Pratt & Whitney F135

Pratt & Whitney F135. The F135 is an advanced afterburning turbofan engine developed by Pratt & Whitney as the exclusive powerplant for the Lockheed Martin F-35 Lightning II, a family of fifth-generation multirole combat aircraft. It is derived from the Pratt & Whitney F119 engine that powers the Lockheed Martin F-22 Raptor, but incorporates significant enhancements for the Joint Strike Fighter program's demanding requirements. The engine provides exceptional thrust, advanced thermal management, and enables key capabilities like short takeoff and vertical landing for the F-35B variant.

Development and design

The F135's development was initiated under the Joint Strike Fighter program, a major international defense procurement effort led by the United States Department of Defense with key partners including the United Kingdom and Italy. The engine's core design is a direct evolution of the Pratt & Whitney F119, leveraging its proven Twin-spool architecture and low-bypass configuration. Critical design goals included achieving unprecedented levels of thrust and reliability while integrating complex systems for the F-35B's Rolls-Royce LiftSystem, which features a swiveling three-bearing exhaust nozzle and a dedicated Lift fan. The program faced significant technical and budgetary challenges, including a intense competitive phase against the General Electric/Rolls-Royce F136 engine before the latter was canceled by the United States Congress. Key technological advancements in the F135 include advanced turbine materials, a more durable fan, and a sophisticated Full Authority Digital Engine Control (FADEC) system.

Operational history

The F135 entered service with the first operational United States Marine Corps F-35B squadron, VMFA-121, in 2015, achieving Initial operating capability with the United States Air Force's F-35A following in 2016 and the United States Navy's F-35C in 2019. The engine has since powered F-35 operations globally for numerous operators, including the Royal Air Force, the Japan Air Self-Defense Force, and the Israeli Air Force. It has accumulated millions of flight hours across diverse combat and training missions, supporting operations in theaters like the Middle East. While demonstrating high reliability, the engine program has encountered issues such as thermal management constraints during extreme operations and isolated incidents involving hypoxia-like symptoms in pilots, leading to ongoing modernization efforts. The F135 remains central to the airpower strategy of NATO and allied nations.

Variants

The F135 is produced in three primary variants, each tailored to a specific F-35 model. The **F135-PW-100** is the conventional takeoff and landing (CTOL) engine for the F-35A, used by the United States Air Force and most international partners. The **F135-PW-600** is the STOVL propulsion system for the F-35B, integrating the Rolls-Royce LiftSystem with its Lift fan and Roll posts to enable vertical flight. The **F135-PW-400** is the carrier-suitable variant for the F-35C, featuring a larger, corrosion-resistant fan and strengthened structure to withstand the forces of catapult launches and arrested landings on Aircraft carriers like the USS Gerald R. Ford.

Specifications (F135-PW-100)

General characteristics * **Type:** Afterburning Turbofan * **Length:** 220 in (5.59 m) * **Diameter:** 46 in (1.17 m) (fan inlet) * **Dry weight:** Approximately 3,750 lb (1,700 kg) Components * **Compressor:** Axial flow, 3-stage fan, 6-stage High-pressure compressor * **Combustors:** Annular combustor * **Turbine:** 1-stage High-pressure turbine, 2-stage Low-pressure turbine Performance * **Maximum thrust:** * 28,000 lbf (125 kN) military thrust * 43,000 lbf (191 kN) with Afterburner * **Overall pressure ratio:** 28:1 * **Bypass ratio:** 0.57:1 * **Thrust-to-weight ratio:** Approx. 7.5:1 (with afterburner)

See also

* Pratt & Whitney F119 * General Electric/Rolls-Royce F136 * Lockheed Martin F-35 Lightning II * Joint Strike Fighter program * Rolls-Royce LiftSystem

Category:Pratt & Whitney aircraft engines Category:Afterburning turbofan engines Category:2000s aircraft engines