JSF’s F135 Engine Meeting Milestones

Unlike current-generation fighters, the F-35 will rely on “more-electric” systems to operate the aircraft that are tightly integrated to save weight, add reliability and improve packaging efficiency. Performing engine starts with the integrated systems demonstrates the maturity of their designs and reduces risk for first flight.

At the heart of the IPP is a small gas-turbine engine “turbomachine” that provides power to the engine-mounted starter/generator, bringing the engine to its threshold starting speed. The engine then increases to idle speed and the electrical system, which includes the engine-mounted starter/generator (ES/G), transitions from operating as a motor to operating as a generator. The IPP is also available for in-flight emergency power.

In 2001, Pratt & Whitney was awarded a 10-year $4.8 billion contract for System Development and Demonstration to develop the F135 propulsion system through flight clearance, flight test, and qualification for Low Rate Initial Production.

To date, the Pratt & Whitney led F135 propulsion team has delivered three Conventional Take-Off and Landing (CTOL)/Carrier Variant (CV) configuration and four Short Take-Off and Vertical Landing (STOVL) configuration F135 engines to test for a total of seven engines delivered on or ahead of schedule. In December, the team will deliver the first flight test engine in preparation for Initial Flight Release in January 2006 and first flight in August 2006. Production deliveries of the F135 are scheduled to begin in early 2009.

The F135 is an evolution of the highly successful F119 engine for the F/A-22 Raptor. Together the F135 and F119 engines will have logged more than one million flight hours in support of the F-35’s introduction to operational service in 2012.

The F135 will be competing with the GE/ Rolls-Royce F136 engine, designed to be completely interchangeable with the F135 in any JSF plane.

The F135 propulsion system team consists of Pratt & Whitney, the prime contractor with responsibility for the main engine and system integration; Rolls-Royce, supplying lift components for the STOVL F-35B; Honeywell International, supplying the integrated power package; and Hamilton Sundstrand, provider of the F135’s control system, engine start system, external accessories and gearbox.

Updates

January 31/23: Problem Identification Raytheon won a $72.8 million order, which provides non-recurring engineering in support of early identification, development, and qualification of corrections to potential and actual F135 propulsion system operational issues, to include safety and reliability/maintainability problems identified through fleet usage. Additionally, this order provides for continued engine maturation, evaluates component life limits based on operational experience, improves operational readiness, and reduces engine maintenance and life cycle costs in support of the F-35 Lightning II program. Work will take place in Connecticut. Expected completion will be in December 2026.

December 2/21: Maintenance Raytheon Technologies won $447.6 million modification, which provides for the procurement of recurring sustainment support activities including maintenance of support equipment, common program activities, unique and common base recurring sustainment, repair of repairables, field service representatives, common replenishment spares, conventional take-off and landing/carrier variant F-135 unique maintenance services, and short take-off and landing F-135 unique services in support of the F-35 Lightning II F135 propulsion system for the Air Force, Marine Corps, Navy, Air National Guard, non-Department of Defense (DOD) participants, and Foreign Military Sales (FMS) customers. Estimated completion date is in May 2022.

December 2/20: Support Raytheon and Pratt and Whitney Military Engines won a $642 million deal, which provides for the procurement of performance-based logistics activities including maintenance of support equipment, common program activities, unique and common base recurring sustainment, repair of repairables, field service representatives, common replenishment spares, conventional take-off and landing/carrier variant F135 unique maintenance services and short take-off and landing F135 unique services in support of the F-35 Lightning II F135 propulsion system for the Air Force, Marine Corps, Navy, non-Department of Defense participants and Foreign Military Sales customers. Pratt & Whitney’s F135 propulsion system powers all the three variants of F-35, the combat-proven fighter jet developed by defense major Lockheed Martin LMT, with BAE Systems BAESY and Northrop Grumman NOC being the co-manufacturers. Notably, F135 delivers more than 40,000 lbs. of thrust and unmatched advances in safety, design, performance, and reliability. An initial contract obligation amounting to $215.5 million will come from the US military’s fiscal 2021 operation and maintenance funds. Work will run at Eglin Air Force Base in Florida; Hill AFB in Utah; Edwards AFB in California; Luke AFB in Arizona; Beaufort Marine Corps Air Station in South Carolina; Oklahoma City; East Hartford, Connecticut; and Camari, Italy, through November 2021.

November 19/20: Testing Testing of a new fan rotor design for the Pratt & Whitney F135 turbofan engine has resumed at Arnold Air Force Base. Being carried out at the J2 Engine Test Cell, work had started back in 2019 but put on pause as the cell required scheduled maintenance. “Test results to date have been positive and encouraging, and early results allowed us to complete an AMT (Accelerated Mission Test) with the same newly-designed rotor,” said 2nd Lt. Gregory Landrum, AEDC Jet Engine Test project manager.

September 8/20: Spare Parts Raytheon Technologies won a $579.8 million deal, which provides unit and depot level F-135 propulsion system spare parts, spare engines and modules in support of the F-135 propulsion initial spares requirements for the Air Force, Navy, Marine Corps, non-Department of Defense participants and Foreign Military Sales customers. The Pratt & Whitney F135 is an afterburning turbofan developed for the F-35 Lightning II. Pratt & Whitney’s F135 propulsion system powers all three variants of the F-35 Lightning II fighter aircraft – the F-35A CTOL (Conventional Takeoff and Landing), F-35B STOVL (Short Takeoff and Vertical Landing) and F-35C CV (Carrier Variant). Work will take place in Connecticut, Indiana and the UK. Estimated completion will be in December 2024.

November 29/18: Logistics Sustainment United Technologies, Pratt & Whitney won a $522 million contract modification, which provides performance based logistics sustainment in support of the F-35 Lightning II F135 propulsion system for the Navy, Air Force, Marine Corps, non-Department of Defense (DoD) participants and foreign military sales (FMS) customers. Pratt & Whitney’s F135 propulsion system powers all three variants of the F-35 Lightning II fighter aircraft – the F-35A CTOL (Conventional Takeoff and Landing), F-35B STOVL (Short Takeoff and Vertical Landing) and F-35C CV (Carrier Variant). It is a two-spool afterburning turbofan engine. The combat-proven F135 delivers more than 40,000lb of thrust and delivers advances in safety, design, performance, and reliability. Work will take place in Connecticut, Oklahoma, Italy, Florida, California, Arizona and South Carolina. Estimated completion is in November 2020.

October 7/19: Material And Support Equipment United Technologies won a $325.2 million fixed-price-incentive-firm contract to provide material and support equipment for depot maintenance facilities, non-recurring sustainment activities, supplies, services and planning for depot activations as well as two F135 full-scale high fidelity mockup engines and four modules for test cells in support of the F-35 Lightning II Program. The Pratt & Whitney’s F135 is an afterburning turbofan developed for the Lockheed Martin F-35 Lightning II, a single-engine strike fighter. Pratt & Whitney’s F135 propulsion system powers all three variants of the F-35 Lightning II fighter aircraft – the F-35A CTOL (Conventional Takeoff and Landing), F-35B STOVL (Short Takeoff and Vertical Landing) and F-35C CV (Carrier Variant). The F135 has evolved from the proven F119 engine, which exclusively powers the U.S. Air Force’s F-22 Raptor, and features best-in-class single-engine reliability, fifth generation stealth capabilities as well as advanced prognostics and health management systems. Work under the contract will take place in various places within as well as outside of the US. Estimated completion will be in January 2023.

May 9/19: Production Delivery Schedule Support Pratt & Whitney won a $55.7 million contract modification for additional funding for F135 long lead items. The deal supports the production delivery schedule, and exercises an option for additional initial spare parts. It also provides program administrative labor for the global spares pool in support of the Navy, Air Force, and Marine Corps, non-US DoD participants and Foreign Military Sales customers.The Pratt & Whitney F135 afterburning turbofan powers all three variants of the F-35 Lightning II fighter aircraft. Ten years ago, Pratt & Whitney delivered its first production version of the engine for the F-35 fighter program. The company managed to reduce the cost of producing each engine by over half in the last ten years. It plans to continue cutting manufacturing costs in the years ahead through tight management of production processes and suppliers. Work under the current modification will take place within the US and the UK and is expected to be finished by April 2022.

March 25/19: Additional Funding The US Navy awarded United Technologies subsidiary Pratt & Whitney an $18.4 million contract modification for additional funding of the F-135. The F-135 is a mixed-flow afterburning turbofan developed specifically for the F-35 Lightning II. The engine’s propulsion system powers all three variants of the fighter aircraft. According to Pratt & Whitney it delivers more than 40.000 Ibs. of thrust. There are three F135 variants: the -100 engine, -400 engine, and the -600 engine. The -400 is similar to the -100, the most important difference being the use of salt-corrosion resistant materials. The initial F-35s went into production with the F135 engines. However, Pratt and Whitney is cooperating with the US Navy on a two-block improvement plan for the F135 engine. The goals of Block 1 are a 10 percent increase in thrust and a 5 percent lower fuel burn. The plans also include better cooling technology for turbine blades. This would increase the longevity of the engine as well as reduce maintenance costs. The goal of Block 2 is to work with the US Air Force’s Adaptive Engine Transition Program, intending to introduce technology for an engine rated at 45,000 lb of thrust, to be used in a sixth-generation fighter. Work under the current deal will take place within the US as well as the UK and is scheduled to be finished in March 2022.

January 22/19: Meggitt to provide engine components Meggitt won a $751.2 million deal to provide advanced engine components for Pratt and Whitney. Meggitt is a British engineering business established in the 1940s. It specializes in aerospace equipment. Pratt and Whitney is an American aerospace manufacturer that supplies engines for US fighter jets. The 10-year contract with the engine maker is to supply advanced components for the F119 and F135 engines which power the F-22 Raptor and F-35 Lightning II aircraft. The F119 and F135 are afterburning turbofan engines with the F135 being a derivative of the F119.

September 20/17: Pratt & Whitney has successfully finished tests of an adaptive three-stream fan paired with a F135 core engine. The fan includes an adaptive bypass airflow that aims to improve fuel efficient and cooling capacity, and is part of a $1 billion program to develop a full-scale, 45,000lb-thrust-class prototype engine under the Adaptive Engine Transition Program (AETP) that could be used to re-engine the F-35 and power a future combat aircraft. At present, most military turbofan engines have only two airstreams, but including an additional, adaptive airstream will give the engine the option to increase its thrust on demand or lower its fuel consumption.

January 17/17: Ethical conflicts at Pratt & Whitney have resulted in the ousting of the head of the company’s F135 engine program alongside nine other employees. The dismissals come after the completion of an internal audit which uncovered an ethics issue linked to a visit by South Korean military officials several years ago. During the trip, the Korean delegation paid a visit to the company’s West Palm Beach facility in Florida, and Pratt & Whitney paid for a rental van to fetch them there. While certainly not the most outrageous form of graft in the industry’s history, causing no violation of US export control or anti-bribery laws, the engine company deemed the move as a breach of their strict ethics laws, amounting to “inappropriate entertainment.”

May 3/16: Following 15 years of work, Pratt & Whitney announced that they are coming to the end of the development of the F-35 Joint Strike Fighter‘s F135 propulsion system. The F135 team is also about 85% of the way through correcting an engine fault inherent in 180 early-model units which caused one aircraft to catch fire on the runway at Eglin AFB, Florida in June 2014. Derived from the F119-100 turbofan that powers the F-22 Raptor, the F135 was selected for both Lockheed X-35 and Boeing X-32 JSF prototypes.

Additional Readings & Sources:

• News Release: Unique Integrated System Starts F-35 Engine in Joint Test By Lockheed Martin, Pratt & Whitney

• News Release: Pratt & Whitney F135 SDD Program Successfully Completes Post Test Critical Design Review

• DID March 11, 2005 – F136 Engine Reaching Test Milestones

• DID March 7, 2005 – GAO Releases Study of F-22, F-35 Programs