Pratt & Whitney F135

Pratt & Whitney F135
Name	Pratt & Whitney F135
Type	Turbofan
First run	2000s
Manufacturer	Pratt & Whitney
Country	United States
Thrust lbf	28,000–43,000

Pratt & Whitney F135 The Pratt & Whitney F135 is a turbofan engine developed for fifth-generation combat aircraft programs, notable for powering the Lockheed Martin F-35 Lightning II and derivative demonstrators. It succeeded earlier initiatives in military turbofan development and integrated advanced materials, stealth-compatible exhaust systems, and high thrust-to-weight design priorities. The engine program involved major aerospace contractors and defense organizations across the United States and allied partners.

Development

Development began as part of competitive initiatives that included companies such as Lockheed Martin, Boeing, and Northrop Grumman competing in programs influenced by requirements from United States Department of Defense, United States Air Force, and United States Navy. The F135 evolved from technology matured in programs like the F119 and collaborations with research centers including NASA, Defense Advanced Research Projects Agency, and the U.S. Navy research establishments. Industrial partners such as Rolls-Royce provided engine modules and support under teaming arrangements, while agencies like Naval Air Systems Command and Air Force Materiel Command overseen integration and testing. Development milestones included first runs in test cells, captive-carry flight tests on platforms such as the Boeing X-32 and demonstration work with companies like General Electric in competitive evaluations. Program management engaged contractors including Raytheon for avionics integration and suppliers from the United Kingdom, Italy, and Japan for subcomponents.

Design and Features

The F135 features a low-bypass turbofan architecture with a single-stage fan, multi-stage compressor, annular combustor, and high-pressure turbine similar in lineage to the F119 used on the Lockheed Martin F-22 Raptor. Structural materials include advanced nickel-based superalloys and single-crystal turbine blades developed through partnerships with firms like General Electric and research bodies such as Oak Ridge National Laboratory. The engine incorporates a three-bearing swivel nozzle for the short takeoff/vertical landing (STOVL) variant and a conventional axisymmetric nozzle for conventional takeoff variants; these nozzle arrangements were tested in facilities at Edwards Air Force Base and Patuxent River Naval Air Station. Thermal management and signature reduction were pursued with assistance from Sandia National Laboratories and Lawrence Livermore National Laboratory. Lifecycle maintenance concepts were informed by logistics models used by United States Marine Corps aviation units and by industrial support strategies from Pratt & Whitney supply chain partners.

Variants

Multiple variants were developed to meet platform requirements and mission profiles. The conventional takeoff/landing (CTOL) variant provides high sustained thrust for models fielded by United States Air Force and allied air arms. The STOVL variant integrates a lift system and swivel nozzle to support operations similar to those required by the Royal Navy and United States Marine Corps. A growth model offers increased thrust ratings to support heavier weapons loads and future airframe developments, with testing conducted at Arnold Engineering Development Complex wind tunnels and altitude test cells. International cooperative maintenance and upgrade packages involved companies such as BAE Systems, Finmeccanica (now Leonardo S.p.A.), and Mitsubishi Heavy Industries for export and sustainment variants.

Operational History

The engine entered operational service with initial deliveries aligned to Lockheed Martin F-35 Lightning II production blocks deployed to units including United States Marine Corps, United States Air Force, and United States Navy squadrons. Early operational testing involved deployments to Marine Corps Air Station Yuma and carrier suitability trials aboard USS Wasp (LHD-1) and USS America (LHA-6). Sustainment challenges and reliability growth were addressed through collaboration with depot-level maintenance organizations such as Ogden Air Logistics Complex and industry partners like Rolls-Royce plc in support roles. International operators that adopted the engine-equipped aircraft included air arms from United Kingdom, Israel, Italy, Japan, and Australia, with logistics sharing and interoperability agreements overseen by entities like NATO and bilateral defense offices.

Applications

The primary application of the F135 is propulsion of the Lockheed Martin F-35 Lightning II family including the F-35A, F-35B, and F-35C variants. Related demonstrator and testbed applications involved platforms from Boeing and McDonnell Douglas heritage programs, and the engine served as a powerplant for propulsion testing rigs used by NASA and defense test agencies. Support infrastructure spans bases such as Eglin Air Force Base, Luke Air Force Base, and international maintenance hubs coordinated with companies like ST Engineering and Saab for component repair.

Performance Specifications

- Type: Low-bypass turbofan with afterburner - Thrust range: approximately 28,000 lbf to 43,000 lbf depending on variant and afterburner mode, comparable to engines like the General Electric F110 and Rolls-Royce RB199 in respective classes - Bypass ratio: low; design prioritizes high specific thrust for supersonic performance and short-field capability similar to requirements for the F-22 Raptor and prototype demonstrators - Materials: single-crystal superalloys, thermal barrier coatings developed with GE Aviation and national laboratories - Features: 3-bearing swivel nozzle (STOVL), full-authority digital engine control (FADEC) integrated with avionics suites from Northrop Grumman and Rockwell Collins (now Collins Aerospace)

Category:Turbofan engines