-abreast single-aisle aircraft designed by the Douglas Aircraft Company. It was initially produced by the developer company as the Douglas DC-9 until August 1967 and then by McDonnell Douglas.
After ...
. The updated JT8D-200 family, covering the 18,900 to 21,000
pounds-force
The pound of force or pound-force (symbol: lbf, sometimes lbf,) is a unit of force used in some systems of measurement, including English Engineering units and the foot–pound–second system.
Pound-force should not be confused with pound-ma ...
(84 to 93 kN), powers the
MD-80 and re-engined
Super 27 aircraft. The
Volvo RM8
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-o ...
was license-built in Sweden for the
Saab 37 Viggen
The Saab 37 Viggen ( Swedish for ''"the Bolt"'' or ''"the Tufted Duck"'' ( see name)) is a retired Swedish single-seat, single-engine, short-medium range combat aircraft. Development work on the type was initiated at Saab in 1952 and, follow ...
fighter. Pratt & Whitney also sells static versions for powerplant and ship propulsion as the FT8.
Design
![1-4 SCALE JT-8D TURBO JET ENGINE - NARA - 17422354](https://upload.wikimedia.org/wikipedia/commons/1/1a/1-4_SCALE_JT-8D_TURBO_JET_ENGINE_-_NARA_-_17422354.jpg)
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
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 ev ...
meant that, compared to subsequently developed turbofans, high noise levels were still produced.
Within the fan inlet case, there are
anti-icing
Deicing is the process of removing snow, ice or frost from a surface. Anti-icing is the application of chemicals that not only deice but also remain on a surface and continue to delay the reformation of ice for a certain period of time, or preve ...
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.
File:CRT SECTOR RIG COMBUSTOR CAN JT-8D - NARA - 17470980.jpg, Canular combustor
A combustor is a component or area of a gas turbine, ramjet, or scramjet engine where combustion takes place. It is also known as a burner, combustion chamber or flame holder. In a gas turbine engine, the ''combustor'' or combustion chamber is f ...
File:JT-8D 20 INCH DIAMETER ROTOR AND BYPASS STATORS - NARA - 17418487.jpg, diameter rotor and bypass stator
File:JT8D COMPRESSOR FAN - NARA - 17418187.jpg, Compressor fan
JT8D COMPRESSOR FAN - NARA - 17418191.jpg, Fan blade
Update programs
![JT-8D REFAN ENGINE - NARA - 17422288](https://upload.wikimedia.org/wikipedia/commons/6/68/JT-8D_REFAN_ENGINE_-_NARA_-_17422288.jpg)
In response to environmental concerns that began in the 1970s, the company began developing a new version of the engine, the JT8D-200 series. 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
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 ev ...
(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 to and reducing fan pressure ratio (from 2.21 to 1.92). Overall engine pressure ratio was also increased from 15.4 to 21.0. 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
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 ...
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, has developed the JT8D-219 as a re-engine powerplant for
Boeing 707-based aircraft.
[''Flug Revue'', May 12, 2002]
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
The Northrop Grumman E-8 Joint Surveillance Target Attack Radar System (Joint STARS) is a United States Air Force airborne ground surveillance, battle management and command and control aircraft. It tracks ground vehicles and some aircraft, col ...
) aircraft, which would allow the JSTARS more time on station due to the engine's 17%
greater fuel efficiency. NATO plans to re-engine their fleet of
E-3 Sentry AWACS aircraft. The -219 is publicized as being half the cost of the competing 707 re-engine powerplant, the
CFM International CFM56
The CFM International CFM56 (U.S. military designation F108) series is a Franco-American family of high-bypass turbofan aircraft engines made by CFM International (CFMI), with a thrust range of . CFMI is a 50–50 joint-owned company of Saf ...
, 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.
[
The proposed ]Aerion SBJ
The Aerion SBJ was a supersonic business jet project designed by American firm Aerion Corporation.
Unveiled in 2004, the designer sought a joint venture with a business aircraft manufacturer for a $1.2–1.4 billion development in 7–8 years ...
supersonic business jet
A supersonic business jet (SSBJ) is a business jet travelling above the speed of sound: a supersonic aircraft. Some manufacturers are designing or have been designing SSBJs, but none are currently available. Usually intended to transport about t ...
, previously under development, was to use a pair of JT8D-219 engines for sustained supersonic flight.
Variants
Production
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. Regular production ended in 1985, but some replacement engines were produced for military aircraft in 2011. Mainline airline use of the JT8D continued until 2020 when Delta Airlines
Delta Air Lines, Inc., typically referred to as Delta, is one of the major airlines of the United States and a legacy carrier. One of the world's oldest airlines in operation, Delta is headquartered in Atlanta, Georgia. The airline, along wi ...
retired their MD-88
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 gene ...
fleet early due to the COVID-19 pandemic
The COVID-19 pandemic, also known as the coronavirus pandemic, is an ongoing global pandemic of coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The novel virus was first identif ...
.
Applications
* Aerion SBJ
The Aerion SBJ was a supersonic business jet project designed by American firm Aerion Corporation.
Unveiled in 2004, the designer sought a joint venture with a business aircraft manufacturer for a $1.2–1.4 billion development in 7–8 years ...
– proposed, not built
* Boeing 707RE
* Boeing 727
The Boeing 727 is an American narrow-body airliner that was developed and produced by Boeing Commercial Airplanes.
After the heavy 707 quad-jet was introduced in 1958, Boeing addressed the demand for shorter flight lengths from smaller airpo ...
- Re-Engined Super 27s have JT8D-200s
* Boeing 737
The Boeing 737 is a narrow-body aircraft produced by Boeing at its Boeing Renton Factory, Renton Factory in Washington (state), Washington.
Developed to supplement the Boeing 727 on short and thin routes, the twinjet retains the Boeing 707, 7 ...
-100 & -200
* Dassault Mercure
The Dassault Mercure is a twin-engined narrow-body jet-powered airliner developed and manufactured by French aircraft firm Dassault Aviation. According to Dassault, it was the first large-scale European cooperative civil aeronautics programme.
...
* Kawasaki C-1
The Kawasaki C-1 (川崎 C-1) is a twin-engined short-range military transport aircraft developed and manufactured by the Japanese conglomerate Kawasaki Heavy Industries. It is solely used by the Japan Air Self-Defense Force (JASDF).
Develop ...
* McDonnell Douglas DC-9
The McDonnell Douglas DC-9 is an American five-abreast single-aisle aircraft designed by the Douglas Aircraft Company. It was initially produced by the developer company as the Douglas DC-9 until August 1967 and then by McDonnell Douglas.
Afte ...
* McDonnell Douglas MD-80
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 gene ...
series - JT8D-200s only
* McDonnell Douglas YC-15
The McDonnell Douglas YC-15 is a prototype four-engine short take-off and landing (STOL) tactical transport. It was McDonnell Douglas' entrant into the United States Air Force's Advanced Medium STOL Transport (AMST) competition to replace the ...
* Northrop Grumman E-8C Joint STARS – single testbed only
* Sud Aviation Caravelle 10B, 10R, 11R, and 12
* Pratt & Whitney FT8 MobilePac and SwiftPac mobile generators
File:Boeing 727 T-tail and engines.jpg, Boeing 727
The Boeing 727 is an American narrow-body airliner that was developed and produced by Boeing Commercial Airplanes.
After the heavy 707 quad-jet was introduced in 1958, Boeing addressed the demand for shorter flight lengths from smaller airpo ...
File:PW JT-8D-17 engine on a Brazilian Air Force VC-96 (2116).jpg, Boeing 737
The Boeing 737 is a narrow-body aircraft produced by Boeing at its Boeing Renton Factory, Renton Factory in Washington (state), Washington.
Developed to supplement the Boeing 727 on short and thin routes, the twinjet retains the Boeing 707, 7 ...
File:Réacteurs de mercure (2890623814).jpg, Dassault Mercure
The Dassault Mercure is a twin-engined narrow-body jet-powered airliner developed and manufactured by French aircraft firm Dassault Aviation. According to Dassault, it was the first large-scale European cooperative civil aeronautics programme.
...
File:JA2012 Centrair (8085933177).jpg, Kawasaki C-1
The Kawasaki C-1 (川崎 C-1) is a twin-engined short-range military transport aircraft developed and manufactured by the Japanese conglomerate Kawasaki Heavy Industries. It is solely used by the Japan Air Self-Defense Force (JASDF).
Develop ...
File:LN-RMT McDonnell Douglas MD-81 (DC-9-81) (cn 53001 1815) Scandinavian Airlines - SAS. (6103442473).jpg, McDonnell Douglas MD-80
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 gene ...
Caravelle Super 10-Air Toulouse tail (MAA).JPG, Sud Aviation Caravelle
Accidents
;18 January 1969:United Airlines Flight 266
United Airlines Flight 266 was a scheduled passenger flight from Los Angeles International Airport, California, to General Mitchell International Airport, Milwaukee, Wisconsin, via Stapleton International Airport, Denver, Colorado. On January 1 ...
– Ten minutes after takeoff, the cockpit received a warning from Engine 1 of an engine fire and cut off power to that engine. A minute later, Flight UA266 suffered a total loss of electrical power, which disabled the aircraft's flight instruments. At 13 minutes after take-off, the plane crashed into the Pacific Ocean, just 12 miles off the coast, killing all 38 people aboard the aircraft, which consisted of 32 passengers and six crew members.
;4 April 1977:Southern Airways Flight 242
Southern Airways Flight 242 was a flight from Muscle Shoals, Alabama, to Atlanta, Georgia, with a stop in Huntsville, Alabama. On April 4, 1977, it executed a forced landing on Georgia State Route 381 in New Hope, Paulding County, Georgia, Unit ...
– both engines on the DC-9
The McDonnell Douglas DC-9 is an American five-abreast single-aisle aircraft designed by the Douglas Aircraft Company. It was initially produced by the developer company as the Douglas DC-9 until August 1967 and then by McDonnell Douglas.
After ...
failed when the pilots flew into a severe thunderstorm after misreading their onboard radar. The flight encountered severe rain and hail. The NTSB concluded that the "loss of thrust was caused by the ingestion of massive amounts of water and hail which in combination with thrust lever movement induced severe stalling in and major damage to the engine compressors." Some 63 people on board and nine on the ground died as a result of the accident.
;22 August 1985:British Airtours Flight 28M
British Airtours Flight 28M (also known as Flight 328) was an international passenger flight which caught fire before takeoff at Manchester Airport, England on 22 August 1985 with the loss of 55 lives. It was en route to Corfu International A ...
– an engine failed during take-off from Manchester Airport and a fire spread into the cabin, resulting in 55 fatalities aboard the Boeing 737
The Boeing 737 is a narrow-body aircraft produced by Boeing at its Boeing Renton Factory, Renton Factory in Washington (state), Washington.
Developed to supplement the Boeing 727 on short and thin routes, the twinjet retains the Boeing 707, 7 ...
-236 Advanced.
;6 September 1985: Midwest Express Flight 105 – NTSB concluded that an unconfined failure of the 9th - 10th stage compressor spacer occurred immediately after takeoff from Milwaukee Mitchell International Airport
Milwaukee Mitchell International Airport is a civil–military airport south of downtown Milwaukee, Wisconsin, United States., effective May 21, 2020. It is included in the Federal Aviation Administration (FAA) National Plan of Integrated Ai ...
(then called Billy Mitchell Field). The plane was observed to have slowed significantly as a result of the engine loss and experienced an accelerated stall condition. The plane rolled to the right 90 degrees and crashed just south of the runway, resulting in 31 fatalities (all passengers and crew) aboard the McDonnell-Douglas DC-9 aircraft.
;3 May 1991: Ryan Airlines – Unconfined failure of 9th stage compressor disc penetrated fuel lines and fuselage on the tarmac at Bradley International Airport
Bradley International Airport is a public international airport in Windsor Locks, Connecticut, United States. Owned and operated by the Connecticut Airport Authority, it is the second-largest airport in New England.
The airport is about hal ...
causing fire and complete loss of aircraft. No fatalities reported.
;21 December 1991:Scandinavian Airlines Flight 751
Scandinavian Airlines System Flight 751 was a regularly scheduled Scandinavian Airlines passenger flight from Stockholm, Sweden, to Warsaw, Poland, via Copenhagen, Denmark. On 27 December 1991, a McDonnell Douglas MD-81 operating the flight, r ...
– The engines on an MD-81 ingested wing ice during takeoff causing engine damage that led to a total loss of thrust on both engines. The aircraft crashed in a forest clearing with no fatalities.
;6 July 1996:An engine explosion happened on an MD-88
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 gene ...
, Delta Air Lines Flight 1288
Delta Air Lines Flight 1288 was a regularly scheduled flight from Pensacola, Florida, to Atlanta, Georgia. On July 6, 1996, the aircraft serving the flight, a McDonnell Douglas MD-88, was on takeoff roll from Runway 17 at Pensacola when it exp ...
, just prior to take-off at Pensacola, Florida
Pensacola () is the westernmost city in the Florida Panhandle, and the county seat and only incorporated city of Escambia County, Florida, United States. As of the 2020 United States census, the population was 54,312. Pensacola is the principal ...
, USA, with two fatalities.
;15 April 2008:A DC-9-51 operated by Hewa Bora Airways
Hewa Bora Airways Sarl (operating as Hewa Bora Airways) was the national airline of the Democratic Republic of the Congo based in Barumbu, Kinshasa, Democratic Republic of the Congo. It was one of Congo's largest airlines and operated regional ...
crashed
"Crashed" is the third U.S. rock Single (music), single, (the fifth overall), from the band Daughtry (band), Daughtry's debut album. It was released only to U.S. rock stations on September 5, 2007. Upon its release the song got adds at those stat ...
and burned at Goma
Goma is the capital of North Kivu province in the eastern Democratic Republic of the Congo. It is located on the northern shore of Lake Kivu, next to the Rwandan city of Gisenyi. The lake and the two cities are in the Albertine Rift, the ...
following an engine fire, with 40 fatalities.
;10 July 2019:A McDonnell Douglas MD-88
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 gene ...
operated by Delta
Delta commonly refers to:
* Delta (letter) (Δ or δ), a letter of the Greek alphabet
* River delta, at a river mouth
* D ( NATO phonetic alphabet: "Delta")
* Delta Air Lines, US
* Delta variant of SARS-CoV-2 that causes COVID-19
Delta may also ...
landed safely after an engine failure.
;2 July 2021: Transair Flight 810
Transair Flight 810, a Boeing 737-200 converted freighter aircraft on a short cargo flight en route from Honolulu International Airport to Kahului Airport on the neighboring Hawaiian island of Maui, experienced mechanical difficulties and cra ...
– One engine on the Boeing 737-200
The Boeing 737 is a narrow-body aircraft produced by Boeing at its Renton Factory in Washington.
Developed to supplement the Boeing 727 on short and thin routes, the twinjet retains the 707 fuselage width and six abreast seating with two u ...
cargo aircraft failed en route from Honolulu
Honolulu (; ) is the capital and largest city of the U.S. state of Hawaii, which is in the Pacific Ocean. It is an unincorporated county seat of the consolidated City and County of Honolulu, situated along the southeast coast of the island ...
to the neighboring Hawaiian island of Maui. The crew attempted to turn back to Honolulu's Daniel K. Inouye International Airport
Daniel K. Inouye International Airport , also known as Honolulu International Airport, is the main airport of Oahu, Hawaii.[ditch
A ditch is a small to moderate divot created to channel water. A ditch can be used for drainage, to drain water from low-lying areas, alongside roadways or fields, or to channel water from a more distant source for plant irrigation. Ditches ar ...](_blank)
the airplane about off the southern coast of Oahu
Oahu () (Hawaiian language, Hawaiian: ''Oʻahu'' ()), also known as "The Gathering place#Island of Oʻahu as The Gathering Place, Gathering Place", is the third-largest of the Hawaiian Islands. It is home to roughly one million people—over t ...
. Both pilots were rescued by the United States Coast Guard
The United States Coast Guard (USCG) is the maritime security, search and rescue, and law enforcement service branch of the United States Armed Forces and one of the country's eight uniformed services. The service is a maritime, military, mult ...
.
;19 October 2021: A Privately Owned MD-87 was recorded on its takeoff roll just after throttling up a "puff of smoke" was observed from the left engine nacelle. Subsequently the aircraft rolled off the end of the runway into a grass field and caught fire. The MD-87 was almost completely destroyed by the resulting fire. The privately owned jet, N987AK McDonnell Douglas MD-87, owned by J. Alan Kent Development LLC, was chartering sports fans to Boston for the ALCS Championship Baseball Games. Only 1 minor injury and no fatalities occurred on this incident. It is still under active investigation.
Specifications (JT8D-219)
See also
References
*
External links
Pratt & Whitney - JT8D page
{{DEFAULTSORT:Pratt and Whitney JT8D
Low-bypass turbofan engines
JT8D
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 ...
1960s turbofan engines