Pratt & Whitney F135
Encyclopedia
The Pratt & Whitney F135 is an afterburning
turbofan
developed for the F-35 Lightning II
single-engine strike fighter. The F135 family has several distinct variants, including a conventional, forward thrust variant and a multi-cycle STOVL
variant that includes a forward lift fan
. The first production engines are scheduled to be delivered in 2009.
Skunk Works
's efforts to develop a stealthy STOVL strike fighter for the U.S. Marine Corps under a 1986 DARPA program. Lockheed employee Paul Bevilaqua
developed and patented a concept aircraft and propulsion system, and then turned to Pratt & Whitney (P&W) to build a demonstrator engine. The demonstrator used the first stage fan from a F119
engine for the lift fan, the engine fan and core from the F100-220
for the core, and the larger low pressure turbine from the F100-229
for the low pressure turbine of the demonstrator engine. The larger turbine was used to provide the additional power required to operate the lift fan. Finally, a variable thrust deflecting nozzle was added to complete the "F100-229-Plus" demonstrator engine. This engine proved the lift-fan concept and led to the development of the current F135 engine.
P&W developed the F135 from their F119
turbofan, which powers the F-22 Raptor
, as the "F119-JSF". The F135 integrates the F119 core with new components optimized for the JSF. The F135 is assembled at a plant in Middletown, Connecticut
. Some parts of the engine are made in Longueuil
, Quebec, Canada, and in Poland.
The first production propulsion system for operational service is scheduled for delivery in 2007. The F-35 will serve the U.S., UK, and other international customers. The initial F-35s will be powered by the F135, but GE/Rolls-Royce
team is developing the F136
turbofan as an alternate engine for the F-35 as of July 2009. The Initial Pentagon planning required that after 2010, for the Lot 6 aircraft, the engine contracts will be competitively tendered. However since 2006 the Defense Department has requested no funding for the alternate F136 engine program, but Congress has maintained program funding.
The F135 team is made up of Pratt & Whitney
, Rolls-Royce
and Hamilton Sundstrand
. Pratt & Whitney is the prime contractor and handles main engine, and systems integration. Rolls-Royce is responsible for the vertical lift system for the STOVL aircraft system. Hamilton Sundstrand is responsible for the electronic engine control system, actuation system, PMAG, gearbox, health monitoring systems, and fuel system,
As of 2009, P&W is developing a more durable version of the F135 engine to increase the service life of key parts. These parts are primarily in the hot sections of the engine (the combustor and high pressure turbine blades specifically) where current versions of the engine are running hotter than expected, reducing life expectancy. The test engine is designated XTE68/LF1, and testing is expected to begin in 2010. This redesign has caused “substantial cost growth.”
Pratt expects to soon be delivering F135s below the cost of the F119, even though it is a more powerful engine.
The conventional and carrier aviation engines, the F135-PW-100 and F135-PW-400, have a maximum (wet
) thrust of approximately 43000 lbf (191.3 kN) and a dry thrust of approximately 28000 lbf (124.6 kN). The major difference between the -100 and -400 models is the use of salt-corrosion resistant materials.
The STOVL variant, F135-PW-600, delivers the same 43000 lbf (191.3 kN) of wet thrust as the other types in its conventional configuration. In STOVL configuration, the engine produces 18000 lbf (80.1 kN) of lift thrust. Combined with thrust from the LiftFan (20000 lbf (89 kN)) and two roll posts (1950 lbf (8.7 kN) each), the Rolls-Royce LiftSystem
produces a total of 41900 lbf (186.4 kN) of thrust, almost the same vertical lifting force for slow speed flight as the same engine produces at maximum afterburner, without the extreme fuel use or exhaust heat as wet thrust.
The STOVL variant engages a clutch to extract around 35000 shp from the LP turbine to turn the forward lift fans, while switching power cycle from mixed (turbofan) to unmixed (turboshaft
). Power is transferred forward through shaft to a bevel gearbox, to drive two vertically mounted contra-rotating fans. The uppermost fan is fitted with variable inlet guide vanes and the fan discharges efflux (low-velocity unheated air) through a nozzle on the underside of the aircraft. This cool air from the lift fan has the added benefit of preventing hot exhaust gases from the core section from being reingested into the engine while hovering. Finally, bypass duct air is sent to a pair of roll post nozzles and the core stream discharges downwards via a thrust vectoring nozzle at the rear of the engine. Measured by lift thrust in full vertical lift mode, the engine operates as 43% turbojet, 48% turboshaft, and 9% turbofan.
Improving engine reliability and ease of maintenance is a major objective of the F135. The engine has fewer parts than similar engines which should help improve reliability. All line-replaceable components (LRCs) can be removed and replaced with a set of six common hand tools. Additionally, the F135's health management system is designed to provide real time data to maintainers on the ground, allowing them to troubleshoot problems and prepare replacement parts before the aircraft returns to base. According the Pratt & Whitney, this data may help drastically reduce troubleshooting and replacement time, as much as 94% over legacy engines.
The F135/F136 engines are not designed to supercruise
.
In August 2010, Pratt & Whitney revealed that the F135 was able to generate in excess of 50,000 lb of thrust.
Afterburner (engine)
An afterburner is an additional component added to some jet engines, primarily those on military supersonic aircraft. Its purpose is to provide a temporary increase in thrust, both for supersonic flight and for takeoff...
turbofan
Turbofan
The turbofan is a type of airbreathing jet engine that is widely used for aircraft propulsion. A turbofan combines two types of engines, the turbo portion which is a conventional gas turbine engine, and the fan, a propeller-like ducted fan...
developed for the F-35 Lightning II
F-35 Lightning II
The Lockheed Martin F-35 Lightning II is a family of single-seat, single-engine, fifth generation multirole fighters under development to perform ground attack, reconnaissance, and air defense missions with stealth capability...
single-engine strike fighter. The F135 family has several distinct variants, including a conventional, forward thrust variant and a multi-cycle STOVL
STOVL
STOVL is an acronym for short take off and vertical landing.This is the ability of some aircraft to take off from a short runway or take off vertically if it does not have a very heavy payload and land vertically...
variant that includes a forward lift fan
Rolls-Royce LiftSystem
The Rolls-Royce LiftSystem is an innovative propulsion system designed for use in the STOVL variant of the F-35 Lightning II developed during the Joint Strike Fighter Program...
. The first production engines are scheduled to be delivered in 2009.
Development
The origins of the F135 lie with the Lockheed CorporationLockheed Corporation
The Lockheed Corporation was an American aerospace company. Lockheed was founded in 1912 and later merged with Martin Marietta to form Lockheed Martin in 1995.-Origins:...
Skunk Works
Skunk works
Skunk Works is an official alias for Lockheed Martin’s Advanced Development Programs , formerly called Lockheed Advanced Development Projects. Skunk Works is responsible for a number of famous aircraft designs, including the U-2, the SR-71 Blackbird, the F-117 Nighthawk, and the F-22 Raptor...
's efforts to develop a stealthy STOVL strike fighter for the U.S. Marine Corps under a 1986 DARPA program. Lockheed employee Paul Bevilaqua
Paul Bevilaqua
Paul Bevilaqua is an aeronautics engineer at Lockheed Martin in California. In 1990, he invented the lift fan for the Joint Strike Fighter F-35B along with fellow Skunk Works engineer Paul Shumpert.-Life and career:...
developed and patented a concept aircraft and propulsion system, and then turned to Pratt & Whitney (P&W) to build a demonstrator engine. The demonstrator used the first stage fan from a F119
Pratt & Whitney F119
|-See also:-External links:* *...
engine for the lift fan, the engine fan and core from the F100-220
Pratt & Whitney F100
-External links:* * *...
for the core, and the larger low pressure turbine from the F100-229
Pratt & Whitney F100
-External links:* * *...
for the low pressure turbine of the demonstrator engine. The larger turbine was used to provide the additional power required to operate the lift fan. Finally, a variable thrust deflecting nozzle was added to complete the "F100-229-Plus" demonstrator engine. This engine proved the lift-fan concept and led to the development of the current F135 engine.
P&W developed the F135 from their F119
Pratt & Whitney F119
|-See also:-External links:* *...
turbofan, which powers the F-22 Raptor
F-22 Raptor
The Lockheed Martin/Boeing F-22 Raptor is a single-seat, twin-engine fifth-generation supermaneuverable fighter aircraft that uses stealth technology. It was designed primarily as an air superiority fighter, but has additional capabilities that include ground attack, electronic warfare, and signals...
, as the "F119-JSF". The F135 integrates the F119 core with new components optimized for the JSF. The F135 is assembled at a plant in Middletown, Connecticut
Middletown, Connecticut
Middletown is a city located in Middlesex County, Connecticut, along the Connecticut River, in the central part of the state, 16 miles south of Hartford. In 1650, it was incorporated as a town under its original Indian name, Mattabeseck. It received its present name in 1653. In 1784, the central...
. Some parts of the engine are made in Longueuil
Longueuil
Longueuil is a city in the province of Quebec, Canada. It is the seat of the Montérégie administrative region and sits on the south shore of the Saint Lawrence River directly across from Montreal. The population as of the Canada 2006 Census totaled 229,330, making it the third largest city in...
, Quebec, Canada, and in Poland.
The first production propulsion system for operational service is scheduled for delivery in 2007. The F-35 will serve the U.S., UK, and other international customers. The initial F-35s will be powered by the F135, but GE/Rolls-Royce
Rolls-Royce plc
Rolls-Royce Group plc is a global power systems company headquartered in the City of Westminster, London, United Kingdom. It is the world’s second-largest maker of aircraft engines , and also has major businesses in the marine propulsion and energy sectors. Through its defence-related activities...
team is developing the F136
General Electric/Rolls-Royce F136
The General Electric/Rolls-Royce F136 is an advanced turbofan engine being developed by General Electric and Rolls-Royce plc for the Lockheed Martin F-35 Lightning II.-Development:...
turbofan as an alternate engine for the F-35 as of July 2009. The Initial Pentagon planning required that after 2010, for the Lot 6 aircraft, the engine contracts will be competitively tendered. However since 2006 the Defense Department has requested no funding for the alternate F136 engine program, but Congress has maintained program funding.
The F135 team is made up of Pratt & Whitney
Pratt & Whitney
Pratt & Whitney is a U.S.-based aerospace manufacturer with global service operations. It is a subsidiary of United Technologies Corporation . Pratt & Whitney's aircraft engines are widely used in both civil aviation and military aviation. Its headquarters are in East Hartford, Connecticut, USA...
, Rolls-Royce
Rolls-Royce plc
Rolls-Royce Group plc is a global power systems company headquartered in the City of Westminster, London, United Kingdom. It is the world’s second-largest maker of aircraft engines , and also has major businesses in the marine propulsion and energy sectors. Through its defence-related activities...
and Hamilton Sundstrand
Hamilton Sundstrand
Hamilton Sundstrand, is a global corporation that manufactures and supports aerospace and industrial products for worldwide markets. It was formed from the merger of Hamilton Standard and Sundstrand Corporation in 1999. A subsidiary of United Technologies Corporation, HS is headquartered in Windsor...
. Pratt & Whitney is the prime contractor and handles main engine, and systems integration. Rolls-Royce is responsible for the vertical lift system for the STOVL aircraft system. Hamilton Sundstrand is responsible for the electronic engine control system, actuation system, PMAG, gearbox, health monitoring systems, and fuel system,
As of 2009, P&W is developing a more durable version of the F135 engine to increase the service life of key parts. These parts are primarily in the hot sections of the engine (the combustor and high pressure turbine blades specifically) where current versions of the engine are running hotter than expected, reducing life expectancy. The test engine is designated XTE68/LF1, and testing is expected to begin in 2010. This redesign has caused “substantial cost growth.”
Pratt expects to soon be delivering F135s below the cost of the F119, even though it is a more powerful engine.
Design
The F135 is a two-shaft engine featuring a three-stage fan (low pressure) and a six-stage high pressure (HP) compressor. The hot section features an annular combustor with a single-stage HP turbine unit and a two-stage LP turbine. The afterburner features a variable converging-diverging nozzle.The conventional and carrier aviation engines, the F135-PW-100 and F135-PW-400, have a maximum (wet
AfterBurner
The AfterBurner is a lighting solution for the Game Boy Advance system that was created by Triton-Labs.Originally, portablemonopoly.net was a website created to petition Nintendo to put some kind of light in their Game Boy Advance system...
) thrust of approximately 43000 lbf (191.3 kN) and a dry thrust of approximately 28000 lbf (124.6 kN). The major difference between the -100 and -400 models is the use of salt-corrosion resistant materials.
The STOVL variant, F135-PW-600, delivers the same 43000 lbf (191.3 kN) of wet thrust as the other types in its conventional configuration. In STOVL configuration, the engine produces 18000 lbf (80.1 kN) of lift thrust. Combined with thrust from the LiftFan (20000 lbf (89 kN)) and two roll posts (1950 lbf (8.7 kN) each), the Rolls-Royce LiftSystem
Rolls-Royce LiftSystem
The Rolls-Royce LiftSystem is an innovative propulsion system designed for use in the STOVL variant of the F-35 Lightning II developed during the Joint Strike Fighter Program...
produces a total of 41900 lbf (186.4 kN) of thrust, almost the same vertical lifting force for slow speed flight as the same engine produces at maximum afterburner, without the extreme fuel use or exhaust heat as wet thrust.
The STOVL variant engages a clutch to extract around 35000 shp from the LP turbine to turn the forward lift fans, while switching power cycle from mixed (turbofan) to unmixed (turboshaft
Turboshaft
A turboshaft engine is a form of gas turbine which is optimized to produce free turbine shaft power, rather than jet thrust...
). Power is transferred forward through shaft to a bevel gearbox, to drive two vertically mounted contra-rotating fans. The uppermost fan is fitted with variable inlet guide vanes and the fan discharges efflux (low-velocity unheated air) through a nozzle on the underside of the aircraft. This cool air from the lift fan has the added benefit of preventing hot exhaust gases from the core section from being reingested into the engine while hovering. Finally, bypass duct air is sent to a pair of roll post nozzles and the core stream discharges downwards via a thrust vectoring nozzle at the rear of the engine. Measured by lift thrust in full vertical lift mode, the engine operates as 43% turbojet, 48% turboshaft, and 9% turbofan.
Improving engine reliability and ease of maintenance is a major objective of the F135. The engine has fewer parts than similar engines which should help improve reliability. All line-replaceable components (LRCs) can be removed and replaced with a set of six common hand tools. Additionally, the F135's health management system is designed to provide real time data to maintainers on the ground, allowing them to troubleshoot problems and prepare replacement parts before the aircraft returns to base. According the Pratt & Whitney, this data may help drastically reduce troubleshooting and replacement time, as much as 94% over legacy engines.
The F135/F136 engines are not designed to supercruise
Supercruise
Supercruise is sustained supersonic flight of an aircraft with a useful cargo, passenger, or weapons load performed efficiently and without the use of afterburners ....
.
In August 2010, Pratt & Whitney revealed that the F135 was able to generate in excess of 50,000 lb of thrust.
Variants
- F135-PW-100 : Used in the F-35A Conventional Take-Off and Landing variant
- F135-PW-400 : Used in the F-35C carrier variant
- F135-PW-600 : Used in the F-35B Short Take-Off Vertical Landing variant